(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

(19) World Intellectual Property Organization

International Bureau

(43) International Publication Date

26 May 2011 (26.05.2011)

Published: (74) Agent: ROBIC; 1001, Square-Victoria, Bloc E - 8th

Floor, Montreal (Quebec) H2Z 2B7 (CA). with international search report (Art. 21 (3))

(81) Designated States (unless otherwise indicated, for every

kind ofnational protection available): AE, AG, AL, AM,

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(51) International Patent Classification:

C21D 9/573 (2006.01) C22C 45/02 (2006.01)

C21D 1/42 (2006.01)

(21) International Application Number:

PCT/CA20 I0/001844

(22) International Filing Date:

18 November 2010 (18.11.2010)

(25) Filing Language: English

(26) Publication Language: English

(30) Priority Data:

61/262,603 19 November 2009 (19.11.2009) US

(71) Applicant (for all designated States except US): HYDRO-QUEBEC [CA/CA]; 75, boul. Rell(~-Levesque

Ouest, 22e Etage, Montreal (Quebec) H2Z IA4 (CA).

(72) Inventors; and

(75) Inventors/Applicants (for US only): FRANCOEUR,

Bruno [CA/CA]; 971 Galilee, Beloeil (Quebec) BG 6MI

(CA). COUTURE, Pierre [CA/CA]; 1027, Jean-Bochart,

Boucherville (Quebec) J4B 4A4 (CA).

AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ,

CA,CH,CL,CN,CO, CR,CU, CZ,DE,DK,DM,DO,

DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT,

HN, HR, HU, ill, IL, IN, IS, JP, KE, KG, KM, KN, KP,

KR,KZ,LA,LC, LK,LR,LS, LT,LU, LY,MA,MD,

ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI,

NO, NZ, OM, PE, PG, PH, PL, PT, RO, RS, RU, SC, SD,

SE, SG, SK, SL, SM, ST, SV, SY, TH, n, TM, TN, TR,

TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW.

(84) Designated States (unless otherwise indicated, for every

kind ofregional protection available): ARIPO (BW, GH,

GM, KE, LR, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG,

ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, n,

TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK,

EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU,

LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK,

SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ,

GW, ML, MR, NE, SN, TD, TG).

Declarations under Rule 4.17:

as to applicant's entitlement to apply for and be granted

a patent (Rule 4.17(ii))

(54) Title: SYSTEM AND METHOD FOR TREATING AN AMORPHOUS ALLOY RIBBON

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FIGURE 1

(57) Abstract: A method and a system for continuously in-line annealing a forwarding ferromagnetic amorphous alloy ribbon in a

curved shape to improve its magnetic properties without causing the ribbon to become brittle and which operates at significant

high ribbon feeding rates. The amorphous alloy ribbon is fed forward, tensioned and guided along a path at a preset feeding rate

and is heated at a point along the path at a rate greater than 103 °C/sec to a temperature to initiate a thermal treatment. Then the ribbon is initially cooled at a rate greater than 103 °C/sec until the thermal treatment ends. During the thermal treatment, a series of

mechanical constraints is applied on the ribbon until the amorphous alloy ribbon adopts a specific shape at rest after the thermal

treatment is ended. After the initial cooling, the amorphous alloy ribbon is subsequently cooled at a sufficient rate to a temperature

that will preserve the specific shape.
WO 2011/060546 PCT/CA2010/001844

1

SYSTEM AND METHOD FOR

TREATING AN AMORPHOUS ALLOY RIBBON

FIELD OF THE INVENTION

The present invention generally relates to amorphous materials. More particularly, it

relates to a system and method for treating an amorphous alloy ribbon. More

particularly, it also relates to a system and method for producing a magnetic core

from a treated ductile amorphous alloy ribbon rolled up on a mandrel.

10

BACKGROUND OF THE INVENTION

Iron-based amorphous alloys are sought for their soft magnetic properties in

applications such as the manufacturing of distribution transformer cores, pulse

power cores, and other item. Iron-based alloys in this document are mainly iron

alloyed with various small percentages of other metals. They are manufactured by

continuous rapid solidification of a stream of molten alloy cast at speeds

approaching 100 km per hour. With casting cooling rates on the order of 106

°Celsius/second, the alloy atomic structure is solidified in a non-crystalline state

20 (amorphous). With the proper atomic composition, amorphous alloy ribbons having

excellent soft magnetic properties can be produced. Particularly, they offer: a high

magnetic induction saturation level, herein referred as Bsat; a high permeability; a low

coercive force; a low exciting power; and very low core loss. When designing

distribution transformers, an alloy sheet candidate can be evaluated once it has

been stacked or rolled up to form a core by considering the peak magnetic induction

level B and associated core loss obtained at a peak applied AC magnetic field up to

80 Aim, herein referred as Bao. Properties obtained at values above this field, even if

they are good, will require excessive exciting power thus, rendering the alloy less

attractive. The magnetic properties of amorphous alloys when the ribbon is stacked

30 or rolled up to form a core can also be evaluated by considering their Bao/Bsat ratio. A
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8ao/8sat ratio close to 1 is sought for as it is indicative of an easy magnetization. A

transformer produced with a magnetic core having a high 8ao will be smaller and will

cost less. As a rule of thumb, an amorphous alloy core having a 8ao greater than

about 1.3 Tesla is worth considering for replacing conventional grain-oriented 3%

silicon steels in the manufacturing of distribution transformers. Additionally, ironbased amorphous alloys produce about one third of the core loss of silicon steels.

Also, a single step continuous casting method for producing an amorphous alloy

ribbon has the advantage of being simpler and cheaper when compared to casting,

annealing, quenching, rolling, decarburising and coating steps involved in producing

10 a grain-oriented silicon steel sheet and which require larger equipments and more

floor space. Iron-based amorphous alloys are the cheapest of all amorphous alloys

because of the relative low cost for iron, its main constituent. With a rapid

solidification process, the production of amorphous alloys is however limited to a

very thin ribbon of various widths. More handling is therefore required to stack the

increased number of layers when building the magnetic cores. Moreover, magnetic

properties of amorphous alloys are highly sensitive to internal mechanical stresses.

Core loss and exciting power deteriorate in presence of random stresses in the alloy.

The origin of these stresses is either residual or applied. Residual stresses appear

during ribbon casting, and applied stresses are produced from external forces

20 imposed by bending or stacking the ribbon. These stresses must therefore be

removed from the ribbon when it adopts a final configuration into a core or, at least

accommodated to a certain extent. Stress removal from the amorphous alloy ribbon

is generally accomplished by annealing the material in a furnace at an elevated

temperature for a predetermined amount of time. Also, the useful magnetic

properties of iron-based amorphous alloy ribbons are obtained if, during the

annealing treatment, the alloy is subjected to a uniform magnetic field or a tensile

stress in direction of the ribbon longitudinal axis. Field or stress annealing reduces

coercive forces and induces uniaxial magnetic anisotropy. With field annealing, the

resulting magnetic anisotropy is oriented parallel to the applied field while with stress

30 annealing, it is either parallel or perpendicular depending on the alloy composition.
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Field or stress annealing will increase the Bao and Bao/Bsat ratio. Furnace annealing

of amorphous alloy cores with an applied magnetic field following the flux path is

widely used to produce enhanced magnetic cores for distribution transformers. The

ribbon is positioned within the core to have its longitudinal axis oriented following the

circulating path of the induced magnetic flux.

When annealing an amorphous alloy, increasing the annealing temperature and

annealing time will eventually lead to onset crystallization of its atomic structure and

lost of their sought magnetic properties. Onset crystallization in amorphous alloys is

10 a temperature-time-transformation (TTT) phenomenon. For example, the time to

onset crystallization at core operating temperatures in distribution transformers must

be well above the time life of the transformers. In an annealing treatment, time to

onset crystallization will be influenced by the heating temperature rising rate, by the

annealing temperature level and soaking time, and by the cooling temperature falling

rate. High temperature heating and cooling rates combined with a short soaking time

will allow use of a higher annealing temperature.

The amorphous alloy ribbon Metglas 2605SA1, from Hitachi-Metals, having a

nominal chemistry FeaoB11Sig, numbers being in atomic percent, is widely used in

20 many applications including transformers and inductors at electrical AC frequencies

of 50 and 60 Hz. This alloy has a Bsat of 1.56 Tesla. When furnace annealed under

an external applied magnetic field or tensile stress, the alloy will acquire an easy axis

of magnetization parallel to the applied field or stress. When the ribbon is stacked or

rolled up to form cores and then field annealed at 350°C for two hours, the alloy has:

a Bao of 1.49 Tesla; a BaolBsat ratio of 0.95; and the core loss is lower than 0.27 W/kg

at 60 HZ at a magnetic induction of 1.3 Tesla. These values were reported by the

alloy manufacturer in an article entitled "Audible Noise From Amorphous Metal and

Silicon Steel-Based Transformer Core", in IEEE Transactions on Magnetics, vol. 44,

no. 11, 4104-4106, and in an article entitled: "Advances in amorphous and

30 nanocrystalline magnetic materials", published in Journal of Magnetism and
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Magnetic Materials, vol. 304, p. 187-191, 2006. Also, US patent 5873954 teaches

that, in order to benefit of such low core loss, the 2605SA1 alloy must be annealed

under an applied magnetic field for two hours at a temperature between 330°C and

380°C as depicted in Figure 2a. Minimal core loss is obtained at an annealing

temperature between 350°C to 360°C. Alternatively, the patent points to some

references where improvements of magnetic properties of amorphous alloys were

obtained by stress-annealing. However, the sample configuration for tensile stress

annealing in the mentioned references has invariably been a flat strip. Therefore, the

authors of the patent consider use of stress annealing in the production of

10 amorphous alloy core transformers impracticable. Trying to furnace anneal the

Metglas-SA1 alloy above 390°C will lead to onset crystallization of the alloy and

thereby, to deterioration of the magnetic properties as reported by Hsu et al. in an

article entitled: "Effect of the annealing Temperature on Magnetic property for

Transformer with Amorphous Core", Proceeding of the 2009 8!h WSEAS

International Conference on Instrumentation, Measurement, Circuit and Systems,

page 171-175.

More recently in US patent application 2006/0180248, an iron-based amorphous

alloy having a chemical composition FeaBbSicCd where 80<a<84, 8<b<18, 0<c::;5

20 and 0<d::;3, numbers being in atomic percent, was identified. The alloy achieves a

saturation magnetic induction greater than 1.60 Tesla wherein the alloy is heattreated to be annealed at a temperature from 300°C to 350°C which is lower than the

temperature required for the 2605SA1 material. Included in the chemical

composition, the new Metglas 2605HB1 alloy ribbon from Hitachi-Metals, having a

nominal chemistry Fea1.8B15.aSi2.1Co.3, has a Bsa! of 1.65 Tesla. When the ribbon is

stacked or rolled up to form cores and then field annealed at 320°C for one hour, the

alloy has: a Bao of 1.55 Tesla; a Bao/Bsa! ratio of 0.95; and the core loss is lower than

0.24 W/kg at 60 HZ at a magnetic induction of 1.3 Tesla, which is an improvement

over the commercially available SA1 material. These values were reported by the

30 alloy manufacturer in the articles cited above.
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However, furnace annealing of most iron-based amorphous magnetic alloy ribbons

undesirably affects the ribbon mechanical structure. The furnace annealing

treatment weakens the alloy which becomes brittle and therefore complicates ribbon

handling. Furthermore, amorphous alloy cores remain highly sensitive to external

stresses after annealing. Care must therefore be taken to limit these stresses in

order to keep the performances within an acceptable limit. Metglas 2605SA1 and

2605HB1 are known to embrittle following conventional field furnace annealing

processes and their magnetic properties are very sensitive to applied stresses.

10

One known method for making a distribution transformer magnetic core with an

amorphous alloy ribbon was disclosed by General Electric in many patents. US

patents 4789849, 5050294, 5093981 and 5310975 disclose steps involved in the

making of amorphous alloy rectangular-wound-cut core distribution transformers

which address all of the particularities related to amorphous alloys mentioned above.

Basically, multiple amorphous ribbons are simultaneously unrolled from supply coils,

piled and then rolled up again together to produce a master coil. Then, multiple

master coils are unrolled and piled to form a composite strip which is forwarded,

stopped and held stationary while it is cut by shear blades into segments of

20 progressively reduced lengths which are successively stacked in appropriate

staggered positions to produce a packet of composite strips. Multiple packets are

then successively wrapped in piggyback on each other on a support frame. After

sufficient numbers of packets have been wrapped, a conventional silicon steel sheet

is wrapped around the formed core with both ends secured together. The frame is

then removed and a second silicon steel sheet is affixed against the inner packet

wall within the core window to prevent the core from collapsing internally. In the

following step, the core is reformed into a rectangular shape with clamps and is

secured in place with supporting members and straps, after which it is batch

annealed in a furnace while applying an external magnetic field for a few hours.

30 When annealing is completed, a coating is applied on the lateral edges of the core
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except in the region where the joints are located to secure the laminations together,

and the strap and supporting members are removed. Finally, core lacing around the

electrical coils is performed by manually opening the core to form a U-shape and by

sliding the core through the window of preformed rectangular electrical coils and

then re-forming the core into its rectangular shape by individually closing and jointing

the expanded lapped sets. Because the core laminations get brittle from the

annealing process, core lacing around the electrical coils must be achieved with

great care to ensure that no broken fragments find their way into the electrical coils

which could lead to short circuit failures. Overall, this known process for making a

10 rectangular-wound-cut core distribution transformer from an amorphous alloy ribbon

involves a great amount of discontinuous steps, which require a lot of time and floor

space. Manufacturing of such rectangular-wound-cut core distribution transformer is

realized at the distribution transformer manufacturing plant. This contributes

significantly to increase transformer costs.

An alternative for producing a distribution transformer core with an amorphous alloy

ribbon is disclosed by Allan et al. in US patent 5566443. In this patent, a number of

electric coils are preformed, each having a portion with a shape of a sector of a

circle. The preformed coils are then assembled together so that their portions

20 combine to form a circular limb and, in order to construct the magnetic core, a

continuous thin amorphous alloy ribbon is rolled up on a circular hollow mandrel

located around the circular limb to produce a circular core. Before being rolled up,

the amorphous alloy ribbon has been previously annealed under magnetic saturation

on a second circular mandrel having the same external diameter as for the circular

hollow mandrel, thus requiring a transfer of the annealed ribbon between mandrels.

It is believed that the power loss associated with the cuts in the above known cut

core transformer is avoided. Rolling-up-after-annealing of an amorphous alloy ribbon

will certainly introduce some stresses in the roll, which will introduce some additional

core loss. However, it is believed that overall introduced stresses will be sufficiently

30 small such that a worthwhile advantage is achieved in having an amorphous alloy
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circular-rolled-uncut core configuration. It is also believed that with a circular-rolleduncut core transformer, all of the above-mentioned disadvantages associated with

making a rectangular-wound-cut core transformer are avoided. Furthermore, the

circular core provides a shorter mean path length for the magnetic flux which

reduces the core and coils sizes and weight. Although this transformer is simpler to

produce than a cut core transformer, numerous discontinuous steps are still involved

in the making of the core, which are: rolling up to form a core; annealing the core in a

furnace under magnetic saturation; unrolling and rolling up the ribbon again to form a

core around a limb of the electrical coils. Also, direct transfer of the annealed

10 amorphous alloy ribbon will introduce unnecessary bending stresses which will

cause increased core loss as the ribbon is not rolled up again at the same layer

position in the circular core (the first outer layer becomes first inner layer and vice

versa). This can be overcome by transferring the ribbon on an intermediate mandrel

first, as taught in US patent 4906960 by Alexandrov but, this technique adds another

step in the making of the core.

Rolling-up-after-annealing of amorphous alloy circular cores as described above,

although simple in appearance, remains a difficult task. The fact that the alloy

becomes brittle when annealed for a significant amount of time makes it less

20 convenient when it needs to be rolled up again around a limb of the electrical coils.

Silgailis et al. in US patent 4668309 demonstrated in Table 2 of the patent that in

each attempt to unroll and roll up again an iron-based amorphous alloy ribbon of a

furnace annealed circular core weighting around 50 kg at speeds up to 0.3 meter per

second, the ribbon broke more than 60 times. They also claimed in the disclosed

invention that annealing the cores in a molten tin bath at a higher temperature for a

shorter period of time does not degrade ductility as much as from conventional

furnace annealing. Silgailis et al. showed in Table 2 that circular cores weighing

around 18 kg and annealed by their method could be unrolled and rolled up again at

a speed of 0.76 meter per second without breaking the ribbon more than 18 times.

30 Even if Silgailis et al. were able to significantly reduce the number of breaks with
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their annealing method, it remains unacceptable. Encountering just one ribbon

breakage during rolling up can eject tiny fragments that will be scattered all around

the assembly line and that may end up within the electrical coils, which then requires

a stop in production for clean-up and a decision on whether or not the coils should

be scrapped. The task becomes more difficult when rolling up of the ribbon must be

performed first on an intermediate mandrel. Annealing-after-rolling of the core

around the coils could overcome the problem, but this would require use of high

temperature insulating materials in the coils which would render the transformer

cost-prohibitive. Rolling-up-after-annealing and annealing-after-rolling of amorphous

10 alloy ribbon cores were both considered to produce large circular cores for a heavy

ion fusion (HIF) driver. A HIF core must sustain a large flux swing in an extremely

short amount of time which requires use of an inter-laminar insulation in the core.

Even if rolling-up-after-annealing would avoid use of a high temperature insulating

material, it was considered to be impractical due to the embrittlement of the ribbon

and an annealing-after-rolling of a core incorporating a high temperature resistant

insulation was rather adopted as reported in articles such as: "Induction Accelerator

Development for Heavy Ion Fusion", L.L. Reginato, IEEE Proceedings of the 1993

Particle Accelerator Conference, vol. 1, p. 656 - 660, and : "Exciting New Coating

For Amorphous Glass Pulse Cores", R.R. Wood, IEEE 1999 12th International

20 Pulsed Power Conference, vol. 1, p. 393 - 396, and: "Induction Core Alloys for

Heavy-ion Inertial Fusion-energy Accelerators", A. W. Molvik, The American

Physical Society, Physical Review Special Topics - Accelerators and Beams, vol. 5,

080401, 2002. Production of circular core distribution transformers made with rollingup-after-annealing of field furnace annealed amorphous alloy ribbon cores is

impractical due to embrittlement of the alloy and therefore manufacturers are

building field-furnace annealing rectangular-wound-cut core design as described

above.

Thermal embrittlement of iron-based amorphous alloys induced by thermal

30 annealing has been a recurring problem for a long time as recently stated by Kumar
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and al. in an article entitled: "Thermal embrittlement of Fe-based amorphous

ribbons" published in 2008 in Journal of Non-Crystalline Solids, vol. 354, p. 882-888.

Amorphous alloy ribbons show a ductile-to-brittle transition at a given temperature

(TdbO) below which they are brittle and above which they are ductile as reported in an

article entitled: "Absence of Thermal Embrittlement in some Fe-B and Fe-Si-B

Alloys", A. R. Yavari, Materials Science and Engineering, vol. 98, p. 491-493, 1988.

The fact that quenched iron-based amorphous alloy ribbons have a Tdbo lower than

normal room temperature (20°C to 25°C) explains their ductility observed at normal

room temperature. The degree of ductility at a given temperature can be estimated

10 by observing at which bending radius the ribbon breaks or cracks, or by observing

how the ribbon responds to shear cutting or tearing. An annealed ribbon having a

high degree of ductility would alleviate the breaking problem and could be rolled up

after annealing. Embrittlement of most iron-based amorphous alloy ribbons following

thermal annealing is believed to be related to an increase of Tdbo associated to a

temperature-time-transformation (TTT) dependent on the alloy composition. Keeping

Tdb° below the handling temperature in order remain ductile is a target to achieve.

Because the embrittlement an iron-based amorphous alloy is a TTT phenomenon

during annealing, the degree of ductility of an annealed ribbon must therefore be

evaluated once the core magnetic properties obtained following the annealing

20 treatment are satisfactory or within expected results, otherwise the annealing

treatment is incomplete and the degree of ductility is misleading. Shorter annealing

times at higher annealing temperatures are believed to yield amorphous alloy

ribbons with greater ductility. Silgailis and al. showed with their iron-based

amorphous alloy ribbon cores annealed in molten tin at a higher temperature for a

shorter time that brittleness could be reduced. However, there is a limit in trying to

shorten the annealing time due to a limit in heat transfer capacity within the core.

Higher heat transfer capacity becomes possible by heat treating a single forwarded

ribbon in-line along a portion of its travelling path.
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In-line annealing of amorphous alloy ribbon without thermal embrittlement has been

explored. An understanding of the amorphous alloy, its annealing dynamics and its

associated embrittlement has been proposed by Taub in an article entitled: "A New

Method for Stress Relieving Amorphous Alloys to Improve Magnetic Properties",

published in IEEE Transactions on Magnetics, vol. Mag-20, no. 4, July 1984, p 564-

569, and in US patent 4482402. The document gives a general description on the

nature of amorphous alloys, the way they are produced, the good magnetic

properties of some classes of these alloys for application in distribution transformers

and most importantly, discloses the necessity of stress relieving the material to

10 benefit from its magnetic properties. According to Taub, mechanical stress relief in

amorphous alloys is governed by flow and structural relaxation. Flow refers to

homogeneous deformation in response to stress and structural relaxation is an

atomic structure change towards an equilibrium configuration. Taub states in column

4, lines 9 to 15, "I have found that the competing material processes of flow and

structural relaxation must be accounted for in order to optimize the development of

soft magnetic properties in amorphous metals. Specifically, flow must be maximized

and structural relaxation must be minimized. Once that state is obtained with the

amorphous metal in its final shape, that state must be preserved."

20 A lower viscosity at an elevated temperature in an amorphous alloy provides a low

flow resistance, which allows stresses to be relieved but, on the other hand, is

believed to allow structural relaxation, which increases the viscosity with time at said

temperature and therefore also increases the flow resistance as the atomic structure

tends to adopt an equilibrium configuration. The temperature dependence below Tg O

(glass transition temperature) of both the viscosity and the viscosity increase rate

with time are believed to closely follow an Arrhenius law. The structural relaxation is

considered as an unavoidable consequence of stress relief annealing, which is

believed to be responsible for the embrittlement of the ribbon. Therefore, prior art

suggests that it is desirable to stress relieve the amorphous alloy without allowing

30 too much structural relaxation in order to have an annealed ductile ribbon. This
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would correspond to keep the resulting Tdbo increase below the ribbon's handling

temperature.

Taub teaches that the only way to obtain benefits of minimized structural relaxation

while stress relieving the alloy is to heat as rapidly as possible to a higher annealing

temperature for a shorter time and to cool the alloy sufficiently rapidly from the

annealing temperature to prevent any significant additional and detrimental structural

relaxation. Taub also adds in column 10, lines 8 to 13, that: "It is essential that the

ribbon not to be heated until after it has reached its final configuration; otherwise,

10 structural relaxation will commence before all the winding stresses have been

applied [. ..]'.Structural relaxation is therefore believed to be a negative side effect of

the amorphous alloy annealing process which can be minimized in rapid annealing

conditions.

Taub disclosed a method and apparatus to perform in-line annealing on a forwarded

ribbon of a predetermined shape. In his apparatus, a heat source, such as: heat

beams; direct contact with a heating media; or resistance self-heating, heats a

ribbon at a high temperature rising rate (more than 300°C/min) after it has attained

its final configuration. The ribbon is then rapidly cooled (at least 100°C/min) by

20 supplying a jet of cooling medium, such as air or an inert gas like nitrogen or streams

of liquid quenchants, to the ribbon immediately after the ribbon exits the area of the

heating region while still in its final configuration in order to freeze the as-annealed

stress-free structure in the ribbon. The apparatus was tested on an iron-based

amorphous alloy ribbon Fea1.sB14.sSi4 which was then rolled up to form a core. For

ribbon feeding rates up to a maximum of 26 em/min (0.5 em/sec), reported results

show a core loss lower than 0.28 W/kg (0.13 W/lb) and an exciting power lower than

1.45 VA/kg (0.66 VA/lb) at an AC magnetic induction of 1.4 Tesla (14 kG) and a

Bao/Bsat ratio (equivalent in the document to B1/B100 using Oersted instead of Tesla)

greater than 0.80. The reported Bao/Bsat ratio is good considering the presence of

30 some stresses in the roll. Above 26 em/min (0.5 em/sec), the magnetic properties get
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worse. Taub also reports achieving heating rates of 500ae/min. The resulting degree

of brittleness or ductility of the iron-based amorphous alloy specimens annealed with

this apparatus is not quantified.

Senno et al. in US patent 4288260 claimed an apparatus for heat-treating an

amorphous alloy ribbon continuously fed under a tensile stress at a predetermined

speed in the range of 1 to 50 em/sec with its surface sliding in contact against a

stationary heating body or being pressed against the surface of a heating roller by an

urging roller, which can be replaced by another heating roller, to enhance the

10 magnetic properties and remove curlings of an amorphous alloy ribbon without

causing any developments of brittleness of the ribbon. In the examples 1 to 6, Senno

et al. disclose results showing magnetic improvements for ribbons of given atomic

compositions that were passed over a heated stationary body at feeding rates

between 3.5 em/sec (1/v-0.28sec/cm) and 9.1 em/sec (1/v-0.11sec/cm). Magnetic

improvements are also disclosed in example 7 for a forwarded ribbon that has been

pressed against the surface of a heating roller by another roller at a slower feeding

rate of 1 em/sec (1/v-1sec/cm). This slower feeding rate is comprehensible as the

pressed contact region between the two rollers is very small. No reference is made

on using iron-based amorphous alloy compositions, as examples are shown only for

20 cobalt-based alloys. No impacts on core loss, on exciting power, on the Bso, on the

Bso/Bsat ratio and on the degree of brittleness of an annealed iron-based amorphous

alloy ribbon are quantified through experimental results. No comparison is made with

the furnace annealing method. Based on Figure 6, the heat treatment of the ribbon

passed over a stationary heating body shows a deterioration of the coercive force

with increase of ribbon speed above 10 em/sec (1/v-0. 1sec/em). Also, no details are

disclosed on heating rates and no references are made about the cooling stage as

the ribbon is simply collected on a take-up mandrel.

Gibbs discloses in UK patent application GB 2148751 a method by which a length of

30 amorphous strip being rolled up onto a mandrel is simultaneously heated by a direct
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current passing through a portion of the strip that is approaching the mandrel. In this

case, two spaced adjustable sliding contact electrodes (or one electrode and the

mandrel) are used to supply the current. The strip is heated by joule losses from the

flowing current and is either cooled before or after reaching the rolling point.

However, no detailed information is disclosed on the configuration of the strip in the

heat-treating and cooling zones other than optionally allowing the strip to coolon the

mandrel. Gibbs only discloses reduced coercive forces measured on two non ironbased alloy samples forwarding respectively at 9 and 14 cm/sec and annealed with

his method when compared to furnace annealing. There is no reference made on

10 heating and cooling rates, to the core loss, the exciting power, the BaD, the Bao/Bsat

ratio, orthe brittleness of the annealed ribbon.

Li et al. in the US patent 5069428 disclose an annealing method by which an

amorphous ribbon slowly forwarded is self-heated by applying an AC or pulsed high

current through a ribbon passing between a pair of electrodes. The circulating

current through the conducting resistance of the ribbon produces joule heating. The

current is passed through the ribbon while being maintained in a predetermined

configuration. For a curved ribbon, the ribbon is passed over an insulated roller,

preferably made of ceramic, with a pair of spring-loaded electrode rollers pressing

20 the ribbon respectively at the entry and exit point of the ribbon on the roller. In

example 1, an iron-based amorphous alloy ribbon Fe78B138ig, alloy type 260582

known to have a Bsatof 1.56 Tesla, annealed at a feeding rate of 0.3 cm/sec with this

process shows an improvement of the magnetic induction from 0.85 to 1.27 Tesla

(8.5 to 12.7 kG) under an applied magnetic field of 160 Aim (2 De) compared to an

as-cast specimen. The annealing embrittlement of the tested specimen has a

fracture strain between 0.9 and 1 by bending test compared to 7x10 to 5x10 for

furnace annealed samples. The document does not specify if the magnetic

properties measurements were performed on a core or on a single ribbon. However,

the resulting core loss is not clearly disclosed and no reference is made on the

30 exciting power. The iron-based samples annealed with this method has a BaD only at
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about 1.0 Tesla as reported in Figure 4 (1 Oe =80 AIm) which gives a low Bao/Bsat

ratio of 0.64. Also, no information is disclosed on the heating rates and on how the

cooling is performed after treatment as the ribbon is simply collected onto a take-up

mandrel. The authors claim a ribbon that can be annealed up to a feeding rate of

10 em/sec with this method.

In French patent application FR 2673954, and in an article entitled "On the

Optimization of Soft-Magnetic Properties of Metallic Glasses by Dynamic Current

Annealing", IEEE Transaction on Magnetics, vol. 28, no. 4 1992, p. 1911-1916,

10 Perron et al. disclosed a joule heating apparatus similar to Li et al. to anneal an

amorphous alloy ribbon in a circular shape. The ribbon is passed over an insulated

fixed drum or rotating roller, preferably made of quartz or alumina, with a pair of

cooled copper electrodes contacting the ribbon respectively at the touching and

separating point of the ribbon on the drum or roller. In addition to Li et al.'s method,

the cooled electrodes are used as a cooling means to freeze the stress relieved

ribbon before it separates from the drum or roller. In example 1, an iron-based

amorphous alloy ribbon, alloy type 2605S2, annealed at a feeding rate of 1 em/sec

with this process shows an improvement of the magnetization curve compared to a

furnace field annealed specimen as shown in Figure 5 of the patent. The applied

20 magnetic field is reduced to 10 AIm compared to 14 AIm at a measured magnetic

induction of 1.0 Tesla. The document does not specify if the measurements were

performed on a core or on a single ribbon. Perron et al. report an average heating

and cooling rates of 70 CO/second achieved with this apparatus. They claim that,

with their invention, a ribbon could be annealed at speeds near 1 em/sec. There is

no reference made to the core loss, the exciting power, the BaD, the Bao/Bsat ratio, or

the brittleness of the annealed ribbon.

Waeckerle et al. in US patent application US2008/0196795 disclosed a ribbon

annealing apparatus using an oven for heat treating a strip of an amorphous material

30 to produce a nanocrystallized magnetic alloy of low permeability having sufficient
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reduced brittleness to carry out the rolling up of the strip to form cores without risk of

breaking. The annealing process is carried out by forwarding the ribbon through a

tunnel furnace in a flat position at a feeding rate greater or equal to 10 em/sec and

under a longitudinal tensile stress. Such heat treatment is intended for

nanocrystallizing an amorphous alloy which is not sought for when the annealed

amorphous ribbon must preserve its amorphous state once annealed. Also, no

details are disclosed on heating rates and no references are made about the cooling

stage as the ribbon is simply collected on a take-up mandrel.

10 If an in-line annealing apparatus was capable of annealing an iron-based amorphous

alloy ribbon in a curved shape and to preserve its ductility then, the outputted ribbon

could be efficiently rolled up to form a circular core around the coils of a transformer

kernel such as the one disclosed by Allan et al. Using such an in-line annealing

treatment would also avoid all the numerous discontinuous steps involved in making

the core when using the furnace annealing method. However, this in-line annealing

treatment must operate at a cost-effective ribbon feeding rate and the ribbon must

acquire acceptable magnetic properties once the ribbon is rolled up to form a core.

Even without considering the magnetic properties and the degree of ductility for all

the in-line curved annealed amorphous ribbons of the above prior art documents, at

20 annealing feeding rates in the 1 to 10 em/sec range as mainly reported, a 22 em

wide and 25 IJm thick ribbon (which is the widest size generally available for making

conventional transformer cores) would be processed at a mass rate of 1.4 to 14

kg/hr (using the 7.2 g/cm3 material density of the Metglas 2605SA1 alloy). An

average core size in a distribution transformer rated between 25 to 167 kVA weighs

around 135 kg. At a mass rate of 1.4 to 14 kg/hr, this will take over 10 to 100 hours

to in-line anneal the ribbon of a single transformer core. This feeding rate range is far

too slow if one wants to render this process profitable. Too many annealing setups, ,

labour and floor space would be required which increase costs. In order to be

profitable, the ribbon feeding rate for a newly developed in-line annealing process

30 must be significantly increased. Doing the treatment at a lower cost within an hour,
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which becomes more reasonable, requires a feeding rate above 1 m/sec, 10 to 100

times faster than the feeding rates reported above. To go beyond this rate, the

heating and cooling temperature rates compared to those reported in the above

methods must be greatly increased, and the annealing time must be shortened by

further increasing the treatment temperature.

Performing annealing treatments in very short times on an amorphous ribbon have

widely been reported in several scientific papers. Many experiments conducted on a

ribbon segment have shown that the annealing time could be made much shorter. In

10 these experiments, a ribbon specimen was generally placed between two

electrodes, making contact at both ends, so that a high current pulse could be

passed through the specimen using, for example, a discharge capacitor. Optionally,

the experiment could be conducted in a liquid coolant for a quicker cooling. Using a

suitable current density, very high heating rates can be obtained and, if followed with

a rapid cooling, the annealing time can be reduced to a fraction of a second with the

ribbon becoming less brittle than after conventional furnace annealing. Such

experiment and results were reported by Kulik et al. in "Influence of Flash Annealing

on the Magnetic Properties of a Co-based Alloy Glass", International Journal of

Rapid Solidification, 1989, Vol. 4, 287-296, and by Matyja et al. in "Rapid heating of

20 alloy glasses", Philosophical Magazine B, 1990, Vol. 61, No.4, 701-713. These

experiments use higher heating and cooling rates than those reported in the above

prior art documents. However, the experiments were conducted on immobilized

ribbon segments. Applying this method for continuously in-line annealing a

forwarding ribbon is impracticable.

None of the prior art methods known to the Applicant teach a way to efficiently in-line

anneal in a curved shape an iron-based amorphous alloy ribbon forwarded at a

feeding rate greater than 1 m/sec and, none of them disclose circular cores made

with said annealed ribbon which exhibit acceptable core loss and exciting power

30 comparable to cores produced with conventional furnace field annealing and which
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have a 8ao greater than about 1.3 Tesla and a ratio 8ao/8sat greater than 0.80 while

remaining ductile for allowing efficient rolling-up-after-annealing.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide methods and

apparatus to overcome at least one drawback of the prior art.

According to the present invention, there is provided a method for treating an

10 amorphous alloy ribbon, comprising steps of:

a) feeding forward, tensioning and guiding the amorphous alloy ribbon along a

path at a preset feeding rate;

b) heating the amorphous alloy ribbon at a point along said path at a rate

greater than 103 °C/sec to a temperature to initiate a thermal treatment;

c) cooling the amorphous alloy ribbon at a rate greater than 103 °C/sec until the

thermal treatment ends;

d) applying a series of mechanical constraints on the ribbon during said thermal

treatment until the amorphous alloy ribbon adopts a specific shape at rest after said

thermal treatment; and

20 e) cooling the amorphous alloy ribbon at a rate to preserve said specific shape,

after said thermal treatment.

Preferably, according to one preferred embodiment of the present invention, the

thermal treatment is performed to maintain an amorphous state of the ribbon.

Preferably, according to another preferred embodiment of the present invention, the

thermal treatment is performed to initiate crystallisation of the amorphous alloy

ribbon.
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Preferably, according to another preferred embodiment of the present invention, the

thermal treatment is performed to obtain partial crystallisation of the amorphous alloy

ribbon.

Preferably, according to another preferred embodiment of the present invention, the

thermal treatment is performed to obtain full crystallisation of the amorphous alloy

ribbon.

Preferably, the preset feeding rate is greater than 1 m/sec.

10

Preferably, in step b), the heating is done at a rate greater than 104 DC per second.

Preferably, in step c), the cooling is done at a rate greater than 104 DC per second.

Preferably, according to one preferred embodiment of the present invention, the

thermal treatment is performed during a period of time that is less than one second.

Preferably, according to another preferred embodiment of the present invention, the

thermal treatment is performed during a period of time that is less than one tenth of a

20 second.

Preferably, step e) cools the amorphous alloy ribbon to a handling temperature

above a temperature threshold Tdb0 to which a complete ductility of the amorphous

alloy ribbon is obtained.

Preferably, the handling temperature is above ambient temperature and below said

temperature to initiate the thermal treatment.

Preferably, in step b) the amorphous alloy ribbon is in contact with at least one first

30 cylinder having a first cylindrical surface located along said path; step b) further
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comprises a step of tensioning the amorphous alloy ribbon with respect to the first

cylindrical surface to obtain a first static contact between the amorphous alloy ribbon

and the first cylindrical surface, the first static contact stretching over a first contact

angle around the first cylindrical surface; step b) further comprises a step of

maintaining said first cylindrical surface at a temperature greater or equal to said

temperature to initiate the thermal treatment; in step c) the amorphous alloy ribbon is

in contact with at least one second cylinder having a second cylindrical surface

located along said path; step c) further comprises a step of tensioning the

amorphous alloy ribbon with respect to the second cylindrical surface to obtain a

10 second static contact between the amorphous alloy ribbon and the second cylindrical

surface, the second static contact stretching over a second contact angle around the

second cylindrical surface; and step c) further comprises a step of maintaining said

second cylindrical surface at a temperature lower than said temperature to initiate

the thermal treatment.

Preferably, in step d) the amorphous alloy ribbon is in contact with at least one third

cylinder having a third cylindrical surface located along said path; step d) further

comprises a step of tensioning the amorphous alloy ribbon with respect to the third

cylindrical surface to obtain a third static contact between the amorphous alloy

20 ribbon and the third cylindrical surface, the third static contact stretching over a third

contact angle around the third cylindrical surface; and step d) further comprises a

step of maintaining said third cylindrical surface at said temperature to initiate the

thermal treatment.

Preferably, the step of tensioning the amorphous alloy ribbon with respect to the

cylindrical surfaces is done at a tension in the range of 25 to 200 MPa.

More preferably, the step of tensioning the amorphous alloy ribbon with respect to

the cylindrical surfaces is done at a tension in the range of 50 to 100 MPa.

30
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Preferably, the step of tensioning the amorphous alloy ribbon is done to favour the

development of a magnetic anisotropy in the ribbon.

Preferably, the amorphous alloy ribbon is in contact with at least one guide roller

proximate a selected one of the first, second or third cylinders, said guide roller

having a radius that is smaller than the selected cylinder and being positioned

proximate both an initial contact point and a final contact point between the ribbon

and the selected cylinder to maximize said contact angle of said selected cylinder.

10 Preferably, in step d) the specific shape is curved and the method further comprises

an additional step of:

f) rolling up a specific amount of the amorphous alloy ribbon onto a mandrel to

form a core having an inner radius and an outer radius, wherein said specific shape

has a radius of curvature selected between said inner radius and said outer radius.

Preferably, in step d) the specific shape is flat and the method further comprises an

additional step of:

f) cutting and stacking segments of the amorphous alloy ribbon.

20 Preferably, in step d) the mechanical constraints change to vary a radius of

curvature of the specific shape of the amorphous alloy ribbon along a length thereof,

and the method further comprises an additional step of:

f) rolling up said length of the amorphous alloy ribbon onto a mandrel to form a

core.

Preferably, the method further comprises an additional step before step f) of:

i) coating at least one side of the amorphous alloy ribbon with a dielectric

material.

30 Preferably, the dielectric material is an organic dielectric material.
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Preferably, in step i) coating is performed by means of electrodepositing.

Preferably, step i) further comprises steps of applying a voltage on the amorphous

alloy ribbon and feed forwarding the ribbon in an emulsion of organic polymers and

de-ionized water for a period of time.

Preferably, the method further comprises an additional step before step f) of:

i) coating at least one side of the amorphous alloy ribbon with a binder.

10

Preferably, a tension is increased or reduced along the path of the amorphous alloy

ribbon by a tensioning apparatus, said tensioning apparatus comprising:

at least one motor having a shaft;

a circular device coupled to the shaft of the motor, said circular device

having a surface making a static contact with the ribbon over an angle, the

surface having a static friction coefficient with respect to the ribbon; and

- a controller for controlling torque of said motor shaft to increase or reduce a

tensile stress in the amorphous ribbon.

20 Preferably, the tensioning apparatus is located along said path to increase the

tensile stress in the ribbon before thermal treatment is initiated.

Preferably, the tensioning apparatus is located along said path to reduce the tensile

stress after said thermal treatment.

Preferably, the tensioning apparatus is located along said path for controlling the

tensile stress in the ribbon during said thermal treatment.

Preferably, the ribbon being fed along the path is delivered to a target position on a

30 structure by a guiding apparatus, said guiding apparatus comprising:
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- a body;

- a guide roller mounted on the body, having a flat peripheral surface lined with

lateral guides for supporting and guiding the ribbon, the guide roller having a

receiving section for receiving the ribbon and a delivering section for delivering the

ribbon at the target position; and

- a pivot for pivotably mounting the body to the structure, the pivot having a pivot

axis tangentially aligned with the delivering section of the roller; in operation, the

body pivots with respect to the structure by means of the pivot so that the receiving

section of the roller receives the ribbon and accommodates translations thereof to

10 deliver via said delivering section the ribbon at the target position.

Preferably, in step e) the amorphous alloy ribbon is in contact with a plurality of

spaced apart cooling cylinders each having a cooling cylindrical surface located

along said path; step e) further comprises a step of tensioning the amorphous alloy

ribbon with respect to the cooling cylindrical surfaces to obtain a cooling static

contact between the moving amorphous alloy ribbon and the cooling cylindrical

surfaces, the cooling static contact stretching over respective contact angles around

the cooling cylindrical surfaces; and step e) further comprises a step of maintaining

said cooling cylindrical surfaces at a temperature lower than said temperature to

20 initiate the thermal treatment.

According to the present invention, there is also provided an iron-based amorphous

alloy cast as a ribbon, heat-treated by in-line annealing at a temperature without

reaching onset crystallization with heating and cooling at temperature rates greater

than 103 °C/sec, preferably greater than 104 °C/sec.

Preferably, when said ribbon is stacked or rolled up to form a core, its Bao/Bao is

greater than 0.80 after annealing.
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Preferably, when said ribbon is stacked or rolled up to form a core, its BaD is greater

than about 1.3 Tesla after annealing.

Preferably, under this treatment, the ribbon is ductile at normal room temperature

and completely ductile above a temperature greater than normal room temperature

According to the present invention, there is also provided an iron-based amorphous

alloy cast as a ribbon comprising a nominal chemical composition FeaoB11Sig,

numbers being in atomic percent, with incidental impurities, heat-treated by in-line

10 annealing at a temperature above 450°C without reaching onset crystallization with

heating and cooling at temperature rates greater than 103°C/sec.

According to the present invention, there is also provided an iron-based amorphous

alloy, comprising a nominal chemical composition FeaBbSicCd where 80<a<84,

8<b<18, 0<c:55 and 0<d:53, numbers being in atomic percent, with incidental

impurities, heat-treated by in-line annealing at a temperature above 425°C without

reaching onset crystallization with heating and cooling at temperature rates greater

than 103DC/sec.

20 Preferably, under this treatment, the ribbon is ductile at normal room temperature

and completely ductile at a temperature greater than 80°C.

Preferably, the iron-based amorphous alloy comprises a nominal chemical

composition Fe81.8B15.8Si2.1Co.3, numbers being in atomic percent, with incidental

impurities.

According to the present invention, there is also provided a heat exchange system

for exchanging heat with an article comprising:

-a support structure;

30 -a heat exchanger ring element capable of being heated;
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-a heat diffuser ring element having an outer surface to be in contact with said

article, said heat diffuser ring element having an inner surface in contact with

said heat exchanger ring element; and

-a frame structure supporting said heat exchanger ring element and said heat

diffuser ring element, said frame structure being rotatably mounted on the

support structure.

Preferably, the heat exchanger ring element is a resistive element capable of being

in sliding rotatable contact with an electrical power source.

10

Preferably, according to another embodiment of the invention, the heat exchanger

ring element is a resistive element further comprising an antenna for heating by

magnetic induction the heat exchanger ring element.

Preferably, the heat exchange system further comprises a slotted structure integrally

formed with the heat exchanger ring element and laterally surrounding said heat

exchanger ring element, the slotted structure having slots extending transversally to

the heat exchanger ring element.

20 Preferably, the heat exchanger ring element is made of stainless steel and the heat

diffuser ring element is made of copper and mounted by electrodeposition on the

heat exchanger ring element.

According to the present invention, there is also provided a system for treating an

amorphous alloy ribbon, comprising:

-a moving device for feeding forward, tensioning and guiding the amorphous

alloy ribbon along a path at a preset feeding rate;

-a heating system for heating the amorphous alloy ribbon at a point along said

path at a rate greater than 103 DC/sec to a temperature to initiate a thermal

30 treatment;
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-a first cooling system cooling the amorphous alloy ribbon at an initial rate

greater than 103 °C/sec until the thermal treatment ends;

-a mechanical constraint application device for applying a series of mechanical

constraints on the ribbon during said thermal treatment until the amorphous alloy

ribbon adopts a specific shape at rest after said thermal treatment; and

-a second cooling system for cooling the amorphous alloy ribbon at a rate to

preserve said specific shape, after said thermal treatment.

Preferably, the preset feeding rate is greater than 1 m/sec.

10

Preferably, the heating system heats at a rate greater than 104oC per second.

Preferably, the first cooling system cools at a rate greater than 104oC per second.

Preferably, the second cooling system cools the amorphous alloy ribbon to a

handling temperature above a temperature threshold Tdb° that is sufficient to obtain

complete ductility of the amorphous alloy ribbon.

Preferably, the heating system comprises at least one first cylinder in contact with

20 the amorphous alloy ribbon, said at least one first cylinder having a first cylindrical

surface located along said path, the system further comprising a first tensioning

apparatus for tensioning the amorphous alloy ribbon with respect to the first

cylindrical surface to obtain a first static contact between the amorphous alloy ribbon

and the first cylindrical surface, the first static contact stretching over a first contact

angle around the first cylindrical surface, a temperature of said first cylindrical

surface being maintained at a temperature greater or equal to said temperature to

initiate the thermal treatment, the first cooling system comprises at least one second

cylinder in contact with the amorphous alloy ribbon, said at least one second cylinder

having a second cylindrical surface located along said path, the system further

30 comprising a second tensioning apparatus for tensioning the amorphous alloy ribbon
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with respect to the second cylindrical surface to obtain a second static contact

between the amorphous alloy ribbon and the second cylindrical surface, the second

static contact stretching over a second contact angle around the second cylindrical

surface, a temperature of said second cylindrical surface being maintained at a

temperature lower than said temperature to initiate the thermal treatment.

Preferably, the mechanical constraint application device comprises in contact with

the amorphous alloy ribbon, said at least one third cylinder having a third cylindrical

surface located along said path, the system further comprising a third tensioning

10 device for tensioning the amorphous alloy ribbon with respect to the third cylindrical

surface to obtain a third static contact between the amorphous alloy ribbon and the

third cylindrical surface, the third static contact stretching over a third contact angle

around the third cylindrical surface, a temperature of said third cylindrical surface

being maintained at said temperature to initiate the thermal treatment.

Preferably, the tensioning apparatuses tension the amorphous alloy ribbon with

respect to the cylindrical surfaces at a tension in the range of 25 to 200 MPa.

More preferably, the tensioning apparatuses tension the amorphous alloy ribbon with

20 respect to the cylindrical surfaces at a tension in the range of 50 to 100 MPa.

Preferably, wherein the tensioning apparatuses tension the amorphous alloy ribbon

to favour the development of a magnetic anisotropy in the ribbon.

Preferably, the system further comprises at least one guide roller to which the

amorphous alloy ribbon is in contact, proximate a selected one of the first, second or

third cylinders, said guide roller having a radius that is smaller than the one of the

selected cylinders and being positioned proximate both an initial contact point and a

final contact point between the ribbon and the selected cylinder to maximize said

30 contact angle of said selected cylinder.
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Preferably, according to one embodiment of the present invention, the system further

comprises a mandrel onto which a specific amount of the amorphous alloy ribbon is

rolled up, said mandrel having an inner radius and an outer radius, said specific

shape having a radius of curvature selected between said inner radius and said

outer radius.

Preferably, according to another embodiment of the present invention, the system

further comprises a cutter and stacking device for cutting and stacking segments of

10 the amorphous alloy ribbon.

Preferably, according to one embodiment of the present invention, the mechanical

constraint application device apply constraints to vary a radius of curvature of the

specific shape of the amorphous alloy ribbon along a length thereof, and the system

further comprises a mandrel onto which a specific amount of the amorphous alloy

ribbon is rolled up.

Preferably, the system further comprises a coating system for coating at least one

side of the amorphous alloy ribbon with a dielectric material.

20

Preferably, the dielectric material is an organic dielectric material.

Preferably, the coating system is an electrodepositing system.

Preferably, the system further comprises a voltage application device for applying a

voltage on the amorphous alloy ribbon, and a bath system comprising an emulsion

of organic polymers and de-ionized water through which the ribbon is fed forward for

a period of time.
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Preferably, the system further comprises a binder application system for coating at

least one side of the amorphous alloy ribbon with a binder.

Preferably, the system further comprises a tensioning apparatus for increasing or

reducing a tension in the amorphous alloy ribbon along the path, said tensioning

apparatus comprising:

at least one motor having a shaft;

- a circular coupled to the shaft of the motor, said circular device having a

surface making a static contact with the ribbon over an angle, the surface

10 having a static friction coefficient with respect to the ribbon; and

- a controller for controlling torque of said motor shaft to increase or reduce a

tensile stress in the amorphous ribbon.

Preferably, the second cooling system comprises a plurality of spaced apart cooling

cylinders in contact with the amorphous alloy ribbon, said spaced apart cooling

cylinders each having a cooling cylindrical surface located along said path, the

system further comprising a tensioning system for tensioning the amorphous alloy

ribbon with respect to the cooling cylindrical surfaces to obtain a cooling static

contact between the moving amorphous alloy ribbon and the cooling cylindrical

20 surfaces, the cooling static contact stretching over respective contact angles around

the cooling cylindrical surfaces, a temperature of said cooling cylindrical surfaces

being maintained at a temperature lower than said temperature to initiate the thermal

treatment.

A non-restrictive description of a preferred embodiment of the invention will now be

given with reference to the appended drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS

PCT/CA2010/001844

Figure 1 is a schematic view of a system for in-line annealing an amorphous alloy

ribbon in a curved shape by forwarding the ribbon over a hot and then over a cold

roller, in accordance with a preferred embodiment of the present invention;

Figure 2 is a schematic view of the system shown in Figure 1 with the addition of a

ribbon feeding reel and a take-up mandrel;

10 Figures 3a and 3b are schematic views of the system shown in Figure 1 with the

addition of a small guide roller for increasing contact angle over the rollers;

Figure 4a is a schematic view of the system shown in Figure 1 with the addition of a

hot roller for pre-heating the ribbon;

Figure 4b is a schematic view of the system shown in Figure 1 with the addition of

two hot rollers for pre-heating the ribbon;

Figure 5 is a schematic view of the system shown in Figure 4b with the addition of

20 three cold rollers for further cooling of the ribbon;

Figure 6a is a schematic view of the system shown in Figure 1 with the addition of a

hot roller for annealing the alloy ribbon at variable curvatures;

Figure 6b is a schematic view of the system shown in Figure 1 with the addition of a

hot roller for annealing the alloy ribbon in a flat bend form;

Figure 7a is a graph showing the temperature profile of the ribbon while moving

along a travelling path within the system shown in Figure 24 when not using pre30 heating;
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Figure 7b is a graph showing the temperature profile of the ribbon while moving

along a travelling path within the system shown in Figure 24 when using pre-heating;

Figure 7c is a graph showing the temperature profile of the ribbon while passing over

the cold rollers shown in Figure 5;

Figure 8 is a graph showing the temperature profile of the ribbon while moving along

a travelling path within the system shown in Figure 24 when cooling the ribbon to a

10 temperature above the ductile to brittle threshold;

Figure 9 is a perspective view of inner and outer cladding rings of a hot roller

according to a preferred embodiment of the present invention;

Figure 10 is a perspective view of inner and outer cladding rings of a hot roller

comprising an induction antenna according to a preferred embodiment of the present

invention;

Figure 11 is a perspective view ofa hot roller construction according to a preferred

20 embodiment of the present invention;

Figure 12 is a perspective view of a hot roller shown in Figure 11 with a flange and a

hollow shaft;

Figure 13 is a side cross-section view and a detailed view respectively of the hot

roller according shown in Figure 12 mounted on a supporting member;

Figure 14 is a side cross-section view of a cold roller according to a preferred

embodiment of the present invention;

30
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Figure 15a is a side cross-section view of a cold roller according to another preferred

embodiment of the present invention;

Figure 15b is a perspective view of some elements comprised in the hollow portion

of the cold roller shown in Figure 15a;

Figure 16 is a schematic view of a system to deliver a ribbon at a precise location on

a guiding roller according to a preferred embodiment of the present invention;

10 Figure 17 is a perspective view of a system to deliver a ribbon at a precise location

on a guiding roller according to another preferred embodiment of the present

invention;

Figure 18a is a schematic illustration of a ribbon passing over a capstan wheel;

Figure 18b is a plotted curve of the tensile force vs. angular position applied by a

capstan wheel on a ribbon;

Figures 19a and 19b are a front view and a perspective view of a capstan drive

20 according to a preferred embodiment of the present invention;

Figures 20a and 20b are a front view and a perspective view of four capstan drives

according to another preferred embodiment of the present invention;

Figure 21 is a schematic view of a ribbon tensioning apparatus with two capstan

drives, according to a preferred embodiment of the present invention;

Figure 22 is a schematic view of a ribbon tensioning apparatus with a plurality of

capstan drives, according to another preferred embodiment of the present invention;

30
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Figure 23 is a schematic view of an in-line annealing apparatus comprising: a

system for in-line annealing an amorphous alloy ribbon in a curved shape; a ribbon

tensioning apparatus, a system to deliver a ribbon at a precise location on a guiding

roller; a feeding reel; and a take-up mandrel according to a preferred embodiment of

the present invention;

Figure 24 is a schematic view of a system for a system for in-line annealing an

amorphous alloy ribbon in a curved shape according to another preferred

embodiment of the present invention;

10

PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Different preferred objects of the present invention will now be presented.

It is an object of the present invention to provide an in-line annealing method and

apparatus for heat treating an amorphous alloy ribbon at high ribbon heating and

cooling rates.

It is another object of the present invention to provide an in-line annealing method

20 and apparatus for heat treating an amorphous alloy ribbon to adopt a specific shape

at rest after the thermal treatment.

Preferably, is another object of the present invention to provide a curved annealed

and ductile iron-based amorphous alloy ribbon that can be used to manufacture

circular magnetic cores at low cost.

Preferably, it is another object of the present invention to provide a low cost process

for in-line annealing an amorphous alloy ribbon.
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Preferably, it is another object of the present invention to provide a process for inline annealing an amorphous alloy ribbon which is compact.

Preferably, it is another object of the present invention to provide a process for inline annealing an amorphous alloy ribbon which operates at high ribbon feeding

rates.

Preferably, it is another object of the present invention to provide a flat annealed and

ductile iron-based amorphous alloy ribbon that can be used to manufacture stacked

10 magnetic cores at low cost.

Preferably, it is another object of the present invention to provide an in-line annealed

an iron-based amorphous alloy ribbon which exhibit acceptable magnetic properties

for manufacturing cores for distribution transformers, HIF, pulse power cores, and

other items.

The present invention is based on the idea that it is not essential to heat, treat and

cool a ferromagnetic amorphous alloy ribbon in the same shape as it will have after

treatment in order to get a ribbon to have acceptable magnetic properties for making

20 distribution transformers, HIF, pulse power cores, and other items. It is believed that

an amorphous alloy ribbon can be in-line annealed with the ribbon following a series

of different predetermined configurations while being forwarded along the treatment.

This is done by controlling the flow sequence occurring in the alloy at the treatment

temperature to ensure its progression towards a structural state where most of the

residual stresses and applied bending stresses will be alleviated when the ribbon will

be bent close to a final shape after treatment. With the apparatus of the present

invention, an amorphous alloy ribbon is in-line annealing to adopt a desired final

shape after treatment. In the present invention, the treatment temperature must be

sufficiently high and must last sufficient long so that the obtained reduced viscosity

30 will allow sufficient flow to occur along the series of imposed configurations in order
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to affect the resulting final shape after treatment. With the present invention, it is

possible to provide a heat transfer rate much higher than the ones obtained with the

above methods of the prior art. Preferably, a high heat transfer rate is provided by

using a prolonged direct static contact between one of the two side surfaces of the

forwarded ribbon and along a significant peripheral portion of a thermally conductive

circular rotating body (a static contact is referred in this document to a non-slipping

direct mechanical contact between two surfaces). Using higher heat transfer rates

for heating and cooling will improve the ribbon temperature rising or falling rate. With

the present invention, it is possible to heat or cool a 20 to 30 ~m thick metal ribbon

10 at a temperature rising or falling rate greater than 103 C/seconds, and preferably, in

certain cases, even greater than 104 C/seconds. With the present invention, cooling

is subdivided in two consecutive stages: There is a first stage cooling operating at a

high temperature falling rate, which will serve to quickly bring the ribbon temperature

sufficiently below the treatment temperature, in order to sufficiently slow flow and

structural relaxation and therefore stopping the thermal treatment. The first stage is

followed by second stage cooling at a sufficient temperature falling rate which will

serve to bring down the ribbon temperature to a point where the ribbon structural

state at the end of the thermal treatment will be preserved. Preferably, after first

stage cooling, flow and structural relaxation are slowed to a point where no

20 significant structural change will further occur to the alloy due to the ribbon handling

occurring in the second stage cooling. With the present invention, according to

preferred embodiments, it is possible to limit structural relaxation in the in-line

annealing treatment to get a ductile ribbon. With the present invention, according to

preferred embodiments, it is possible to in-line anneal an iron-based amorphous

alloy ribbon at a treatment temperature above conventional furnace annealing

temperatures without reaching onset crystallization. With the present invention, it is

possible to use stress annealing in the production of amorphous alloy cores usable

to manufacture cores for distribution transformers, HIF, pulse power cores, and other

items. With the present invention, according to preferred embodiments, it is possible

30 to continuously in-line anneal a forwarding ribbon in a period less than a second,
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preferably less than one tenth of a second, to limit structural relaxation and therefore

to get a ductile ribbon. With the present invention, according to preferred

embodiments, it is also possible to in-line anneal an amorphous ferromagnetic alloy

ribbon at feeding rates greater than 1 m/sec, even at feeding rates greater than

about 5 m/sec, even in the 101 m/sec rate range, therefore allowing a high mass

production rate of annealed ribbon material for making rolling-up-after-annealing

cores. With the present invention, according to preferred embodiments, the size of

the in-line annealing apparatus is small and requires minimal floor space, which

significantly contributes to reduce costs. With the present invention, according to

10 preferred embodiments, it is possible to produce rolling-up-after-annealing cores that

exhibit lower core loss compared to conventional annealing-after-rolling cores. With

the present invention, according to preferred embodiments, it is possible to produce

rolling-up-after-annealing cores that exhibit a Bao greater than about 1.3 Tesla. With

the present invention, according to preferred embodiments, it is possible to produce

rolling-up-after-annealing cores that exhibit a Bao/Bsat greater than 0.80. With the

present invention, according to preferred embodiments, it is possible to in-line

anneal an iron-based amorphous alloy ribbon which is cuttable after treatment, for

allowing easy rolling-up-after-annealing. With the present invention, according to

preferred embodiments, it is possible to in-line anneal an iron-based amorphous

20 alloy ribbon which is foldable on at least one side after treatment. With the present

invention, according to preferred embodiments, it is possible to in-line anneal an

iron-based amorphous alloy which remains ductile after treatment. With the present

invention, according to preferred embodiments, it is possible to in-line anneal an

iron-based amorphous alloy which can be handled in a complete ductile state after

treatment. With the present invention, according to preferred embodiments, it is

possible to in-line anneal an iron-based amorphous alloy in a completely ductile

state during the whole treatment process to minimize risk of breakage. With the

present invention, according to preferred embodiments, it is possible to in-line

anneal an iron-based amorphous alloy ribbon where Tdb0 remains below the normal

30 room temperature after treatment. With the present invention, according to preferred
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embodiments, it is possible to in-line anneal an iron-based amorphous alloy ribbon

which can be punch, cut or torn, after treatment.

In the present invention, according to preferred embodiments, there is provided an

iron-based amorphous alloy, when cast in a ribbon, such an amorphous alloy heattreated by in-line annealing at temperatures without reaching onset crystallization

with heating and cooling at temperature rates greater than 103 °C/sec, preferably

greater than 104 °C/sec, has a Bso/Bsa! greater than 0.80 when the ribbon is stacked

or rolled up to form a core. In addition, such an amorphous alloy is ductile at normal

10 room temperature. In addition, such an amorphous alloy is completely ductile above

a temperature slightly greater than normal room temperature.

In the present invention, according to preferred embodiments, there is provided an

iron-based amorphous alloy having a nominal chemical composition FesoB11Sig,

numbers being in atomic percent, with incidental impurities. When cast in a ribbon,

such an amorphous alloy heat-treated by in-line annealing at temperatures above

450°C without reaching onset crystallization with heating and cooling at temperature

rates greater than 103 °C/sec, preferably greater than 104 °C/sec, has a Bso/Bsa!

greater than 0.80 when the ribbon is stacked or rolled up to form a core. In addition,

20 such an amorphous alloy is ductile at normal room temperature. In addition, such an

amorphous alloy is completely ductile above a temperature slightly greater than

normal room temperature, preferably above 100°C. In addition, such an amorphous

alloy in a core has a Bso greater than about 1.3 Tesla. In addition, such an

amorphous alloy in a core has a core loss lower than 0.25 W/kg at 60 Hz at a

magnetic induction of 1.3 Tesla.

In the present invention, according to preferred embodiments, there is provided an

iron-based amorphous alloy having a chemical composition FeaBbSicCd where

80<a<84, 8<b<18, 0<cs;5 and 0<ds;3, numbers being in atomic percent, with

30 incidental impurities. When cast in a ribbon, such an amorphous alloy heat-treated
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by in-line annealing at temperatures above 425°C without reaching onset

crystallization with heating and cooling at temperature rates greater than 103°C/sec,

preferably greater than 104 °C/sec, has a Bso/Bsat greater than 0.80 when the ribbon

is stacked or rolled up to form a core. In addition, such an amorphous alloy is ductile

at normal room temperature. In addition, such an amorphous alloy is completely

ductile above a temperature slightly greater than normal room temperature,

preferably above 80°C. In addition, such an amorphous alloy in the core has a Bso

greater than about 1.3 Tesla, even greater than about 1.4 Tesla, even greater than

about 1.5 Tesla. In addition, such an amorphous alloy in the core has a core loss

10 lower than 0.25 W/kg at 60 Hz at a magnetic induction of 1.5 Tesla.

In the present invention, according to preferred embodiments, there is provided an

iron-based amorphous alloy having a nominal chemical composition

Fes1.8B15.sSi2.1Co.3, numbers being in atomic percent, with incidental impurities. When

cast in a ribbon, such an amorphous alloy heat-treated by in-line annealing at

temperatures above 425°C without reaching onset crystallization with heating and

cooling at temperature rates greater than 103 °C/sec, preferably greater than 104

DC/sec, has a Bso/Bsat greater than 0.80, preferably greater than 0.90, when the

ribbon is stacked or rolled up to form a core. In addition, such an amorphous alloy is

20 ductile at normal room temperature. In addition, such an amorphous alloy is

completely ductile above a temperature slightly greater than normal room

temperature, preferably above 80o

C. In addition, such an amorphous alloy in the

core has a Bso greater than about 1.3 Tesla, even greater than about 1.4 Tesla, even

greater than about 1.5 Tesla. In addition, such an amorphous alloy in the core has a

core loss lower than 0.25 W/kg at 60 Hz at a magnetic induction of 1.5 Tesla.

Referring to Figure 1, there is shown an apparatus for in-line annealing an

amorphous alloy ribbon comprising: a hot roller 1 having an outer radius r1; a cold

roller 2 having a smaller outer radius r2 and rotating in parallel and at a selected

30 distance d from roller 1. The hot and cold rollers outer surfaces are constituted of a
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PCT/CA2010/001844

material having a thermal conductivity and a thermal inertia. The hot and cold rollers

comprise a heat source and/or heat sink for controlling the heat flux entering in or

exiting out from each roller. The flow of heat between the heat source and/or heat

sink and a roller can be performed using a heat transfer fluid, or gas, circulating in

contact with the thermally conductive inner surface of a sealed hollow roller and

passing through the roller via entry and exit holes located in the center of the shaft.

For heat flux entering in a roller, the heat transfer fluid, or gas, can be substituted by

a flame from a burner or by an electrical heating element in contact with the thermal

conductive inner surface of a hollow roller. The electrical heating element can be

10 connected to an electrical power supply via sliding contacts provided on the roller

shaft, or preferably, by using a fixed High frequency (HF) magnetic induction heating

antenna located within the hollow portion of the roller and in close proximity to the

inner roller surface which has an electrical conductivity, the HF magnetic induction

antenna being connected to an HF electrical source through an opening in the roller

shaft.

A thin amorphous alloy ribbon is fed at entry point 3 at a given ribbon feeding rate, a

temperature Tin° and under a first mechanical tensile stress 81 applied along the

ribbon longitudinal axis. The ribbon is then guided through a selected path along

20 which it will be subjected to a series of physical deformations and thermal treatments

before leaving at exit point 7 at the same feeding rate, at a temperature Tout

O and

under a second applied mechanical tensile stress 82. Preferably, the ribbon entering

at point 3 shows little structural change compared to its as-cast state. The treatment

sequence can be best described by selecting a segment of the ribbon located at

entry point 3 and to follow the series of thermal and structural changes while moving

along the travelled path. From point 3 and moving along, the ribbon first makes a

static contact at point 4 on the outer surface of hot roller 1 where it bends to radius

r1. From this point, the ribbon starts to heat up at a high temperature rising rate and

is kept in contact with hot roller 1 for a given rotation angle 81, up to point 5. While

30 rotating along with hot roller 1 outer surface, the ribbon temperature goes up to a
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treatment temperature below or equal to the hot roller 1 outer surface temperature.

At point 5, the hot ribbon breaks contact with hot roller 1 and goes through in a flat

configuration and at the treatment temperature to point 6 located at a travel distance

d from point 5 to make a second static contact with the outer surface of cold roller 2

parallel to roller 1 and, where it bends on the same side again to radius r2. From this

point, the ribbon starts to cool down at a high temperature falling rate. The ribbon is

kept in contact with cold roller 2 for a given rotating angle 82 up to point 8. While

rotating along on cold roller 2, the ribbon temperature goes down to a temperature

ToutO above or equal to the cold roller 2 outer surface temperature. After leaving cold

10 roller 2, the ribbon is either taken-up on a mandrel and slowly cools down to normal

room temperature or, is moved away for further cooling (for example: additional cold

rollers) or processing before being rolled on a take-up mandrel.

The setup apparatus of Figure 1 is best suited to continuously stress relieve a

forwarding thin amorphous alloy ribbon to adopt a curved shape. Normally, the

amorphous alloy ribbon will have a thickness up to 50 IJm, more typically at about 20

to 30 IJm. In the present invention, the post-process natural bending radius ra in a

rest position at which the ribbon will show maximum alleviated stress is greater than

radius r2 after treatment. In order to be so, the ribbon temperature must go up to a

20 treatment temperature for a sufficient period of time in order to relieve the residual

and applied bending stresses due to increased flow and to the presence of a tensile

stress in the ribbon. The controlling of the flow sequence occurring in the alloy at the

treatment temperature is controlled by the sequence of bending stresses imposed on

the ribbon with rollers rotating in contact with the forwarded ribbon along the thermal

treatment path. During treatment, the ribbon successively changes configuration

from being bent to radius r1, then being flat and, being bent again on the same side

to radius r2. A portion of the stress relieving is occurring on roller 1 when the

treatment temperature is reached. The travel path from point 5 to point 6 on cold

roller 2 is done in a flat configuration at the treatment temperature and an added

30 unbending applied stress is getting relieved. Once point 6 reached, stress relief
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action of the reapplied bending stress imposed at a small radius r2 on the same

bending side as on roller 1 is occurring while the ribbon's temperature is still near the

treatment temperature during the initial portion of the first cooling stage. This way,

the ribbon will regain a substantially alleviated stress condition when bent close to

radius ra which is greater than r2. When leaving the roller at point 8, the first cooling

stage is done and the ribbon temperature ToutO has dropped sufficiently below the

treatment temperature to allow further ribbon handling while continuing to cool down

in the second cooling stage without provoking further significant detrimental stress

relief. As the alloy's viscosity increases with the reciprocal of the temperature by

10 closely following an Arrhenius law, a drop of a few tens of degrees from the

treatment temperature is sufficient. Second stage cooling can be done when the

ribbon is rolled on the take-up mandrel or preferably, using any additional cooling

means such as additional cold rollers, or a cooling jet of gas, before being taken-up

on a mandrel. The resulting natural bending radius ra in a rest position after

treatment becomes a function of ribbon thickness and feeding rate, temperatures of

rollers 1 and 2, radius r1 and r2, contacting angles 81 and 82 and distance d. Also, a

tensile stress is maintained all along the displacement of the ribbon during treatment

to induce a magnetic anisotropy oriented along or perpendicular to the ribbon

longitudinal axis, depending on the alloy composition.

20

In the apparatus of Figure 1, the highest ribbon feeding rate that can be achieved,

while keeping an acceptable annealing treatment, is limited by the heat transfer rate

between a roller and the ribbon, by the ribbon thickness, by the angular distance (8 x

r) of the contact region, and by the roller temperature. The heat transfer rate

between a roller and the ribbon is dependent on the contact area between both

mating surfaces. Due to some roughness characteristics of both mating surfaces, the

contact area is reduced to a fraction which is influenced by the applied contact

pressure. The contact area will be improved if some pressure is applied. Also, a

reduced viscosity at elevated temperature will improve the contact area under the
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PCT/CA2010/001844

pressuring force. Furthermore, the contact area will improve for amorphous alloy

ribbons having a reduced surface roughness. In the shown apparatus, a contact

pressure is exerted by the applied mechanical tensile stress in the forwarded ribbon

in order to strangle the roller. This strangling force creates a contact pressuring force

which is proportional to the tensile stress and inversely proportional to the roller

radius. The radius r2 of roller 2 being smaller than radius r1 of roller 1, the ribbon will

have a higher contact area on roller 2 at cool down. Also, the temperature rate of

change in the ribbon while in contact with a roller evolves closely following a

negative exponential decay: _e-x (heating ribbon), or positive exponential decay: e-x

10 (cooling ribbon), as the temperature gap between the ribbon and the roller surface

diminishes, as shown in Figure 7a. Preferably, the surface temperature of roller 2 is

well below the treatment temperature to take benefit of the higher falling temperature

rate occurring at the initial portion of the closely followed positive exponential decay

(e-X). The maximum ribbon feeding rate for maintaining the same annealing

curvature is achieved when the temperature ToutO has not dropped sufficiently below

the treatment temperature at point 8 to allow further ribbon handling while continuing

to cool down in the second cooling stage without provoking further significant

detrimental stress relief. In this case, thermal treatment is not ended and the first

cooling stage must be continued by contacting on a second cold roller 2 in close

20 proximity to the first cold roller 2. The resulting final curved shape will be determined

by considering the effect of this added roller on the thermal treatment.

Preferably, the annealing process of the present invention is carried out to minimize

structural relaxation in order to get a ductile ribbon. It is believed that the

dependence to the reciprocal of the temperature of the amorphous alloy

instantaneous viscosity and rate of viscosity increase with time closely follow an

Arrhenius law for temperatures below Tgo. At an elevated temperature but still below

TgO, the reduced viscosity will cause flow to increase in response to stress. For an

initial applied or residual stress, the effect of flow will gradually relieve the stress with

30 time with an associated time constant. In a constant structure (i.e.: with no structural
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PCT/CA2010/001844

relaxation), this time constant is exponentially proportional to the reciprocal

temperature of the alloy. The higher the temperature, the shorter the required stress

relief time will be. Furthermore, if there is a constant applied stress, there will be a

constant flow. However, with structural relaxation also occurring, there will be an

increasing resistance to flow due to a continuing increase of the viscosity as the alloy

atomic structure rearranges towards an equilibrium state. This will stretch the time

constant to relieve the stresses which will be irreversible since there has been a

structural change in the alloy. Due to the effect of structural relaxation, the required

time to stress relieve a sudden applied stress on an amorphous alloy specimen at a

10 predetermined temperature below Tg

0 will increase depending on the thermal history

the specimen was subjected to. In a preferred embodiment of the present invention,

the heating time, the annealing time, the treatment configurations' sequence and the

cooling method are realized based on how the structural change will affect the

annealing time constant and the ductility of the ribbon. The thermal treatment is

performed for the minimum time required to adequately relieve the residual and the

series of applied stresses, which is dependent on the time constant associated with

a chosen treatment temperature and with the evolution of the structural state during

treatment. Going beyond this minimum time is unnecessary and will allow too much

structural relaxation to occur which will be detrimental to the ductility of the ribbon.

20 The shorter time constant available for alleviating applied stresses occurs at the

beginning of the treatment once the treatment temperature is reached. Accordingly,

the residual and applied bending stresses are mainly relieved when reaching point 5

in Figure 1. Preferably, the travelling distance d is kept short by placing roller 2 very

close to roller 1 to limit further structural relaxation. Preferably, the choice of roller 2

radius r2 is determined in order to obtain a cooled alloy ribbon showing maximum

alleviated stress when bent at a curved radius close to r1 after treatment.

Preferably, the in-line annealed amorphous alloy ribbon is still in its amorphous state

once the thermal treatment ends. However, in another embodiment, the thermal

30 treatment temperature and time may be increased in order to reach onset
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crystallization of the alloy. The choice of treatment temperature and time can be set

to end the thermal treatment with the alloy being partially or completely crystallized.

Such use of the in-line annealing apparatus of the present invention can be

advantageous for amorphous alloys requiring crystallization annealing.

Referring now to Figure 2, the apparatus further preferably comprises a feeding

ribbon reel 9 and a take-up mandrel 10. The ribbon reel mandrel and the other

mandrel are respectively coupled via a shaft to a motor. In operation, one of the

motors rotates to adjust the ribbon speed while the other is in torque control mode to

10 regulate the mechanical tensile stress in the forwarding ribbon. Rollers 1 and 2 are

free to rotate and are driven by the ribbon acting as a driving belt and the tensile

stresses S1 and S2 are the same.

In the apparatus of Figure 1, the treatment time on roller 1 at a given ribbon feeding

rate is proportional to contact angle 81 and the cooling time on roller 2 is proportional

to contact angle 82. Referring now to Figures 3a and 3b, there are shown modified

versions of the apparatus shown in Figure 1 which provides a wider contact angle 81

or 82 by adding a small guide roller 10 rotating in parallel and in close proximity to

hot roller 1 or 2. The guide roller 10 can either be located just after the entry point 3

20 or just before the exit point 7 of the ribbon in its travelling path. In both apparatus,

the ribbon feeding and take-up mandrels can be located at a remote location. The

guide roller radius is preferably small to maximize 81 or 82. With the modified

apparatus of Figures 3a and 3b, the ribbon feeding rate can be increased while

keeping the same treatment time and temperature on hot roller 1 as for the

apparatus shown in Figure 1. In Figure 3b, 82 is also increased.

Since the stress relief action occurs mainly when the ribbon is near the treatment

temperature, no significant stress relief is occurring while the ribbon is heating up

starting from Tin

o to reach the treatment temperature as shown in Figure 7a. The full
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angular distance (81 x r1) can be employed for alleviating stresses if the ribbon

temperature Tin0 is near the treatment temperature when making contact at point 4

and preferably, in a state where structural relaxation has not made significant

progress compared to its initial structural condition characterizing its as-cast state.

This way, the treatment time on roller 1 at a given ribbon feeding rate and roller

temperature can further be increased.

In another preferred embodiment, the heating of the ribbon is performed before

subjecting the ribbon to a series of treatment configurations. It is true that the

10 structural relaxation will commence, but the heating time in the present invention is

comparable to the treatment time and, considering that the structural relaxation

progression speed increases exponentially with the reciprocal of temperature and

that the temperature is in a rising mode while being heated, no significant structural

relaxation will occur if the rising temperature gets near the treatment temperature

just a moment before the ribbon makes contact with hot roller 1. Referring now to

Figure 4a, there is shown a modified version of the apparatus of Figure 1, where a

second hot roller 11 having a radius r3 and rotating in parallel and in close proximity

to roller 1 has been added. The travelling path of the ribbon has been modified to

add the hot roller 11 in its path. Before making contact with roller 1 at point 4, the

20 ribbon makes a static contact with the hot surface of roller 11 at point 12, where it

also bends to the hot roller radius r3 and starts to heat up at a high temperature

rising rate. The ribbon is kept in contact with the hot roller surface for a given rotation

angle 83. While moving along with the hot roller 11 surface in rotation, the ribbon

temperature goes up to a temperature below or equal to the hot roller 11

temperature. At point 13, the hot ribbon breaks contact with hot roller 11 and goes

through in flat configuration to point 4 of the hot roller 1 and follows the same route

path as described for Figure 1. The resulting temperature profile is shown in Figure

7b. Preferably, while rotating along in contact with roller 11, the ribbon temperature

is constantly in a rising mode. More preferably, when breaking contact with roller 11
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PCT/CA2010/001844

at point 13, the ribbon temperature has substantially reached the treatment

temperature. The hot roller 1 heat sourcing or sinking is then adjusted to keep the

incoming ribbon at the treatment temperature while in contact for the whole rotating

angle 81. Also, the hot roller 11 is placed in close proximity to roller 1 to minimize the

travelled path length between points 13 and 4 in the flat configuration between roller

11 and roller 1. The choice of roller 11 surface temperature, outer radius r3 and

contact angle 83 is optimized to reduce temperature rising time in order to limit the

progression of the structural relaxation before reaching point 4. A reduced

temperature rising time is possible by setting the temperature of roller 11 above the

10 treatment temperature with the ribbon leaving roller 11 when its temperature gets

near the treatment temperature in order to benefit from the higher temperature rising

rate of the initial portion of the negative exponential decay (_e-X

) closely followed by

the ribbon temperature. Furthermore, any slow progressive change in the ribbon

thickness, which would affect the temperature rising rate on roller 11 and therefore

the ribbon temperature at the leaving point, can be compensated by correcting the

temperature of roller 11. Such thickness changes can be easily detected by

monitoring the power supplied to roller 1 for maintaining the treatment temperature

on the incoming pre-heated ribbon. Another way to further reduce temperature rising

time is to use more than one hot roller 11 having a smaller outer radius and being

20 disposed side by side and in parallel for pre-heating the ribbon which follows a

snaking path from one roller to the other. A ribbon snaking around multiple smaller

hot rollers will heat up alternately from each side of the ribbon and more rapidly at a

given tensile stress as the pressuring contact on a roller increases in an inversely

proportional manner with respect to its outer radius. Alternately heating from each

side of the ribbon also reduces the gradient temperature through the thickness as

compared with heating from only one side, thus offering a more uniform temperature

increasing rate through the ribbon thickness. At equivalent ribbon temperature rising

rates, smaller rollers can therefore be used to reduce the ribbon tensile stress, thus

lowering the risk of a breakage during treatment. In Figure 4b, the hot roller 11 of
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Figure 4a has been replaced by two smaller rollers 11a and 11 b of radius r3a and

r3b. With this modified apparatus, the sum of the angular distances of both rollers

11 a and 11 b, (83a Xr3a + 83b x r3b) can be made smaller than the angular distance

(83 x r3) of Figure 4a for equivalent ribbon tensile stresses as the ribbon temperature

rises more rapidly as shown in Figure 7b, thus further limiting the progression of the

structural relaxation before reaching point 4.

In the present invention, the operation of heating and cooling the amorphous alloy

ribbon by a direct static contact between one of the two side surfaces of the ribbon,

10 or alternately on each side, and along a significant peripheral portion of a thermally

conductive roller has to take into account the thermal expansion or contraction of the

alloy. When submitted to a temperature change, the alloy seeks to expand while its

temperature is rising, or to contract while its temperature is falling. This phenomenon

will create concentrated surface shearing stresses at the anchoring contact points of

the ribbon with the surface of the roller which are preventing the ribbon from slipping.

During the heating stage of the in-line annealing process, as the ribbon seeks to

expand with the temperature getting higher, the alloy viscosity drops and the

appearing surface shearing stresses are getting relieved with increasing flow.

Therefore, no significant surface shearing stresses will build-up while the ribbon is

20 heating up. However, this is a different story at the cooling stages using cold rollers.

As the temperature is falling, the ribbon seeks to contract while its viscosity

increases rapidly. This will introduce increasing concentrated surface shearing

stresses which can cause collapsing of the anchoring contact points and therefore

an abrasive wear of the surface of the cold roller will occur. In the present invention,

this abrasive wear problem can be significantly attenuated by snaking the ribbon

through multiple cold rollers over a series of small angular distances (8 x r) during

the decrease in the ribbon temperature as shown in Figure 5. Jumping over multiple

cold rollers will null the accumulating concentrated shearing stresses at each jump

before they get to a point on the roller where the abrasive wear becomes a serious
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problem. If cold rollers are used in the second cooling stage, their number and each

angular distance (8 x r) may be chosen according to a maximum admissible

temperature drop LlTo on each roller as shown on Figure 7c and on the final

temperature TFO at which the ribbon will be taken-up on a mandrel. As for cold roller

2 in Figure 1 to 5, it is preferable to minimize the angular distance (82 x r2) until the

ribbon temperature ToutO, when leaving the roller at point 8, has dropped sufficiently

below the treatment temperature to allow further ribbon handling while continuing to

cool down without provoking further significant detrimental stress relief, otherwise

avoidable abrasive wear will occur if dropping further below that point. Also,

10 repetitively nulling the accumulating concentrated surface shearing stresses will

attenuate introduction of residual stresses which contribute in deteriorating the

magnetic properties of the ribbon after treatment.

Referring now to Figure 6a, there is shown a modified version of the apparatus

shown in Figure 1 which is used for in-line annealing an amorphous alloy ribbon that

will show maximum stress relief after treatment at a programmable radius ra. The

controlling of the flow sequence occurring in the alloy at the treatment temperature is

modified by further bending the ribbon on an additional roller rotating in contact with

the forwarded ribbon along the thermal treatment path. The apparatus further

20 comprises a roller 14 having a predetermined radius r4 and contacting the ribbon

somewhere between point 5 and point 6 and parallel to rollers 1 and 2. While going

from roller 1 to roller 2, the ribbon bends backwards on roller 14 on a contact angle

84 to relieve bending stresses opposite to the treatment bending side on roller 1.

Depending on ribbon thickness and feeding rate, the choice of rollers' radius r1, r2

and r4, the temperature of rollers 1, 2 and 14 and the covering angle 81, 82, 84 are

determined in order to obtain a cooled alloy ribbon showing maximum alleviated

stress when bent to a radius ra greater than r2 after treatment. The radius ra can be

programmed by either displacing roller 14 perpendicularly against the ribbon or by

displacing roller 2 around roller 14 to increase or decrease the contact angle 84.
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This way, an amorphous ribbon could be in-line annealed to a radius ra progressively

increasing as material is forwarded and contacting angle 84 is increased in order to

match the increasing bending radius when it is rolled to form a circular core.

Referring now to Figure 6b, there is shown an apparatus of the present invention

which is used for in-line annealing an amorphous alloy ribbon in a flat configuration.

This apparatus is similar to the apparatus shown in Figure 6a, but configured to inline anneal the ribbon at an infinite radius ra. Roller 1 serves mainly to heat up the

ribbon in a similar manner as explained for roller 11 in Figure 4a. When the ribbon

10 breaks contact with hot roller 1 at point 5 and at the treatment temperature, it

progresses forward at high speed in a flat configuration for a predetermined distance

before making contact at point 15 with roller 14. In this case, the desired stress relief

is occurring while travelling at the treatment temperature in a flat configuration

towards roller 14. The flat configuration treatment time becomes a function of the

ribbon travelling distance from point 5 to point 15 at a given ribbon feeding rate. The

required flat configuration treatment time is very short in respect to the temperature

decay time constant while travelling from point 5 to 15, so that no significant

temperature drop will have occurred when point 15 will be reached. Although the flat

treatment zone of the ribbon could be located within a furnace to maintain

20 temperature, this is not necessary in the present invention. When the hot ribbon

touches roller 14, added bending stresses are relieved. The added relieved bending

stresses will then be reverted when it will be bent backwards at initial cool down on

cold roller 2. Preferably, roller 14 and roller 2 are in close proximity. Depending on

ribbon thickness and feeding rate, the choice of radius r2 and r4, the temperature of

roller 2 and 14, the covering angle 82 and 84 and the travelling distance between point

13 and 15 are determined in order to obtain a cooled alloy ribbon showing maximum

alleviated stress in a flat configuration.
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The apparatus of the present invention shown in Figures 1 to 6 are best suited to inline anneal in a normal atmosphere an amorphous alloy ribbon such as iron-based

Metglas 2605SA1 and 2605HB1 under an applied tensile stress with post-annealing

limited or no acquired embrittlement. Magnetic properties of amorphous alloy ribbons

2605SA1 and 2605HB1 have been greatly improved after they were in-line annealed

at high speed with the apparatus of the present invention. Magnetic performances of

rolling-up-after-annealing circular cores compare favourably to circular cores

processed using the conventional field furnace anneal,ing method.

10 Referring now to Figures 9 to 13, there is shown a detailed construction of a hot

roller. The hot roller comprises an inner heat source ring 16 and an outer cladding

heat diffuser ring 17 rotating together around a central axis 13. The outer cladding

ring 17 is made of a good thermal conductive material, such as copper, and has a

predetermined thickness e2. If the chosen material is prone to severe oxidation at

high temperatures which eventually leads to mechanical degradation, as it is the

case for copper, its exposed surface may be plated with a thin metal film 17a having

a substantial stainless property, such as nickel, to protect its surface from severe

oxidation. The inner ring 16 is made of an electrically resistive conductor material.

The electrical resistive conducting nature of the inner ring 16 serves as a means to

20 produce heat by a joule effect of circulating currents. Ring 16 could be omitted if a

burning flame would be used to heat the thermal diffuser from underneath. With ring

16, such produced heat may be generated by an electrical self heating element ring

16 provided with two electrical conductors that are connected outside of the ring to a

current source via a pair of sliding contacts located somewhere along the ring

rotating axis 13. Preferably, the inner ring 16 is made of an electrically resistive

conductor material such as stainless steel, and has a predetermined thickness e1.

To provide an efficient heat transfer and from the inner ring 16 to the outer cladding

ring 17, preferably, the outer cladding ring 17 is welded or is build up on ring 16 by

using an electroplating process after which the outer surface of the ring 17 is

30 machined. Heat can also be produced by electrical induced internal AC currents
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which are looping in the ring. The current loops are induced by a high frequency

fluctuating magnetic field produced with an induction heating antenna 18 and are

looping following the circular path delimited by the ring 16. The induction heating

antenna 18 is essentially made of insulated copper tubing which is cylindrically

coiled, aligned, centered and fixed within the hollow portion of ring 16 and which is

also separated from it by an air gap 18a. Coolant is allowed to flow within the

antenna copper tubing to evacuate the coil conducting joule losses. Preferably, the

thickness e1 of ring 16 is greater than the skin depth of the induced AC currents at

the antenna power supply frequency. The copper cladding thickness e2 is chosen to

10 be thick enough so to act as a thermal diffuser to ensure uniform heat distribution

and transfer from the heated inner ring 16 to the ribbon in contact with the outer

cladding ring 17. The two-ring assembly 19 has a much greater thickness when

compared to the ribbon thickness and serves, with its thermal inertia, as a heat

buffer reservoir to level the temperature all around the periphery when heating a

ribbon that is moving along in contact with the roller surface in rotation. The two-ring

assembly 19 is at least as wide as the ribbon width. To support the two-ring

assembly in rotation, extending thin tube walls 20 having a thickness e3 protrude

from both sides of the inner ring 16. The tube walls 20 are preferably made of a poor

thermal conducting material such as stainless steel and the wall thickness e3 is

20 made sufficiently thin to limit heat leakage towards the tube walls opposite

extremities but, is made sufficiently thick to support the pulling forces exerted by the

ribbon in tension on the roller surface in order to maintain concentricity while the

roller is rotating. The tube walls opposite extremities each have a thicker wall 21 for

receiving holding flanges 22. If the tube walls 20 material are made of stainless

steel, as it is preferably the case, induced current loops will extend beyond both

sides of the inner ring 16. This side effect will generate parasitic heat within the tube

walls. Therefore, the tube walls 20 are provided with axial periodically spaced slots

23, slotted from the edges of both sides of the stainless steel ring 16 on a length

long enough to break the circular path loop for induced current to flow through within

30 the vicinity of the two-ring assembly 19. Moreover, these slots create finger-like
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supporting means for holding both sides of the two-ring assembly and which can

bend radially to accommodate thermal radial expansion of the two ring assembly 19

while keeping it concentric with the rotating axis. As shown in Figures 12 and 13,

each side flange 22 comprises a hollow shaft 24 supported on bearing 25 which is

inserted in an opening of wall 27. In an inverted version, the opening 26 may be

localised in flange 22 with shaft 24 being incrusted in wall 27. To allow the axial

thermal expansion of the two-ring assembly 19 and of the tube walls 20, a spring 28

is inserted on the shaft 24 between flange 22 and bearing 25, and the shaft and

bearing are allowed to slide one onto the other. The induction heating antenna 18 is

10 supported in its central hollow portion by the supporting means 29 which is attached

to the shaft 30 that passes freely through the hollow portion of the shaft 24 in order

to be held from outside of the roller by the plate 31 which is secured on the

supporting structure wall 27. The two insulated copper tubing ends 18a and 18b of

the induction heating antenna 18 extend freely through the opposite hollow shaft 24

to reach the HF electrical AC power supply. Therefore, the hot roller is allowed to

rotate on both supporting bearings while the induction heating antenna 18 remains

fixed without physical interference with the hot roller.

Referring now to Figure 14, there is shown a cut view of a detailed construction of a

20 cold roller. The cold roller comprises a thermal conducting ring 32 having a thickness

e4 and being supported by side flanges 33. The junctions between the thermal

conducting ring 32 and the flanges 33 are provided with a seal 34. The cold roller

also comprises an inner part 35 having an outer cylindrical surface 36 centered

within the hollow portion of the thermal conducting ring 32 and from which it is

separated by a small gap. The inner part 35 is held by the two side flanges 33 with

attaching means. The side flanges 33 are each provided with a central recess to

insert and hold the outer rotating part of a bearing 37. The side flanges 33 also

comprise a tube tip 38 protruding from the center of the flange to allow a coolant to

pass through. At least one opened path link 39 is provided within both extremities of

30 the inner part 35 to allow the coolant flowing in the tube tip to reach the gap.
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Therefore, coolant entering in one of the two tube tips 38 will be guided through the

gap in contact with the inner surface of the thermal conducting ring 32 to exchange

heat. Then, the coolant follows its way out via the other tube tip at the opposite

flange location. The cold roller assembly is supported by the inner rotating part of the

bearings 37 on two hollow shafts 40 fixed to a wall structure. The tube tip 38 rotates

in the hollow portion of the shaft 40 separated from the shaft inner wall by a sliding

seal 41. Preferably, the coolant fluid is water. A higher ribbon cooling rate can be

obtained using a sub-zero temperature fluid such as glycol.

10 In the cold roller of Figure 14, the ribbon falling temperature is quicker on one side of

its edge as the coolant is getting hotter while flowing underneath the thermal

conducting ring 32 from one side to the other. Referring now to Figures 15a and 15b,

there is shown a modified version of the cold roller that distributes incoming coolant

uniformly underneath the thermal conducting ring 32. The central portion 36 has

been replaced by a stack of thin disc separators 42 spaced apart by spacers 43 and

43a. The disc separators 42 diameter is slightly smaller than the thermal conducting

ring 32 inner diameter in order to create a small gap 44. The spacers 43 and 43a

have a smaller diameter than the discs 42 to create a gap 45 for distributing to and

collecting coolant from gap 44. Two series of parallel aligned openings 46 and 47

20 are perforated through the center portion of the stacked arrangement with each of

the spacers having a transverse opening 48 between the corresponding gap 45 and

one of the two parallel openings in an alternate stacked order. The parallel and

transverse openings 46, 47 and 48 then form two manifolds, one intake and one

outtake. Two spacers 43a are respectively located at both ends of the stacked

arrangement to connect each tube tip 38 to a corresponding manifold which will

allow coolant flowing in one tube tip 38 to be distributed via the outtake manifold in

one out of the two gaps 45 and to reach the inner wall of the thermal conducting ring

32. The coolant will then return to the intake manifold via the small gap 44 and the

corresponding gaps 45 and will exit the roller via the tube tip at the other extremity of

30 the roller.
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When processing a ril;>bon unrolled from a reel, the ribbon may travel with some

sideways instability due to some factors like the sourcing reel being warped. If the

ribbon necessarily has to pass by a precise location on a roller, as required on a hot

roller of the present invention, a mechanism must be used to fix the ribbon trajectory.

Preferably, the present invention further comprises a device to deliver a ribbon at a

precise location on a guiding roller.

Referring to Figure 16, there is shown a pivoting roller 115 rotating on an axis 118

10 and provided with two guiding side flanges 116 that are each inclined and which are

separated by a distance just slightly greater than the ribbon width. The roller 115

also has a swivel axis 117 tangential to its peripheral surface and located at midpoint

between the flanges 116. The ribbon is guided onto the roller surface over a given

angle a up to the tangential point with the swivel axis where it exits. The travel

trajectory is best corrected if the ribbon entry point on the roller is at 180 degrees

with respect to the exit point. From an observer view point looking at the roller from

the left as shown in Figure 16, a ribbon entering the roller with some sideways

instability (for example: ribbon axis fluctuating back and forth from position in1, in2,

in3) will swivel the roller by pushing on the roller flanges with its edges so that the

20 entry point will continuously be aligned with the incoming ribbon axis, and the

outgoing ribbon will always exit the roller on the same axis (out1, out2 and out3

aligned together). The radius of the swivel guiding roller is chosen in relation to the

ribbon width and to the magnitude of the lateral instability. A bigger roller diameter

will swivel less to correct the same sideways instability. When the roller swivels, the

incoming and outgoing portions of the ribbon will slightly twist on their axis.

Therefore, the swivel roller must be located at some distance from other guiding

rollers in order to allow some free space for the ribbon to slightly twist as it

approaches or exits the roller as shown on Figure 17.
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When processing a ribbon at a high feeding rate with an added tensile stress, trying

to control said tensile stress by controlling the torque on the unrolling source reel

and the torque on the rolling up take-up mandrel as shown in Figure 2 is less

convenient because of the following reasons: large quantity of rolled up material

have a high inertia; a ribbon loosely rolled up on a mandrel may suddenly slip when

unrolled with a tensile stress; and it may be desired to roll up the ribbon at a lower

tensile stress than required for treatment to limit the tightening radial force

accumulating in the rolled up ribbon. Preferably, the present invention comprises an

10 apparatus to drag a ribbon and to change the mechanical tensile stress in a

forwarding ribbon at a passage point in its traveled path. The drag and tensioning

system uses the static friction between two surfaces in contact with each other.

The ratio of the maximum applicable force Fs that can be applied on an object

leaning on a surface without slipping to the normal force Fn exerted by the object on

the surface is the coefficient of static friction J.ls. As long as the applied force is

inferior to Fs, the object will not move.

20

The static frictional force also acts on a ribbon surrounding the outer perimeter of a

wheel over an angle 0 with a tensile force. Figure 18a illustrates this situation. In this

case, we are assuming that the wheel cannot rotate. Two tensile forces, Fin and Fout,

of different values are exerted on the ribbon on either side of the wheel. By these

forces, the ribbon strangles the wheel and also exerts a normal force to the surface

of the wheel that puts in action the mechanism of static friction. As for the object on a

surface, the difference of the two forces is opposed by a static friction force of same

amplitude between the wheel and the ribbon surfaces that prevents the ribbon from

slipping. When the difference in applied forces reaches the static frictional limit force,
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the ribbon starts to slip on the wheel. The maximum exerted forces between the

input and the output closely follows this equation:

F - F ef-LS¢

out - in

Therefore, for two tensile forces exerted on the ribbon on either side of the wheel

over an angle 0, the ribbon will start to slip when the output force will be superior to

F out for a given input force Fin and static coefficient of friction Jls. The tensile force in

the ribbon along the surface of the wheel will have an exponential profile as shown in

10 Figure 18b. This is known as the capstan effect.

Static frictional capstan drives are used in the present invention to drag the ribbon at

a high travelling speed either to control its speed or to increase or reduce the

mechanical applied tensile stress. The dragging apparatus allows:

1. Smoother tensile stress transition.

2. Uniform distribution of the applied tensile stress along the width of the ribbon.

3. Precise control on the added tensile stress amplitude.

4. Precise control of the ribbon feeding rate.

5. The amplitude of the desired added tensile stress can be independent from

20 the static friction coefficient.

1. Smoother Tensile Stress Transition

Any attempts to increase the tensile stress in a forwarding and tense thin alloy

ribbon within a short distance on a point along a travelled path will create a

continuous step up stress transition level on the ribbon material. If the ribbon is

forwarded at great speed, the transition time will be very short and, if the added

tensile stress is high, the ribbon will be submitted to a strong mechanical shock and

therefore risks breakage. In the present case, a tensile force is gradually added
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along the covering angle of the capstan wheel in contact with the ribbon. Therefore,

the stress step-up transition time can be considerably increased by using either a

large diameter capstan wheel or by using multiple cascaded smaller capstan wheels,

thus ensuring a continuous high speed reliable feeding of a tight ribbon.

2. Uniform Distribution of the Applied Tensile Stress along the Width of the

Ribbon

For large ribbons, uniformly distributing the increasing tensile stress along the width

10 of the very thin ribbon is necessary. For high tensile stresses, a non-uniform

distribution of the stress combined to any potential physical defects, like a small

inclusion at the ribbon edge, can tear the ribbon apart from the edge. With the

capstan drive, the ribbon lies on a uniform surface and the tensile stress is

progressively added over a significant length, thus avoiding any significant

imbalance of tensile forces along the width of the ribbon.

3. Precise Control on the Added Tensile Stress Amplitude

The added tensile stress on the ribbon is performed by applying a clockwise or

20 counterclockwise torque on the capstan wheel. High precision torque can be easily

provided by a torque regulated electrical motor mechanically coupled to the capstan

wheel axis of rotation.

4. Precise Control of the Ribbon Feeding rate

By using a capstan wheel in static friction mode with the ribbon, the wheel surface

tangential speed is synchronised with the ribbon feeding rate. It is therefore easy to

precisely control the ribbon feeding rate by controlling the capstan wheel rotating

speed. In a system where a ribbon is unrolled from a reel to another while following a

30 path through a series of rollers and capstan static friction drives, it is possible to
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control the feeding rate of the ribbon if rotation of one of the capstan drives is speedcontrolled and that all other drives are torque-controlled. The speed control of the

capstan wheel can easily be performed using a speed controlled motor drive

mechanically coupled to the wheel axis of rotation.

5. The Amplitude of the Desired Added Tensile Force can be Independent from

the Static Friction Coefficient

Regardless of the coefficient of static friction, any amount of tensile stress can be

10 added or subtracted from a point along the path of the forwarded ribbon. The

maximum tensile stress that can be applied for a given coefficient of static friction is

limited by the number of capstan wheels encountered by the ribbon on its travelling

path.

Figures 19a/19b and 20a/20b show examples of a static friction capstan drive used

for adding or subtracting a tensile stress on a forwarded amorphous alloy ribbon

having a given tensile stress. The capstan wheel is made of aluminum and its outer

periphery is covered with rubber to increase the coefficient of static friction. Two

rollers are placed side by side near the outer periphery of the capstan wheel to guide

20 the ribbon in and out of the wheel surface.

Referring to Figure 21, there is shown a static capstan ribbon drive apparatus to

impose a mechanical tensile stress Sc between an incoming ribbon having an input

tensile stress SIN and the outgoing ribbon having an output tensile stress SOUTo The

apparatus comprises two capstan static friction driving wheels 110 each provided

with a pair of guiding rollers 112. Preferably, the outer surface periphery of each

capstan wheel is covered with a high friction coefficient material such as silicon

rubber. The incoming ribbon is guided by the guiding rollers 112 to wrap around

each capstan wheel 110 over the maximum covering angle possible. Each capstan

30 wheel is mounted on a shaft of a motor. To control Sc, the shaft torque Trq1 is
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adjusted to produce a tangential force at the radius r of the wheel that will be added

on the incoming ribbon having an input tensile stress SIN in order to get the desired

tensile stress Sc once the ribbon exits from the capstan wheel. The tensile stress is

changed again to an output value SOUT by passing over the second capstan wheel,

in which the shaft torque is adjusted to Trq2. For example, to increase the tensile

stress on a ribbon between the two capstan wheels, a positive counterclockwise

Trq1 and a clockwise torque Trq2 is required. For ribbons travelling at high speeds,

multiple capstan wheels are used as shown in Figure 22. The ribbon travels in a

snake path around the wheels, each driven by a fraction Trq1 (a-d) of the total torque

10 Trq1 in order to add the tensile stress in a series of smaller steps. Use of multiple

capstan wheels for decreasing the tensile stress is not necessary as the ribbon can

easily withstand a sudden step down in tensile stress. Referring back to Figure 1 to

6, any of the rollers included in the in-line annealing apparatus can be provided with

a shaft coupled directly or via a drive-belt to a motor to add or subtract a tensile

stress on the guided ribbon. It has been found that the reduced viscosity at elevated

temperature of an amorphous alloy ribbon significantly increases the friction

coefficient with the roller surface it is in contact with. Therefore, the tensile stress

within the ribbon can be changed along the treatment path by applying a torque on

rollers 1, 2 11 or 14 to improve annealing and the magnetic the properties of the

20 alloy.

Figure 23 discloses an apparatus to continuously in-line anneal a ferromagnetic alloy

ribbon unrolled from a reel 136 which will then be rolled up on a mandrel 135. The

apparatus comprises: two tensioner rollers 130; an apparatus to laterally reposition

an incoming ribbon 131; a first drag and tensioning system for a moving thin ribbon

132; an apparatus to in-line anneal a forwarding ribbon 133; a second drag and

tensioning system for a moving thin ribbon 134; and a take up mandrel 135. A

tensioner roller 130 is commonly used in the art for providing easier control on the

tension of a ribbon unrolling from or rolling up on a large roll of ribbon. Preferably,
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the feeding rate of the ribbon within the apparatus is controlled by controlling the

capstan wheel rotating speed in the drag and tensioning system 134.

Preferably, the in-line annealing process of Figure 23 includes an automated ribbon

switcher to provide uninterrupted forwarding of ribbon at the entry of the treatment

process, and continuous rolling up onto take-up mandrels of outgoing treated ribbon.

Continuous forwarding of ribbon can be provided by bringing a new reel of ribbon in

rotation in proximity of the emptying reel, and by launching and welding the ribbon

end of the new reel to the trailing end of the ribbon leaving the emptying reel.

10 Continuous rolling up of outgoing treated ribbon can be provided by bringing a new

mandrel in rotation in proximity of the filling mandrel, and by cutting the ribbon and

fixing the incoming ribbon end to the new mandrel while the filled mandrel is moved

away.

A prototype was built according to the above-described in-line annealing process of

Figure 23 to process a one-inch wide amorphous alloy ribbon at a constant ribbon

feeding rate. Referring now to Figure 24, there is shown the detailed configuration of

the in-line annealing setup 133. It comprises two identical hot rollers 1 and 11 built

using wall thickness e1 and e2 of 100 mils and e3 of 25 mils. The heat source two20 ring assembly 19 is 1.10 inches wide and the roller outer radius is 3 % inches. The

slotted walls 20 are a few inches long on both sides of the two-ring assembly 19 and

are supported on flanges and bearings. Figure 11, 12 and 13 are scaled perspective

and cut views of the hot roller built according to the present invention. Both hot

rollers are located in order to be separated by a gap smaller than 1/32 inch when

hot. Each hot roller comprises an induction antenna connected to a HF power

supply operating respectively at a frequency of 80 kHz and 150 kHz to avoid

magnetic coupling interferences between proximity antennas. The hot roller 11

acting as a ribbon heating roller could also be disabled just by shutting off its

corresponding HF power supply if no pre-heating was desired, in which case it was

30 simply used as a guiding roller. The setup also comprises two cold rollers 2 and 51.
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Cold roller 2 has a 5/8 inch radius and is used for first stage cooling. Cold roller 51

has a 3 inches radius and is used for the second stage cooling to bring the

temperature towards or above the water temperature. The ribbon leaving roller 51

will be taken-up on a mandrel where it will slowly go back to normal room

temperature. Both rollers were supplied with cooling water at 20 degrees Celsius.

When snaking the ribbon around roller 1 and 2, the contact angle 81 on the hot roller

1 is near 210 degrees and 82 on cold roller 2 is near 120 degrees. A first infrared

pyrometer 49 was installed to measure the ribbon temperature just after leaving

roller 1. A second infrared pyrometer 50 was also installed to measure the

10 temperature on the outer surface of the pre-heating roller 11. The pyrometers were

connected to a computer used as a controller to adjust the antennas respective input

power in order to read the desired temperature at each pyrometer. When pre-heating

on roller 11 was activated, the roller temperature and the contact angle 83 were

adjusted by relocating a guide roller 10 around roller 11 until the rising temperature

reached the treatment temperature a few angular degrees before reaching exit point

13. The treatment temperature was then maintained on hot roller 1. The treatment

setup of Figure 24 is intended to in-line anneal an iron-based amorphous ribbon in a

curved shape having a natural bending radius in a rest position close to 3 Yt inches

after treatment. Such a bending radius is close to the average bending radius found

20 in a circular core of a 25 kVA distribution transformer as disclosed in US patent

5566443. The ribbon was unrolled at a tensile stress of a few MPa from a source

reel and forwarded at different feeding rates snaking around four capstan wheel

drives to increase the ribbon tensile stress to S1 before going through the treatment

and then, after leaving treatment at the same tensile stress S2 = S1, it went over one

capstan wheel drive to reduce the ribbon tensile stress to a few MPa before being

taken-up on a mandrel. All source reel mandrel, rolling mandrel and capstan wheels

were coupled to motors controlled by a drive system and a main computer. The

whole setup including motors and drives, except for the HF power supplies and

computer, was mounted on a 4' x 8' table, thus illustrating the compactness of the
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apparatus of the present invention. Figures 7a and 7b give the two temperature

approximate profiles that the ribbon was subjected to while moving along its

travelling path within the setup. In Figure 7a, no pre-heating on roller 11 is

performed. The ribbon is heated and treated only on hot roller 1. For a given ribbon

tensile stress, the heating rising time interval is independent of the ribbon feeding

rate. Therefore, for high feeding rates, the heating temperature rising time will start

to dominate as the time period the ribbon rotates along the surface of hot roller 1

gets shorter (due to the increasing feeding rate) and therefore leaving less time for

the treatment time interval on roller 1 to act. The ribbon will have an upper feeding

10 rate limit where the treatment efficiency on roller 1 dramatically deteriorates. In

Figure 7b, the added pre-heating roller 11 eliminates the heating time interval from

the time period the ribbon rotates along the surface of hot roller 1 which now serves

exclusively for treatment. This setup will push-up the ribbon feeding rate limit for a

treatment time on roller 1 identical to the situation in Figure 7a if the initial cool down

on roller 2 is sufficient to end the thermal treatment.

Series of treatments at applied different tensile stresses (S1 =S2) ranging from 25 to

200 MPa and at different treatment temperatures above 400DC and feeding rates

ranging from 1 to 5 m/sec were conducted with the apparatus on the amorphous

20 alloy ribbon Metglas 2605SA1 and 2605HB1 supplied by Hitachi-Metals. At 1 m/sec,

the thermal treatment was lasting less than a second in the built apparatus. At 5

m/sec, the thermal treatment was lasting less than one tenth of a second. During

treatment, it is desired to subject the ribbon to the smallest tensile stress which

provides acceptable magnetic properties improvements, as further increasing the

tensile stress will only increase the risk of rupturing the ribbon. The heating

temperature rising rate starting at tensile stresses of 25 MPa and at the hot roller

mentioned diameter was found to be greater than 103 DC/sec, above 104 DC/sec at

about 75 to 125 MPa, therefore showing the high heat transfer capacity of the

pressure static contact of the thin ribbon on the hot roller. For the first cooling stage,

30 the temperature falling rate was found to be greater than 104 DC/sec and close to 105
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°C/sec on cold roller 2. Following the treatment, the natural bending radius in a rest

position was measured. Then, approximately 1 kg of the treated material was rolled

at a chosen tensile stress on a stainless steel hub having an outer radius of 2.9

inches. With the amount of rolled up material, the final circular core had a mean

radius at about 3 }4 inches, which is close to the radius of roller 1 in the apparatus of

Figure 24. The rolled up ribbon was then placed in a circular shell and two copper

wires were coiled around the shell to form a drive and a sense coil. The shell served

as a support frame for the coils to avoid any outside stress to be applied onto the

core. The drive and sense coil were then connected to a Walker Scientific AMH-25

10 instrument which serves to characterize the magnetic properties of coiled

ferromagnetic cores. Before performing a measurement, parameters related to the

circular core net cross sectional area and mean path length, the drive and sense coil

respective turns and the material density, were entered in the instrument software.

The sample was then magnetized with a sinusoidal magnetic induction waveform at

a frequency of 60Hz. From the recorded hysteresis loop, the following parameters

were computed: the material core loss; the exciting power; and the peak magnetic

field, all at specific magnetic induction levels and, the Bso and Bso/Bsat ratio were

noted. Significant effects of the thermal treatments on the amorphous alloys were

ob~erved at treatment temperatures above 425°C.

20

For the Metglas 2605SA1 material, good results were obtained at treatment

temperatures above 425°C, more preferably above 450°C, more preferably at about

480°C, and increasing with ribbon feeding rate. Going beyond this temperature until

onset crystallization was reached and at the corresponding feeding rate did not

provide further significant improvements to the magnetic properties of the alloy. It

rather unnecessarily prolonged structural relaxation, which was detrimental to the

ductility of the ribbon. An efficient induced magnetic anisotropy was obtained at

tensile stresses between 25 and 200 MPa, preferably between 75 and 125 MPa.
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For the Metglas 2605HB1 material, an efficient induced magnetic anisotropy was

obtained at tensile stresses between 25 and 200 MPa, preferably between 50 and

100 MPa. Low core loss was obtained at treatments temperatures above 400°C,

more preferably above 425°C, more preferably at about 455°C. Going beyond this

temperature until onset crystallization was reached and at the corresponding feeding

rate did not provide further significant improvements to the magnetic properties of

the alloy. It rather unnecessarily prolonged structural relaxation, which was

detrimental to the ductility of the ribbon. Also, core loss was tending to reduce as the

ribbon feeding rate was increased along with the treatment temperature, showing the

10 advantages of a higher and short lasting treatment temperature.

When onset crystallization was reached for both alloys, the degree of crystallization

was dependant on the adjusted treatment temperature above onset crystallization

thus, making possible to use the treatment process of the present invention to initiate

and control the degree of crystallization in an amorphous alloy ribbon.

The following examples taken from the series of conducted treatments show the

benefits of the present invention to improve magnetic properties of amorphous alloy

ribbon such as the 2605SA1 and 2605HB1.

20

Example 1:

Material: Metglas 2605SA1

Ribbon feeding rate: 2.0 meters/sec

Ribbon applied tensile stress: 100 MPa

No pre-heating

Treatment temperature: 480°C

Natural bending radius after treatment: between 3.0" to 3.5"

Ribbon rolled up tensile stress: 5 MPa

30 Core weight: 1.04 kg (excluding hub)
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Core inner diameter: 5.80 inches (excluding hub)

Core outer diameter: 6.83 inches

Core loss @ 1.3 Tesla, 60Hz: 0.20 W/kg

Exciting power @ 1.3 Tesla, 60Hz: 1.76 VAlkg

Peak magnetic field @ 1.3 Tesla, 60 Hz: 80 Aim

Bao: 1.3 Tesla

Bao/Bsat: 0.83

Example 2:

10

Material: Metglas 2605SA1

Ribbon feeding rate: 5.0 meters/sec

Ribbon applied tensile stress: 100 MPa

Pre-heating angle 83: near 180 degrees

Pre-heating roller temperature: 485°C

Treatment temperature: 485°C

Natural bending radius after treatment: between 3.0" to 3.5"

Ribbon rolled up tensile stress: 5 MPa

Core weight: 1.04 kg (excluding hub)

20 Core inner diameter: 5.80 inches (excluding hub)

Core outer diameter: 6.83 inches

Core loss @ 1.3 Tesla, 60Hz: 0.20 W/kg

Exciting power @ 1.3 Tesla, 60Hz: 2.37 VAlkg

Peak magnetic field @ 1.3 Tesla, 60 Hz: 97 Aim

Bao: 1.27 Tesla

Bao/Bsat: 0.81

Example 3:

30 Material: Metglas 2605HB1

PCT/CA2010/001844
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65

Ribbon feeding rate: 2.0 meters/sec

Ribbon treatment applied tensile stress: 75 MPa

Treatment temperature: 455°C

No pre-heating

Natural bending radius after treatment: between 3.0" to 3.5"

Ribbon rolled up tensile stress: 5 MPa

Core weight: 1.04 kg (excluding hub)

Core inner diameter: 5.80 inches (excluding hub)

Core outer diameter: 6.83 inches

10 Core loss @ 1.3 Tesla, 60Hz: 0.14 W/kg

Exciting power@ 1.3 Tesla, 60Hz: 0.19 VAlkg

Peak magnetic field @ 1.3 Tesla, 60 Hz: 6.6 AIm

Core loss @ 1.4 Tesla, 60Hz: 0.18 W/kg

Exciting power @ 1.4 Tesla, 60Hz: 0.35 VAlkg

Peak magnetic field @ 1.3 Tesla, 60 Hz: 16.2 AIm

Core loss @ 1.5 Tesla, 60Hz: 0.22 W/kg

Exciting power @ 1.5 Tesla, 60Hz: 1.56VAlkg

Peak magnetic field @ 1.3 Tesla, 60 Hz: 80 AIm

Bao: 1.5 Tesla

20 Bao/Bsatt: 0.91

Example 4:

Material: Metglas 2605HB1

Ribbon feeding rate: 5.0 meters/sec

Ribbon treatment applied tensile stress: 75 MPa

Treatment temperature: 460°C

Pre-heating angle 83: near 180 degrees

Pre-heating roller temperature: 460°C

30 Natural bending radius after treatment: between 3.0" to 3.5"

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Ribbon rolled up tensile stress: 5 MPa

Core weight: 1.04 kg

Core inner diameter: 5.80 inches (excluding hub)

Core outer diameter: 6.83 inches (excluding hub)

Core loss @ 1.3 Tesla, 60Hz: 0.13 W/kg

Exciting power @ 1.3 Tesla, 60Hz: 0.17 VA/kg

Peak magnetic field @ 1.3 Tesla, 60 Hz: 6 A/m

Core loss @ 1.4 Tesla, 60Hz: 0.18 W/kg

Exciting power @ 1.4 Tesla, 60Hz: 0.33 VA/kg

10 Peak magnetic field @ 1.4 Tesla, 60 Hz: 15 A/m

Core loss @ 1.5 Tesla, 60Hz: 0.22 W/kg

Exciting power @ 1.5 Tesla, 60Hz: 1.55 VA/kg

Peak magnetic field @ 1.5 Tesla, 60 Hz: 80 A/m

Bao: 1.5 Tesla

Bao/Bsat: 0.91

PCT/CA2010/001844

The core loss and exciting power measured on the above circular cores made with a

rolled up ribbon in-line annealed at 5 m/sec are set forth in table 1 with those

reported by the alloy manufacturer with field furnace annealing. Core loss for field

20 furnace annealed 60g SA1 and HB1 toroidal samples was reported in a table by the

alloy manufacturer in an article entitled "Advances in Amorphous and

Nanocrystalline Magnetic Materials", by Ryusuke Hasegawa in Journal of

Magnetism and Magentic Materials, 2006, vol. 304, 187-191, Table 2. Exciting

powers for furnace annealed rectangular-wound-cut cores weighting 73 kg for SA1

and 75 kg for HB1 samples were deduced from plotted curves traced by the alloy

manufacturer in an article entitled "Audible Noise From Amorphous Metal and Silicon

Steel-Based Transformer Core", by Daichi Azuma and Ryusuke Hasegawa in IEEE

Transactions on Magnetics, vol. 44, no. 11, 4104-4106, Figures 2 and 4. By

comparison, rolling-up-after-annealing cores produced with the present invention

30 using Metglas 2605SA1 and 2605HB1 amorphous alloys are showing significant
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lower core loss, especially for 2605HB1. Exciting power is lower up to 1.4 Tesla but

higher at 1.5 Tesla. The Bao/Bsa! ratio remains higher for furnace annealed cores

compared to the present roll of in-line annealed ribbon due to introduction of some

allowed stresses in the roll.

The examples disclosed above show the efficiency of the method and apparatus of

the present invention to in-line anneal an iron-based amorphous in a post-treatment

state which is usable for making rolling-up-after-annealing cores having: reduced

core loss compared to conventionally field furnace annealed cores; low exciting

10 power; a Bao greater than about 1.3 Tesla; and a Bao/Bsa! greater than 0.80. The

2605HB1 alloy has an even better Bao/Bsa! ratio which is greater than 0.90. As it can

be observed, the optimal treatment temperature differs for the 2605SA1 and

2605HB1 at equivalent ribbon feeding rates. This difference is linked to the alloy

composition. The optimal setting of the treatment temperature in the present

invention is therefore dependant on the alloy composition.
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B= 1.3T B = 1.4T B = 1.5T

60Hz 60Hz 60Hz

W/kg VA/kg W/kg VA/kg W/kg VA/kg

2605SA1 0.27 -0.4

Furnace annealed

2605SA1 0.20 2.37

present invention

2605HB1 0.24 ~0.4 0.29 0.5 0.38 1.0

Furnace annealed

2605HB1 0.13 0.17 0.18 0.33 0.22 1.55

present invention

Table 1

Examples shown above were conducted on a test bench where the ribbon feeding

rate was limited by some of its mechanical and electrical elements rather than by the

geometric configuration of the hot and cold rollers. With the high cooling rate

obtained in the present invention on cold roller 2, in-line annealing a ribbon at

feeding rates up to 20 m/sec is expected with the above test bench by adding a

second hot roller 11 and a second cold roller 51, if required. Also, an apparatus to in10 line anneal a ribbon for larger circular cores will require scaled-up rollers. As the

annealing treatment is mainly a function of temperature and time, a scaled-up design

will allow a proportional ribbon feeding rate increase. For example: if a similar setup

as shown in Figure 24 was used for in-line annealing a ribbon in a curved shape

having twice the final radius, than the ribbon feeding rate could go up as high as 40

m/sec. Therefore, the apparatus of the present invention can be efficiently used for

massively in-line annealing an amorphous alloy ribbon in a curved shape. As the

casting process for making an amorphous alloy is performed at a speed near 30
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m/sec, adding an in-line annealing unit at the output of the casting line could be

foreseen.

In the present invention, the ribbon is continuously in-line annealed at a high feeding

rate with an impulse heat treatment which limits the progression of structural

relaxation and therefore has a different impact on the ribbon embrittlement

compared to conventional field furnace annealing. For ribbons that are continuously

in-line annealed with the apparatus of the present invention, once the ribbon exits

the treatment, it must be handleable in order to roll up the material on mandrels, and

10 it also needs to be cuttable in order to allow easy switching of the rolling up ribbon

from a filled mandrel to an new mandrel, or to continuously roll up ribbon to form

cores in series. Any loss of ductility following the annealing treatment of iron-based

amorphous alloy ribbons will increase the potential event of a ribbon break, which

will lower the yield in the production of annealed ribbon reels or cores, and cause an

increase of cost. This yield will reduce further if the ribbon is moving under a

significant amount of applied tensile stress.

Amorphous iron-based alloy ribbons, which normally become brittle when annealed

in a furnace and that have been annealed with the apparatus of the present

20 invention, show good ductility characteristics. To best qualify the degree of ductility

of the ribbons annealed with the apparatus of the present invention, three methods

are used.

Ductility is first estimated by performing a bending fracture strain test. The ribbon is

bent once over 180 degrees by being squeezed progressively between two parallel

plates to measure the gap distance (ribbon bending diameter) at which a visible

sudden rupture through the ribbon layer is occurring. The bending fracture strain is

expressed bye, wherein e, =tI(D-t), t is the ribbon thickness and D is the bending

diameter of the fractured ribbon. One must also take into account the type of fracture

30 occurring at the bending radius as an additional indicator of the ductility. A fracture
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can be the occurrence of a local rupture appearing somewhere along the axial

bending length or, a sudden ribbon complete rupture. For a same fractured bending

diameter, a ribbon rupturing completely is considered more brittle than one rupturing

partially. The bending side also influences the bending fracture strain diameter. A

brittle ribbon having a natural bending curve in a rest position will be more prone to

fracture when bent on the opposite side of its natural curved radius as the bending

stress is more intense.

Ductility is also estimated with a shear cutting test. The ductility can be expressed

10 with the ability for the ribbon to be sheared cut in a straight line that follows the

cutting blades. A good ductile ribbon will smoothly be cut along the cutting line where

both shear blade edges meet. A slightly brittle ribbon will partially rupture sideways

at one or several places along the edge of the cutting line. However a very brittle

ribbon will suddenly and completely rupture.

Ductility is also estimated with a tearing test. Ductility can be expressed with the

ability for the ribbon to be torn apart like doing so with a paper sheet. A good ductile

ribbon will smoothly be torn apart from one edge to the other, while a more brittle

ribbon would be subject to sudden partial ruptures over a short distance. For a

20 significantly brittle ribbon, an immediate and complete rupture apart will occur.

A "completely ductile" alloy ribbon according to the present invention will never

rupture in all three performed tests as opposed to a very brittle alloy ribbon which will

always completely and suddenly break.

Before an iron-based amorphous alloy ribbon was annealed with the apparatus of

the present invention, a series of as-cast samples were submitted to each of the

three tests to ensure that they were completely ductile. After the annealing

treatment, a long segment of ribbon was sampled and was tested to estimate its

30 ductility. The following tables give the results for the series of three ductile tests that
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10

were performed at normal room temperature on annealed ribbon segments sampled

from each run of examples 1 to 4. Each ductility test was done 10 times. For each

test, the following expressions are used to describe the ribbon physical behavior

under test. The bending fracture strain test is expressed by the e, interval and also

includes the type of fracture observed: foldable (e, =1 with no rupture); partial

rupture; and not complete rupture. The shear cut test is expressed in terms of:

cuttable (smooth progressive cut with no rupture); partial rupture; and complete

rupture. Lastly, the tear test result is expressed in terms of: tearable (smooth

progressive tear with no rupture); partial rupture; and complete rupture.
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Example e, Foldable Partial rupture Complete rupture

1 .01-1 8 2 0

2 .01-1 8 2 0

3 .01-1 4 6 0

4 .01-1 4 6 0

Table 2-Bending fracture strain test results - opposite side to natural bending curve

Example e, Foldable Partial rupture Complete rupture

1 1 10 0 0

2 1 10 0 0

3 1 10 0 0

4 1 10 0 0

Table 3-Bending fracture strain test results - same side to natural bending curve

Example Cuttable Partial rupture Complete rupture

1 10 0 0

2 10 0 0

3 10 0 0

4 10 0 0

Table 4-Shear cutting test results
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Example Tearable Partial rupture Complete rupture

1 2 5 3

2 2 7 1

3 5 5 0

4 8 2 0

Table 5-Tearing test results

All iron-based amorphous alloy ribbons that were curved annealed with the in-line

annealing apparatus of the present invention and disclosed in the cited examples

show good ductility. According to the present invention, a curved annealed ribbon is

considered "ductile" if it is cuttable and foldable on the same side of the natural

bending curve. The curved annealed iron-based amorphous alloy ribbons in-line

annealed with the apparatus of the present invention are ductile at normal room

10 temperature. The annealed ribbon coming out of the in-line annealing apparatus can

be continuously rolled up on a mandrel to make reels of ribbon or cores and switch

from reels of ribbon or cores at very high production yields. The in-line annealing

apparatus of the present invention can be used to massively produce reels of

annealed iron-based amorphous alloy ribbons that show excellent magnetic

properties and which are acceptable for making cores for distribution transformers,

HIF, pulse power cores, and other elements.

Although the treated ribbons in the cited examples are "ductile", they are not

"completely ductile" compared to as-cast ribbons. This loss of ductility still represents

20 a small risk of breaking the ribbon after cool down during in-line annealing and after

treatment during handling. Based on the fact that most iron-based amorphous alloy

ribbons show a ductile-to-brittle transition at a temperature (TdbO) below which they

are brittle and above which they are ductile, the iron-based amorphous alloy ribbons

that were annealed with the annealing apparatus of the present invention and
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disclosed in the cited examples have a ductility level which would correspond to a

Tdbo which has shift-up just below normal room temperature as shown in Figure 8.

Therefore, increasing the temperature of the alloy should render the ribbon more

ductile. The ductility of ribbons annealed with the apparatus of the present invention

has been found to have a great dependency on temperature. The annealed ribbons

were submerged in an oil bath heated at different temperatures and were submitted

again to the same ductility tests. The number of observed ruptures significantly

started to drop for a few degrees above the normal room temperature. Above 50°C,

the numbers of ruptures were down by half. The sensitivity to the temperature was

10 so high that for temperatures at about 100°C, the 2605SA1 alloy ribbons became

completely ductile according to the present performed ductile tests. For the

2605HB1, complete ductility was reached at about 80e. Therefore, the handling,

rolling up and cutting of iron-based amorphous alloy ribbons that have been in-line

annealed with the apparatus of the present invention can be done at optimal ductility

just by handling the ribbon above a temperature a few tens of degrees over normal

room temperature, preferably above 80°C for 2605HB1 and above 100°C for

2605SA1. As most dielectric materials in transformers are irreversibly deteriorated at

temperatures above 150e, rolling up of the ribbon to form a core around the coils of

the transformer could be achieved at a temperature up to 150e to benefit from a

20 maximum gain in ductility.

In the apparatus shown in Figure 24, a third infrared sensor 52 has been added to

measure the ribbon temperature that exits the treatment apparatus. The flow of

coolant through cold roller 51 can be controlled in order for the ribbon to exit the

treatment apparatus at a temperature ToutO greater than normal room temperature,

preferably greater than 80°C for 2605HB1 and above 100°C for 2605SA1, so that

the ribbon remains optimally ductile for the following post handling operations, as

shown in Figure 8. Since complete ductility is reached at a temperature dependant

on the alloy composition, the handling temperature will be set accordingly. To

30 maintain the ribbon temperature during post handling, any cutting tool or guiding
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surfaces need to be kept near the same temperature. Once taken-up on a mandrel,

the ribbon was allowed to gradually cool down to normal room temperature without

any further deterioration of the properties. By keeping the alloy completely ductile all

along the forwarded treatment path, risk of a ribbon breakage during treatment is

reduced to minimum and production yield is therefore maximized.

The flat or curved annealed and cuttable amorphous ferromagnetic ribbon produced

with the in-line annealing apparatus of the present invention applies to building of

ferromagnetic cores for use in equipment such as distribution transformers, HIF,

10 pulse power cores, and other elements. With the apparatus of the present invention,

the in-line annealing of the amorphous alloy ribbon can be performed at such a high

feeding rate that it makes-it more beneficial in term of economies of scale to locate

the apparatus next to the amorphous alloy casting system at the alloy manufacturing

plant. Because the in-line annealed ribbon remains ductile after treatment, stored

ribbons in large reels around a mandrel at the casting plant can then be shipped to

the transformer manufacturer using the same methods used for shipping as-cast

ribbon. The received in-line annealed reels will then be unrolled by the transformer

manufacturer to be rolled again onto a mandrel located around the coils of the

transformer. This eliminates all necessary equipments, associated floor space and

20 labour required for making conventional field furnace annealing rectangular-cutcores and which is normally performed at the transformer manufacturing plant. As it

is cuttable, the ribbon could also be used as a magnetic shielding foil for electronic

devices, or for making magnetoimpedance sensors, or for making markers for article

surveillance systems. The ribbon is flexible and can be punched into the desired

shape. The form can either be circular at a given radius ra, or flat, depending if the

ribbon has been curved or flat annealed.

A flat annealed iron-based amorphous ferromagnetic alloy ribbon in-line annealed

with the apparatus of the present invention can be used for producing stack cores.

30 Reels containing flat cuttable annealed ribbon can be unrolled and cut or punched in
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segments having a predetermined length or outline. These segments are then

stacked and grouped to form cores having a predetermined shape. Stacked cores

can be used in the fabrication of transformers. However, amorphous alloy ribbons

are very thin and therefore have no stiffness. To be more handleable, a group of

segments can be stacked and bound with either an organic or inorganic binder to

give a rigidity equivalent to a thick steel sheet. Since the performances of iron-based

amorphous ferromagnetic alloys such as Metglas 2605SA1 and 2605HB1 are

sensitive to external applied stresses, the binder, when cured, must not introduce

significant stresses on the surfaces of the ribbons which would lead to a serious

10 deterioration of magnetic performance. Furthermore, the coefficient of thermal

expansion of the binder should match that of the ribbon to avoid the creation of

stresses due to differential thermal expansion, which could also lead to serious

deterioration of the magnetic performances. Also, a binder can be applied on a

curved-in-line-annealed ribbon before it is to be rolled up to from a core to obtain a

self consistent core.

A curved annealed ribbon in-line annealed with the apparatus of the present

invention can be used for producing circular cores. During rolling up of the ribbon to

form a core, a minimal tensile stress must be applied to properly roll up the ribbon. A

20 high ribbon rolling up tensile stress improves the filling factor of the material in the

core but introduces stresses that remain in the core once completely rolled up and

which can seriously deteriorate the magnetic performances. Therefore, the rolling up

tensile stress must be controlled to limit the residual stresses in the final formed

core. Also, each rolled up layer of ribbon will have a final bending radius according to

its own radial position within the core. There will be a bending stress in each rolled

up layer and its intensity will depend on the curvature change imposed on the ribbon

compared to the radius ra where maximum alleviated stresses occur. To minimize

the curvature change, the inner to outer radius of the circular core will preferably be

close to ra. More preferably, the radius ra of the curved in-line annealed ribbon of the

30 present invention will be situated between the inner radius and outer radius of the
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circular formed core. More preferably, ra will be closer to the outer radius of the

circular formed core as the exciting magnetic field gets weaker close to the outer

peripheral portion of the core thus, benefiting of a stronger field in the inner

peripheral portion of the circular core for compensating the increased force field

required to magnetize the slightly deformed ribbon in the inner region of the core.

However, magnetic performance of circular cores having a very thick amount of

rolled up ribbon can be improved by rolling up successive quantities of ribbons each

annealed at a specific radius which increases from one quantity of ribbons to the

next (ra1 < ra2 < ra3 ...).

10

Part of the core loss produced in a stacked or rolled up ferromagnetic core under an

applied AC magnetic field is caused by the induced currents flowing through the

inter-laminar contacts. Increasing the frequency of the applied AC field will increase

the inter-laminar voltages, which increase the inter-laminar currents and therefore

increase the core loss. The inter-laminar voltages also increase with the width of the

core. Attenuating these currents will greatly improve the magnetic performances of

the core, especially at high frequency. To reduce these inter-laminar currents, it is

necessary to increase the ribbon surface resistivity. With the in-line annealed

amorphous alloy ribbon of the present invention, because it can be rolled-up-after20 annealing, the surface of the ribbon can be coated either with an organic or inorganic

insulating coating before it is stacked in a core. However, there is a drawback of

coating the ribbon. It will affect the stacking factor of the core as the coating will

occupy some space between each layer. Only one side coating is required to

increase inter-laminar insulation. On a ribbon having a thickness at about 25 f,Jm, the

coating has to be very thin if one wants to keep a good stacking factor. For 60Hz

frequency operations, applying a very thin insulating coating «1 f,Jm) on the ribbon is

enough to increase the inter-laminar electrical resistance and will therefore

significantly improve the magnetic performances of the core, especially for wide

cores. A slightly thicker insulating layer having a high dielectric strength may be

30 required for providing proper insulation in a pulse power core such as required in a
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HIF accelerator. However, coating such a very thin insulating layer requires precise

control of the coating process.

The E-coat process, also known as Electrocoat, electrophoretic paint, EDP or

electrodeposited paint, consists of applying a voltage on the conductive material to

be coated when it passes is an emulsion of organic polymers and de-ionized water.

The voltage is applied between the conductive material and an auxiliary electrode

submerged in the emulsion. Charged polymers within the emulsion will migrate

electrophoretically to the target electrode of the opposite charge (the alloy ribbon),

10 become insoluble, and form the coating. The thickness of the coating depends on

the applied voltage or the submerged time. Such a coating process can be efficiently

used to coat a very thin insulating layer on at least one side of the in-line annealed

amorphous alloy ribbon of the present invention. A reel of ribbon is mounted on an

insulated hub. The ribbon is then unrolled and plunged into an electrophoretic bath

for a predetermined period of time and at a specific voltage to be coated with an

organic polymer. The ribbon is then dried and rolled up again on an insulated takeup mandrel. The performances of amorphous ferromagnetic alloys being sensitive to

external applied stresses, the coating must not introduce significant stresses on the

surfaces of the ribbons, which would lead to a serious deterioration of magnetic

20 performance. Furthermore, the coefficient of thermal expansion of the coating should

match that of the ribbon to avoid the creation of stresses due to differential thermal

expansion which could also lead to serious deterioration of magnetic performance.

Although preferred embodiments of the present invention have been described in

detailed herein and illustrated in the accompanying drawings, it is to be understood

that the invention is not limited to these precise embodiments and that various

changes and modifications may be effected therein without departing from the scope

or spirit of the present invention.
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1. A method for treating an amorphous alloy ribbon, comprising steps of:

a) feeding forward, tensioning and guiding the amorphous alloy ribbon along a

path at a preset feeding rate;

b) heating the amorphous alloy ribbon at a point along said path at a rate

greater than 103 °C/sec to a temperature to initiate a thermal treatment;

c) cooling the amorphous alloy ribbon at a rate greater than 103 °C/sec until

the thermal treatment ends;

10 d) applying a series of mechanical constraints on the ribbon during said

thermal treatment until the amorphous alloy ribbon adopts a specific shape at rest

after said thermal treatment; and

e) cooling the amorphous alloy ribbon at a rate to preserve said specific shape,

after said thermal treatment.

2. The method according to claim 1, wherein the thermal treatment is performed

to maintain an amorphous state of the ribbon.

3. The method according to claim 1, wherein the thermal treatment is performed

20 to initiate crystallisation of the amorphous alloy ribbon.

4. The method according to claim 1, wherein the thermal treatment is performed

to obtain partial crystallisation of the amorphous alloy ribbon.

5. The method according to claim 1, wherein the thermal treatment is performed

to obtain full crystallisation of the amorphous alloy ribbon.

6. The method according to claim 1, wherein in step a), the preset feeding rate is

greater than 1 m/sec.

30
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7. The method according to claim 1, wherein, in step b), the heating is done at a

rate greater than 104oC per second.

8. The method according to claim 1, wherein, in step c), the cooling is done at a

rate greater than 104oC per second.

9. The method according to anyone of claims 1 to 8, wherein the thermal

treatment is performed during a period of time that is less than one second.

10 10. The method according to anyone of claims 1 to 8, wherein the thermal

treatment is performed during a period of time that is less than one tenth of a

second.

11. The method according to anyone of claims 1 to 10, wherein step e) cools the

amorphous alloy ribbon to a handling temperature above a temperature threshold

Tdb to which a complete ductility of the amorphous alloy ribbon is obtained.

12. The method according to claim 11, wherein said handling temperature is above

ambient temperature and below said temperature to initiate the thermal treatment.

20

13. The method according to anyone of claims 1 to 12, wherein:

in step b) the amorphous alloy ribbon is in contact with at least one first cylinder

having a first cylindrical surface located along said path;

step b) further comprises a step of tensioning the amorphous alloy ribbon with

respect to the first cylindrical surface to obtain a first static contact between the

amorphous alloy ribbon and the first cylindrical surface, the first static contact

stretching over a first contact angle .around the first cylindrical surface;

step b) further comprises a step of maintaining said first cylindrical surface at a

temperature greater or equal to said temperature to initiate the thermal treatment;
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10

20

in step c) the amorphous alloy ribbon is in contact with at least one second

cylinder having a second cylindrical surface located along said path;

step c) further comprises a step of tensioning the amorphous alloy ribbon with

respect to the second cylindrical surface to obtain a second static contact between

the amorphous alloy ribbon and the second cylindrical surface, the second static

contact stretching over a second contact angle around the second cylindrical

surface; and

step c) further comprises a step of maintaining said second cylindrical surface

at a temperature lower than said temperature to initiate the thermal treatment.

14. The method according to claim 13, wherein:

in step d) the amorphous alloy ribbon is in contact with at least one third

cylinder having a third cylindrical surface located along said path;

step d) further comprises a step of tensioning the amorphous alloy ribbon with

respect to the third cylindrical surface to obtain a third static contact between the

amorphous alloy ribbon and the third cylindrical surface, the third static contact

stretching over a third contact angle around the third cylindrical surface; and

step d) further comprises a step of maintaining said third cylindrical surface at

said temperature to initiate the thermal treatment.

15. The method according to claim 13 or 14, wherein the step of tensioning the

amorphous alloy ribbon with respect to the cylindrical surfaces is done at a tension in

the range of 25 to 200 MPa.

16. The method according to claim 13 or 14, wherein the step of tensioning the

amorphous alloy ribbon with respect to the cylindrical surfaces is done at a tension in

the range of 50 to 100 MPa.
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17. The method according to claim 15 or 16, wherein the step of tensioning the

amorphous alloy ribbon is done to favour the development of a magnetic anisotropy

in the ribbon.

18. The method according to claim 14, wherein the amorphous alloy ribbon is in

contact with at least one guide roller proximate a selected one of the first, second or

third cylinders, said guide roller having a radius that is smaller than the selected

cylinder and being positioned proximate both an initial contact point and a final

contact point between the ribbon and the selected cylinder to maximize said contact

10 angle of said selected cylinder.

19. The method according to anyone of claims 1 to 18, wherein in step d) the

specific shape is curved and the method further comprises an additional step of:

f) rolling a specific amount of the amorphous alloy ribbon onto a mandrel to form

a core having an inner radius and an outer radius, wherein said specific shape has a

radius of curvature selected between said inner radius and said outer radius.

20. The method according to anyone of claims 1 to 18, wherein in step d) the

specific shape is flat and the method further comprises an additional step of:

20 f) cutting and stacking segments of the amorphous alloy ribbon.

21. The method according to anyone of claims 1 to 18, wherein in step d) the

mechanical constraints change to vary a radius of curvature of the specific shape of

the amorphous alloy ribbon along a length thereof, and the method further comprises

an additional step of:

f) rolling said length of the amorphous alloy ribbon onto a mandrel to form a

core.

22. The method according to anyone of claims 19 to 21, comprising an additional

30 step before step f) of:
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i) coating at least one side of the amorphous alloy ribbon with a dielectric

material.

23. The method according to claim 22, wherein the dielectric material is an organic

dielectric material.

24. The method according to claim 22, wherein in said step i), coating is performed

by means of electrodepositing.

10 25. The method according to claim 22, wherein said step i) further comprises steps

of applying a voltage on the amorphous alloy ribbon and feed forwarding the ribbon

in an emulsion of organic polymers and de-ionized water for a period of time.

26. The method according to anyone of claims 19 to 21, comprising an additional

step, before said step f), of:

i) coating at least one side of the amorphous alloy ribbon with a binder.

27. The method according to anyone of claims 1 to 12, wherein a tension is

increased or reduced along the path of the amorphous alloy ribbon by a tensioning

20 apparatus, said tensioning apparatus comprising:

at least one motor having a shaft;

a circular device coupled to the shaft of the motor, said circular device

having a surface making a static contact with the ribbon over an angle, the

surface having a static friction coefficient with respect to the ribbon; and

a controller for controlling torque of said motor shaft to increase or reduce a

tensile stress in the amorphous ribbon.

28. The method according to claim 27, wherein said tensioning apparatus is

located along said path to increase the tensile stress in the ribbon before thermal

30 treatment is initiated.
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29. The method according to claim 27, wherein said tensioning apparatus is

located along said path to reduce the tensile stress after said thermal treatment.

30. The method according to claim 27, wherein said tensioning apparatus is

located along said path for controlling the tensile stress in the ribbon during said

thermal treatment.

31. The method according to anyone of claims 1 to 30, wherein the ribbon being

10 fed along the path is delivered to a target position on a structure by a guiding

apparatus, said guiding apparatus comprising:

- a body;

- a guide roller mounted on the body, having a flat peripheral surface lined with

lateral guides for supporting and guiding the ribbon, the guide roller having a

receiving section for receiving the ribbon and a delivering section for delivering the

ribbon at the target position; and

- a pivot for pivotably mounting the body to the structure, the pivot having a pivot

axis tangentially aligned with the delivering section of the roller; in operation, the

body pivots with respect to the structure by means of the pivot so that the receiving

20 section of the roller receives the ribbon and accommodates translations thereof to

deliver via said delivering section the ribbon at the target position.

32. The method according to claim 13, wherein:

in step e) the amorphous alloy ribbon is in contact with a plurality of spaced

apart cooling cylinders each having a cooling cylindrical surface located along said

path;

step e) further comprises a step of tensioning the amorphous alloy ribbon with

respect to the cooling cylindrical surfaces to obtain a cooling static contact between

the moving amorphous alloy ribbon and the cooling cylindrical surfaces, the cooling
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static contact stretching over respective contact angles around the cooling cylindrical

surfaces; and

step e) further comprises a step of maintaining said cooling cylindrical surfaces

at a temperature lower than said temperature to initiate the thermal treatment.

33. An iron-based amorphous alloy cast as a ribbon, heat-treated by in-line

annealing at a temperature without reaching onset crystallization with heating and

cooling at temperature rates greater than 103 °C/sec.

10 34. The iron-based amorphous alloy according to claim 33, wherein, when said

ribbon is stacked or rolled up to form a core, said ribbon has a 8ao/8sat that is greater

than 0.80.

35. The iron-based amorphous alloy according to claim 33, wherein the ribbon is

ductile at normal room temperature and completely ductile at a temperature greater

than normal room temperature

36. An iron-based amorphous alloy cast as a ribbon comprising a nominal chemical

composition Fea0811Sig, numbers being in atomic percent, with incidental impurities,

20 heat-treated by in-line annealing at a temperature above 450°C without reaching

onset crystallization with heating and cooling at temperature rates greater than 103

DC/sec.

37. The iron-based amorphous alloy according to claim 36, wherein, when said

ribbon is stacked or rolled up to form core, the ribbon has a core loss lower than 0.25

W/kg at 60 Hz at a magnetic induction of 1.3 Tesla.

38. The iron-based amorphous alloy according to claim 36, wherein, when said

ribbon is stacked or rolled up to form core, said ribbon has a 8ao that is greater than

30 about 1.3 Tesla after annealing.
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39. The iron-based amorphous alloy according to claim 36, wherein, when said

ribbon is stacked or rolled up to form a core, said ribbon has a Bao/Bsat that is greater

than 0.80.

40. The iron-based amorphous alloy according to claim 36, wherein the ribbon is

ductile at normal room temperature and completely ductile at a temperature greater

than 100°C.

10 41. The iron-based amorphous alloy according to claim 33, comprising a nominal

chemical composition FeaBbSicCd where 80<a<84, 8<b<18, 0<c:55 and 0<d:53,

numbers being in atomic percent, with incidental impurities.

42. The iron-based amorphous alloy according to claim 41, wherein, when said

ribbon is stacked or rolled up to form core, the ribbon has a core loss lower than 0.25

W/kg at 60 Hz at a magnetic induction of 1.5 Tesla.

43. The iron-based amorphous alloy according to claim 41, wherein, when said

ribbon is stacked or rolled up to form core, said ribbon has a BaD that is greater than

20 about 1.3 Tesla after annealing.

44. The iron-based amorphous alloy according to claim 41, wherein, when said

ribbon is stacked or rolled up to form core, said ribbon has a BaD that is greater than

about 1.4 Tesla after annealing.

45. The iron-based amorphous alloy according to claim 41, wherein, when said

ribbon is stacked or rolled up to form core, said ribbon has a BaD that is greater than

about 1.5 Tesla after annealing.
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46. The iron-based amorphous alloy according to claim 41, wherein, when said

ribbon is stacked or rolled up to form a core, said ribbon has a Bso/Bsat that is greater

than 0.80.

47. The iron-based amorphous alloy according to claim 41, wherein, when said

ribbon is stacked or rolled up to form a core, said ribbon has a Bso/Bsat that is greater

than 0.90.

48. The iron-based amorphous alloy according to claim 41, wherein the ribbon is

10 ductile at normal room temperature and completely ductile at a temperature greater

than about 80°C.

49. The iron-based amorphous alloy according to anyone of claims 41 to 48,

comprising a nominal chemical composition Fes1.8B15.sSiz.1Co.3, numbers being in

atomic percent, with incidental impurities.

50. An amorphous alloy ribbon treated in accordance with the method of anyone of

claims 1 to 32.

20 51. The amorphous alloy ribbon according to claim 50, comprising a nominal

chemical composition FeaoB11Sig, numbers being in atomic percent, with incidental

impurities.

52. The amorphous alloy ribbon according to claim 50, comprising a nominal

chemical composition FeaBbSicCd where 80<a<84, 8<b<18, 0<c~5 and 0<d~3,

numbers being in atomic percent, with incidental impurities.

53. The amorphous alloy ribbon according to claim 52, compnslng a nominal

chemical composition FeS1.8B15.SSiz.1CO.3, numbers being in atomic percent, with

30 incidental impurities.
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54. A heat exchange system for exchanging heat with an article comprising:

- a support structure;

- a heat exchanger ring element capable of being heated;

- a heat diffuser ring element having an outer surface to be in contact with

said article, said heat diffuser ring element having an inner surface in contact

with said heat exchanger ring element; and

- a frame structure supporting said heat exchanger ring element and said heat

diffuser ring element, said frame structure being rotatably mounted on the

10 support structure.

55. The heat exchange system according to claim 54, wherein the heat exchanger

ring element is a resistive element capable of being in sliding rotatable contact with

an electrical power source.

56. The heat exchange system according to claim 54, wherein the heat exchanger

ring element is a resistive element, further comprising an antenna for heating by

magnetic induction the heat exchanger ring element.

20 57. The heat exchange system according to anyone of claims claim 54 to 56,

further comprising a slotted structure integrally formed with the heat exchanger ring

element and laterally surrounding said heat exchanger ring element, the slotted

structure having slots extending transversally to the heat exchanger ring element.

58. The heat exchange system according to anyone of claims claim 54 to 57,

wherein the heat exchanger ring element is made of stainless steel and the heat

diffuser ring element is made of copper and mounted by electrodeposition on the

heat exchanger ring element.

30 59. A system for treating an amorphous alloy ribbon, comprising:
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- a moving device for feeding forward, tensioning and guiding the amorphous

alloy ribbon along a path at a preset feeding rate;

- a heating system for heating the amorphous alloy ribbon at a point along said

path at a rate greater than 103 °C/sec to a temperature to initiate a thermal

treatment;

- a first cooling system cooling the amorphous alloy ribbon at a rate greater

than 103 °C/sec until the thermal treatment ends;

- a mechanical constraint application device for applying a series of mechanical

constraints on the ribbon during said thermal treatment until the amorphous alloy

10 ribbon adopts a specific shape at rest after said thermal treatment; and

- a second cooling system for cooling the amorphous alloy ribbon at a rate to

preserve said specific shape, after said thermal treatment.

60. The system according to claim 59, wherein the heating system and the first

cooling system are set so that the thermal treatment is performed to maintain an

amorphous state of the ribbon.

61. The system according to claim 59, wherein the heating system and the first

cooling system are set so that the thermal treatment is performed to initiate

20 crystallisation of the amorphous alloy ribbon.

62. The system according to claim 59, wherein the heating system and the first

cooling system are set so that the thermal treatment is performed to obtain partial

crystallisation of the amorphous alloy ribbon.

63. The system according to claim 59, wherein the heating system and the first

cooling system are set so that the thermal treatment is performed to obtain full

crystallisation of the amorphous alloy ribbon.
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64. The system according to claim 59, wherein the preset feeding rate of the

moving device is greater than 1 m/sec.

65. The system according to claim 59, wherein the heating system heats at a rate

greater than 104oC per second.

66. The system according to claim 59, wherein the first cooling system cools at a

rate greater than 104oC per second.

10 67. The system according to anyone of claims 59 to 66, wherein the heating

system and the first cooling system are set so that the thermal treatment is

performed during a period of time that is less than one second.

68. The system according to anyone of claims 59 to 66, wherein the heating

system and the first cooling system are set so that the thermal treatment is

performed during a period of time that is less than one tenth of a second.

69. The system according to anyone of claims 59 to 68, wherein the second

cooling system cools the amorphous alloy ribbon to a handling temperature above a

20 temperature threshold Tdb that is sufficient to obtain complete ductility of the

amorphous alloy ribbon.

70. The system according to claim 69, wherein said handling temperature is above

ambient temperature and below said temperature to initiate the thermal treatment.

71. The system according to anyone of claims 59 to 70, wherein the heating

system comprises at least one first cylinder in contact with the amorphous alloy

ribbon, said at least one first cylinder having a first cylindrical surface located along

said path, the system further comprising a first tensioning apparatus for tensioning

30 the amorphous alloy ribbon with respect to the first cylindrical surface to obtain a first
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static contact between the amorphous alloy ribbon and the first cylindrical surface,

the first static contact stretching over a first contact angle around the first cylindrical

surface, a temperature of said first cylindrical surface being maintained at a

temperature greater or equal to said temperature to initiate the thermal treatment,

the first cooling system comprises at least one second cylinder in contact with the

amorphous alloy ribbon, said at least one second cylinder having a second

cylindrical surface located along said path, the system further comprising a second

tensioning apparatus for tensioning the amorphous alloy ribbon with respect to the

second cylindrical surface to obtain a second static contact between the amorphous

10 alloy ribbon and the second cylindrical surface, the second static contact stretching

over a second contact angle around the second cylindrical surface, a temperature of

said second cylindrical surface being maintained at a temperature lower than said

temperature to initiate the thermal treatment.

72. The system according to claim 71, wherein the mechanical constraint

application device comprises in contact with the amorphous alloy ribbon, said at

least one third cylinder having a third cylindrical surface located along said path, the

system further comprising a third tensioning device for tensioning the amorphous

alloy ribbon with respect to the third cylindrical surface to obtain a third static contact

20 between the amorphous alloy ribbon and the third cylindrical surface, the third static

contact stretching over a third contact angle around the third cylindrical surface, a

temperature of said third cylindrical surface being maintained at said temperature to

initiate the thermal treatment.

73. The system according to claim 71 or 72, wherein the tensioning apparatuses

tension the amorphous alloy ribbon with respect to the cylindrical surfaces at a

tension in the range of 25 to 200 MPa.
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74. The system according to claim 71 or 72 wherein the tensioning apparatuses

tension the amorphous alloy ribbon with respect to the cylindrical surfaces at a

tension in the range of 50 to 100 MPa.

75. The system according to claim 73 or 74, wherein the tensioning apparatuses

tension the amorphous alloy ribbon to favour the development of a magnetic

anisotropy in the ribbon.

76. The system according to claim 72, further comprising at least one guide roller to

10 which the amorphous alloy ribbon is in contact, proximate a selected one of the first,

second or third cylinders, said guide roller having a radius that is smaller than the

one of the selected cylinders and being positioned proximate both an initial contact

point and a final contact point between the ribbon and the selected cylinder to

maximize said contact angle of said selected cylinder.

77. The system according to anyone of claims 59 to 76, further comprising a

mandrel onto which a specific amount of the amorphous alloy ribbon is rolled up,

said mandrel having an inner radius and an outer radius, said specific shape having

a radius of curvature selected between said inner radius and said outer radius.

20

78. The system according to anyone of claims 59 to 76, further comprising a cutter

and stacking device for cutting and stacking segments of the amorphous alloy

ribbon.

79. The system according to anyone of claims 59 to 76, wherein the mechanical

constraint application device apply constraints to vary a radius of curvature of the

specific shape of the amorphous alloy ribbon along a length thereof, and the system

further comprises a mandrel onto which a specific amount of the amorphous alloy

ribbon is rolled up.

30
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80. The system according to anyone of claims 77 to 79, further comprising a

coating system for coating at least one side of the amorphous alloy ribbon with a

dielectric material.

81. The system according to claim 80, wherein the dielectric material is an organic

dielectric material.

82. The system according to claim 80, wherein the coating system is an

electrodepositing system.

10

83. The system according to claim 80, further comprising a voltage application

device for applying a voltage on the amorphous alloy ribbon, and a bath system

comprising an emulsion of organic polymers and de-ionized water through which the

ribbon is fed forward for a period of time.

84. The system according to anyone of claims 80 to 83, further comprising a

binder application system for coating at least one side of the amorphous alloy ribbon

with a binder.

20 85. The system according to anyone of claims 59 to 70, further comprising a

tensioning apparatus for increasing or reducing a tension in the amorphous alloy

ribbon along the path, ,said tensioning apparatus comprising:

at least one motor having a shaft;

- a circular coupled to the shaft of the motor, said circular device having a

surface making a static contact with the ribbon over an angle, the surface

having a static friction coefficient with respect to the ribbon; and

a controller for controlling torque of said motor shaft to increase or reduce a

tensile stress in the amorphous ribbon.
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86. The system according to claim 85, wherein said tensioning apparatus is located

along said path to increase the tensile stress in the ribbon before thermal treatment

is initiated.

87. The system according to claim 85, wherein said tensioning apparatus is located

along said path to reduce the tensile stress after said thermal treatment.

88. The method according to claim 85, wherein said tensioning apparatus is

located along said path for controlling the tensile stress in the ribbon during said

10 thermal treatment.

89. The system according to anyone of claims 59 to 88, further comprising a

guiding apparatus for delivering the ribbon to a target position on a structure, said

guiding apparatus comprising:

- a body;

- a guide roller mounted on the body, having a flat peripheral surface lined with

lateral guides for supporting and guiding the ribbon, the guide roller having a

receiving section for receiving the ribbon and a delivering section for delivering the

ribbon at the target position; and

20 - a pivot for pivotably mounting the body to the structure, the pivot having a pivot

axis tangentially aligned with the delivering section of the roller, in operation, the

body pivots with respect to the structure by means of the pivot so that the receiving

section of the roller receives the ribbon and accommodates translations thereof to

deliver via said delivering section the ribbon at the target position.

90. The system according to claim 72, wherein the second cooling system

comprises a plurality of spaced apart cooling cylinders in contact with the amorphous

alloy ribbon, said spaced apart cooling cylinders each having a cooling cylindrical

surface located along said path, the system further comprising a tensioning system

30 for tensioning the amorphous alloy ribbon with respect to the cooling cylindrical
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surfaces to obtain a cooling static contact between the moving amorphous alloy

ribbon and the cooling cylindrical surfaces, the cooling static contact stretching over

respective contact angles around the cooling cylindrical surfaces, a temperature of

said cooling cylindrical surfaces being maintained at a temperature lower than said

temperature to initiate the thermal treatment.
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INTERNATIONAL SEARCH REPORT

A CLASSIFICATION OF SUBJECT MATTER

IPC: C21]) 9/573 (2006.01), C21]) 1/42 (2006.01) C22C 45/02 (2006.01)

According to International Patent Classification (IPC) or to both national classification and IPC

B. FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)

IPC: C21]) 9/573 (2006.01), C21]) 1/42 (2006.01) C22C 45/02 (2006.01)

International application No.

PCT/CA20 10/001844

Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched

Electronic database(s) consulted during the international search (name of database(s) and, where practicable, search terms used)

TotalPatent. Canadian Database. ScienceDirect and ACS Publication.

Keywords: amorphous, Iron, alloy, ribbon, rate, crystallisation, tensile, coat, magnetic core, annealmg, transformer, FesoBIlSi9, FeaBbSl"Cct

C DOCUMENTS CONSIDERED TO BE RELEVANT

CategOlY*

x

A

A

A

A

Citation of document, with indication, where appropriate, ofthe relevant passages

US 5,069,428 (Li et a1.) 03 December 1991 (03-12-1991)

*whole document*

A New Alethodfc)f' Stress Relieving AmOlpholls Allov to Improve Alagnetic

Properties, by Taub, IEEE Transactions of Magnetics, VoL MAG-20, NO.4,

JULY 1984, Page 564-570.

* cited by the applicant*

E.!lect (?l the annealing temperature on magnetic property.fin' tran~fimner with

amOl]7holls core, by Hsu et aL, IMCAS 2009 Proceedings ofthe 8th WSEAS

international conference on Instrumentation, measurement, circuits and systems,

Page 171-175.

* cited by the applicant*

CA 2,279,981 Al (Liebermann) 06 August 1998 (06-08-1995)

US 4,288,260 (Sermo et a1.) 08 September 1981 (08-09-1981)

Relevant to claim No.

54-58

1-53 and 59-90

1-53 and 59-90

1-53 and 59-90

1-53 and 59-90

[Xl Further documents are listed in the continuation ofBox C.

Special categories of cited docmnents

")"." dOCUlllt:;l1t de±1ning the general state of the 3rt which is not considered to be of partIcular rele,\Tance

"E" earlier application or patent but published on or at1er the international

fil111g date

''L'' document ,"'hich may thrmv doubts on priority claim(s) or ,'.'hich is clted to estabhsh the pubhcatron date of another cltatlon or other

specwl reason (as specdied)

document referring to an oral disclosure, use, exhibition or other means

"p" document published prior to the international filing date but later than

the pnont:v date claImed

Date of the actual completion of the international search

26.Tanuary2011 (26-01-2011)

Name and mailing address of the ISAICA

Canadiall hltellectual Property Otlice

Place du Portage I, C114 - 1st Floor, Box PCT

50 Victoria Street

Gatineau, Quebec KIA OC9

Facsimile No. 001-819-953-2476

Form PCTIISAl210 (second sheet) (July 2009)

[X] See patent tinnily almex.

"T" later docmnent publisheda±1er the international filing date or priority

date and not 111 con111ct "\'lith the apl)hcatton but clteato understand - the pnnciple or theory lUlderlymg t le lll\ientIon

C"X" document of particular relevance', the claimed invention cmIDot be conSIdered novel or cannot be consldered to 111volve an 111ventlve step "1;vhen the doclUl1ent is taken alone

'.y.. docmnent of partIcular relevance. the clallned 111ventlOn emmot be conSIdered to Il1\/Olve an 111\ientr\'e step yvhen the document lS

comb111ed YVlth one or more other such documents, such combination

being obvious to a person skilled in the art

"&" document member of the same patent family

Date ofmailing of the international search report

25 Febmary 2011 (25-02-2011)

Authorized otlicer

Patrick Mamputu (819) 994-9537

Page 3 of5
INTERNATIONAL SEARCH REPORT International application No.

PCT/CA20 10/00 1844

Box No. II Observations where certain claims were found unsearchable (Continuation of item 2 of the first sheet)

This international search report has not been established in respect of certain claims under Aliicle 17(2)(a) for the following

reasons:

1. [ ] Claim Nos..

because they relate to subject matter not required to be searched by this Authority, namely:

2 [] Claim Nos..

because they relate to parts ofthe international application that do not comply with the prescribed requirements to such an extent

that no meaningful international search can be carried out, specifically'

3. [ ] Claim Nos.

because they are dependent claims and are not drafted in accordance with the second and third sentences ofRule 6.4(a).

Box No. III Obserrations where unity of invention is lacking (Continuation of item 3 of first sheet)

This International Searching Authority found multiple inventions in this international application, as follows:

Group A Claims 1-53 and 59-90

A method and a system for continuously in-line producing a magnetic core, fi'om a treated ductile amorphous alloy ribbon, tensioned and

guided along a path at a rate greater than [03 °C/ser.

Group B Claims 54-58

A heat exchange system for exchanging heat with an article.

[ ] As all required additIOnal search fees were timely paid by the applicant, this mternational search report covers all

searchable clmms.

2. [X] As all searchable claims could be searched without effort justifying additional fees, this Authority did not invite

payment of additional fees.

3. [ ] As only some of the required additional search fees were timely paid by the applicant, this international search report

covers only those clmms for which fees were paid, specifically claim Nos..

4. [ ] No required additional search fees were timely paid by the applicant. Consequently, this international search report is

restricted to the invention first mentioned in the claims: it is covered by claim Nos.

Remark on Protest [ ] The additional search fees were accompanied by the applicant's protest and, where applicable,

the payment of a protest fee.

[ ] The additional search fees were accompanied by the applicant's protest but the applicable protest

fee was not paid within the time limit specified in the invitation.

[ ] No protest accompamed the payment of additional search fees.

Form PCTIISAl210 (contmuatwn offirst sheet (2» (July 2009) Page 201'5
INTERNATIONAL SEARCH REPORT International application No.

PCT/CA20 10/00 1844

C (Continuation) DOCUMENTS CONSIDERED TO BE RELEVANT

Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No.

A US 5,494,534 (Leu) 27 Februmy 1996 (27-02-1996) 1-53 and 59-90

A US 4,053,331 (Graham, Jr, et aL) 11 October 1977 (11-10-1977) 1-53 and 59-90

Form PCTIISAl210 (contllluatlOn of second sheet) (July 2(09) Page 4 ot 5
Patent Document

Cited in Search Report

INTERNATIONAL SEARCH REPORT

Information on patent family members

Publication

Date

Patent Family

Member(s)

International application No.

PCT/CA20 10/00 1844

Publication

Date

US5069428A 03 December 1991 (03-12-1991) None

CA2279981A1 06 August 1998 (06-08-1998) AU6052898A

BR9807979A

CN1252106A

CN1234885C

EP0970257A1

JP2001510508T

US5873954A

W09833945A1

25 August 1998 (25-08-1998)

15 February 2000 (15-02-2000)

03 May 2000 (03-05-2000)

04 January 2006 (04-01-2006)

12 January 2000 (12-01-2000)

31 July 2001 (31-07-2001)

23 February 1999 (23-02-1999)

06 August 1998 (06-08-1998)

US4288260A

US4053331A

US5494534A

08 September 1981 (08-09-1981)JP54083622A

JP59034780B

JP1257859C

11 October 1977 (11-10-1977) None

27 February 1996 (27-02-1996) None

03 July 1979 (03-07-1979)

24 August 1984 (24-08-1984)

29 March 1985 (29-03-1985)

Form PCTIISAl2l0 (patent famIly mmex) (July 2009) Page 5 01'5