Alloy powders for bond magnet and bond magnet

It is an object of the present invention to provide a fire resistance bond magnet having superior temperature properties and most suitable for convergence use in picture tubes for display and high precision television, and alloy powders for bond magnet, without containing Co which is restricted in resources. The flame retardancy bond magnet having superior temperature properties and most suitable for convergence use in picture tubes for display and high precision television can be provided at low cost without containing Co, by using the alloy powders for bond magnet consisting of Al-Ni-Cu-(Ti, Nb)-Fe without Co, and having an isotropy and mean particle sizes of 10 .mu.m to 200 .mu.m, and kneading, molding and curing the 20 wt % to 80 wt % alloy powders together with a chlorine flame retardant, a flame retardant assistant such as antimony trioxide and zinc boric acid and a binder.

TECHNICAL FIELD 
The present invention relates to alloy powders for a bond magnet which can 
be molded into various shapes, and and particularly to alloy powders for a 
bond magnetic having superior temperature characteristics, bond magnet. 
BACKGROUND ART 
A bond magnet is manufactured by molding a compound prepared by mixing and 
kneading magnetic alloy powders of desired compositions with resins, a 
flame retardant and so on, into various shapes by means of injection 
molding, compression molding and extrusion molding, so that thin and 
complicated shapes can be easily manufactured and uniform characteristics 
obtained without cracks and chips. Such magnets are widely used in 
magnetic circuits of electronic components, in audio equipment, OA 
equipment and the like. 
Conventionally, a ferrite magnet powder and a rare earth magnet powder are 
generally used as the magnet powders for the bond magnet, and alnico 
magnet alloy powder is also used in a focusing magnet for focusing 
electronic beams and in color adjusting convergence in picture tube in 
television or display Braun tubes, because of its (1) superative 
temperature characteristics, (2) a higher saturated magnetic flux density 
than the ferrite magnet powder, and superior oxidation resistance and 
weatherproof as compared with the rare earth magnet powder. Such powders 
are furthermore low in cost. 
As the alnico magnet, alnico 8 having a coercive force of 1000 Oe or more 
and alnico 5 having a coercive force of about 500 to 700 Oe are well 
known, both having a low temperature change of magnet characteristics of 
0.05%/.degree.C. or less. 
The inventor has previously proposed bond magnets of alnico 5 and alnico 8 
(Japanese Patent Application Laid Open No. Hei 4-239103), and an alnico 
bond magnet is also disclosed in the Japanese Patent Application Laid Open 
Nos. Hei 3-239306 and Hei 3-259502. 
However, since the Alnico type magnet alloys consisting of alnico 5 and 
alnico 8 all contain a large amount of Co, i.e., about 25% to 40%, there 
was the possibility of high product cost and uncertainty in supply of raw 
materials. 
Also, though fire resistance is required a bond magnet used in domestic 
appliances and in OA equipment, some products using a bromic flame 
retardant have the possibility of producing dioxine having a toxicity at 
the time of combustion, thus the regulation of its use is being studied in 
U.S.A. and Europe. 
It is an object of the present invention to provide alloy powders for bond 
magnet which do not contain cobalt, which is scarce in resources, and is 
composed mainly of Fe-Ni-Al-Cu having good temperature characteristics, 
and to provide a bond magnet containing a flame retardant which is safe to 
dispose and at the time of combustion such as a fire. 
SUMMARY OF THE INVENTION 
In the present invention, as a result of various studies made on alloy 
compositions which do not contain precious Co such as alnico 5 and alnico 
8 as a bond magnet used, for example, in convergence which is used, for 
correcting beams of picture tubes in the color televisions and display 
Braun tubes, while making a good use of low temperature coefficient 
characteristics of the magnet characteristics, we found that it is 
possible to use as same as the costly Co alnico types, when pulverized 
into desired particles at the specific compositions substantially 
containing no Co, and as a result of various studies on blending for fire 
resistance as the bond magnet, by containing a necessary amount of 
specific flame retardants, the bond magnet having the fire resistance 
qualified by a combustion test of UL-94 Vo, and having little possibility 
of exhausting toxic substances such as dioxine can be obtained. 
The alloy powders for bond magnet of the present invention is characterized 
by containing 10 wt % to 16 wt % Al, 23 wt % to 33 wt % Ni, 2 wt % to 8 wt 
% Cu, less than 5 wt % of one or two kind of Ti, Nb, and balance Fe and 
unavoidable impurities, and by having an isotropy and mean particle sizes 
of 10 .mu.m to 200 .mu.m. 
The present invention also proposes, in the above-mentioned configuration, 
alloy powders for bond magnet having the coercive force (iHc) above 550 
Oe, and the alloy powders for bond magnet which can be pulverized 
mechanically easily and contains 0.5 wt % to 5.0 wt % of one or two kinds 
of Ti and Nb. 
The present invention is directed to the bond magnet which is flame 
retardant and characterized by, containing 10 wt % to 16 wt % Al, 23 wt % 
to 33 wt % Ni, 2 wt % to 8 wt % Cu, 5 wt % or less one or two kinds of Ti 
and Nb, and Fe and unavoidable impurities, and by having an isotropy, 
alloy powders of 10 .mu.m to 200.mu. mean particle sizes and a binder. 
The present invention also proposes, in the above-mentioned configuration 
of the bond magnet, 
a bond magnet containing 20 wt % to 98 wt % alloy powders, 
a bond magnet containing 20 wt % to 80 wt % alloy powders, 
a bond magnet which contains 5 wt % to 50 wt % flame retardant, having a 
fire resistance and is most suitable for convergence use, 
a bond magnet containing 2 to 45% silicate of components other than the 
alloy powders as an inorganic filter, and 
a bond magnet having 150 G to 1300 G Br, 150 Oe to 500 Oe iHc and 0.01 MGOe 
to 0.15 MGOe(BH) max, and 0.07 %/.degree.C. or less temperature 
coefficient of magnetic property. 
In the present invention, by pulverizing an isotropic permanent magnet 
obtained by melting the alloy having the above-mentioned compositions for 
predetermined heat treatment into powder having the mean particle sizes of 
10 .mu.m to 200 .mu.m, the Fe-Ni-Al-Cu magnet powders most suitable as the 
bond magnet and having a good magnetic property and temperature 
characteristics is obtained. 
Though a so-called alnico magnet such as alnico 5 and alnico 8 contains, 7 
to 10 wt % Al, 12 to 18 wt % Ni, 5 to 40 wt % Co and 1 to 8 wt % Cu as the 
essential compositions, and is further added with several % Ti, Nb, Si and 
the like, according to the present invention, the superior magnetic 
property is obtained by increasing the contents of Al and Ni even though 
Co, which is scarce in resources, is not contained, and by containing a 
predetermined amount of Cu, Ti and Nb to improve the heat treatment and 
grindability, the alloy powders for bond magnet and the bond magnet using 
said powders which are technically valuable can be realized.

BEST MODE FOR CARRYING OUT THE INVENTION 
In the following, restricted reasons of compositions of alloy powders for 
bond magnet and the bond magnet according to the present invention are 
described. 
Al is an essential composition to obtain superior magnet characteristics 
without containing Co, and it is preferably contained by 10 wt % to 16 wt 
%, because that a coercive force will drop when below 10 wt %, and both 
the coercive force and a residual magnetic flux density are lowered when 
above 16 wt %. 
Ni is an essential composition to obtain the superior magnet 
characteristics without containing Co, and it is preferably contained by 
23 wt % to 33 wt %, because that the coercive force will drop when below 
23 wt %, and the residual magnetic flux density is lowered when above 33 
wt %. 
Cu is preferably contained by 2 wt % to 8 wt %, because that the coercive 
force as well as the residual magnetic flux density are lowered within the 
range of heat treatment conditions to be described later, when below 2 wt 
% and above 8 wt %. 
Though Ti and Nb are added to improve the residual magnetic flux density 
and grindability, when more than 5 wt %, each of Ti and Nb are added, or 
when adding the two above 5 wt % in total, the residual magnetic flux 
density is lowered, but since it is difficult to grind at 0.1 wt % or 
less, it is preferably 0.1 wt % to 5 wt %, and more preferably, 0.5 wt % 
or more to grind efficiently. 
Fe is a nucleus of Fe-Ni-Al-Cu and occupies the remainder of Ni, Al and Cu. 
Besides the above-mentioned essential compositions, Si is effective in 
improving, particularly, a cooling speed from fusing temperature in the 
heat treatment and a castability thus it may be added by 0.01 wt % to 0.5 
wt %. 
Co is, basically, not an essential component of the present invention. 
However, sometimes it is mixed by utilizing scraps at the time of 
dissolution. 
Containing Co itself does not exert negative effects on the magnetic 
property, but when it is contained in a large amount, the principal 
feature of the present invention, that is to provide a low cost product 
can not be achieved, so that Co is preferably contained below 5 wt %. 
The alloy powders for bond magnet according to the present invention having 
the mean particle sizes of 10 .mu.m to 200 .mu.m is manufactured by well 
known grinding methods such as a jaw crusher, a ball mill and the like, 
after two-stage heat treatments of fusing at 900.degree. C. to 
1200.degree. C. and aging at 500.degree. C. to 700.degree. C. of an alloy 
(an ingot) prepared by the high-frequency dissolution at atmospheric 
temperature of, for example, 1600.degree. C. to 1700.degree. C. 
In the alloy powders of the present invention, it is not preferable if the 
mean particle size is below 10 .mu.m, because that the grinding cost is 
too high and, at the same time, a coercive force becomes lower, and since 
the moldability and uniformity as the bond magnet deteriorate when the 
mean particle sizes exceeds 200 .mu.m, the mean particle sizes is 
preferably within the range of 10 .mu.m to 200 .mu.m. 
As the methods of obtaining the alloy powders, it is not only the method of 
grinding the ingot obtained by dissolution, but as far as the particle 
sizes is within the range of 10 .mu.m to 200 .mu.m, the well known 
grinding and pulverizing methods such as an atomizing method, which 
injects gas or water for pulverizing after the dissolution, may be 
selected suitably. 
Also, the heat treatments such as fusing and aging treatments need not be 
performed independently, they may be performed continuously by controlling 
the cooling after dissolution. 
As a method for manufacturing the bond magnet of the present invention, 20 
wt % to 98 wt % of alloy powders having the aforementioned compositions 
and a binder are mixed, and molded into a predetermined shape by the 
molding methods such as injection molding, compression molding, extrusion 
molding and the like. 
The amount of alloy powders is preferably 20 wt % to 98 wt %, because that 
magnetic property as the bond magnet is lowered when below 20 wt %, and it 
is difficult to mold as a bond magnet when above 98 wt %, particularly 20 
wt % to 80 wt % is preferable for convergence use in picture tubes. 
In order to obtain the bond magnet having a high fire resistance, a 
predetermined amount of flame retardant may be mixed besides the alloy 
powders and the binder, and the same methods as stated above may be 
adopted. 
As the flame retardant, those of bromine type such as 
decarbromo-diphenyloxide, pentabromo-diphenyloxide, ethylene 
bistetrabromo-phthalmide, dibromo-neopentyl glycol and the like, and of 
chlorine type such as chlorinated paraffin, chlorinated polyphenyl, 
perchlor-pentacyclodecane, dichloranplus, chlorinated diphenyl and the 
like may be used. Also, those prepared adding 5 wt % to 25 wt % of flame 
retardant assistants such as synergist of antimony trioxide, additives of 
zinc boric acid, zinc chloride and the like to these flame retardants may 
also be used. 
Since some of the bromine type flame retardants are prone to produce toxic 
dioxine at the .mu.me of disposition and combustion at a fire, 
particularly, it is preferable to use the chlorine flame retardants, which 
is to be added, at least, 5 wt % or more to obtain the fire resistance of 
UL-94 Vo, but when the amount of additive exceeds 50 wt %, the moldability 
is deteriorated and also the cost increases, and hence 5 wt % to 50 wt % 
is the preferable range. 
As the bromine type flame retardants, ethylene bistetrabromo-phthalmide 
excluding pentabromo-diphenyl-oxide, octabromo-diphenyl-oxide and 
decabromo-diphenyl-oxide which are prone to produce dioxane, is 
preferable, and the amount of additive is preferably 5 to 20 wt %. 
Nonhalogen flame retardants containing no halogen elements such as bromine 
and chlorine, but containing alumina hydrate and magnesia hydrate can be 
used. 
As the binders, thermoplastic resins such as nylon, polypropylene, 
polyethylene, polyvinyl chloride, polyphenylene sulfide and the like, 
thermosetting resins such as phenol resin, epoxy resin and the like, or 
metal binders such as Al, Zn, Sn, Pb and so on can be selected suitably. 
In order to mix and knead the binder, flame retardant and alloy powders and 
a lubricant may be added or pretreatment may be performed. 
It is also efficacious, for improving thermal resistance and strength, to 
replace a part of flame retardant (including the flame retardant 
assistant) and/or binder with an inorganic filler consisting of silicates 
such as magnesium silicate, calcium silicate and the like, and the amount 
of additive of 2% or more of the components other than the alloy powders 
is effective, but it is not preferable above 45% because that the 
moldability is worsened. 
The alloy powders for bond magnet of the present invention has properties 
of 5 KG or more Br, 500 Oe or more iHc and 1 MGOe or more (BH) Max, and by 
mixing the alloy powders, binder, flame retardant and so on at a 
predetermined mixing ratio, the bond magnet of the present invention shows 
properties of 200 G or more Br, 150 Oe or more iHc, 0.01 MGOe or more (BH) 
max and 0.07%/.degree.C. or less temperature coefficient of Br, 
particularly, the bond magnet containing 20 wt % to 80 wt % alloy powders 
shows the high characteristics of 150 G to 1300 G Br, 150 Oe, to 500 Oe 
iHc, 0.01 MGOe to 0.15 MGOe (BH) max and 0.03% /.degree.C. to 0.05% 
/.degree.C. temperature coefficient of Br, and is most suitable for 
convergence use in the picture tubes. 
EMBODIMENT 1 
Magnetic property and grindability of the powders obtained by pulverizing, 
in a ball mill for 10 hours, an alloy having the compositions shown in 
Table 1, which was dissolved by using a high-frequency smelting furnace, 
and fused at 1200.degree. C. for 15 minutes, aged at 550.degree. C. for 
24 hours and further crushed to 35 meshes or less with a jaw crusher, are 
shown in Table 2. The grindability is shown by yields of the powders 
passing through 100 meshes. 
In Table 1 and Table 2, Samples Nos. 1-1 to 1-8 represent the present 
invention and Sample Nos. 1-9 to 1-13 represent comparative examples. 
As it is apparent from Table 2, in the case of alloy powders whose Al 
content is below 10 wt % such as the comparative example 1-9, or in the 
case of alloy powders whose Ni content is above 33 wt %, such as the 
comparative example 1-10. the magnetic characteristics is deteriorated as 
compared with the alloy powders according to the present invention. 
Also, though the magnetic properties of the alloy powders shown in the 
comparative examples 1-11 to 1-13 surpass those of the present invention, 
since a large amount of Co which is precious and scarce in resources is 
contained, the product is difficult to be provided at low cost. 
TABLE 1 
______________________________________ 
Sample Alloy Compositions (wt %) 
Nos. Al Ni Cu Ti Nb Si Co Fe 
______________________________________ 
Present 1-1 11.0 26.0 4.0 1.5 -- 0.1 -- 57.4 
Invention 
1-2 13.0 25.0 3.0 2.5 -- 0.05 -- 56.45 
1-3 12.0 29.0 4.0 -- 1.5 0.15 -- 53.35 
1-4 13.0 30.0 5.0 3.0 1.5 0.1 -- 47.4 
1-5 13.0 26.0 7.0 0.5 1.0 0.2 -- 52.3 
1-6 13.0 25.0 4.0 0.2 -- 0.3 -- 57.7 
1-7 12.0 25.0 4.0 0.3 -- 0.1 -- 58.6 
1-8 13.0 26.0 4.0 -- 0.4 0.15 -- 56.45 
Com- 1-9 9.0 21.0 3.0 2.0 -- 0.1 -- 64.9 
parative 
1-10 15.0 35.0 4.0 -- 3.0 0.1 -- 42.9 
Example 1-11 8.0 14.0 3.0 0.1 -- 0.6 24.0 50.3 
1-12 7.0 14.0 3.0 5.5 -- 0.1 35.0 35.4 
1-13 7.0 18.0 3.0 4.0 2.0 0.1 25.0 40.9 
______________________________________ 
TABLE 2 
______________________________________ 
Alloy Compositions (wt %) 
Sample Br iHc (BH)max Grind- 
Nos. (G) (Oe) (MGOe) ability 
______________________________________ 
Present 1-1 6.5 605 1.6 40 
Invention 
1-2 6.3 650 1.5 50 
1-3 5.6 640 1.3 55 
1-4 5.1 750 1.1 70 
1-5 5.3 550 1.2 60 
1-6 6.3 590 1.3 3 
1-7 6.3 600 1.4 10 
1-8 6.1 580 1.2 5 
Comparative 
1-9 6.7 450 0.9 -- 
Example 1-10 4.8 490 0.6 -- 
1-11 13.0 600 5.5 -- 
1-12 9.0 1500 5.5 -- 
1-13 7.0 1100 2.3 -- 
______________________________________ 
EMBODIMENT 2 
To the alloy powders of the present invention of Samples No. 1-2 of the 
Embodiment 1, nylon 6 powder was added as a binder, bromine type ethylene 
bistetrabromo-phthalmide was added as a flame retardant and antimony 
trioxide was added as a flame retardant assistant by the compositions 
shown in Sample nos. 2.about.8 to 2.about.3 in Table 3, mixing in a V 
mixer for 30 minutes and then kneaded in a kneader for 10 minutes as 
heating at 250.degree. C. to obtain pellets. 
The pellets were further molded by an injection molding machine at 
280.degree. C. to obtain a 10 mm.times.10 min.times.5 mm mold for magnet 
properties measurement, and a 12.7 mm.times.12.7 min.times.0.8 mm mold for 
fire resistance measurement. 
Evaluations on the magnetic properties and fire resistance of the bond 
magnet are shown in Table 4. The fire resistance evaluation was judged by 
carrying out the vertical firing test according to the JIS K6911 heat 
resistant test B to pass a V-o class as the fire resistance or not. The 
magnetic characteristic evaluation was judged by convergence properties 
after preparing the magnet for convergence use. 
Since the Sample No. 2-3* has a relatively little content of the flame 
retardant and flame retardant assistant as compared with Samples 2-1 and 
2-2, though it does not pass the V-o class as the thermal resistance, its 
magnetic properties is equal, thus by using in uses not requiring a high 
thermal resistance, effects of the present invention can be realized. 
Also in the following embodiments, as to those having a mark * on the 
sample numbers, the alloy powders, binder, flame retardant, flame 
retardant assistant, inorganic filler and so on are not necessarily 
contained at a proper amount, and the magnetic properties and fire 
resistance are relatively low as compared with the other samples. However, 
similar to the Sample No. 2-3*, by selecting their use, the effects of the 
present invention can be realized. 
EMBODIMENT 3 
A bond magnet was prepared by the same method as the Embodiment 2, except 
using nylon 6 powder as a binder and dichloranplus which is a chlorine 
flame retardant as a flame retardant, and using antimony trioxide as a 
flame retardant assistant A and zinc chloride as a flame retardant 
assistant B by blending compositions shown in Table 3. 
Evaluations on magnetic properties and fire resistance of the bond magnet 
are shown in Table 4. The fire resistance was evaluated by the same method 
as the embodiment 2. The magnet properties was evaluated on convergence 
properties after preparing the magnet for convergence use. 
TABLE 3 
______________________________________ 
Blending Compositions (wt %) 
Fire 
Retardant 
Sample 
Alloy Fire Assistant 
Nos. Powders Resin Retardant 
A B 
______________________________________ 
Embodiment 
2-1 50.0 23.0 22.0 5.0 -- 
2 2-2 50.0 15.0 25.0 10.0 -- 
2-3* 50.0 28.0 18.0 4.0 -- 
Embodiment 
3-1 50.0 20.0 13.0 15.0 2.0 
3 3-2 30.0 28.0 21.0 19.0 3.0 
3-3 40.0 25.0 16.0 17.0 2.0 
3-4 60.0 15.0 18.0 6.0 1.0 
3-5 70.0 10.0 12.0 7.0 1.0 
3-6* 15.0 35.0 29.0 18.0 3.0 
3-7* 70.0 20.0 4.0 5.0 1.0 
______________________________________ 
TABLE 4 
______________________________________ 
Eval- 
Magnetic uation 
Property on Evaluation 
Sample Br iHc (BH)max 
Magnet on flame 
Nos. (G) (Oe) (MGOe) Property 
retardancy 
______________________________________ 
Embodi- 
2-1 370 250 0.03 good qualified 
ment 2-2 410 270 0.03 good qualified 
2 2-3* 420 260 0.03 good not 
qualified 
Embodi- 
3-1 530 300 0.04 good qualified 
ment 3-2 210 160 0.01 good qualified 
3 3-3 340 230 0.02 good qualified 
3-4 850 360 0.08 good qualified 
3-5 1210 430 0.14 good qualified 
3-6* 130 110 0.005 poor qualified 
3-7* 830 370 0.07 good not 
qualified 
______________________________________ 
EMBODIMENT 4 
A bond magnet was prepared by the same method as the Embodiment 2, except 
magnesium silicate (a talc) was added as an inorganic filler, by the 
blending compositions shown In Table 5, to the same binder, fire retardant 
and fire retardant assistant as the Embodiment 3. 
Evaluation on magnetic characteristics, injection moldability and fire 
resistance of the bond magnet are shown in Table 6. 
The injection moldability was evaluated by judging as good or poor of the 
injection molding of the embodiment. The flameretardancy was evaluated by 
the same method as the Embodiment 2. 
EMBODIMENT 5 
A bond magnet was prepared by the same method as the Embodiment 2, by using 
the same flame retardant and flame retardant assistant as the Embodiment 
3, using a block copolymer of propylene powders of 450 .mu.m mean particle 
sizes as a resin, and using calcium silicate (wollastonite) as an 
inorganic filler, except the blending compositions shown in Table 5. 
Evaluation on magnetic characteristics, injection moldability and fire 
resistance of the bond magnet are shown in Table 6. 
The injection moldability was evaluated by judging as good or poor of the 
injection molding of the embodiment. The flameretardancy was evaluated by 
the same method as the Embodiment 2. 
TABLE 5 
______________________________________ 
Blending Compositions (wt %) 
Flame 
Alloy Flame Retardant 
In- 
Sample Pow- Re- Assistant 
organic 
Nos. ders Resin tardant 
A B Filler 
______________________________________ 
Embodi- 
4-1 30.0 21.0 15.0 4.0 1.0 29.0 
ment 4-2 40.0 15.0 16.0 5.0 1.0 23.0 
4 4-3 50.0 13.0 12.0 3.0 2.0 20.0 
Embodi- 
4-4* 30.0 5.0 12.0 3.0 1.0 49.0 
ment 4-5* 30.0 15.0 4.0 2.0 2.0 47.0 
5 4-6* 30.0 10.0 55.0 4.0 1.0 -- 
5-1 30.0 18.0 17.0 5.0 1.0 29.0 
5-2 40.0 15.0 15.0 4.0 2.0 24.0 
5-3 50.0 14.0 13.0 4.0 2.0 17.0 
5-4* 30.0 20.0 4.0 3.0 1.0 42.0 
______________________________________ 
TABLE 6 
______________________________________ 
Magnetic 
Property 
Evaluation 
Evaluation 
Sample 
Br iHc of Injection 
of flame 
Nos (G) (Oe) Moldability 
retardancy 
______________________________________ 
Embodiment 
4-1 220 170 good qualified 
4 4-2 430 250 good qualified 
4-3 610 320 good qualified 
Embodiment 
4-4* -- -- poor -- 
5 4-5* 240 180 good not qualified 
4-6* -- -- poor -- 
5-1 205 160 good qualified 
5-2 410 230 good qualified 
5-3 580 310 good qualified 
5-4* 260 190 good not qualified 
______________________________________ 
EMBODIMENT 6 
A bond magnet was prepared by adding 3 wt % epoxy resin to the alloy 
powders of the present invention, Sample No. 1-1 of the Embodiment 1, and 
curing at 150.degree. C. for one hour after mixing and compression 
molding. The bond magnet of the present invention has superior properties 
of 2.8 kG Br, 570 Oe iHc, and 0.5 MGOe (BH) max. 
INDUSTRIAL APPLICABILITY 
In the present invention, alloy powders for bond magnet having, high 
magnetic properties can be obtained without containing Co which is 
restricted in resources, by compositions of Al-Ni-Cu-(Ti, Nb)-Fe 
containing no Co; and by kneading, molding and curing the alloy powders 
for bond magnet together with a chlorine flame retardant, flame retardant 
assistants such as antimony trioxide and zinc boric acid and a binder, the 
flame reterdancy bond magnet having superior temperature properties and, 
particularly, most suitable for convergence use in picture tubes for 
display and high precision television can be provided at low cost, besides 
the bond magnet of the present invention is free from discharging toxic 
dioxane and has a high industrial value.