28 June 2022

High-damping Alloy M2052
Examples of application in various field

CONFIDENTIALJTQ Co., Ltd〒221-0822
Nishikanagawa 3-152, Kanagawaku, Yokohama-city, Kanagawa, Japan
TEL: 045-642-5670 FAX: 045-432-0900
http://www.m2052.co.jp

Summary
・High performance not found in the previous generation of dumping alloys
This alloy is a Mn-based alloy consisting of Mn73, Cu20, Ni5 and Fe2 (atom %). Twinning activity (appearance,
disappearance, moving) in alloys occurs, when receiving a vibration load. But this material is expected to produce highdamping performance by a unique activity that has not been seen in previous alloys.
In spite of the fact that is a metal, it has the highest value of a loss coefficient similar to that of rubber (Figure 1).
Compered to rubber, the elastic module is an order of magnitude higher (Table 2), and it has strength of mild steel anddoes not have wobbling of soft materials like rubber. Although light-metal-alloy and lead have cheap strength, this alloy canalso serve as a structural material and should be a useful alloy in this age of light, thin and short.
・Excellent molding processability allows products to be made in any shape.
The shape and size are arbitrary because of the extremely high formability. This is one of the features that has not beenfound in any other alloy until now. Moreover, it is also easy to weld, braze and solder, and can be joined to different metals(e.g. 18-8 stainless steel), and precision casting is also possible. Thin plate, foil and ultrafine wire are available (Figure
14,15). It has reported that damping was achieved by attaching foils as small as 0.1 mm can be cut with scissors into small
pieces to device and equipment (Figure 36,37).
・High damping properties spanning from 0.01Hz to ultrasonic
It exhibits high damping performance over a wide frequency range from 0.01 Hz to 8 MHz in the ultrasonic range (Figure8,10). In the ultrasonic range, the damping is said to be as good as rubber. Rubber absorbs high frequency efficiently, butcannot eliminate low frequency. This alloy not only has a high ability to remove high frequencies, but with a little ingenuity,
it can also remove low frequencies that rubber cannot. The low frequency with large amplitude cause twinning activity to
be suppressed and damping performance to be degraded because it tends to lead the alloy to plastic deformation, whichleads to lattice defects and distortion. As a countermeasure, designing structure so that it can transform stresses applied tothe parts into “bent, twist and shear” and it can receive the vibration within the elastic range, the damping performance will
not be compromised. (Figure 17-21).
・High damping performance and high ductility at very low temperatures
Even in the extremely cold conditions of helium temperature, the damping performance is sufficient. Moreover, it ishighly ductile and does not exhibit low-temperature brittleness (Figure 9). Both lead and polymers lose their damping
properties and become more embrittled at lower temperatures, but this alloy is different.
・Easy to apply to precision instruments as it is not ferromagnetic
Since it is either paramagnetic or antiferromagnetic, it is advantageous for applications in a strong magnetic fieldenvironment.
・Easy to use
The higher the stress (i.e., the greater the amplitude), the higher the damping performance, if the use does not exceed theelastic deformation (Figure 9,10). This shows that it is easy to use. In ferromagnetic damping alloys, the effective amplitudeof vibration absorption is limited to a narrow range and therefore requires strong constraints on implementation conditions.
However, this alloy can bring out the damping effect even just by laid or pinched on the parts. In addition, a state witheven higher damping performance can be seen under conditions where a certain amount of load is applied. Because it is soeasy to use, the evaluation of the damping effect can be immediately verified. The reason why the spillover of this alloy
was from the acoustic world is that they were able to immediately distinguish between good and bad effects using only goodhearing, without the use of logic or expensive measuring equipment.

I・Some practical examples
Initially, it was popularized in the acoustic field. First, the insulator of the speaker, and then it is well receiver as a fastenerof washers, screws, etc (Figure 23-37). Some of the high-end models of major home appliance manufacturers use thesefasteners in abundance. There is also an example of improvement in noise and performance by simply putting two washers
in the installation point of a hard disk (Figure 52,53). Nowadays, it has spread to all industries and is used for various ideas
in the field of machine tools and precision equipment. By sandwiching a thin sheet of this alloy in the tool, it is possible toachieve "eliminate chatter" (Figure 41) and "a super-finishing of the Hale cutting and polishing surface" (Figure 38-40).
Several car manufacturers are also considering using this alloy. Nissan's Cima already use it as a ring for countermeasuresagainst noise when injectors are seated (Figure 54,55). It is planned to be used in the various form of motorcycles, model
airplanes, and helicopters for chemical spraying, etc.
An example was reported in which the resonance frequency of 25 Hz was significantly reduced by laying an M2052 alloy
mount as the result of study that the effect of the material of the mount installed on a surface grinder in order to eliminate
the resonance on the low-frequency side of the machine (Figure 43, 44). This is proof that we were able to remove the low
frequency by reducing the spring constant. It is also excellent results were obtained when the alternative use of rubber wastested by bending a 1mm thick sheet of M2052 alloy into a U shape so that large displacements could be obtained (Figure
64,65).
In the national project TAMA300 (Gravity Wave Detection Project Preliminary Test), it is necessary to measure the laser
beam under the conditions of ultra-high vacuum and extremely low temperature, and rubber, polymer and cast iron cannot
be used because the material must have high damping performance at low temperatures and gas release from material isextremely hated. Therefore, this alloy has attracted attention and has been reported in detail (Figure 56-62).
As in the case of the application to CD mechanism, the simplification of the structure itself by using this alloy and theimprovement of the damping performance (Figure 26) can only be seen in the creation of a new product. In addition to
improved performance, it is possible to reduce processes and reduce the weight and size of products.
These two examples suggest that fresh applications and products are possible if the characteristics of this alloy are used
well.
・Problems and issues
The production system for this alloy is not yet mass-produced, so the high cost is a concern. If mass-produced, it is expected
to be as good as stainless steel.
Since the principal component, Mn, is an active element, surface coating is required in some cases. FA coatings and nickel
plating are already in use. Other plating products such as black dye, copper, gold and silver are already on the market.
・Creation of products with new proposals
A noteworthy recent achievement is the recognition of a breakthrough effect in preventing bolt and nut loosening.
Evaluation and comparison of the anti-loosening effects of S45C, Fe-Mn-Cr and M2052 alloy showed that the bolt and nutof the iron-based damping alloy was the best, while the anti-loosening effect of M2052 alloy was confirmed to be close tothat of the iron-based damping alloy by using only one washer with a thickness of 1 mm instead of a bolt and nut (Fig.63,
Table 4). This is groundbreaking data from a maintenance and safety perspective. We can be sure that this application will
expand.
Rather than simply replacing conventional damping materials, this completely unique damping alloy can be used creatively
from a new perspective.

IIContents
1

Current status and problems of damping alloys

9 Automobiles

21

9.1 Application to engines・・・・・・・・・・・ 21

1

1.1 Current status of damping alloys・・・・・・・ 1
1.2 Problems with conventional damping alloy・・・1

10 Ultra-high vacuum equipment22

10.1 Comparison by frame structure ・・・・・・・22
2Novelty of the alloy M2052

3

10.2 Gas in an ultra-vacuum・・・・・・・・・

23

3Outline of the alloy M2052

3

10.3 Damping of the suspension system・・・・・ 23

3.1 Vibration absorption mechanism of alloy M20523・3
11 Common Countermeasure Effects
4 Main properties of the alloy M2052

4

24

11.1 Effect of the washer to stop the bolt from

4.1 Mechanical properties and workability・・・・・ 4loosening・・・・・・・・・・・・・・・・・・24

4.2 Temperature dependence・・・・・・・・・・・5

11.2 U-plate absorbing low frequency・・・・・ 25

4.3 Frequency and Amplitude Dependence・・・・・ 6
4.4 Other properties ・・・・・・・・・・・・・ 7

12 Summary

5 The problem of vibration transfer rate and high damping

Contents of Figureratio

1 Damping performance and strength of major damping

7

25

alloys・・・・・・・・・・・・・・・・・・・ 1
6 How to use the alloy M2052

2 Simplified diagram of twinned tissue・・・・・・ 3

8

6.1 Can be used in any shape from a variety of materials 8

3 Twinning activity due to external force・・・・・・・ 4

6.2 New function by devising a shape that lowers the spring

4 Twinning under an electron microscope・・・・・4constant -Low frequency removal that is not possible

5 The main mechanical properties of M2052・・・・・ 4

with rubber・・・・・・・・・・・・・・・・ 9

6 Change in transition temperature due to the shift in alloy
composition ・・・・・・・・・・・・・・・・・・5

7 Examples of applications

11

7 Performance change by process・・・・・・・・・・5

7.1 Audio

11

8 Vibration control at very low frequencies・・・・・・6

7.1.1 insulator・・・・・・・・・・・・・・・ 11

9 Damping in the vicinity of 4.2K・・・・・・・・・・ 6

7.1.2 Vibration-absorbing screws and washers・・12

10 Example of amplitude and frequency dependence of

7.1.3 CD player・・・・・・・・・・・・・・13

M2052・・・・・・・・・・・・・・・・・・・・ 6

7.1.4 Analog-record・・・・・・・・・・・・ 14

11 Transmission rate via spring and dashpot・・・・・・ 8

16

12 Transmission rate through rubber・・・・・・・・・8

7.2.1 Cutting tool holder・・・・・・・・・・ 16

13 Typical usage examples・・・・・・・・・・・・・9

7.2.2 Spacers for underlay of cutting tool・・・ 18

14 Products such as screws, washers, springs, pedestals and7.2.3 Mount of machine tool・・・・・・・・ 18

thin wires・・・・・・・・・・・・・・・・・・・ 9

7.2 Machining

15 Pipe Products・・・・・・・・・・・・・・・・・9
19

16 Examples of New Products in the Acoustic World ・10

8.1 γ-ray detector・・・・・・・・・・・・・・ 19

17 Application of high frequency and low amplitude・・ 11

8.2 Finely machined parts by the etching method・・ 20

18 Application

8.3 Bearing・・・・・・・・・・・・・・・・・ 20

amplitude ・・・・・・・・・・・・・・・・・・・11

8.4 Surface polishing machine・・・・・・・・・ 21

19 Application of low-frequency and high-amplitude coil

8.5 Computer・・・・・・・・・・・・・・・

type・・・・・・・・・・・・・・・・・・・・・・12

8 Precision Equipment

21

ofsemi-highfrequency

and

low

20 Application of low frequency and high amplitude・・12i21 Application of high frequency and low amplitude to low

57 Damping Effects of Different Frame Materials・・・23

frequency and high amplitude conversion・・・・・・・12

58 M2052 alloy tested on telescopes・・・・・・・・・23

22 Insulators for Speakers・・・・・・・・・・・・・1259 Enlarged view of the damper section of the telescope23

23 The effect of damping screws when striking an iron

60 Results of the M2052 alloy in telescopes・・・・・・23

plate・・・・・・・・・・・・・・・・・・・・・13

61 Damping of stainless steel coils・・・・・・・・・24

24 Screw fasteners on the base of the pre-main amplifier13

62 Damping of M2052 coil・・・・・・・・・・・・24

25 Mechanical set screw on CD player・・・・・・・・ 14

63 Effects of damping alloys on bolts and nuts・・・・24

26 Improving the CD mechanism・・・・・・・・・・1464 Substitution of rubber with a U-shaped plate・・・・25

27 Open CD・・・・・・・・・・・・・・・・・・14

65 The effect of replacing rubber with a U-shaped

28 Paste the M2052 link to the CD clamper・・・・・・ 14

M2052・・・・・・・・・・・・・・・・・・・・ 26

29 M2052 alloy for clamper damping・・・・・・・・1530 Even with the disturbance, the effect is still there・・ 15

Contents of table

31 Silent effect with analog record arm・・・・・・・・15

1 Typical damping alloys・・・・・・・・・・・・・2

32 SME tone arm and improvement parts・・・・・・・15

2 Major Physical and Mechanical Properties of the Alloy

33 Improvement in the sound pressure change in the entire

M2052・・・・・・・・・・・・・・・・・・・・・7

frequency range・・・・・・・・・・・・・・・・・16

3 Typical elastic bodies and their comparison・・・・・11

34 The sound pressure improvement effect seen below

4 Anti-loosening effect by various combinations・・・・25

1kHz・・・・・・・・・・・・・・・・・・・・・16

5 Differences in strength between polymeric materials and

35 Application of damping alloys to record cartridges・16

metals・・・・・・・・・・・・・・・・・・・・・26

36 Application to Stabilizers for Records and CDs・・・17

6 Loss factor of rubber and M2052 alloy・・・・・・・26

37 Application of MD to Clamping Plates・・・・・・17
38 Hale tool holders and damping alloys・・・・・・・17
39 Results with the Hale tool holder・・・・・・・・・1740 Hale machined surface finishing results by 6-axis
control・・・・・・・・・・・・・・・・・・・・・17
41 Effect of using spacers for cutting tool・・・・・・ 18
42 Example of use with bearings 1・・・・・・・・・ 18
43 M2052 alloy mount・・・・・・・・・・・・・・18
44 Damping effect of M2052 mounts・・・・・・・・19
45 Onboard γ-ray detectors・・・・・・・・・・・・19
46 Improvement of accuracy of γ-ray detectors・・・・19
47 Example of extraction of a 0.1 mm thick plate by etching
method・・・・・・・・・・・・・・・・・・・・20
48 Metal blind screen in CRT・・・・・・・・・・・20
49 Example of use with bearings 2・・・・・・・・・20
50 Improving the accuracy of surface polishing・・・・21
51 Boring arm vibration control・・・・・・・・・・21
52Hard Disk Seek Time Shortening Effect・・・・・・21
53Improved hard disk transfer speed・・・・・・・・・22
54 Damping rings used in direct-injection engines・・・2255 Noise reduction near 1kHz in vehicles・・・・・・ 22
56 Example of use in the frame of a suspension device・22ii

1 Current status and problems of damping alloys
1.1 Current status of damping alloys
With the advanced development of science and technology,
the problem of vibration has emerged more rapidly than everbefore. We have entered an era in which not only noise but
also nanometer amplitude noise is a problem in the precisionequipment sector. As a countermeasure against this problem,
the rigid structure of the equipment that can be the source
and the shielding of the source itself have a certain reduction
effect by the design considerations, but these are limited intheir own right, and the use of damping materials is essential.
Traditionally, rubber, lead, resin, and cast iron have been
widely used for vibration absorption, but now the muchneeded material is a damping alloy that functions as a

Figure 1 Damping performance and strength of major damping alloys

structural member.

performance, so there is no unified method at this point.

Polymers such as rubber and gel absorb vibration well andFigure 1 shows the contrast between the damping

generally have better damping performance than alloys.

performance and the strength of a typical metal material

However, their strength is orders of magnitude lower thanlimited to an integral type.

that of alloys, so they cannot be used alone as a structural

Familiar materials such as brass, carbon steel, stainless steel,member, and polymeric materials are only an adjunct inaluminum alloys, and titanium alloys are clustered at theterms of damping measures [1]. If possible, a damping

bottom of the figure and do not have much damping

material that doubles as a structure is required. It's inevitableproperties. Lead and cast iron, which are known to absorb

in this age of pursuing the light, thin, short and small. In

vibrations, belong to damping materials, but their

response, further development of damping alloys is required.

logarithmic damping rate is only 0.05, which is not very high.

Several damping alloys have been reported to have been

The alloy indicates the damping performance on the line

developed so far. Recent representative damping alloys areconnecting the two points in the black circle3), usually 0.3.

shown in Table 1. In terms of damping mechanisms, they are

The logarithmic decay rate of 0.72 is obtained if theclassified into four categories, and damping alloys withconditions such as grain size adjustment, removal of

excellent characteristics have been developed for each ofcontamination from raw material and furnace wall, andthem, and recently products with composite technologies

appropriate process control are met, and this value is 0.23,

such as damping steel plates1) have been marketed.

which is close to that of rubber. Even in the normal

Sonostone, as it has been known for a long time, is still going

manufacturing process, the logarithmic decay rate of 0.2 tostrong on military ships, but other damping alloys are not as

0.4 (0.3 on average) is maintained, and even at these values,

widespread as one might think2). This is because many

the performance is high in the figure. Recently, alloys with

damping alloys have too many limitations in terms ofless damping performance and more economic efficiency

application other than damping performance.

have been attracting attention. The Serena and WEL-CALM

Due to the differences in vibration-absorbing mechanisms

are just some of them, so there's a lot of room for applicationand material composition (bonded or integrated), it is

options. But there are problems with them too.

difficult to compare and evaluate vibration-absorbing
1)

This is not strictly a damping alloy, but a means of damping that consists

3)

It consists of Mn73, Cu20, Ni5, and Fe2 in atomic percentages, and isof a metal plate and resin.

called M2052 with M of manganese followed by a value of 20, 5, and 2,2)

which is the percentage of each remaining component element.

There are many examples of discontinuation of production.

1

Chapter 2

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
Table 1 Typical damping alloys

1.2 Problems with conventional damping alloy

are originally high in strength.

Cast iron has long been known as a structural member with

Therefore, vibration absorption does not work unless highdamping properties, and it is still used today as the base andstresses are applied, severely limiting its application. In

foundation of machine tools. However, cast iron contains aother words, the damping performance of wheels, gears,

large amount of carbon, and the embrittlement problem

rails, etc., is not common because it is only under high loadcaused by the notch effect cannot be ignored. Even thoughthat the damping performance appears. And the damping

cutting is easy, molding is extremely difficult. Magnesium

performance is not so high.

alloys are lightweight and are an attractive material. But in

Composite materials, such as damping steel sheets, havereality, the strength is low and molding is not possible.

problems related to their structure, and weldability andAluminum bronze and Nitinol also have workability

formability cannot be expected. In addition, it is not suitableproblems and are not commonly used as damping alloys.

for structures that can support high loads, so it cannot be

Mn-Cu alloys such as Sonostone and Inclamute have beenused to make complex shapes, large products, precision

known for a long time and are finding a way to be used forparts, or dense products, and is mainly used as a plate. It islarge parts, mainly as castings.

suitable for lightly molded lids and containers, but has

Ferromagnetic alloys represented by Silentalloy show highlimited application in other fields. Besides, the peelingperformance (maximum 0.3), but the fatal drawback

during operation is also troublesome. However, it is worth

common to this type cannot be dispelled. In other words, thenoting that it is inexpensive.

range of effective amplitude (effective strain) in which

M2052 alloy can also be precision cast, making it ideal for

damping performance appears is narrow, and if the

products with complex structures. Moreover, since theamplitude is outside this range, the damping effect is

amplitude

significantly reduced, and the material can no longer be

performance is proportional to the amplitude, it can be usedcalled a damping material. External vibration signals canat high amplitudes as long as it is within the limit where

only be accepted within a limited tolerance range, whichplastic deformation does not occur. There is no difficulty incauses disadvantages and complicates the design andusing it because its damping performance is flat, unlike

hampers the application.

alloys that show steep peaks in response to stress.

Iron-based damping alloys belonging to the dislocation type2

dependence islinearandthedamping

Chapter 3

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

2 Novelty of the alloy M2052

problems.

At first, the M2052 has gained a reputation among acoustics

3 Outline of the alloy M2052

enthusiasts, but it has recently made its way into precision

3.1 Vibration absorption mechanism of alloy M2052

instruments, machine tools, automotive, marine and space

The vibration absorption mechanism is described in more

technology. The reason for this is related to the following

detail in the rest of this article.Four damping mechanisms

characteristics.4)

have been discussed in alloys, and M2052 alloy belongs to

1.

The damping characteristics correspond to a wide

the twinned type. According to optical microscopy, twins arerange of stresses, frequencies and temperatures. In theoften observed as banded structures as shown in Figure 2. It

elastic region, the higher the amplitude, the higher theis called so because of the contrasting crystal structures that

damping performance. The frequency can absorb

are found at the interface between the mother phase and thevibration over a range of < 0.01Hz to 5MHz. Theband as if they were twins. (Figure 3 (6))

operating temperature ranges from 4.2K to 200C.

Figure 3 illustrates the mechanism of how the twinning2.

The strength is about mild steel, and it functions as astructural member.

3.

It has excellent moldability and can be supplied as foil,
sheet, thin wire or wire in any shape and size. Normal
sized planks and bars are no problem to provide.

4.

Cutting, drilling and rolling are the same as stainlessFigure 2 Simplified diagram of twinned tissue

steel.
5.

absorbs external vibrations. As shown in (1), the crystal

Casting is also possible, which is effective for mass

deforms elastically when an external force is applied to it,

production of precision products with complex shapes.
6.

leading to (2). When the external force is further increased,

Welding (between different types of TIG, laser,

it is not able to resist it and twinning occurs as shown in (3).

electron beam, and 18-8 stainless steel), brazing is easy,

Any further loading will result in the growth and widening

and paintability is good.
7.

of twins or the formation of new twins at other locations, as

Hard and soft plating such as copper, nickel, gold, andin (4) and (5). Except for external forces, the twinning will

black staining is possible, and FA treatment is alsoshrink or disappear. It is thought that the external force isavailable.
8.

received by such a twinning motion, where energy is

A stable supply of logarithmic damping rate of 0.3 isconsumed and the vibration is reduced.

obtained, and under optimum conditions, 0.72 is

Optical and electron microscopic observations show thatobtained.
9.

twins of various sizes are formed or exist depending on theDamping properties are maintained even at helium

manufacturing process, ranging from very small twins ofliquefaction temperatures, and ductility is not lost.

only a few tens of nanometers to several centimeters in

10. The design of the shape that reduces the spring constantlength in unidirectional solidified specimens.

creates a function that absorbs low-frequency and high-An example of an electron micrograph of this alloy is shown

amplitude vibrations in addition to shock relaxation.

in Figure 4. Circumstances in which the twinning is parallel

Until now, there had been no alloy with such a multifacetedor orthogonal are seen. Compared to ordinary alloy twinning,combination of features and comprehensive strength.

the size is much smaller, the quality of the twinning is

In this paper, we would like to introduce some practicaldifferent, and it has the following characteristics

examples5) that have been published so far and use them asa reference to create new objects and breakthroughs of
4)

The description of the M2052 alloy is already partly described in a
separate journal.
5)
There are many examples that cannot yet be disclosed due to theconclusion of a duty of care agreement.

Twinning is easily generated by external forces.



The interface between the generated and existing
twinning is easily displaced by the external force, andthe twinning is reduced or lost by the removal of the3Chapter 4

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 5 The main mechanical properties of M2052
Figure 3 Twinning under an electron microscope

made from such thin sheets by hydraulic or welding methods,
and the effect has been measured.
The hardness depends on the process history, and after
annealing, the hardness of Hv100 to 130
range. Since the work hardening ratio is small, it is possible
to cold-roll a sheet 50 mm wide from 5mm to 0.5mm
without intermediate annealing. In line drawing, the work
hardening is small, and the concave phenomenon tends tooccur, so intermediate annealing is essential to avoid it. The
machinability in cutting and drilling is close to that ofaustenitic stainless steels and belongs to the category ofsoftened alloys, but there are no difficulties in cutting as longas you understand the compatibility with the tool and the

Figure 4 Twinning activity due to external force

proper cooling conditions.

external force, and the shape is restored to its initial

Figure 5 shows the performance of the mechanical tests fromstate.

helium liquefaction temperature to 150°C. The tensile

Many twins of different sizes, depending on the size of thestrength at room temperature is about that of mild steel. The

external force, and the small twinning contributes to thestrength increases at lower temperatures, and the ductility

damping of small amplitude high frequency oscillations anddecreases, as in the case of general alloys.

the large twinning contributes to the damping of large

What is noteworthy is the cryogenic properties. In otheramplitude low frequency oscillations. Thus, the removal ofwords, the alloy is sufficiently ductile even at the helium

small vibrations of amplitude is easy, but large amplitudesliquefaction temperature, and only dimples are observed onrequire a touch of ingenuity, as will be mentioned in the next

the fracture surface, explaining the high toughness of theissue.

alloy. Moreover, the damping performance is maintained

4 Main properties of the alloy M2052

even at such a temperature. These features are expected to

4.1 Mechanical properties and workability

be applied in the cryogenic field. Most of the ordinary

This alloy can be easily formed and machined, and there arematerials, not to mention rubber, lead and resin, reduce orno problems with lathing, drilling, hot or cold working. We

lose most of their vibration-absorbing capacity below -70°C,

can supply not only thick and thin sheets, but also fine wires

and even lead makes a metallic sound when tapped. In

and foils in micron units. In fact, fine wire of 0.1 mm

contrast, this alloy exhibits an exceptional behavior, anddiameter and foil of 0.05 mm are available. The bellows areeven when exposed to extremely low temperatures, the4Chapter 4

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

sound of striking is similar to that of a piece of wood.

from that of M2052, but the amount of each alloy element is

Since the damping performance is dominated by the motion

slightly changed to shift the transition temperature to theof the twinning, it is necessary to avoid factors that interfere

high temperature side. Alloy A is an alloy with a standard

with the motion as much as possible. Machining operations
and rapid cooling operations from annealing temperatureoften cause distortion of the alloy, and the damping
performance is extremely low as it is. However, if the
product is annealed again at around 900°C after processing
and then treated with slow-cooling from that temperature,
the damping performance is almost restored, no matter how
severe the processing is.
Since the grain size can be adjusted to some extent by the
combination of processing and heat treatment, thecorrelation between damping performance and strength canFigure 6 Change in transition temperature due to the shift inalloy composition

be established. For the tensile strength of 600 MPa and 200
MPa, the logarithmic damping rates were 0.1 and 0.7,
respectively, as shown in Figure 1. If a damping ratio of 0.1
is selected, it can be applied as a strong damping structuralmember, and even if the damping ratio is 0.3, it issufficiently qualified as a structural member.
The residual strain and the presence of precipitates anddispersed particles will eventually reduce the grain size andshorten the kinetic distance of the twins, leading to a
reductionin the vibration

absorption

performance.

Therefore, in order to demand the highest possible vibration
damping performance, attention to detail is essential and the

Figure 7 Performance change by process

manufacturing process is difficult. In fact, in many cases,

composition. The so-called transition temperature, in whichstrength is the main factor rather than performance. In thethe damping performance suddenly deteriorates, is aroundnormal process, a logarithmic decay rate of 0.2 to 0.4 can be

50 °C. In the case of alloy B, the transition temperature rises

obtained, and even this value can be said to be revolutionary.

and there is no degradation up to about 120 °C. Alloy C
retains its damping properties up to about 150°C. In addition,

4.2 Temperature dependence

even when the composition is kept constant, a high

The temperature dependence of damping performance

temperature type up to nearly 180°C can be obtained

varies greatly between alloy types. Ferromagnetic types

depending on the combination of the process and heat

maintainhightreatment. Figure 7 shows an example of the effect on

temperatures, while damping steel sheets are determined bydamping performance that appears when different processes

the flow temperature of the resin. The twinning is dominatedare used for the same lot of test specimens. The performanceby the temperature at which the martensitic transformationof Process B was in accordance with the existing process,takes place, so it cannot be handled as a high-temperature

while Process A showed that the high temperature

type, and 200°C is considered to be the limit.

performance was improved by the combination of the

Figure 66) shows the temperature dependence of the three

processing rate and annealing. around 180 °C, and the Tan

theirperformanceuptorelatively

alloys in which the basic composition is not so different

6)5This data shows a low damping performance due to experimental reasons,but the value increases if the standard treatment is followed.

Chapter 4

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 10 Example of amplitude and frequency dependence of M2052

vibration control under the extreme environment.

Figure 8 Vibration control at very low frequencies

4.3 Frequency and Amplitude Dependence
Attenuation of this alloy has been found to occur over a wide
area from < 0.01 Hz at low frequencies to MHz at ultrasonicfrequencies.
Figure 10 shows the results of measurements based on thefrequency sweep method in the 75 Hz to 4.3 kHz range. The
attenuation rate increases in proportion to the amplitude,
whereas it is inversely proportional to the frequency. The
Figure 9 Damping in the vicinity of 4.2K

ninth-order resonant frequency, 4.3 kHz, has the lowest

δ value of 0.045 was secured, exceeding the normal 0.027).

attenuation, and this data may lead one to believe that the

It is possible to achieve the desired high temperaturealloy is incompetent for high-frequency and low-amplitude

performance by simply adjusting the process without

vibrations. However, practical examples in the acoustic

shifting the basic composition of the M2052 alloy. By

world prove that such vibrations can be eliminated without

shifting the composition and combining the heat treatment

a doubt. In addition, a logarithmic attenuation rate of more

and the process, we can be sure that the temperature up to

than 0.7 was obtained in the ultrasonic frequency range of 3

200°C can be achieved.

to 5 MHz8), which was comparable to that of rubber.

This alloy has a unique damping property at low

Therefore, the data shown in Fig. 10, where the damping

temperatures. Figure 8 shows a standard composition

performance decreases as the amplitude decreases, is not

M2052 alloy with a mountain near -50°C and a wide hem.

necessarily correct. There may be a problem lurking in the

The ease of use lies in the fact that the top of the mountainmeasurement method. The details of the damping

is not a steep peak. The measured frequencies range fromperformance at each frequency are not yet clear due to the

0.1 to 10 Hz, but the greater the distortion amplitude, thecomplexity and variety of factors involved in the damping

higher the damping performance. According to theperformance of this alloy.

measurement from 300K to 4.2K, as shown in Fig. 9, as thetemperature gradually decreases from the peak at 230K, thedamping property decreases, and at 150K, it significantly
decreases, and then rises again, and at 70K, a small, thoughstill small, peak appears again. The existence of such a
damping property near the extreme temperature is importantand can be expected, and research is underway to apply it to7)

8)

Even at this value, the function of the damping alloy is still maintained.

6

In this case, the frequency is much higher and the amplitude is very small.

Chapter 5

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

4.4 Other properties

The thermal expansion can be considered to be the same as

The main property values are shown in Table 2.

that of aluminum. The specific gravity is close to Fe, with avalue of 7.25. (Continued)

Table 2 Major Physical and Mechanical Properties of the Alloy M2052

5 The problem of vibration transfer rate and highdamping ratio
The magnitude of the transmission of vibrations from thesource to adjacent sites is expressed by the following
equation, as is well known in vibration theory.
1 + 2𝜍(𝜔⁄𝜔 )𝑇 =(1)(1 − (𝜔⁄𝜔 ) ) + 2𝜍(𝜔⁄𝜔 )𝑇 is the transmission coefficient, ςis the damping ratio,
ω is the forced angular frequency, 𝜔

is the specificfrequency. A mechanism or material with a damping
function at the boundary of the transmission path, such as acoil spring, dashpot, or rubber, is intervened to adjust ς.
Fig. 11 shows the relationship between 𝑇

and 𝜔⁄𝜔

when some of values of ς are given.
What we're about to find out from this isa: Calculated from Poisson's ratio

1.

b: Equivalent to Al, Mg, Pb and Sn

the vibrational insulation effect appears in √2 >c: Equivalent to Fe, Ni and Ti, d: Equivalent to Bi, Sb and Ti

𝜔⁄𝜔 . Therefore, the smaller the specific frequency

e: Equivalent to Cr, Fe, In, Sn and Zn

𝜔 is, the greater the effect.

Magnetism is paramagnetic around room temperature or2.

In the region √2 > 𝜔⁄𝜔 , the vibration insulation

above, and antiferromagnetic below the temperature attends to deteriorate as the damping ratio increases.

which the twinning appears. Therefore, it is likely to be of

From the damping side, the effect is diminished whenhigh value for precision instruments that do not like√2 > 𝜔⁄𝜔magnetism.

Therefore, as a compromise, it is usually designed to be

The Young's modulus is sensitive to composition. This isabout 0.1 <ς< 0.15.

along with a larger damping ratio.

because the composition causes the transformation point toAfter all, in the range of √2 > 𝜔⁄𝜔 , it is sufficient tofluctuate. Because the transformation point has a wide range,

remove the damper by reducing the spring constant of theeven if the composition is constant, it is not always

vibration insulator as much as possible, but the machine

determined by the temperature at which it is used. This canbecomes unstable as the spring constant becomes smaller.

be easily understood from Figure 8. The minimum value ofThis paradox is due to the fact that the coil spring itself has

the Young's modulus is 70°C, but the value changes at otherlittle damping capacity. If the coil has damping ability, thetemperatures. There is a tendency to increase with low

situation would be completely different.

temperature and converge to a constant value. The figure

M2052 coils can have a much lower spring constant thanshows 70 GPa at room temperature, but it ranges from 30 toordinary steel coils, but they can also be used not in the form

70 GPa depending on the composition, process and heatof coils but in the form of high spring constants, such as intreatment. Broadly speaking, they are close to or exceed

the form of mounts, so the above-mentioned paradox can bealuminum, silver, etc.

overcome if vibration isolation is achieved with such mounts.

Its thermal conductivity and specific heat are close to that ofIn other words, it is possible to create a vibration isolator

titanium, which is one of the hardest metals for heat transfer.

that is stronger and more damp than the coil type, and that7

Chapter 6

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 11 Transmission rate via spring and dashpot

Figure 12 Transmission rate through rubber

has both stable support and high vibration insulation..

6 How to use the alloy M2052

In the case of rubber, unlike the case of metal springs andThis alloy can be used in the following ways. Although there

dash pots, the following equation is considered reasonable

are definite differences, at first glance they have many uses

using the loss factor η.

in common with rubber. M2052 alloy can be supplied in awide variety of shapes, including plates and bars, pipes, wire

𝑇 =

1+𝜂
(1 − (𝜔⁄𝜔 ) ) + 𝜂

rods, fine wires, foils, and powders, and it has good(2)

machinability, plastic formability, and castability, as well as

According to this, the transmission disadvantage that occurs

mastery of microfabrication by etching, so it has a wide

at high K sites does not arise as the damping ratio increases.

range of applications.

When anti-vibration rubber is used, as shown in Figure 12,Insert into the vibration path.

even in the range of √2 > 𝜔⁄𝜔 , there is no worsening ofAdhere to the vibration source

the vibration isolation effect that appears with a larger lossApply powder to the vibration source

coefficient. Because of this, anti-vibration rubber is alsoSurrounding the source of the vibration

used frequently.

Connect the vibration sources.

M2052 alloy has the same advantages as rubber, being a

If we make a conceptual diagram, we can see Figure 13. (A)metal that can use the advantages of rubber. In other words,

pinch or insert, (B) support, (C) tie, (D) paste, (E) gather, (F)the attribute can be functioned effectively without worrying

enclose. As will be discussed below, these are proven to beabout the size of the high attenuation capacity. The

effective in real-world cases.

following points are the peculiarities of M2052 alloy that aresuperior to rubber.

6.1 Can be used in any shape from a variety of materials

1.

Ordinary metal coil springs themselves have little

Because of the ease of forming, it is possible to obtain a

damping property, but this alloy has a large damping

material of a variety of shapes and products as one pleases.

value.

Examples of actual materials are shown in Figures 14, 15

Rubber has very low strength and is susceptible toand 16. The screws in the upper left of Figure 14 are those"wobbling" and "dancing".

plated with various types of gold, copper, nickel, and black

The space required for installation of air springs is huge.

dye. Electrical components require continuity, and we are

The M2052 alloy has overcome these problems. As shown

able to handle gold and copper plating. The long round barin Table 1 below, there is a remarkable advantage when thison the left end is a special bolt with a 1mm diameter internalalloy is used as a coil spring.

thread that has been applied to the parts of precision

2.
3.

8

Chapter 6

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 13 Typical usage examples:

instruments. The fact that plating is possible suggests thatthe corrosion and wear resistance of this alloy can be greatly
improved, not only for screws. Although not shown, 0.1 mm

Figure 14 Products such as screws, washers, springs, pedestals andfoil is also produced. It can be cut into free shapes withthin wires

household scissors and used as a paste or roll.
There are also speaker insulators, pedestals, and washers.
There are also coil springs for tension and compression andbent plate type springs. A wire with a diameter of 0.1 mm isalso shown. Figure 15 shows the pipes, which were made by
cutting on the left and welding on the right. Figure 16 showsa recent hot topic in the field of acoustic products. a) is theshell of a cartridge for an analog record, b) is the spacer that

Figure 15 Pipe Products

goes underneath that cartridge, c) and d) are a pair, the power

6.2 New function by devising a shape that lowers thebox tap. It has become common sense that there is a limit tospring constant -Low frequency removal that is not

the improvement of sound quality without taking measurespossible with rubber

to eliminate noise from the power supply, and this productThe damping performance found in this alloy is a rare

is sold as a part of this. e) and f) are disk stabilizers. These

damping alloy that can cover the range of absorbableare noise absorbing goods that can be placed on a disc. g) isfrequencies from 0.01Hz or less to 10MHz. As experienced

a stabilizer for turntables. h) is a knob for a volume switch,with rubber, while polymeric materials can easily remove

which is said to be effective in isolating vibration through ahigh frequencies, their ability to remove low frequencies isshaft. i) is a stabilizer for a breaker. j) is a thick insulator. k)

small. Therefore, in the field of precision instruments,

is a foot for a device, case or rack. Thus, in the field ofexpensive anti-vibration tables and equipment are used inacoustics, the use of this technology has been evolving

abundance, but the problem is that the function of anti-

rapidly.

vibration cannot be brought out effectively because low
frequencies cannot be removed. We are also struggling withSince the parts can be welded together, complex products

this low frequency in high-voltage electron microscopy.

can be created. It also has a track record of bellows andThere is also the problem of ultra-low frequency pollution

atypical foaming.

emanating from transformers in substations. The M2052
alloy could be a clue to solve this traditional problem, sinceno material has ever absorbed low frequencies by itself.
The problem with low-frequency removal lies in how to
9Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
the low frequency vibration of the mount to reduce the low
frequency. d) is a mount that is deliberately prepared toapply pre-strain of tension by the load of the main body inorder to facilitate the generation of twinning. In any case,the spring constant is low in such a shape, and the frequency
and amplitude of the vibrations that can be absorbed are
categorically determined by the shape. Qualitatively, thelower the spring constant, the more low frequency and highamplitude can be eliminated. The low frequency around 25
Hz was significantly reduced, as in the practical example ofthe mount described below.

Figure 16 Examples of New Products in the Acoustic World

overcome the large amplitude. This can be achieved by

Figure 19 is an application of the coil shape. A metal coil canadjusting the spring constant by devising the shape of thebe used to reduce the spring constant easily and obtain highpart to correspond to the magnitude of the amplitude. For the

reliability. Ordinary springs are made of a high-strength

removal of high frequencies with small amplitudes, simply

alloy, and the alloy itself has little vibration-absorbing

inserting this into the vibration path will be effective. Most

capacity, so high frequencies come and go freely through itsof the applications in the acoustic world have been in thiscoils, sometimes causing a surging phenomenon, and low

category. However, for large amplitude vibrations, even at

frequencies can't be reduced much either. However, coils

low frequencies, the twinning should be made to movemade of M2052 alloy are not springs, they bring a whole

easily inside the alloy. For this purpose, it is necessary to

new function.

convert the vibrational external force into bending, twisting

Table 3 contrasts the specificity of the damping coil with theand shear stress.

structure showing the typical spring function. One of the

Figure 17 is a typical example of using it while remaining

characteristic features is that the damping performance is not

rigid. Low amplitude vibrations can be achieved with thelost even at near absolute temperature if the product is madesimple shapes shown in the figure. a) insulators and washers,of M2052 alloy, as shown in the previous article. Dependingb) gasket packing rings, c) spacers for large precisionon the structure, it is possible to create the lowest natural

perforators with a diameter of 100 mm and a thickness of 5

frequency for a spring-elastic material. Comparing coils, i.e.,

mm. d) is an example of a flange for a rotating body, right iscoil springs and M2052 coils, there is a clear difference inan example of a flange made of steel with a plate made ofperformance. Since metal coil springs usually have small

M2052 pressed against one side, e) to h) are sleeves forhigh-frequency insulation properties, the difference between

bearings and examples of the use of a holder/inner/outer.

stainless steel and M2052 coil springs is evident in the

These applications are for small amplitudes and are notcomparison as described below. When the two coils weredifficult as long as the load is not concentrated on a point or

vibrated at the same amplitude and the time taken to comeline contact and the M2052 is not plastically deformed

to rest was compared, the stainless steel coil still had alocally.

significant amount of vibration after 40 seconds, but the

Figure 18 shows an example of a mount on the base of a

M2052 alloy coil stopped in two seconds, one-twentieth ofdevice or equipment. The device absorbs unwanted

that time. As shown in Figure 19, it is possible to change notvibrations by using a mount with damping properties for

only the spring constant but also the natural frequency bylarge shaking vibrations of the device itself. The shapes fromvarying the cross-sectional shape and area of the coil. Also,a) to c) are capable of converting vibrations into

coils can be assembled as shown in c). d) and e) arecompressive and bending loads. It absorbs the low

examples of changing the spring constant according to afrequency transmitted from the main body, or interferes withdifferent shape from the coil. Because of its excellent
10Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
Table 3 Typical elastic bodies and their comparison(*1) A: excellent, B: good, C:passing, D: inferior, (*2) The ultrasonic absorption capacity of M2052 alloy is comparable to that of rubber.

Figure 17 Application of high frequency and low amplitude
Figure 18 Application of semi-high frequency and low amplitude

molding processability, you can create works of art as you

small spring constants to electronic circuits that emit highwish, depending on your ideas.

frequencies and low amplitudes. This is a resonator made by

Figure 20 is an example of an application that can be

M2052.

achieved with a simpler structure than the previous figures.

7 Examples of applicationsa) a board bent into a U-shaped shape, b) an elaborate shape

7.1 Audio

like a chair, c) a wire or a pipe made into a circle for an o-

7.1.1 insulator

ling-like application, and d) and e) are the use of pipes. In

The first application in the field of acoustics was the

addition to the absorption of the passing high frequency,

insulator of the speaker. It was easy to verify the effect bysuch a deflective use creates the possibility of eliminating

simply placing it underneath the speaker and using an ultra-

the low frequency due to the interference with the springsensitive device called an ear. Figure 22 is an example of aconstant depending on its structure. The results of the U-

loudspeaker used. It' s just a matter of sandwiching itboard will be described later.

between the speaker box and the base, and it worked very

Figure 21 shows a) a bellows, b) a damper wire, and c) to f)

well. Care must be taken if the speaker is lightweight or if

are parts that control vibration by attaching terminals with

the installation floor is soft. The higher the weight on the11Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure19 Application of low-frequency and high-amplitude coil typeFigure 21 Application of high frequency and low amplitude to low
frequency and high amplitude conversion

Figure 22 Insulators for Speakers

Figure 20 Application of low frequency and high amplitude

insulator, the more effective the damping effect will be, andtaps. Each waveform is a sound struck under the same

when the floor is soft, there will be no opportunity for theconditions. Clearly, the effect of the screw can be confirmed

twinning inside the alloy to work, so it will not have ato be decisive.

sufficient damping effect. Since then, this type of insulator

A large number of screws are used inside electrical products

has become one of the best-selling insulators in terms ofand equipment. When all the conventional screws wereshape and thickness.

replaced with damping screws and washers, the sound

7.1.2 Vibration-absorbing screws and washers

quality was transformed into a much better model. An

There were no examples of damping alloys being applied toexample of screw fastening is shown in Figure 24. This is an

so-called fasteners for screws and washers, but the M2052

example of a pre-main amp, with the M3×6 and M4×15

alloy did it.

screw washers in 11 places each. Just by using a damping

The screws, bolts, nuts and washers have a reputation as

device in such a situation, an extraordinary improvement inabsorbers and screws. It has already been adopted by somesound quality can be obtained. Figure 25 shows the CDof the major audio manufacturers, contributing to theplayer, which has four white stops, and the rubber was

improvement of sound quality. There are experimental data

removed, and M6 washers were inserted into the top andon the effects of damping screws. This is shown in Figure

bottom of the mechanism, and then the top was fixed. It is

23. An iron plate 300 long, 40 wide, and 3 mm thick issaid that even if it is a simple task, the reformation istapped and a microphone is used to compare the two-second

remarkable.

measurement records. On the left is a solid steel plate, andThe replacement of the screws that attach the chassis and theon the right is a test specimen with 4mm taps cut at five

IC circuit board has also had an effect, sparking debate about

points on the plate and 4mm damping screws attached to thethe fact of such an effect on digital signals. The mechanism
12Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 24 Screw fasteners on the base of the pre-main amplifier
Figure 23 The effect of damping screws when striking an iron platetransmits vibrations from the roadway. Pioneer overcomeshas not yet been clarified. The detailed results of the screw-

this problem by developing the Kalotu Area RS-D7X, aon experiments are reported as good. There is no way tosystem that creates the ultimate in sound quality in the cabin

determine which screw is the best to replace, except by trialof a car. There are several factors that contribute to this, but

and error, but the number of fans is increasing rapidly.

the biggest one is the creative use of the M2052, a CD player

7.1.3 CD playerthat uses a clamper to compensate for the setting and rotation

The mechanical base of the CD player was tested to improveof the discs. Figure 28 shows the construction of the clamper

the sound quality, and a groundbreaking result was obtained.

and the ring made of M2052.

An embodiment of this is shown in Figure 26. The

It was found that the CD set in the clamper had a resonanceimprovement was not in the use of screws, but in the use ofat around 700Hz (at 12cm) due to its own rotation, and thewashers and supports. The conventional type on the left usedsound quality was degraded. However, by attaching a single

rubber and springs, but the new type on the right eliminated

0.1 mm thick donut-shaped M2052 sheet to the side of thethem, and the sound quality is said to have improved

upper clamper in contact with the disc, the disc's vibrations

remarkably despite the simplification of the structure. What

were perfectly absorbed. Figure 29 shows the measurement

is noteworthy here is that the extermination of the rubber has

data for the new and old clampers. The solid line is the datataken place. The rubber has a large stroke, which in somefor the new model. The peak vibration around 700 Hz thatcases can induce second order disturbance vibrations. Basedappeared in the old model was reduced by more than a dozen

on the damping effect of the washer, it is also useful for

dB. Figure 30 shows the change in the error signal of thegasket and packing.

focus servo of the CD spindle due to the deliberate

In the case of an open CD, when an M2052 alloy disc (10mmdisturbance of the vibration from the road surface. The large

thick, 50mm diameter) was mounted on a stand made of

amplitude waveform at the bottom of the figure is theCorian (a resin with damping properties) and the CD's

disturbance signal, and the waveform at the top left and right

pickup mechanism was installed on it, the noise disappearedis the stopping effect of the servo. The results of using theand the playback sound was dramatically improved. Figure

damping sheet on the right show that the disturbance of the

27 is a real example of this. The top is an overview and the

CD due to external disturbance was significantly reduced

bottom is the black M2052 disc with the pickups installed.

compared to the left side without the sheet, proving that the

It is believed that the sound quality was improved because

disturbance to the sound quality was less affected. The fact

the damping discs absorbed miscellaneous signals from thethat a mere 0.1 mm of foil could have such a significant

parts connected to the pickups.

effect on vibration control is difficult to understand by

Even though the same CD player is used, the CD installed

experts who are familiar with vibration problems.

in the car is subjected to harsh conditions, and the demandfor high quality acoustics is a challenge because the CD
13

Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 25 Mechanical set screw on CD player

Figure 27 Open CD

Figure 26 Improving the CD mechanism

Figure 28 Paste the M2052 link to the CD clamper

7.1.4 Analog-record

alloy to further improve the sound quality, and theGood results have also been reported in tests on straight

improvement was so great that they had to rethink the soundarms and cartridges for analog records, as well as in theof the record. The SME arm is shown in Figure 32, which

installation of wiring cords. Remnants of washer punchesfeatures a plastic edge to support the arm in a balanced(known as punching belts) can also be used effectively. A

manner to maintain high sound quality. The improved parts

noteworthy example is the amazing effect that the belt has

are the knife edge at the bottom right of the photo and thehad on the arm of the record. Figure 31 shows its

spacer (a board to attach the arm to the turntable) at theexperimental apparatus. It' s twisted to make the belt

bottom left of the photo, which is an attempt to use M2052

stronger, but it' s a simple structure with a cartridge on thealloy. The result is a record that "sounds as fresh as if it's justleft end and a stand to connect the belt to the right end. They

been pressed after decades of listening to it on a variety ofrave, "Scratch noise is as small as it disappears, there is noplayers.” Several LP records were played, the first part of

known resonance in the tone arm, and the howling"Take Five" was recorded on CD-R and its waveform wasphenomenon is almost gone, and there is no need for

examined. The entire waveform is shown in Figure 33. One

exaggerated anti-vibration parts."

thing you immediately notice is the difference in soundThe tone arms made by SME are well known for their goodpressure in the high frequency range. The original arm issound quality among record enthusiasts. They used M2052

located at the top of the range and there is not much
14

Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 29 M2052 alloy for clamper damping

Figure 31 Silent effect with analog record arm

Figure 30 Even with the disturbance, the effect is still there

Figure 32 SME tone arm and improvement parts

difference of sound pressure between the upper and lower

place. In both cases, the effect was great.

arms. If you compare the lower frequencies below 1kHz, thedifference is clear. Figure 34 shows it, and if you look

The sheet is thin and can be easily cut up with scissors, soclosely at around 200Hz, you can see that the M2052 has

the shape and size can be adjusted by the user. A number ofmore up and down sound pressure, while the original has

unique results have been reported by processing andless variation. In other words, it can be interpreted that theattaching them in the right places9). Figure 36 shows a

improvement in sound quality is due to the fact that thephotograph of the record and CD stabilizers viewed from theM2052 alloy shows more vivid and subtle changes, evenback. Even a simple process of attaching three damping

though the volume is lower than that of the original.

sheets to the side of the disc that makes contact with it is said

Probably, it is still unexplored at the moment, but I canto be effective in improving sound quality.

predict a dramatic improvement in sound quality byreplacing the tubular arm made of Al with an M2052 alloy.

Simply screwing this alloy disc to the speaker's core caseIn addition, as an example of the application of the foil, theproduced the effect, and when the 0.1mm damping sheet ispresentation showed the tremendous effect of cutting 0.1mm

attached to the clapping plate located in the center of the MD,

thick foil into small pieces and attaching them to various

it has been found to be unexpectedly effective. Figure 37

parts of the cartridge and to stabilizers such as records.
Figure 35 shows the cartridge with the washer and foil set in

9)15

It appears in "A&V Village" magazine every time.

Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 33 Improvement in the sound pressure change in the entire

Figure 34 The sound pressure improvement effect seen below 1kHz

frequency range

shows the MD. The one on the left is a conventional productand the one on the right is a finished product with a thin discattached with epoxy adhesive. Such a simple measure10) was
said to have produced an amazing sound quality.
The effect of the paste is accused of being a "glue" effect andnot that of the M2052 alloy, but even the "glue" It is true thatthe sound quality will be changed no matter what kind of
material is pasted on, but the problem is not the change but
the modification. The M2052 alloy produces a modification.

Figure 35 Application of damping alloys to record cartridges

Recently, it has become possible to produce fine powders,

7.2 Machining

and new applications are emerging. The powder is dissolved

7.2.1 Cutting tool holder

in resin and applied to small, light-weight parts to remove

The requirements for machining accuracy are becoming

vibration.

stricter and stricter every year, and it is important to improve
the quality of the finished surface and the accuracy of bevel
cutting. It is serious. Various measures have been taken, andexpensive holders made of cemented carbide are said to beeffective. On the other hand, M2052 is also very effective,
and is already being used as a spacer for tools and a holder
for boring tools. It is commercially available. Most alloys
used in tools, including cemented carbides, are designed toreduce vibration from the standpoint of weight and rigidity,
but it should be kept in mind that vibrations propagating
through the tool are rarely absorbed and may interfere with

10)

vibrations coming from other sources, which may contribute

Easy to test with double-sided tape.

16Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
Figure 39 shows the results of testing a commerciallyavailable SCM435 hale tool holder and M2052 hale tool
holder and the resulting surface roughness. When the depthof incision is shallow, there is little difference between thetwo, but the larger the depth of incision, the more obvious
the effect is, and the M2052 surface roughness wasevaluated. Made in M2052 has the upper hand. The vibration
amplitude was significantly reduced and the surface
roughness was reduced to 0.1 micron in the case of

Figure 36 Application to Stabilizers for Records and CDs

aluminum processing. A mirror finish was achieved. Figure
40 shows an example of mirror finish obtained by hailingthe curved surface of an automobile sunroof (Al product)using six axes of control. The two columns on the left are
the results of the M2052 holders. The two columns on theleft are the results of the M2052 holder. The reflection image
is clearly clearer than the ball and end mill finishes of the

Figure 37 Application of MD to Clamping Plates

two examples on the right. High quality finishes are now

to unintended harm.

possible without the need for wrapping finishes.

The processing method of cutting wood with a planer iscalled hale processing, and the holder used to support thetool. The material of SCM435 is commonly used. Since it
was made of highly rigid material, it was prone to vibrations,which caused dissatisfaction on the surface finish. However,M2052 was adopted as the holder, and the results wereexcellent. Figure 38 shows the holder used in this study.
Commercial products with a notch (left), without a notch(center), and M2052 one without a notch (right). Threedifferent holders were tested and the results of this alloy
were tremendous.

Figure39 Results with the Hale tool holder

Figure 40 Hale machined surface finishing results by 6-axis control

Figure 38 Hale tool holders and damping alloys

17

Chapter 7

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

7.2.2 Spacers for underlay of cutting tool
Figure 41 shows an example of a spacer made of M2052
placed underneath a turning tool in the lathe machining
process. This is the result of an experiment in which an SS6
square beam was cut with a HSS tool11). Marks □■ arecommon mild steel spacers and ○● are data from M2052.
The data filled in the marks indicate that "chatter" occurredunder those cutting conditions. If the protrusion of mild steel
spacers exceeds 35 mm, regardless of the number ofworkpiece rotations, chatter occurs. However, with theM2052 spacer, chatter only appeared at the hardest conditionin this experiment, i.e., when the quantity was 50 mm andFigure 42 Example of use with bearings 1

the workpiece speed was 1900 rpm, but not other condition.
Just a 1mm thick spacer placed underneath the bite improves

and is not strong enough to resist the "chatter" pulse signal

dimensional accuracy and surface finish. Similarly, it iswhen used underneath a bite. In particular, as the thickness

known that some chatter has been detected, but within theof the plate increases, the stopping power decreases. Rubber

finishing accuracy, as in the case of the anti-chatter results

is unsuitable for such heavy duty applications. It should beof a sleeve used for center milling and the results of center

noted that, even in alloy M2052, the increase in thickness ismilling of a single crystal with a tool diameter of 5 mm andeffective in absorbing low frequencies, but the "chatter"a protrusion of 150 mm.

control force due to its elastic deformation may be reduced.

Figure 42 shows an example of a measurement from anotherThin materials are suitable for micro vibrations.

precision instrument manufacturer. It is used as a sleeve
7.2.3 Mount of machine tool
Various types of mounts are used to support machines andequipment. One of the purposes of these mounts is to reduce
vibration, and cast iron and polymer mounts are commonly
used. In the case of the M2052 alloy, it is necessary to create
an environment in which the elasticity of the M2052 alloy
can be deflected to the extent that it flexes in order to achieveeffective damping at low frequencies. This inference wassubstantiated by modeling experiments on the mount. Using
the shape of the mount shown in Fig. 43, it was installed
under a test surface grinder weighing one ton in four places,
Figure 41 Effect of using spacers for cutting tool

and adjusted with a torque wrench so that each of the mounts

spacer. The influence of the inner and outer plates made of

was loaded evenly. The excitation was evaluated by tapping

thin plate on the strength of vibration when they are inserted
around the bearing is examined. The strong vibrations ataround 5000 Hz are clearly suppressed.
Dramatically reducing "chatter" in thin plates and pipes, asin the example above, is difficult for rubber, the king of
damping materials. The rubber is extremely low in strength
11)

Figure 43 M2052 alloy mountThe feed rate was 0.15 mm/rev and no cutting oil was used.

18

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JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

the back of the column of the spindle head with an impulse

Rubber does not have this kind of damping ratio problem.

hammer, fixing an eddy-current displacement gauge on an

The M2052 alloy is not difficult to use because it doesn't

aluminum flange on the work table, which was assumed tohave it either.

be the grinding wheel, and detecting the cross-receptance
between the wheel and the table. The result is shown in

8 Precision Equipment

Figure 44. Four different types of tests were conducted with

8.1 γ-ray detector

combinations of mount and mounting bolt materials, which

Gamma-ray detectors are often used to measure radiation.

yielded some interesting facts. Resonance peak is seenThis M2052 sleeve was adopted as a part of the γ-ray

around 25Hz, but when both the mount and the bolt are steel,detector. Figure 45 shows a detailed view of it, the black

maximum displacement of 0.244 is shown at around 25 Hz

sleeve being the one in black. The vibration of theand even if only the bolt is changed, it decreases to 0.221.

compressor on the right side disturbs the gamma-ray

However, using the M2052 as a mount, the displacement

incidence window on the left side, resulting in the detection

declines dramatically to 17%. This result seems noteworthy.

sensitivity significantly lower. Figure 46 shows the data with

Importantly, this is an example of how even a rigid bodyits vibration propagation reduced by the damping alloy andsuch as an alloy can reduce low frequencies by reducing the

a 10% increase in accuracy, this detection device wasspring constant if the material has high damping

marketed.

performance.

Figure 45 Onboard γ-ray detectors

Figure 44 Damping effect of M2052 mounts

The rate at which vibration from the source is transmitted toother parts of the system is called the transmission
coefficient. When the ratio (ω/ωn) of the frequency of thevibration (ω) to the natural frequency of the system (ωn) is
1, the resonance occurs. And since the transfer rate is lessthan 1 for conditions where it is more than √2, we havetaken various measures to damp the vibration by increasing(ω/ωn) in the system. In order to do so, increase this ωn, or
add coil springs, air springs, dash pots, and orifices to the
Figure 46 Improvement of accuracy of γ-ray detectors

transmission points in hopes of achieving a damping effect.
In practice, when the damping ratio is high, the transmission
rate becomes unfavorable at the high point of (ω/ωn), so theThis type of sleeve also functions as a structural member, an

damping ratio is from 0.1 to 0.15 is recommended and highexample of which is nearly impossible to achieve withattenuation conditions are not necessarily acceptable.

rubber.
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JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

8.2 Finely machined parts by the etching method

at a point where we can accept it. The vibration problem

This alloy is very good at forming processes, so micron-seems to exist not only in the screen type CRT but also in

sized foils can be obtained. Therefore, a method similar tothe shadow mask type. From this, it is assumed that it can be

photo-etching can be used to achieve a fine finish, and thisused as a sealing (packing or gasket) with a thin and precise

special parts unique to the alloy can be acquired. Figure 47

structure and damping effect. Mostly rubber or copper strips

shows an example of a product that has been etched out.

are trying to fulfill their purpose, but sealing with this alloythat also serves as a damping device is also expected to havea unique demand.
8.3 Bearing
Vibrations from bearings often cause serious problems in
improving accuracy. As a countermeasure to this problem,
there are examples of its use in the inner-outer of a bearing
and in a stand. Figure 49 shows an example of themeasurement of the outer of a ball bearing. Compared to thestandard vibration, the two examples of M2052 alloy areboth more effective in damping vibrations at higher speeds.

Figure 47 Example of extraction of a 0.1 mm thick plate by etching method

Using this method, for example, it is possible to make ascreen made of metal foil for use in a vacuum environment.
Figure 48 shows a screen enclosed in a CRT, which operates
in a vacuum and is constantly vibrating and Sometimes large
vibrations occur and last for several minutes. To counteract
this, as shown in the figure, the screen, which tends to swing
easily, is fixed with two tungsten wires welded to the top andbottom. When the screen turned white, the line (called thedamper line) was identified, and since this line wascompletely nonsensical from a functional point of view and
was not to be used if at all possible, we were asked to

Figure 49 Example of use with bearings 2 :consider countermeasures.

It is more effective to use it as an inner layer than an outerlayer. It is important to note that the design should notexceed the yield strength of this alloy. The thicker the plate,the more effective it is for absorbing vibration. Although too
thick is effective for low-frequency absorption, the thicker
the material, the greater the elastic displacement, so thinneris recommended to avoid this. When targeting only highfrequencies, it is thin.
Elastic displacement under load is a fatal problem in the case

Figure 48 Metal blind screen in CRT

of rubber. However, it is not so serious with damping alloys,

The screen is made up of dozens of grids with a thickness of

whose strength is orders of magnitude higher than that of

0.1 mm in each of the thickness of the plates, the spacing

rubber.

between the grooves, and the width of the grids. At that time,
we had no experience in black plating or manufacturing foilsof severe smoothness and their heat treatment. We are now
20Chapter 9

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

8.4 Surface polishing machine

8.5 Computer

Slight runout of the rotational axis can be a problem when

As computers compete for higher and higher speeds,

surface grinding finishes are required to be precise. Grinding

micron-sized vibrations cannot be ignored. In particular,of lenses and silicon wafers is a typical example. Figure 50

anti-vibration measures for hard disks are fierce. The use ofshows an example of a thin ring of M2052 alloy that solves

these alloy washers in combination with the hard discs in thethe problem of rotational runout. A similar problem wascase has proved to be a revolutionary improvement and theysolved by using a ring of M2052 thin plate (large washer)are strongly recommended. Disk vibrations have a negative

between the existing holder and the spindle to prevent the

impact on head seeking the stronger the miscellaneous

boring tool from shaking, as shown in Figure 51. Thin plates

vibrations are in accessing the disk. In other words, a

are essential. The thicker the plate, the greater the ability tonegative impact on the head seeking prolongs the time it

absorb vibration, but the more elastic deformation of thetakes to reach the desired track, and in addition, increases

plate itself, which has other effects.

the probability of a misread. Figures 52 and 53 are examplesof this effect. Figure 52 shows that it takes half the time topinch just two washers, and Figure 53 shows that all of thewashers have increased the speed of file transfer as an effectof the washers. Although the effect is often thought to be
marginal, further speeding up of the disk and CPU will makea significant difference. With the recent increase in the speedof disk rotation, more complex hydraulic mechanisms haveemerged. In some cases, the M2052 alloy washer can beused for this purpose easily. The M2052's applications are

Figure 50 Improving the accuracy of surface polishingnot limited to hard drives, but can also be used for DVDs,
CDs, power supplies, fans, and even the legs of the casing.

Figure 51 Boring arm vibration control

Figure 52 Hard Disk Seek Time Shortening Effect

9 Automobiles
9.1 Application to engines
As shown in the schematic diagram in Figure 54, Nissan has
adopted M2052 washers as a measure to improve injector
seating noise as part of its efforts to make direct-injectionengines quieter, and these washers have already been21

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JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”

Figure 55 Noise reduction near 1kHz in vehicles

damping materials for ultrahigh vacuum equipment to verify

Figure 53 Improved hard disk transfer speed

gravitational waves), and the basic data and possibilities
were obtained and reported.

installed in a luxury car (Cima) and have been well received.
As shown in Figure 55, this is because a 5dB reduction in

10.1 Comparison by frame structure

the muffled sound near 1kHz was achieved. The application

In order to use M2052 alloy as the structure of theto other parts is also being considered.

TAMA300 project, a frame to suspend the optical elements
was considered, and the frame shown in Fig. 56 was madeof stainless steel and M2052 alloy and its effect was studied.
The frame consists of a top plate, a bottom plate and fourpillars. The results of a test with the frame mounted on ashaking table are shown in Figure 57. The obvious
difference is seen in the height of the resonance, with theM2052 alloy having a lower resonance peak and thedamping effect was excellent.

Figure 54 Damping rings used in direct-injection engines

Other major car manufacturers have reviewed the alloy's
performance and have indicated that they will soon adopt it.
While anti-vibration rubber is widely used in the automotive
industry, there are some parts of rubber that are problematic.
The lower the frequency and the more minute the vibration,
the more the weakness of the rubber is exposed. so it isconceivable that it could be used as part of mounts, torsion
bars, suspensions, bushings, dampers, etc.

10 Ultra-high vacuum equipment

Figure 56 Example of use in the frame of a suspension device

One of the requirements for materials used in an ultrahighvacuum is the issue of gas release from the material.
Candidates for damping materials that can be used in suchan environment are scarce. M2052 was selected as one of
the target alloys for the TAMA300 project (research on
22

Chapter 10

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
plate, which is suspended from a frame supported it.
Stainless steel springs and tungsten wires were previously
used for the suspension. In this test, the tungsten was
replaced with M2052 alloy. Figure 59 shows an enlarged
version of this section. In the past, the wire oscillated, which
took a long time to reduce the oscillation and caused
problems during observation. The measurement results of
the new installation are shown in Figure 60. Three cases

Figure 57 Damping Effects of Different Frame Materials

10.2 Gas in an ultra-vacuum
The vacuum characteristic of the material is important in ahigh vacuum environment. The gas release from the surfaceof M2052 alloy by the thermal desorption method wasinvestigated. Although the gas release rate is about 10 times
higher than that of 18-8 stainless steel, it has been judgedthat the material is sufficiently suitable for ultrahigh vacuum

Figure 59 Enlarged view of the damper section of the telescopewith appropriate surface treatment and baking.

were tested, which are tungsten wire only, M2052 alloy wire
only, and both wire and damper in M2052 alloy. As shown10.3 Damping of the suspension systemin the figure 60 below, the effect of the M2052 alloy was

In the TAMA 300 project, a number of devices areevident and it was found to decay more than 10 times fastersuspended in order to avoid vibrations coming from various

than before. This system was judged to be practical and hassources. One of them, the M2052 alloy, was tested on abeen incorporated into the TAMA 300 and is working well.

telescope apparatus for mode matching. A schematic
diagram is shown in Figure 58. The main optical elements
are two off-axis parabolic mirrors with accompanying
mirrors and a mechanical adjustment mechanism. All ofthese optical elements are assembled on a single aluminum

Figure 60 Results of the M2052 alloy in telescopes

The data for the springs are shown in Figure 61 and 62. The
damping performance of a coil spring made of stainless steel
and M2052 is shown in Figure 61 and 62, respectively. The
Figure 58 M2052 alloy tested on telescopes

comparison is made when the coil and wire diameters are23

Chapter 11

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
11 Common Countermeasure Effects
11.1 Effect of the washer to stop the bolt from loosening
There is a concern that the fastening force of bolts and nuts
made of high-strength alloys may decrease during use,which is called "loosening". It is expected that the use of analloy that absorbs vibrations would alleviate this concern. It
was found to be correct. The results are shown in Figure 63
and Table 4. A combination of M10 x 60 bolts andnuts/washers of different materials is used to fasten them
together and repeated impact loading, after that, loosenesswas detected from the values of the strain gauges applied at
a given position.
Figure 61 Damping of stainless steel coils

It is clear from Figure 63 and Table 4 that the effect of theiron-based damping alloy (Fe-Mn-Cr system) is tremendous,
and while more than 10 kN of tightening is required for
S45C alone, only 4 kN is found to be sufficient when thedamping alloy is used. In the experiment with the M2052
alloy, the bolts and nuts were S45C steel, and only one
M2052 washer with a thickness of only 1 mm was used, but
despite this, only 6 kN was sufficient for the tightening force.
When compared in terms of the volume of the damping
alloys used in the tests, the results of the 1 mm M2052 alloycertainly outperformed the iron-based alloys. If it is two
1mm or more thick plate washers, we can infer that further
effect is certain. The M2052 alloy is most promising if all of
the bolts and nuts are made of M2052 alloy, but since its
strength is about the same as that of mild steel, the cross-

Figure 62 Damping of M2052 coilsectional area must compensate for the use of high strength

approximately equal, and the damping alloy is damped at an

and tightening, and it is not suitable for applications where

overwhelmingly fast rate. While the stainless steel still

this is not allowed. If you only intend to stop it from getting

showed strong residual vibrations after 40 seconds, theloose, one M2052 washer is enough to meet yourM2052 alloy stopped after about 2 seconds. This is a natural

expectations.

consequence of the fact that ordinary metal coil springs havealmost no damping properties in themselves. A uniqueapplication is possible by using a damping alloy as the shapeof the coil.

Figure 63 Effects of damping alloys on bolts and nuts

24Chapter 12

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
Table 4 Anti-loosening effect by various combinations

The high loosening prevention effect of the bolts and nuts isdirectly related to the simplification of maintenance andensuring safety. The M2052 alloy requires only one 1mm
washer to make it happen.
11.2 U-plate absorbing low frequency
Rubber tends to be easily used to counteract minor
vibrations. Sometimes it works, but if the conditions aredifferent, a "rubber dance" can occur and the tremendous
resonance can destroy the parts. Figure 64 shows a device
holding a box consisting of a powerful low-frequency
Figure 64 Substitution of rubber with a U-shaped plate

vibration source. Here is an example of the difficulty ingroundbreaking results are certain to be achieved.

preventing the vibration from being transmitted to thevarious equipment and materials in the vicinity. When nocountermeasures were taken at all, as shown in the top graph

12 Summaryof Figure 65, the acceleration was slightly right-handed,

If you are familiar with polymers, especially rubber, forcentered on 3G, and appeared to be generally low and not a

vibration control, you don't usually have damping alloys inproblem. However, small peaks appear in small increments

mind. The damping performance is not as good as that ofof 70Hz, 130Hz and 200Hz, and these vibrations interact

rubber, but the cost is higher and the use of the material iswith other vibrations to cause problems. So, they operated

more complicated. However, the M2052 alloy is an insanewith rubber installed at key locations, but as shown in thealloy, and as shown in Table 5, when the manufacturing

data in the center of the figure, there was a strong resonanceprocess and raw material selection were optimal, aof 18G at 25 Hz, and this resonant wave induced various

logarithmic decay rate of 0.73 was obtained. When

problems. As a countermeasure, a trial to reduce the spring

converted to a manufacturing loss factor, it is equivalent toconstant was carried out using M2052. Rubber was used for0.23. It can be understood that this is the same as rubber. In

the black areas in Figure 64, and a U-bent plate of this alloythese days of today's quasi mass production regime, an

was applied to the black areas. The results are shown in the

average loss factor of 0.11 is offered. It is not necessarily an

data below in Figure 65, where the resonant acceleration is

exaggeration to say that the performance is close to rubber,

reduced to almost half that of the rubber case, and the rest ofeven if it does not reach the maximum performance ofthe high-frequency component is almost gone. Although thisrubber. In addition, as shown in Table 6, the alloy has an

test was merely a result of bending a hand-held plate, if theorder of magnitude higher strength than rubber, which can

optimum conditions are met by changing the plate thickness,compensate for the shortcomings of rubber.

width, radius of curvature, length, etc., we can infer that25

Chapter 12

JTQ Co., Ltd “Examples of application of High-damping Alloy M2052”
Table 5 Differences in strength between polymeric materials and metals

Table 6 Loss factor of rubber and M2052 alloy*1)Highest Price. Usually 0.06 to 0.16

temperatures, from the upper limit of 200°C to thelower limit of the helium liquefaction temperature.
4.

Figure 65 The effect of replacing rubber with a U-shaped M2052

M2052 alloy than for butyl rubber, obviously, thefunction is a structural member.

Rubber can cause the following problems in vibration

5.

control.
1.

The lower the frequency, the less it is absorbed.

2.

The smaller the amplitude, the less it is absorbed.

3.

The temperature range in which high performanceStrength is an order of magnitude lower than metal.

5.

The rubber must be selected to match the environment

6.

Fears of "dipping" and "dancing" and quality

coating, and nickel, gold, copper, black oxide, FA, zinc,and various paint treatments are available.
6.

The new alloy has features not seen in conventional damping
alloys, and also offers high performance never before
reported for damping alloys, and it can be used in any
casting or molding process, and can be used to weld or

Although M2052 alloy is inferior in terms of loss factor, it

otherwise bond products. Therefore, there is a wide variety

completely overcomes all the problems of rubber.

of options for the size and shape of the object, and it can be

The frequency can absorb vibrations over a wide range

used as an alloy suitable for structural members for vibrationfrom 0.01 Hz to MHz in the ultrasonic range.
2.

damping. By taking advantage of this feature, we can not

It can be considered to absorb vibration whose

only solve the current problems, but also subsidize new

amplitudes range from nm for small displacements anddesigns at times, which will contribute in some way tofrom mm to cm for large displacements if the shape isexisting or new fields of industry.

well designed.
3.

"Dipping", " dancing" and quality deterioration areunlikely to occur.

degradation follow.

1.

It is sensitive to weak acids on bare surfaces, but its
corrosion resistance can be improved with a surface

appears is relatively narrow.
4.

The elastic modulus ratio is 12,500 times higher for theVibration absorption capability over a wide range of26