DE2106687A1 - Friction pairing materials, especially for sliding pairings - Google Patents

Description

The invention relates to a friction mating material, in particular for gloite pairings.

In the case of sliding parts for a wide variety of devices that are used in industry, the following are usually used Features required:

a) Seizing should not actually occur.

b) The wear resistance must be high.

c) The shape of one sliding part must match the shape of the other Adjust the sliding part, keep this shape and use the material of the other sliding part do not attack.

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Based on the previously known alloys for sliding pairs are these debts incompatible with each other, d. H. So far there are no pairings that meet the above three requirements.

If you choose metals with great hardness for bearing couples, for example hard chrome and molybdenum alloys, ie steels, stainless steels, "Hastelloy" and stellite, as well as super hard Materials composed primarily of tungsten carbide, or Ceramic substances, the main part of which is aluminum oxide, are found to have all three of the aforementioned properties are not present. In the case of friction or sliding pairings made of alloys such as stainless steel or Hastelloy, it is true excellent shape can be obtained, which is also maintained, however, the requirements related to the seizure become and wear resistance are not satisfied because the alloys are relatively soft. These requirements are now again, super-hard materials such as ceramic substances and the like suffice because they are hard enough, but their malleability is insufficient. Hard metals with chrome and Molybdenum, as it has been used up to now, does not completely satisfy any of the requirements a} to c). This shows that the known Sliding or Friction pairing materials always depending on the intended use need to choose alloys that are universal are useful, have not been known so far.

The object of the present invention is therefore to create a friction pairing material, in particular for sliding pairings, which is very resistant to seizure and abrasion, has excellent formability and adaptation properties with respect to the corresponding friction pair components and which is shaped as a sliding part, does not attack the sliding surface of the other sliding part.

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In the friction pairing material according to the invention, this object is achieved by an intermetallic compound in the form of a Ni-Ti alloy with 4.55 kis 53.5 atom% Ti, remainder Ni, in which 1 to ± 5 % of the Ni atoms have been replaced by at least one of the elements Fe, Mo, Co, Cr, Ta, Nb, W, Hf and V and optionally 0.5 to 30 % of the Ti atoms by Al and / or Zr.

The elements Fe, Mo, Co, Cr, Ta, Nb, W, Hf and V introduced instead of the Ni atoms are summarized below under "M ¹¹ , while the elements replacing the Ti atoms with Al and / or Zr "N" can be designated.

If you put this Reibpaarungsmat erial for example Sliding parts, it can be seen that seizure on the respective sliding surfaces during the sliding process almost or at all, does not occur, regardless of whether both sliding parts are made from the friction pairing material according to the invention or only one sliding part is made from it. The friction pairing material according to the invention still has one with the conventional alloys high wear resistance as well as excellent hardness and can be brought into the shape corresponding to the sliding surface of the counter friction part for the sliding movement in a simple manner, the is also retained, so that the desired contact can be achieved without the sliding surface of the counter friction part is subject to wear and tear.

The fact that in the intermetallic compound according to the invention, which is in the form of a binary Ni-Ti alloy, the nickel atoms in the listed proportion by a -or several of the elements M are replaced, once the one induced by temperature changes in binary Ni-Ti alloys Conversion, for example by heating after cold rolling, avoided, which would otherwise lead to changes in dimensions and shape. On the other hand, the wear resistance and the Resistance to eating increased.

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Of the elements M, which are intended to replace the Ni atoms in order to avoid the conversion, Fe is particularly suitable, this effect _{decreasing in the order Mo, Co 1} Cr, Ta, Nb, W, ilf and V. Cr is particularly suitable for improving the resistance to scuffing and wear, with this effect again _{decreasing in the order Mo, Co, Fe, W, Ta, Nb 9} Uf and V. The resistance to wear and seizing can be further improved by replacing Ti atoms in the stated proportion with one of the elements N or with the elements N if 1 to 45 % of the Ni atoms have already been replaced by M. However, since the formability of the alloys is reduced as the percentage of replacement of Ti atoms by the elements N increases, the upper limit is set at 3 ° / ° _{9 in} order to still allow hot and cold working.

In order to improve the machinability of the material according to the invention, a Ti content of 47 to 51 atomic Ω, in particular 49 to 51 atomic Ω, is preferred and 1 to 30%, in particular 1 to 20%, of the Ni atoms are replaced by M. If some of the Ti atoms are replaced by N, it is preferred to replace 0.5 to 10 % and in particular 0.5 to 5 % of the Ti atoms.

In order to improve the seizure resistance together with the machinability of the material of the present invention, the Ti content is 4? up to 51 atomic%. Then 1 to 30 % of the Ni atoms are replaced by one or more of the elements Fe, Mo, Co and / or Cr. To improve the machinability, the resistance to scuffing and the wear resistance at the same time, a Ti content of 49 to 51 atoms is selected and 1 to 20 % of the Ni atoms are replaced by one or more of the elements Fe, Mo and / or Co and, if necessary, from 5 to 5 % of the Ti atoms by Cr and / or Al.

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Optimal properties are obtained with friction pairings when the Ti content is 49 to 51 atom% and 1 to 2p % of the Ni atoms through Cr and Mo in a ratio of Cr / Mo> 1 and optionally 0.5 to 5 % of the Ti atoms are replaced by Al and / or Zr.

The good properties of the friction pairing according to the invention » terials are based on the fact that the alloy according to the invention is an intermetallic compound in which the atomic bond generally differs substantially from that of metals and alloys. With metals and alloys the atoms have the so-called metal bond, i.e. H. the Electrons in the electron shell of the atom can move freely in the crystal when they leave their orbit around the atom because. As a result of the attraction between these free electrons and the regularly arranged metal ions, the solid form to be kept. The release of the electrons in this association does not break the bond between the atoms, even if the relative positions of the atoms are changed to a considerable extent. As a result of this bond, the metals have and alloys in general have plasticity or formability. Because the bond between atoms is based on the above Bond type is limited, wear resistance and hardness of such metals and alloys are in a certain Interrelationship, with the general rule that the The higher the wear resistance, the higher the hardness.

In contrast, in the friction pairing material according to the invention The type of bond between the atoms is different, since in addition to the bond through free electrons there is an essential covalent bond There is a bond between the atoms. That means that the Properties of the material according to the invention of the interchangeable * Drawing between wear resistance and hardness are not subject, d. H. the material according to the invention has what at

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Metals and alloys of the conventional type does not have many specific properties, including an excellent one Resistant to seizure with the metallic Appearance is paired.

The present invention will be explained with reference to the accompanying drawings explained in more detail.

Fig. 1 shows a three-component diagram of the components Ni, Ti, M.

2 shows in a diagram a comparison of the wear values of stainless steel; n j '.ahl and titanium with that according to the invention Material.

The composition range of the material according to the invention, shown in a ternary phase diagram of the substances Ni, Ti and M in FIG. 1, lies in a rectangle which is obtained by connecting the points A, B, C and D with straight lines. The composition in point A is. 45.5 atom- Ji Ti, ο, 55 atom-% M, remainder Ni, in point B 53.5 atom-% Ti, ο, 47 atom- / »M, remainder Ni, in point C 53.5 atom- Ji Ti, 2o, 9 atomic% M, remainder Ni and at point D 45.5 atomic Sa Ti, 24.5 atomic% M ₁ remainder Ni.

To the left of the line AD there is an area with a brittle intermetallic compound Ni Ti _{1 which is} unsuitable for solving the task according to the invention, while to the right of the line BC there is a likewise brittle and unusable intermetallic compound NiTi _n , both of which are deposited in a secondary phase, thereby reducing the formability of the material and impairing the hot and cold workability of the material. Below line AB is the effect of Ni atoms occurs by the replacement of a portion of M is low. Not only the properties of the alloys to reduce a composition close NiTi on the line CD, but also deteriorates the formability and a hot and cold working is difficult.

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In Fig. 2 the result of a wear test is shown, which is carried out in the Ohgoshi tester. The abrasion resistance of the material according to the invention is with your of titanium and of a stainless steel (SUS 27), which both have a similar hardness as the material according to the invention to have.

In the experiment mentioned, the mechanism of abrasion changes with the rotational or circumferential speed of the sliding ring. As shown, for example, by the curve entered for titanium, the higher the peripheral speed from a zone with "Oxydatioiisabriet" i.c t less Incline in one zone with "Abrasion on bare surface" steep ascent finally to a zone with "melt abrasion", where the slope is lower again. It can be seen that the inventive Material in the speed range shown in Fig. 2 neither the zone with "abrasion on bare surface" still reaches the zone where the surface of the material is torn away by direct contact with the sliding ring.

The increase in peripheral speed causes a rise in temperature the friction surface. One can therefore assume that the mechanism of abrasion on or on the bare Surface is identical to the mechanism of seizure or seizure. The experimental results shown in Fig. 2 show thus that the material according to the invention in much less Dimensions than conventional materials or works at all tends to eat and therefore for much greater stress can be used.

As mentioned earlier, it is believed to have excellent wear resistance of the material according to the invention on the simultaneous presence of a covalent bond, whose

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The binding force is strong enough to give the material its strength to give, and is due to a metallic bond, comes from plasticity or malleability. In addition to the properties, there is also the fact that the material according to the invention is strong, tough and to a high degree wear-resistant, the feature that the sliding surface easily adapts to the shape of the sliding surface of the sliding partner adjusts or can be adjusted so that one obtains perfect contact over the entire surface, with dcis Material does not attack the surface of the opposite. This characteristic is due to the fact that the ratio of the yield strength compared to the breaking strength of the material is very low to common high-strength alloys, which is also on the coexistence of the different binding arias is due. The material according to the invention is thus for a universal Suitable for use, which was previously not achievable with conventional materialion.

Intermetallic compounds and substances as the main component containing an intermetallic compound are generally hard and brittle and in many cases leave a favorable deformability or ductility and a pliable Lack of behavior or favorable ductility, so that their plastic processing is not possible. The usage is thus limited to areas of application such as the manufacture of magnets, semiconductors and the like, where the Usability is conditioned by the special properties. The use of these substances for the manufacture of devices and parts, which have mechanical and chemical properties is extremely rare.

Although the friction pairing material according to the invention is now the main component has an intermetallic compound, it has an extremely high plasticity or malleability, can easily be made into sliding eggs with any desired shape,

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For example, to bars, discs, rings, bushings and the like by various machining processes processed and furthermore plastically deformed by pressing, hammering, rolling, etc., hot or cold. The manufacturing costs of the parts made from material according to the invention are therefore the same as or less than those used in the manufacture of friction pairing parts from known materials. In this case, a conversion due to temperature changes, as occurs with the known materials and to considerable changes in physical and mechanical Properties in the working temperature range leads to what in turn the cause of the changes in measure and shape when heated after cold working is prevented.

The invention is explained in more detail on the basis of the examples below.

EXAMPLE 1

The materials according to the invention listed in Table 1 are melted in a graphite vessel at about l'ilo C by induction heating at a vacuum of 2 to 5 × 10 Hg and the melts are poured. This is followed by hot working in the sequence of pressing, hammering and rolling at 93o to 700C, so that sheets with a thickness of 5 mm are obtained, the tensile strength and 0.2% yield strength of which are measured. The results are shown in the table 1 contrasted with those of conventional fabrics.

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üB687

-Io -

Ti TABEL 4V i8, 5Ti 1 0.2 %
Stretch
border,,
kg / mm Stretch limit/
Tensile strength
speed material composition lit IMo 5oTi train
firm
speed _o
kg / may " 91 o, 93 6Al ι ino 5 ο Ti 98 57 o, 8l conventional Stel 5oTi 7o 93 Ο.89 lich high Strength he stole 5oTi Io5 55 o, 44 5o, IFe I 126 63 o, 51 invent 42, , 5Fe 123 54 o, 57 dungs
according to 47, , 5Fe 95 45 o, 49 , 5 Ni IMo 92 49 0.51 , 5Ni 6 IMo 97 , 5Ni .1 4oNi 9Co ii 8Cr

As can be seen from Table 1, the inventive egg Material compared the ratio of yield strength to breaking strength very little with conventional fabrics. This property shows that the material according to the invention is easy with relatively can be deformed at low stress, while the material is very strong, which is crucial for good formability is.

EXAMPLE 2

5 mm

Strong sheets of materials according to the invention, the composition of which is shown in Table 2, are produced as described in Example 1, freed from an oxide scale by sandblasting and pickled brightly in an aqueous solution with 10% nitric acid and 10% hydrofluoric acid. Square pieces with an edge length of 30 mm are cut out of the metal sheets and their surfaces are cut to an accuracy of 4 with emery paper and a buffing wheel

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bcjcirboj tet. These pieces are then used for the abrasion test in carried out according to the Ohgoshi test arrangement. The results are shown in Table 2.

The test proceeds so that each of the square specimens is arranged parallel to the axis of rotation of the sliding ring, which is made of a high-speed steel with a diameter of 3o mm and a thickness of 3 i-un is made. The ring will against the surface of the sample with different pressures pressed, allowing it to slide at a fixed speed. The width of the on the surface of the sample evoked grooves is measured and the amount of specific Abrasion according to the formula

Ws = B · b ^3/8 · rP 1 determined, ο oo

where Ws is the amount of specific abrasion, B is a constant, b the width of the friction grooves, r the radius of the sliding ring, P is the pressure with which the ring is pressed against the specimen, 1 is the sliding path, calculated from the circumference times the number of performed Revolutions are. In the present experiment, the values for B - 3 j ° 5 j r = 3 ° now, P = 6.5 kg / cm, 1 = 2oo mm,

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TABEL

210B687

material

Composition Relcitive Abrasion Amounts χ lo "at an abrasion speed in

m / s of 1.4 3.6

•H
U

5Fe 5oTi
4oNi loFe poTi 4o, 5Mo 5oTi

5Mo 5oTi
4oNi loMo 5oTi I5M0 5oTi 5Co 5oTi
4oNi loCo 5oTi

o, 5Cr 5oTi ICr. 5oTi 48Ni 2Cr 5oTi 45Ni 5Cr 5oTi 4oNi loCr'5oTi 35Ni 15Cr 5oTi 3oNi 2oCr 5oTi 5Cr 49Ti 5Cr 45Ti 5Cr 4oTi loZr 5Cr 47Ti 5Cr 52 Ti

, 5Fe IMo 5oTi 47.5Ni IMo 1.5Co 5oTi 48 Ni IMo ICr 5ο Ti 4oNi 5Mo 5Cr 5oTi 4oNi 8Mo 2Cr 49Ti IZr 47.5Ni 1.5Fe IMo 45Ti

1,5Fe IMo 4oTi loAi, 1,5Fe IMo 4oTi 5Zr 5AI 48.5Ni 1.5W 5oTi 5Ta 5oTi

5oTi 109837/1036

IZr 5Zr

48Ni

2.3 2.2 2.3 2.0 2.2 1.9 2.1 2, o 2.3 2, o 1.9 2.2 1.8 1.7 1.6 2.5 2, 5 2.4 2.0 2.3 2.2 2.1 2, o 1.8 1.9 2.3 2.1 2 _S 2 2, o 2.1 2.4

68 60 58 22 Io

24 11

61 54 23 15

7 5 5

14 12 Io

13th

16

31

15th

24 9 9

29 25 26

51 28

33

2 10668?

material

Composition

Relative amounts of abrasion

χ Io at an abrasion speed in

m / s from

3.6

according to the charge

5oTi i 5V 5oTi

2.2
2.3

29 31

conventional

titanium 572 stainless steel 167 Hastelloy C 124 Stellite 38

763 198 180

Table 2 shows that the material according to the invention with respect to the wear resistance is superior to the known materials to a large extent and that the wear resistance by Replacing part of the Nl and Ti atoms with elements M and N, respectively, is improved.

This improvement is greatest when replaced with Cr atoms, followed by Mo, Ta and Nb. The best result is obtained with a combination of Cr and Mo. With regard to the influence of the amount of M and N, it can be seen that, when selected in the oxidative wear zone, where the friction speed is low, almost no difference can be observed in the wear zone on bare surface, where the abrasion speed is high, the effect of the replacement begins in the vicinity of 0.5% and the amount of specific abrasion increases with. increasing exchange rate up to 3 ° % .

Because the increase in the friction speed increases the temperature the friction surface results in, is shown at this example shows that the temperature where the oxidation

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Abrasion turns into abrasion on the bare surface, shifts to the side of the higher temperature when the Ni-Atorac is replaced by M and the Ti-atoms by N.

Since the seizure can be considered as tearing of the friction surface by abrasion, the seizure corresponds to the abrasion on bare surface, so that the replacement of Ni and Ti atoms and N durclM counteracts the seizure and prevents it. The results of this example show that the material according to the invention has little tendency to seize and is therefore suitable for far more severe working conditions than conventional materials.

Example 3

Made from material according to the invention with those shown in Table 3 Compositions are rods with a diameter of 22 mm produced according to the method described in Example 1, from the cylinder with an outer diameter of 20 mm and an inner diameter of 16 " and 50 mm height made by machining will. The abrasion properties are in an arrangement determined according to Suzuki. The results are shown in Table 3 Test values of test specimens made from traditional borrowed materials juxtaposed.

The test is carried out in such a way that two cylindrical test pieces with the dimensions mentioned are arranged concentrically vertically so that their end faces are completely in contact with one another. One sample is rotated at a certain speed under constant contact pressure, while the other is fixed in position. After this, carried out over a specific period sliding the weight change is measured of each test piece to determine the abrasion amount. Be as insurance conditional

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selected: load 2.5 kg / cm ", speed 275 rpm, number of completed revolutions 3 ° ooo.

Furthermore, the appearance of the sliding surface is made with the help using a magnifying glass or microscope determine the stage of feeding or conformity or adaptation. The character "0" in Table 3 stands that the sliding surface is glossy or mirror-like throughout and that no seizure can be detected. The sign "Y" shows that there is a slight seizure that can be seen on all or part of the sliding surface is. The sign "X" means that intensive seizure can be determined on the entire sliding surface.

From Table 3 it is clear that the abrasion of the 'invention Material, regardless of the material of the friction partner, is substantially less than that of conventional ones Materials detectable «and that the abrasion of conventional Materials can be increased by the fact that a friction partner of the friction pair is made of material according to the invention is made.

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TABLE 3

Friction pairing

Composition of parts (A, B)
the friction pairing

Abrasion in mg

Appearance of the sliding surface

A + B

from conventional
Alloys

titanium

stainless

Steel (SUS27)

Hastelloy C

Steep

titanium

stainless
Steel (SUS27)

Hastelloy C
Stellite

carbon steel

titanium

stainless
Steel (SUS27)

Hastelloy C
Steep

6.5

7, c

6.8

751

272 394 173

4ol

113 2o5 133 1537

557 775 342

Y Y Y Y 0 Y X X X X X X Y Y

From a
inventive unil
a conventional one
material

5oTi

5oTi

15Fe 5oTi
47.5 Ni 2.5Mo 5oTi
2.5Cr 5oTi
2.5Go 5oTi
2.5V, ^T 5oTi

stainless
stole

II
ti
II
It
Il

6.5 5.3 5.6 3.8 6.3

7.2

7.1 8, ο 7.5 7.9 6.6 8.5

O O O O O O O O O O O O

TABEL

Friction pairing

Composition of parts (A, B) of the friction pairing

Abrasion in mg

Appearance of the sliding surface

A + B

O From a CD inventive CO measured and O3 one here • <l convenient —Α material O cn

5oTi

5oTi

4?, PNi 1.5Co IMo 5oTi
4?, 5Ni 1,5Fe IMo 5oTi
47.5Ni 1.5Co IMo 5oTi
5oNi 45Ti 5Al
5oNi 45Ti 5Zr
47.5Ni 2.5Fe poTi
45Ni 5Fe 5oTi
35Ni 15Fe; ioTi

stainless steel

7,

2,3 Mo 5oTi
2.5Cr 5oTi
2.5Co 5oTi
2.3W 5oTi
2.5Ta 5oTi
2.5Nb 5oTi
1.5Fe IMo 5oTi
1.5 Co IMo 5oTi

11 Il I! It U II It 11

η ti

11

Il ti ti M Il

2.3
2.4
3.4
2.9
3.7
2.8

5.3

5-2 3.7 4.2 4, ο 5.4 5.7 3.3 3.1 2.1 2.3 2.5 2.7 2.5 3.2 3.6 2.6 2, 7th

8.7

8.8 6.3 6.5 6.4 8.8 8.6 7, ο

5.9 4, ο

4.7 5.1 5.4 4.8 6.7 7.1 5.3 5.5

O Y O O O O O O O O O Y Y O O O O O O O O O O O O O Y ü Y Y O O O O

TABEL

Friction pairing

Composition of parts (A, B) of the friction pairing Abrasion in mg

Appearance of. Sliding surface

A + B

O From a CD invention OO appropriate and ^ O one here , ^ convenient _ » material O cn

47.5Ni 1.5Fe IMo 4? Ti stainless

5Al steel

45Ni 5Cr 45Ti 5Zr "

45Ni 5Cr 5oTi "

47.5Ni 1.5Cr 1 Mo 5oTi "

47.5Ni 1.5Cr IMo

48Ti IZr IAl »

2.7 2.7

5.4

2, 5 O , 4 4, 9 O O I. 2, 1 2 , 3 4th O O co 2, O 2 , 3 4, 5 O O I. 2, 1 , 2 4, O O

When the same materials slide on top of each other, you notice severe seizure and abrasion with conventional fabrics, with their sliding surfaces becoming very rough. In contrast, no seizure whatsoever can be observed with a friction pairing made from a material according to the invention. When replacing the elements that contribute particularly to preventing abrasion, i.e. Mo, W and Cj-, an improvement in abrasion resistance is found with an increasing proportion of replacement. If, however, in the case of a combination of a friction part made of conventional material with a friction part made of a material according to the invention, consideration is given to avoiding attacking the friction partners, then replacing it with Fe and Co ','j; uteii results, with the best Result achieved by a combination of Co and Mo wii ^ d. While the abrasion of the material according to the invention generally becomes smaller with increasing exchange amount, an exchange of up to 20 % (within 10% as gelia.lt) is expedient when considering the abrasion of the other friction part. Similar to the combination of friction parts made of only one material according to the invention, when combining the material according to the invention with conventional materials, it is found that there is almost no roughness on the sliding surface, caused by seizing *, which in turn shows that the material according to the invention has an excellent effect in terms of it has to stop eating.

The friction pairing material according to the invention is thus special for the production of crankshafts, tapered bars, cylinders, Suitable for bearing bushes and bearing plates. It is used for transmission parts, machine parts, valves, as a sealing ring, For pump parts such as bushings, pistons and impellers, for shafts, axles, their bearings, for gear wheels, cutting blades of machine tools and other machining equipment, for parts of separators, such as cyclones and decanting equipment, in devices in the textile industry, for example for

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Thread holders, guide rollers and pulleys, in the plastics industry for nozzles and cylinders of extractors and injectors, for sports equipment, e.g. for skiers, sled runners, with pimples and spades, with medical instruments such as knives and tweezers, with drawing implements and can be used for many other purposes.

- patent claims -

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Claims (8)

PATENTAN'S PRICE 1. Reibpaarungsnmterial, especially for sliding pairs, characterized by an intermetallic compound in the form of a Ni-Ti alloy with 45.5 to 53.5 atom% Ti, the remainder Ni. which 1 to 45 % of the Ni atoms by at least one of the elements Fe, Mo, Co, Cr, Ta ₁ Nb, W, Hf, V are replaced. 2. Friction pairing material according to claim 1, characterized in that the alloy contains 47 to 51 atom-90 Ti and 1 to 3o % of the Ni atoms are replaced. 3. Friction pairing material according to claim 1, characterized in that the alloy contains 49 to 51 Afcom-Jfi Ti and 1 to 20 % of the Ni atoms are replaced. 4. Friction pairing material according to one of the preceding claims, characterized in that ο, 5 to ^ o% of the Ti atoms are replaced by Al and / or Zr. 5. Friction pairing material according to one of Claims 1 to 3j ^^ characterized in that ο, 5 to Io % of the Ti atoms are replaced by Al and / or Zr. 6. Reibpaari-ngsmateria 1 according to one of claims 1 to 3, characterized by dai? 0.5 to 5% of the Ti atoms are replaced by Al and / or Zr. 7. Reibpaarungsmaterial according to any one of the preceding claims, characterized gekurmzeiclme c that in Vox'handensein of Cr and Mo, the content ratio of Cr / Mu) · 1. 109837/1036 ^ 106687 8. Friction pairing material according to one of the preceding Claims, characterized in that the Ni-Atoine by one or more of the elements Fe, Co, Cr and Mo are replaced. 109837/103 $ Lee r side