ANTI-FRICTION LACQUER AND SLIDING BEARING LAMINATE COMPRISING SAME

Abstract

The invention relates to an anti-friction coating (11, 12, 41, 42, 43) and an anti-friction coating composite (10) comprising at least 25 vol. % of a binder (16) and comprising fillers, which include zinc sulfide (18) and barium sulfate (20) and optionally additional fillers, wherein the volume ratio of barium sulfate (20) to zinc sulfide (18) is between 0.1 and 15.7, preferably between 0.8 and 4.88, and particularly preferably between 1.5 and 3.44. The anti-friction coating composite (10,40) comprises at least two anti-friction coatings (11, 13) of different compositions. The invention further relates to sliding bearing layered composite materials comprising such coatings and use thereof in internal combustion engines.

Claims

1. An anti-friction coating comprising at least 25 vol. % of a binder and comprising fillers, which include zinc sulfide and barium sulfate, wherein the volume ratio of barium sulfate to zinc sulfide is between 0.1 and 15.7.

2. The anti-friction coating according to claim 1, wherein in total the zinc sulfide and the barium sulfate are contained in the total composition in a proportion of 2 to 35 vol. %.

3. The anti-friction coating according to claim 28, wherein in total the zinc sulfide, the barium sulfate and the additional fillers are contained in the total composition in a proportion of at most 75 vol. %.

4. The anti-friction coating according to claim 1, wherein, the zinc sulfide and the barium sulfate are present in powder form at a d50 value in the range of 0.1 m to 1.0 m.

5. The anti-friction coating according to claim 1, wherein the zinc sulfide and barium sulfate fraction is present in the form of lithopone.

6. The anti-friction coating according to claim 1, wherein the binder is selected from the group consisting of PAI, PI, epoxy resins, PBI, silicone resins and highly aromatic thermoplastics.

7. The anti-friction coating according to claim 1, wherein the coating has a thickness of 1 m to 40 m.

8. The anti-friction coating according to claim 28, wherein the additional fillers contain at least one solid lubricant.

9. The anti-friction coating according to claim 8, wherein the at least one solid lubricant is selected from the group comprising metal sulfides having layer structure, graphite, hexagonal boron nitride, and PTFE.

10. The anti-friction coating according to claim 28, wherein the additional fillers contain at least one hard material having a total proportion of not more than 10 vol. %.

11. The anti-friction coating according to claim 10, wherein the at least one hard material is selected from the group comprising nitrides, carbides, borides, oxides, in particular SiC, Si3N4, B4C3, cubic boron nitride, TiO2, and SiO2.

12. An anti-friction coating according to claim 28, wherein the additional fillers (28) include at least one metal powder having a total proportion of not more than 30 vol. %.

13. The anti-friction coating according to claim 12, wherein the at least one metal powder is selected from the group comprising the elements Ag, Pb, Au, Sn, Al, Bi, Cu, and alloys of these elements.

14. The anti-friction coating according to claim 28, wherein the additional fillers comprise up to 15 vol. % iron-(III)-oxide.

15. An anti-friction coating composite comprising at least two anti-friction coatings of different compositions according to claim 1.

16. A sliding bearing layered composite material comprising at least one metal layer and an anti-friction coating according to claim 1 applied on a surface of the metal layer.

17. The sliding bearing layered composite material according to claim 16, wherein the surface of the at least one metal layer has a roughness Rz of 1 m to 10 m.

18. The sliding bearing layered composite material according to claim 16, wherein the at least one metal layer comprises a bearing metal layer made of an alloy based on one of the elements selected from the group consisting of Cu, Al, Ni, Sn, Zn, Ag, Au, Bi, and Fe.

19. The sliding bearing layered composite material according to claim 16, wherein the at least one metal layer comprises a bearing metal layer made of an alloy selected from the group consisting of CuSn, CuNiSi, CuZn, CuSnZn, AlSn, AlSi, AlSnSi, and AlZn.

20. A sliding bearing layered composite material according to claim 18 wherein the at least one metal layer comprises a steel support layer and optionally an intermediate layer made of Ni, Ag, Cu, or Fe applied on the steel support layer, wherein the bearing metal layer is applied on the steel support layer or, if present, on the intermediate layer, and wherein the anti-friction coating or the anti-friction coating composite is applied on a surface of the bearing metal layer on the side facing away from the steel support layer.

21. An internal combustion engine having a sliding bearing layered composite material according to claim 18 any one of claims 16 to 20 or 27 in a bearing element for an internal combustion engine.

22. The internal combustion engine according to claim 21, wherein the bearing element is a bearing shell of a crankshaft bearing or of a connecting rod bearing, a connecting rod bushing or a thrust washer.

23. The anti-friction coating according to claim 1, wherein the volume ratio of barium sulfate to zinc sulfide is between 0.8 and 4.88.

24. The anti-friction coating according to claim 1, wherein the volume ratio of barium sulfate to zinc sulfide is between 1.5 and 3.44.

25. The anti-friction coating according to claim 2, wherein in total the zinc sulfide and the barium sulfate are contained in the total composition in a proportion of 5 to 25 vol. %.

26. The anti-friction coating according to claim 28, wherein the additional fillers comprise 4 to 10 vol. % of iron-(III)-oxide.

27. The sliding bearing layered composite material according to claim 16, wherein the surface of the at least one metal layer, has a roughness RZ of 3 m to 8 m.

28. The anti-friction coating of claim 1, including additional fillers.

29. The anti-friction coating of claim 6, wherein said highly aromatic thermoplastics is selected from the group consisting of polyarylates, PEEK and PES.

30. A sliding bearing layered composite material comprising at least one metal layer and an anti-friction coating composite according to claim 15 applied on a surface of the metal layer.

31. The sliding bearing layered composite according to claim 30, wherein the surface of the at least one metal layer has a roughness R.sub.z of 1 m to 10 m.

32. The sliding baring layered composite according to claim 30, wherein the at least one metal layer comprises a bearing metal layer made of an alloy based on one of the elements selected from the group consisting of Cu, Al, Ni, Sn, Zn, Ag, Au, Bi, and Fe.

33. The sliding bearing layered composite according to claim 30, wherein the at least one metal layer comprises a bearing metal layer made of an alloy selected form the group consisting of CuSn, CuNiSi, CuZn, CuSnZn, AlSn, AlSi, AlSnSi, and AlZn.

34. The sliding bearing layered composite material according to claim 30, wherein the at least one metal layer comprises a steel support layer and optionally an intermediate layer made of Ni, Ag, Cu, or Fe applied on the steel support layer, wherein the bearing metal layer is applied on the steel support layer or, if present, on the intermediate layer, and wherein the anti-friction coating or the anti-friction coating composite is applied on a surface of the bearing metal layer on the side facing away from the steel support layer.

35. The sliding bearing layered composite material according to claim 30, wherein the surface of the at least one metal layer has a roughness R.sub.z of 3 m to 8 m.

Description

[0056] FIG. 1 a schematic diagram illustrating the inventive anti-friction coating on a substrate;

[0057] FIG. 2 a schematic diagram illustrating an embodiment of the inventive anti-friction coating composite on a substrate;

[0058] FIG. 3 a schematic diagram illustrating an alternative embodiment of the inventive anti-friction coating composite on a substrate;

[0059] FIG. 4 a perspective representation of an inventive bearing shell having an anti-friction coating; and

[0060] FIG. 5 a schematic diagram illustrating the layer construction of a sliding bearing layered composite material according to the invention.

[0061] In FIG. 1, a simple construction comprising an anti-friction coating 12 according to the invention on a not clearly specified substrate 14 is depicted schematically simplified. The geometrical relationships, in particular the layer thicknesses, are not closely drawn to scale for illustration purposes. The anti-friction coating 12 consists of a binder 16 as matrix component, in which a plurality of fillers is embedded. Fillers contained according to the invention are zinc sulfide 18 and barium sulfate 20. The anti-friction coating 12 shown further contains as optional fillers hard material particles 22, metal powder particles 24, and solid lubricant particles 26.

[0062] In FIG. 2, an exemplary construction of an anti-friction coating composite 10 consisting of a lower anti-friction coating 11 and an upper anti-friction coating 13 is shown. The lower anti-friction coating 11 is applied on a substrate 14 and more precisely on the surface 15 thereof and the upper anti-friction coating 13 is applied on the lower anti-friction coating 11. Both anti-friction coatings 11 and 13 comprise, in addition to a binder 16 as a matrix component the fillers zinc sulfide 18, barium sulfate 20, and Fe.sub.2O.sub.3 28, according to the invention, but otherwise contain further different filler compositions. Both anti-friction coatings 11 and 13 in turn contain as examples the optional fillers hard material particles 22, metal powder particles 24 and solid lubricant particles 26, but with different emphases. While a higher proportion of solid lubricant particles 26 and hardly any hard material particles 22 are contained in the matrix of the lower anti-friction coating 11, the situation is exactly opposite in the case of the upper anti-friction coating 13. This composition is so chosen that the upper anti-friction coating 13, which comes into contact first with the counter rotor in the initial operation of the bearing, acts abrasively due to the hard materials and promotes a wear-in of the sliding partner. The lower anti-friction coating 11, however, first enters into contact with the counter rotor after the wearing-in process, i.e. after wear-out of the upper anti-friction coating 13 and acts to reduce friction due to the higher proportion of solid lubricant. Small hard material proportions are useful to slow down the wear of the layer.

[0063] However, in deviation from the illustration, the hard particles in the lower anti-friction coating 11 and/or the solid lubricant in the upper anti-friction coating 13 can be entirely dispensed with. The important point here is the increased fraction of hard materials in the upper anti-friction coating and the increased fraction of the solid lubricants and/or metal powder particles in the lower.

[0064] In FIG. 3, an alternative construction of an anti-friction coating composite 30 consisting of a lower anti-friction coating 31 and an upper anti-friction coating 33 is shown. The lower anti-friction coating 31 is applied on a substrate 14 and precisely on the surface 15 thereof and the upper anti-friction coating 33 is applied on the lower anti-friction coating 31. Both anti-friction coatings 31 and 33 comprise in addition to a binder resin 16 as matrix component the fillers zinc sulfide 18, barium sulfate 20, and Fe.sub.2O.sub.3 28 according to the invention, but otherwise contain different further filler compositions. In both anti-friction coatings 31 and 33 the optional fillers, metal particles 24, and solid lubricant particles 26 are contained in turn by way of example. Additionally, hard material particles 22 are again also contained in the matrix of the lower anti-friction coating 31. On the contrary, the upper anti-friction coating 33 contains a smaller binder proportion and no hard material particles. This composition is selected so that the upper anti-friction coating 33, which comes into contact first with the counter rotor in the initial operation of the bearing, can adapt more rapidly to the counter rotor partner due to the lower proportion of binder. The lower anti-friction coating 31, on the contrary, first enters into contact with the counter rotor after the wear-in process, i.e. after the wear-out of the upper anti-friction coating 33 and has higher wear resistance and load capacity due to the higher binder content.

[0065] In deviation from the illustration, a hard material component may also be contained in the upper anti-friction coating 33. The important point here is the smaller proportion of binder.

[0066] FIG. 4 depicts a bearing shell 38 in perspective illustration, wherein a sliding bearing layered composite material is used. The layer structure of the sliding bearing layered composite material is then limited, in that the anti-friction coating 11 is applied on a non-differentiated depicted substrate 14. The substrate itself consists of at least one metal layer, whose function may be varied. First of all, it serves the mechanical stability of the bearing shell. For this purpose, it has either a fixed bearing metal solid material or a steel support layer with a bearing metal layer arranged thereon. The bearing metal layer undertakes in both cases the supporting function of the bearing. Due to emergency properties and embeddability for dirt particles, it can also be designed for direct contact with the sliding partners. Thereupon is then optionally a sliding or top layer made of metal. In this case the anti-friction coating 11 by itself takes on the function of a wear-in layer. Otherwise the anti-friction coating 11 may function as sliding layer by itself with choice of suitable fillers. Of course, instead of the single anti-friction coating 11 an anti-friction coating composite having different function can be provided, as explained above with reference to FIG. 2 and FIG. 3.

[0067] All lubricant lacquers are low-viscose, so that upon application, in particular by spray processes without action by pressure, they form a smooth running surface. After the subsequent drying or hardening processes (thermally or under UV-light) the binder of the lubricant coating is crosslinked or chemically or physically transformed, so that the sliding layer forms a dimensionally stable, to the greatest extent insoluble, and highly loadable thin layer on the substrate. The smooth layer formed by itself, i.e. without action of pressure, makes possible the application of an anti-friction coating also on already transformed sliding elements, such as the bearing shells shown in FIG. 3.

[0068] FIG. 5 shows a schematic diagram illustrating the layer structuring of a sliding bearing layered composite material according to the invention, in which once again several of the above-mentioned layer combinations are summarized by way of example.

[0069] The sliding bearing layered composite material comprises on the one hand an anti-friction coating composite 40 having several anti-friction coatings 41, 42, 43 and on the other hand a substrate 50 made of several metal layers 51, 52, 53. At the very bottom a steel support layer 51 is provided as stabilizing element. A bearing metal layer 52 is disposed on this. An intermediate layer 53 is disposed on the bearing metal layer 52 as adhesion promoter to the overlying anti-friction coating composite 40. This adhesion promoter can also be dispensed with, depending on the composition of the bearing metal, if the bearing metal layer forms an adequate adhesive base, for example, has a sufficient roughness. The anti-friction coating composite 40 is applied on the top side that is on the surface 54 of the intermediate layer 53 facing away from the steel support layer 51. This composite includes a first anti-friction coating 41, which is applied directly on the surface 54. The anti-friction coating 41 can be designed functionally different. Depending on the properties of the bearing metal or the intermediate layer, it can also serve as adhesion promoter for the overlying anti-friction coating. In this case, the coating can contain only a little or even no fillers at all and thus would not necessarily be counted among the anti-friction coatings according to the invention. Otherwise, it may serve to further increase the operational reliability, if a filler combination is chosen, which is optimized relative to the wear resistance thereof, so that a complete passage through the bearing material can be delayed, after the lower anti-friction coating 42 disposed thereover is worn out. This can take place e.g. by increasing the binder content and the proportion of the harder components, whereby the properties adaptability, galling resistance and friction fade into the background. It is thereby assumed that this layer is exposed only locally and slowly and thus the sliding properties of the total surface are not substantially impaired over a longer time period.

[0070] The lower anti-friction layer 42 according to the invention comprises zinc sulfide and barium sulfate and further solid lubricants and/or metal powder, if appropriate also hard material particles and/or iron-(III)-oxide in a composition, which forms the best compromise for bearing capacity and wear resistance on the one hand and adaptability, friction, and galling resistance on the other, and in this way a long-term stable layer is created under the given conditions of use. The upper anti-friction coating is then applied on the lower anti-friction coating 42, corresponding to the above in connection with FIG. 2.

[0071] Particularly preferred embodiments of particular anti-friction coatings have the following components:

Example a: PAI, BaSO.sub.4, ZnS, h-BN, Fe.sub.2O.sub.3
Example b: PAI, BaSO.sub.4, ZnS, MoS.sub.2, Fe.sub.2O.sub.3
Example c: epoxy resin, BaSO.sub.4, ZnS, MoS.sub.2, Fe.sub.2O.sub.3
Example d: PEEK, BaSO.sub.4, ZnS, PTFE, Fe.sub.2O.sub.3
Example e: silicone resin, BaSO.sub.4, ZnS, graphite, Fe.sub.2O.sub.3

[0072] Underwood tests were carried out to evaluate the performance capacity of the anti-friction coatings or the sliding bearing layered composite materials. Thereby, a shaft rotates with eccentric weights in rigidly mounted connection rods. The mounting in the connecting rods is formed by the test bearings. The test bearings have a wall thickness of 1.4 mm and a diameter of 50 mm. The specific load is adjusted over the bearing width, the rotational speed is 4000 rpm. Evaluation criteria are sliding layer fatigue and wear after a 100 h continuous run. The load limit (UW load) is given in MPa, wherein the layer up to the substrate is worn down up to a maximum of 5% of the sliding surface or fatigue is present.

[0073] The following Table 1 reports the test results for sliding bearing layered composite materials comprising steel backs and a CuNi2Si bearing metal as substrate and various anti-friction coatings based on a PAI-binders and without an intermediate layer. Three comparative materials R1 to R3, which contained either only barium sulfate, only zinc sulfide, or none of the two fillers, are compared with examples according to the invention having different ratios of barium sulfate to zinc sulfide. The filler proportions were otherwise selected to be the same in each case, based on the anti-friction coatings.

TABLE-US-00001 TABLE 1 Total Content max Ratio BaSO4 + UW BaSO4 ZnS BaSO4/ ZnS Solid load No. Substrate Binder [vol. %] [vol. %] ZnS [vol. %] lubricant [MPa] R1 CuNi2Si PAI 0 0 0 40 vol % MoS2 90 R2 CuNi2Si PAI 15 0 15 25 vol % MoS2 80 R3 CuNi2Si PAI 0 15 0 15 25 vol % MoS2 85 1 CuNi2Si PAI 1.4 13.6 0.10 15 25 vol % MoS2 95 2 CuNi2Si PAI 6.7 8.3 0.81 15 25 vol % MoS2 100 3 CuNi2Si PAI 9 6 1.50 15 25 vol % MoS2 105 4 CuNi2Si PAI 11 4 2.75 15 25 vol % MoS2 110 5 CuNi2Si PAI 11.8 3.2 3.69 15 25 vol % MoS2 105 6 CuNi2Si PAI 12.4 2.6 4.77 15 25 vol % MoS2 100 7 CuNi2Si PAI 14.1 0.9 15.67 15 25 vol % MoS2 95

[0074] The ratios of BaSO.sub.4 to ZnS in Table 1 are selected so that the effectiveness of the advantageous ranges according to the invention is clear. In the range of the ratio of 0.1 to 15.7 the load capacity is above those of ratios not in accordance with the invention, that is, at 95 MPa or more. Between 0.8 and 4.88, values result above 100 MPa; between 1.5 and 3.44, the highest values occur at a BaSO.sub.4/ZnS-ratio of 2.75 with an optimum of 110 MPa.

[0075] The following Table 2 reports the test results for sliding bearing layered composite materials comprising steel backs and a CuSn8Ni-bearing metal as substrate and various anti-friction coatings based on PAI-binder and without an intermediate layer. Three reference examples not associated with the invention are compared with four examples according to the invention having approximately the same ratio of barium sulfate to zinc sulfide, but different total contents of barium sulfate and zinc sulfide and partly different further filler proportions of the solid lubricant MoS.sub.2.

TABLE-US-00002 TABLE 2 Total Content max Ratio BaSO4 + UW BaSO4 ZnS BaSO4/ ZnS Solid load No. Substrate Binder [vol. %] [vol. %] ZnS [vol. %] lubricant [MPa] R4 CuSn8Ni PAI 0.73 0.26 2.81 0.99 25 vol % MoS2 75 R5 CuSn8Ni PAI 44 16 2.75 60 0 25 R6 CuSn8Ni PAI 38.9 14.1 2.76 53 25 vol % MoS2 30 8 CuSn8Ni PAI 38.9 14.1 2.76 53 20 vol % MoS2 45 9 CuSn8Ni PAI 1.47 0.53 2.77 2 25 vol % MoS2 80 10 CuSn8Ni PAI 4.4 1.6 2.75 6 25 vol % MoS2 85 11 CuSn8Ni PAI 18.3 6.7 2.73 25 25 vol % MoS2 85

[0076] The total amounts of the BaSO.sub.4ZnS mixture are selected in Table 2, so that the effectiveness of the advantageous ranges according to the invention are clear. In the quantity range of 2 to 25 vol. %, the load capacities are above those not according to the invention or less advantageous according to the invention, as the comparison of examples 9, 10, 11 with the reference examples R4 and R5 shows. The comparison of R6 (78 vol. %) with example 8 (73 vol. %) proves the effect of an overdose of the content of all fillers together. The load capacity of example 8 at 45 MPa is certainly rather low, but this can be quite sufficient for a wear-in layer, e.g. in a multilayer system. Example 8 is moreover significantly better than example R6, which is not in accordance with the invention, wherein the total filler content exceeds the limiting value of 75%.

[0077] The following Table 3 reports the test results for sliding bearing layered composite materials comprising steel backs and a CuNi2Si-bearing metal as substrate and various anti-friction coatings based on a PAI-binders and without an intermediate layer. Four examples according to the invention are compared having substantially the same ratios and the same total content of barium sulfate and zinc sulfide, wherein these fillers are added in two cases, however, in the form of lithopone having a BaSO.sub.4/ZnS volume ratio 2.13 (quantity detail marked L). Furthermore, the solid lubricant was varied in each case, but its respective proportion in the total composition remained the same. Additionally, Fe.sub.2O.sub.3 was used in three examples.

TABLE-US-00003 TABLE 3 Total Content max Ratio BaSO4 + UW BaSO4 ZnS BaSO4/ ZnS Solid Amount load No. Substrate Binder [vol. %] [vol. %] ZnS [vol. %] lubricant Fe.sub.2O.sub.3 [MPa] 12 CuNi2Si PAI 10.2 L 4.8 L 2.13 15 25 vol % MoS2 110 13 CuNi2Si PAI 11 4 2.75 15 20 vol % MoS2 5 115 14 CuNi2Si PAI 10.2 4.8 2.13 15 20 vol % hBN 5 115 15 CuNi2Si PAI 10.2 L 4.8 L 2.13 15 20 vol % hBN 5 120

[0078] Table 3 proves that further improvements are achievable by use of lithopone in place of a mixture of BaSO.sub.4 and ZnS as well as the use of Fe.sub.2O.sub.3, optimally up to a load capacity of 120 MPa.

[0079] The following Table 4 reports the test results for sliding bearing layered composite materials comprising steel backs and a CuNi2Si-bearing metal as substrate and various anti-friction coatings based on different matrix materials without intermediate layer. Ten comparative materials are compared marked with prefix R, which contain neither barium sulfate nor zinc sulfide, and in each case a material assigned according to the invention having identical total filler content but different filler compositions. Also here, in one case the barium sulfate and the zinc sulfide were added in the form of lithopone (distinguishing mark L).

TABLE-US-00004 TABLE 4 Total Content max Ratio BaSO4 + Amount UW BaSO4 ZnS BaSO4/ ZnS Solid Hard Fe.sub.2O.sub.3 load No. Substrate Binder [vol. %] [vol. %] ZnS [vol. %] lubricant material Metal [vol. %] [MPa] 16 CuNi2Si PAI 7.3 2.7 2.65 10 20 vol % hBN 5 vol % 110 SiC R16 CuNi2Si PAI 0 20 vol % hBN 5 vol % 85 SiC 17 CuNi2Si PAI 11 4 2.75 15 20 vol % MoS2 105 R17 CuNi2Si PAI 0 20 vol % MoS2 85 18 CuNi2Si PAI 5.9 2.1 2.81 8 15 vol % WS2 110 R18 CuNi2Si PAI 0 23 vol % WS2 90 19 CuNi2Si PAI 3.7 1.3 2.84 5 12 vol % Graphite 3 95 R19 CuNi2Si PAI 0 12 vol % Graphite 3 90 20 CuNi2Si PAI 10.2 L 4.8 L 2.13 15 20 vol % PTFE 95 R20 CuNi2Si PAI 0 30 vol % PTFE 80 21 CuNi2Si PEEK 10 5 2 15 20 vol % MoS2 100 R21 CuNi2Si PEEK 0 35 vol % MoS2 85 22 CuSn10Bi3 PAI 4 1 4 5 15 vol % MoS2 5 vol % 5 95 R22 CuSn10Bi3 PAI 0 20 vol % MoS2 5 vol % 5 85 23 CuSn10Bi3 PES 18 7 2.57 25 15 vol % MoS2 105 R23 CuSn10Bi3 PES 0 40 vol % MoS2 95 24 CuSn10Bi3 EP 11 4 2.75 15 20 vol % MoS2 105 R24 CuSn10Bi3 EP 0 20 vol % MoS2 85 25 CuSn10Bi3 PAI 3.7 1.3 2.84 5 15 vol % hBN 5 3 95 vol % Sn R25 CuSn10Bi3 PAI 2.84 0 20 vol % hBN 15 3 80 vol % Sn

[0080] In all cases, the use of the BaSO.sub.4/ZnS mixture according to the invention in the particularly preferred composition and content achieves a significant improvement. Examples 21, 23, and 24 show by means of the thermoplastic PEEK and PES, and the duroplastic epoxy-resin that this also applies for other binder types than the PAI used predominantly in the tests.

[0081] The following Table 5 reports the test results for sliding bearing layered composite materials comprising a steel back and CuSn10Bi3-bearing metal as substrate and various anti-friction coatings based on a PAI-binder having two different intermediate layers. Three comparative materials are compared, marked with prefix R, which contain neither barium sulfate nor zinc sulfide, and in each case a material assigned according to the invention having different filler compositions. Also here, in one case the barium sulfate and the zinc sulfide was added in the form of lithopone (distinguishing mark L).

TABLE-US-00005 TABLE 5 Total Content max Ratio BaSO4 + UW Intermediate BaSO4 ZnS BaSO4/ ZnS Solid load No. Substrate Layer Binder [vol. %] [vol. %] ZnS [vol. %] lubricant [MPa] 26 CuSn10Bi3 Ni PAI 11 4 2.75 15 20 vol % 110 MoS2 R26 CuSn10Bi3 Ni PAI 0 20 vol % 90 MoS2 27 CuSn10Bi3 Ni PAI 7.3 2.7 2.65 10 30 vol % 95 MoS2 R27 CuSn10Bi3 Ni PAI 0 40 vol % 90 MoS2 28 CuSn10Bi3 Ag PAI 10.2 L 4.8 L 2.13 15 30 vol % 110 MoS2 R28 CuSn10Bi3 Ag PAI 0 40 vol % 90 MoS2

[0082] It can be seen that the use of intermediate layers does not impair the effectiveness of the BaSO.sub.4/ZnS mixture. A comparison of example 26 with example 17 In Table 4 shows that also by the change of the substrate of CuNi2Si into CuSn10Bi3 having an Ni-intermediate layer achieves improvement of the load capacity.

[0083] The following Table 6 reports the test results for sliding bearing layered composite materials comprising various aluminum-based substrates and various anti-friction coatings based on different matrix materials without intermediate layer. Compared are 6 examples according to the invention with different ratios of barium sulfate to zinc sulfide and different total amounts of these fillers. The other filler contents were also varied. Finally, in one case here the barium sulfate and zinc sulfide were added in the form of lithopone (distinguishing mark L).

TABLE-US-00006 TABLE 6 Total Content max Ratio BaSO4 + Amount UW BaSO4 ZnS BaSO4/ ZnS Solid Hard Fe.sub.2O.sub.3 load No. Substrate Binder [vol. %] [vol. %] ZnS [vol. %] lubricant material Metal [vol. %] [MPa] 29 ALSn10Ni2MnCu PAI 3.7 1.3 2.84 5 20 vol % hBN 90 S 30 ALSn10Ni2MnCu PES 10.2 L 4.8 L 2.13 15 15 vol % MoS2 3 95 S 31 AlNi2MnCu PAI 18 7 2.57 25 15 vol % WS2 5 vol % 95 SiC 32 AlNi2MnCu EP 18 7 2.57 25 15 vol % hBN 5 95 33 AlSn6Si4CuMnCr PAI 7.3 2.7 2.65 10 20 vol % MoS2 3 vol % 5 80 S B4C 34 AlSn6Si4CuMnCr PEEK 4 1 4 5 20 vol % hBN 7 vol % 3 85 S Ag

[0084] The results demonstrate that also on substrates based on aluminum, the load capacity by addition of BaSO.sub.4/ZnS mixtures to the lubricant coating is further improved. Since the Al alloys are less fatigue-resistant than the Cu alloys, the maximum load in the tests is often not limited by the anti-friction coating, but rather by the fatigue of the substrate itself. In these cases, the results are marked with S. However, the fatigue resistibility of the Al-alloys is significantly improved by the lubricant lacquers, and this improvement is also dependent upon the type of lubricant used, which is clearly seen in Table 6.

LIST OF REFERENCE NUMERALS

[0085] 10 anti-friction coating composite [0086] 11 lower anti-friction coating [0087] 12 anti-friction coating [0088] 13 upper anti-friction coating [0089] 14 substrate [0090] 15 surface of the substrate [0091] 16 binder, matrix [0092] 18 zinc sulfide (ZnS) [0093] 20 barium sulfate (BaSO.sub.4) [0094] 22 hard material [0095] 24 metal particle [0096] 26 solid lubricant [0097] 28 iron-(III)-oxide [0098] 30 anti-friction coating composite [0099] 31 lower anti-friction coating [0100] 33 upper anti-friction coating [0101] 38 bearing shell [0102] 40 anti-friction coating composite [0103] 41 first anti-friction coating [0104] 42 lower anti-friction coating [0105] 43 upper anti-friction coating [0106] 50 metal coating composite [0107] 51 steel support layer [0108] 52 intermediate layer [0109] 53 bearing metal coating [0110] 54 surface of the bearing metal coating