Anti-friction lacquer and sliding element having such an anti-friction lacquer

Abstract

The invention relates to an anti-friction lacquer having a polymer as a resin matrix and functional fillers, the functional fillers containing mixed-phase oxides and optionally further functional fillers. The invention further relates to a sliding element having a metallic substrate layer and a coating which is applied thereon and made of at least such an anti-friction lacquer and to a method for the production thereof.

Claims

1. A sliding bearing, comprising: a non-porous metallic substrate; a cured lacquer layer of a polymer resin matrix applied to the non-porous metallic substrate, the matrix containing functional fillers in the form of mixed-phase oxides having a Rosiwal grinding hardness of below 55 and present at a proportion of 0.1 to 15% by volume of the cured lacquer layer; wherein the mixed-phase oxides have a D50 mean particle size n the range of 0.05 to 2.0 μm.

2. The sliding bearing of claim 1, wherein the mixed-phase oxides are present at a proportion of 0.5 to 8% by volume.

3. The sliding bearing of claim 1, wherein the mixed-phase oxides comprise at least two of the oxides of titanium, cobalt, aluminium, nickel, antimony, chromium, iron or zinc.

4. The sliding bearing of claim 3, wherein the mixed-phase oxides consist of oxides of titanium and at least two oxides of cobalt, aluminium, nickel, antimony, chromium, iron or zinc.

5. The sliding bearing of claim 3, wherein the mixed-phase oxides are selected from Co—Al oxide, Ni—Sb-TI oxide, Fe—Al oxide and Co—Ti—Ni—Zn oxide.

6. The sliding bearing of claim 3, wherein the polymer is selected from polyimides (PI), polyamideimides (PAI), polyetherimides (PEI) and polyesterimide, epoxy resins (EP), phenol resin, polybenzimidazole (PBI), silicone resins, refractory thermoplastics having a melting point above 220 C, polyarylates, polyetheretherketone (PEEK) and poly(oxy-1-4-phenylsulfonyl-1-4-phenyl) (PES).

7. The sliding bearing of claim 3 wherein the substrate includes an intermediate layer of Sn, Ni, Ag, Cu, Fe, or alloys thereof.

8. The sliding bearing of claim 1, wherein the mixed-phase oxides have crystalline structures of rutile, spinel or hematite.

9. The sliding bearing of claim 1, wherein the mean particle size is in the range of 0.1 to 0.5 μm.

10. The sliding bearing of claim 1, wherein the matrix further includes solid lubricant fillers.

11. The sliding bearing of claim 10, wherein the matrix further includes hard particle fillers.

12. The sliding bearing of claim 11, wherein the hard particles comprise nitrides, carbides, borides and oxides.

13. The sliding bearing of claim 12, wherein the hard particles comprise SiC, Si.sub.3N.sub.4, B.sub.4C.sub.3, cubic BN or SiO.sub.2.

14. The sliding bearing of claim 10 wherein the solid lubricants comprise MoS.sub.2, WS.sub.2, SnS.sub.2, graphite, hexagonal BN, PTFE or ZnS/BaSo.sub.4 or combinations or admixtures thereof.

15. The sliding bearing of claim 1, wherein the matrix includes metallic powders comprising Ag, Pb, Au, Sn, Al, Bi or Cu.

16. The sliding element of claim 1, wherein the matrix includes additional fillers of Fe.sub.2O.sub.3, TiO.sub.2 or mixed oxides thereof.

17. The sliding bearing of claim 1, wherein the total quantity of all additives of the matrix is not more than 75% by volume of the cured lacquer matrix, of which the mixed-phase oxides comprise no more than 10% by volume.

18. The sliding bearing of claim 17, wherein the mixed oxides are present in no more than 5% by volume.

19. The sliding bearing of claim 1, wherein the cured lacquer layer has a thickness of 1 to 50 um.

20. The sliding bearing of claim 1, wherein the substrate has a surface roughness of Rz=1 to 10 um.

21. The sliding bearing of claim 1, wherein the substrate comprises a multi-layer metallic substrate comprising a steel backing and at least one metallic sliding layer on which the lacquer is applied.

22. The sliding element of claim 21, wherein the sliding layer is a sputter layer of AlSn or a galvanic sliding layer.

23. The sliding bearing of claim 1, wherein the substrate has an exposed surface layer of Cu, Al, Ni, Sn, Zn, Ag, Au, Bi or Fe alloy on which the lacquer is applied.

24. The sliding layer of claim 1, including an additional run-in lacquer layer applied to the existing lacquer layer.

Description

THE DRAWINGS

(1) Other features, advantages and applications are explained in greater detail below with reference to embodiments and the Figures. In the Figures:

(2) FIG. 1 is a schematic layered structure of a sliding element according to a first embodiment of the invention;

(3) FIG. 2 is a schematic layered structure of a sliding element according to a second embodiment of the invention;

(4) FIG. 3 is a schematic layered structure of a sliding element according to a third embodiment of the invention;

(5) FIG. 4 is a schematic layered structure of a sliding element according to a fourth embodiment of the invention, and

(6) FIG. 5 is a schematic layered structure of a sliding element according to a fifth embodiment of the invention.

DETAILED DESCRIPTION

(7) All the embodiments have a metal substrate layer 11, 21, 31, 41, 51 and a coating 12, 22, 32, 42, 52 which is applied thereto and which comprises at least one anti-friction lacquer according to the invention, wherein the inner structure of the substrate layer and/or the coating vary. The thickness of the coating is between 1 and 50 μm, wherein the schematic illustrations depict the real layer thickness relationships neither precisely nor in a proportionally correct manner, but instead merely to illustrate the sequence of the layers.

(8) The metal substrate layer 11 of the sliding element according to FIG. 1 has a support layer 13, generally of steel, and a bearing metal 14, in most cases based on a Cu or Al alloy, and an intermediate layer 15, which itself may be constructed from one or more individual layers and which can be used to improve the bonding between the bearing metal layer and the coating 12. Depending on the application, the intermediate layer may also be configured in such a manner that, in the event of wear of the layer above, it has improved sliding or emergency running properties. The coating 12 comprises in this embodiment an individual layer 16 of the anti-friction lacquer according to the invention.

(9) In principle, with adequate strength of the bearing metal in this embodiment and the following embodiments the support layer of steel can be dispensed with. Also under some application conditions, the bearing metal layer may also be dispensable. The intermediate layer is also optional, as some of the following embodiments show.

(10) In FIG. 2, the metal substrate layer 21 of the sliding element again comprises a steel support layer 23 and a bearing metal layer 24 to which the coating 22 is applied, this time without an intermediate layer, again in the form of an individual layer 26 of the anti-friction lacquer according to the invention.

(11) The embodiment according to FIG. 3 has a metal substrate layer 31, which comprises a steel support layer 33, a bearing metal layer 34, an intermediate layer 35 and a thin metal sliding or covering layer 37 which is applied thereto. The sliding or covering layer 37 is sputtered on the intermediate layer 35 or galvanically deposited at that location. In this instance, the intermediate layer 35 serves to improve the bonding of the metal sliding or covering layer 37 to the bearing metal layer 34. The coating 32 is applied in the form of an individual layer 36 of the anti-friction lacquer according to the invention to the sliding layer 37 and acts as a run-in layer. It is possible to use as a run-in layer both a lacquer composition which is optimised for conditioning the counter-movement member and a lacquer composition which is optimised in terms of adaptation.

(12) FIG. 4 shows an embodiment having a metal substrate layer 41 which comprises a steel support layer 43 and a bearing metal layer 44. There is arranged thereon the coating 42 in the form of a multi-layered system comprising at least two anti-friction lacquers, of which at least one anti-friction lacquer is constructed according to the invention. The coating 42 specifically has an upper anti-friction lacquer layer 46 which is constructed as a run-in layer and below this an anti-friction lacquer layer 48 which is in contact with the metal substrate 41 and which is constructed as a sliding layer with a long service-life. The service-life anti-friction lacquer layer 48 comprises the anti-friction lacquer according to the invention with mixed-phase oxides, the run-in layer 46 which is applied thereto may optionally contain these. It is also possible to use here as a run-in layer a lacquer composition which is optimised for the conditioning of the counter-movement member, or a lacquer composition which is optimised with regard to the adaptation.

(13) Finally, FIG. 5 shows an embodiment having a metal substrate layer 51 which comprises a steel support layer 53 and a bearing metal layer 54. There is arranged thereon the coating 52 in the form of a multi-layered system comprising at least two anti-friction lacquers, of which at least one anti-friction lacquer is constructed according to the invention. The coating 52 has on the metal substrate 51 a lower anti-friction lacquer layer 58 and on top of this an upper anti-friction lacquer layer 56. The upper anti-friction lacquer layer 56 forms a sliding layer with good sliding and adaptation properties or a sliding layer with a long service-life and contains the mixed-phase oxides. The lower anti-friction lacquer layer is optimised in terms of the bonding to the substrate and has, similarly to a primer, the purpose of improving the bonding of the anti-friction lacquer layer located above and may optionally contain the mixed-phase oxides.

EXAMPLES

(14) The following Table 1 sets out some example compositions of the anti-friction lacquer according to the invention.

(15) TABLE-US-00001 TABLE 1 Matrix polymer Additional fillers Metal phase oxides PAI hBN/SiC Co—Al oxide PAI BaS0.sub.4/ZnS/hBN/SiC Ni—Sb—Ti oxide PAI MoS.sub.2 Fe—Al oxide PAI PTFE/hBN/M0S.sub.2 Ni—Sb—Ti oxide PI MoS.sub.2/BaS0.sub.4/ZnS Co—Ti—Ni—Zn oxide PI PTFE/Si.sub.3N.sub.4 Co—Al oxide PEI MoS.sub.2 Co—Ti—Ni—Zn oxide

(16) The exposed layers of the substrate comprise, for example, the alloys set out in Table 2 and have the associated function in each case of the sliding element

(17) TABLE-US-00002 TABLE 2 CuNi2Si Bearing metal CuSn8Ni Bearing metal CuSn6Bi3 Bearing metal CuPb23Sn Bearing metal Ni Intermediate layer AlSn20CuMn Bearing metal and sliding layer AlSn8Ni2MnCu Bearing metal and sliding layer AlNi2MnCu Bearing metal and sliding layer AlSn10Si3CuCr Bearing metal and sliding layer AlSn6Si4CuNiCr Bearing metal and sliding layer AlZn5Mg3Cu Bearing metal AlZnMgCu1.5 Bearing metal AlSn20 Bearing metal and sliding layer AlCu4MgSi Bearing metal AlSi10Cu Bearing metal Sn, galvanic or vpd Sliding layer SnCu6, galvanic or vpd Sliding layer Bi, galvanic or vpd Sliding layer BiCu3, galvanic or vpd Sliding layer Ag, galvanic or vpd Sliding or intermediate layer