Sliding member and production process thereof

• US 20050100701A1
• Filed: 08/06/2004
• Published: 05/12/2005
• Est. Priority Date: 08/08/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kano, Makoto, Hamada, Takahiro, Mabuchi, Yutaka
• Granted Patent: US 7,458,585 B2
• Time in Patent Office: Days
• US Class Current: 428/36.910
• CPC Class Codes: C10M 141/10 at least one of them being an organic phosphorus-containing compound
• CPC Class Codes: C10M 163/00 Lubricating compositions characterised by the additive being a mixture of a compound of unknown or incompletely defined constitution and a non-macromolecular compound, each of these compounds being essential
• CPC Class Codes: C10M 167/00 Lubricating compositions characterised by the additive being a mixture of a macromolecular compound, a non-macromolecular compound and a compound of unknown or incompletely defined constitution, each of these compounds being essential
• CPC Class Codes: C10M 2207/022 containing at least two hydroxy groups
• CPC Class Codes: C10M 2207/281 of (cyclo)aliphatic monocarboxylic acids
• CPC Class Codes: C10M 2207/283 of polyhydroxy compounds
• CPC Class Codes: C10M 2215/04 having amino groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2215/28 Amides; Imides
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2060/14 by boron or a compound containing boron
• CPC Class Codes: C23C 28/044 coatings specially adapted for cutting tools or wear applications
• CPC Class Codes: C23C 28/046 with at least one amorphous inorganic material layer, e.g. DLC, a-C:H, a-C:Me, the layer being doped or not
• CPC Class Codes: C23C 28/048 with layers graded in composition or physical properties
• CPC Class Codes: F16J 9/26 characterised by the use of particular materials
• CPC Class Codes: Y10T 428/1393 Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

There is provided a sliding member including a base body and a hard carbon coating formed on the base body to define a sliding surface for sliding contact with an opposing member under lubrication according to one embodiment of the present invention. The hard carbon coating has an outermost surface portion lower in hydrogen content than a remaining portion thereof, or an outermost coating layer lower in hydrogen content than at least one other coating layer.

Claims

1. A sliding member, comprising:

a base body; and

a hard carbon coating formed on the base body to define a sliding surface for sliding contact with an opposing member under lubrication, the hard carbon coating having an outermost surface portion lower in hydrogen content than a remaining portion thereof.

2. A sliding member according to claim 1, wherein the outermost surface portion of the hard carbon coating has a hydrogen content of 20 atomic % or less.

3. A sliding member according to claim 2, wherein the outermost surface portion of the hard carbon coating has a hydrogen content of 10 atomic % or less.

4. A sliding member according to claim 3, wherein the outermost surface portion of the hard carbon coating has a hydrogen content of 5 atomic % or less.

5. A sliding member according to claim 4, wherein the outermost surface portion of the hard carbon coating has a hydrogen content of 0.5 atomic % or less.

6. A sliding member according to claim 1, wherein the hard carbon coating has a hydrogen content gradually decreasing from a base body side to a sliding surface side in a thickness direction thereof.

7. A sliding member according to claim 1, further comprising a lubricating oil applied to the sliding surface, the lubricating oil containing therein at least one friction modifier selected from the group consisting of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

8. A sliding member according to claim 7, wherein said at lease one friction modifier has a C₆-C₃₀ hydrocarbon group and is contained in an amount of 0.05 to 3.0% by mass based on a total mass of the lubricating oil.

9. A sliding member according to claim 7, wherein the lubricating oil contains polybutenyl succinimide and/or a derivative thereof.

10. A sliding member according to claim 9, wherein the polybutenyl succinimide and/or derivative thereof is contained in an amount of 0.1 to 15% by mass based on a total mass of the lubricating oil.

11. A sliding member according to claim 7, wherein the lubricating oil contains zinc dithiophosphate in an amount of 0.1% or less by mass in terms of phosphorus element based on a total mass of the lubricating oil.

12. A sliding member according to claim 1, further comprising a lubricating agent applied to the sliding surface, the lubricating agent being predominantly composed of a hydroxyl group containing compound.

13. A sliding member according to claim 12, wherein the hydroxyl group containing compound is an alcohol.

14. A sliding member according to claim 13, wherein the alcohol is either glycerol or ethylene glycol.

15. A sliding member according to claim 1, wherein the base body has been given undercoating by at least one process selected from the group consisting of a chromium plating process, a chromium nitride process and a nitriding process before the formation of the hard carbon coating.

16. A sliding member according to claim 1, wherein the sliding member is an engine piston ring.

17. A sliding member according to claim 16, wherein the piston ring is at least one of a top ring or an oil ring.

18. A sliding member, comprising:

a base body; and

a hard carbon coating formed on the base body to define a sliding surface for sliding contact with an opposing member under lubrication, the hard carbon coating having two or more coating layers laminated together in a thickness direction thereof, the laminated coating layers including an outermost coating layer lower in hydrogen content than at least one other coating layer.

19. A sliding member according to claim 18, wherein the outermost coating layer is lower in hydrogen content than any other coating layer.

20. A sliding member according to claim 18, wherein the outermost coating layer has a hydrogen content of 20 atomic % or less.

21. A sliding member according to claim 20, wherein the outermost coating layer has a hydrogen content of 10 atomic % or less.

22. A sliding member according to claim 21, wherein the outermost coating layer has a hydrogen content of 5 atomic % or less.

23. A sliding member according to claim 22, wherein the outermost coating layer has a hydrogen content of 0.5 atomic % or less.

24. A sliding member according to claim 18, further comprising a lubricating oil applied to the sliding surface, the lubricating oil containing therein at least one friction modifier selected from the group consisting of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

25. A sliding member according to claim 24, wherein said at lease one friction modifier has a C₆-C₃₀ hydrocarbon group and is contained in an amount of 0.05 to 3.0% by mass based on a total mass of the lubricating oil.

26. A sliding member according to claim 24, wherein the lubricating oil contains polybutenyl succinimide and/or a derivative thereof.

27. A sliding member according to claim 26, wherein the polybutenyl succinimide and/or derivative thereof is contained in an amount of 0.1 to 15% by mass based on a total mass of the lubricating oil.

28. A sliding member according to claim 24, wherein the lubricating oil contains zinc dithiophosphate in an amount of 0.1% or less by mass in terms of phosphorus based on a total mass of the lubricating oil.

29. A sliding member according to claim 18, further comprising a lubricating agent applied to the sliding surface, the lubricating agent being predominantly composed of a hydroxyl group containing compound.

30. A sliding member according to claim 29, wherein the hydroxyl group containing compound is an alcohol.

31. A sliding member according to claim 30, wherein the alcohol is either glycerol or ethylene glycol.

32. A sliding member according to claim 18, wherein the base body has been given undercoating by at least one process selected from the group consisting of a chromium plating process, a chromium nitride process and a nitriding process before the formation of the hard carbon coating.

33. A sliding member according to claim 18, wherein the sliding member is an engine piston ring.

34. A sliding member according to claim 33, wherein the piston ring is at least one of a top ring and an oil ring.

35. A process for producing a sliding member, comprising:

providing a base body of the sliding member; and

forming a hard carbon coating on the base body in such a manner that the hard carbon coating has an outermost surface portion lower in hydrogen content than a remaining portion thereof.

36. A process according to claim 35, wherein said forming includes controlling the hydrogen content of the outermost surface portion to 20 atomic % or less.

37. A process according to claim 35, further comprising applying a lubricating oil to the hard carbon coating, wherein the lubricating oil contains therein at least one friction modifier selected from the group consisting of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

38. A process according to claim 35, further comprising applying a lubricating agent to the hard carbon coating, wherein the lubricating agent is predominantly composed of a hydroxyl group containing compound.

39. A process for forming a sliding member, comprising:

providing a base body of the sliding member; and

forming, on the base body, a hard carbon coating in such a manner that the hard carbon coating an outermost coating layer lower in hydrogen content than at least one other coating layer.

40. A process according to claim 39, wherein said forming includes controlling the hydrogen content of outermost coating layer to 20 atomic % or less.

41. A process according to claim 39, further comprising applying a lubricating oil to the hard carbon coating, wherein the lubricating oil contains therein at least one friction modifier selected from the group consisting of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

42. A process according to claim 39, further comprising applying a lubricating agent to the hard carbon coating, wherein the lubricating agent is predominantly composed of a hydroxyl group containing compound.