Thermally applied coating for piston rings, consisting of mechanically alloyed powders

• US 20030180565A1
• Filed: 03/03/2003
• Published: 09/25/2003
• Est. Priority Date: 09/21/2000
• Status: Active Grant

• Current Assignee: Federal-Mogul Burscheid GmbH (Apollo Global Management, Inc.)
• Original Assignee: Federal-Mogul Burscheid GmbH (Apollo Global Management, Inc.)
• Inventors: Herbst-Dederichs, Christian
• Granted Patent: US 6,887,585 B2
• Time in Patent Office: Days
• US Class Current: 428/553
• CPC Class Codes: C22C 1/1084 by mechanical alloying (blending, milling)
• CPC Class Codes: C23C 4/06 Metallic material
• CPC Class Codes: Y10S 428/937 Sprayed metal
• CPC Class Codes: Y10T 29/49281 including coating or plating
• CPC Class Codes: Y10T 428/12014 having metal particles
• CPC Class Codes: Y10T 428/12063 Nonparticulate metal component
• CPC Class Codes: Y10T 428/12174 Mo or W containing
• CPC Class Codes: Y10T 428/12806 Refractory [Group IVB, VB, or VIB] metal-base component
• CPC Class Codes: Y10T 428/12826 Group VIB metal-base component
• CPC Class Codes: Y10T 428/12847 Cr-base component

Abstract

The invention relates to a wear-resistant coating used for bearing surfaces and flanks of piston rings in internal combustion engines. The wear-resistant inventive coating is obtained by mechanically alloying powders which form a metallic matrix with hard material dispersoids and lubricant material dispersoids. The coating is then thermally applied to the workpieces, especially by means of high velocity oxygen fuel spraying (HVOF). The workpieces coated are bearing surfaces and parts of flanks pertaining to piston rings in internal combustion engines.

Claims

1. A wear-resistant coating for the bearing surfaces and flanks of piston rings comprising:

a mechanically alloyed powder mixture obtainable by mechanical alloying, wherein said powder mixture includes;

a metallic matrix comprising at least one of nickel and iron and at least one of a nickel and an iron-alloying element selected from carbon, silicon, chromium, molybdenum, cobalt, iron, and nickel, said at least one of said nickel and iron present in a quantity of from 5 to 70% by volume relative to said total powder mixture, whereby said alloying elements do not exceed 70% by weight of said metallic matrix; and

at least one of a ceramic phase selected from Al₂O₃, Cr₂O₃, TiO₂, ZrO₂, Fe₃O₄, TiC, SiC, CrC, WC, BC or diamond, wherein said ceramic phase has a particle size of up to 10 μ

m and said ceramic is present in an amount of from 30 to 95% by volume relative to said total powder mixture;

wherein said mechanically alloyed powder mixture is applied by means of thermal spraying.

2. A wear-resistant coating according to claim 1 further comprising a powdered solid lubricant selected from the group comprised of graphite, hexagonal boron nitride, polytetrafluorethylene, wherein said powdered solid lubricants are present in an amount of up to 30% by volume of said powder mixture.

3. A wear-resistant coating according to claim 1 further comprising at least one additive selected from the group of elements Ti, Zr, Hf, Al, Si, P, and B, wherein said additive is present in an amount of up to 2% by weight relative to said total alloying element of said metallic matrix.

4. A wear-resistant coating according to claim 1 wherein said ceramic phase is further defined as being present in an amount of from 70 to 90% by volume relative to said powder mixture.

5. A wear-resistant coating according to claim 1 wherein said metallic matrix is further defined as comprising nickel and chromium, wherein said chromium is present in an amount up to 50% by weight of said metallic matrix.

6. A wear-resistant coating according to claim 5 wherein said metallic matrix is further defined as comprising nickel, chromium, and molybdenum, wherein said chromium is present in an amount of to 30% by weight of said metallic matrix and said molybdenum is present in an amount of up to 30% by weight of said metallic matrix.

7. A wear-resistant coating according to claim 1 wherein said metallic matrix is further defined as comprising iron and chromium, wherein said chromium is present in an amount of up to 50% by weight of said metallic matrix.

8. A wear-resistant coating according to claim 7 wherein said metallic matrix is further defined as comprising iron, chromium, and molybdenum, wherein said chromium is present in an amount of up to 30% by weight of said metallic matrix and said molybdenum is present in an amount of up to 30% by weight of said metallic matrix.

9. A wear-resistant coating according to claim 4 wherein said ceramic phase is further defined as comprising Al₂O₃.

10. A wear-resistant coating according to claim 1, wherein the mechanical alloyed powder mixture is prepared in at least one of a hammer mill, a ball mill and an attritor.

14. A wear resistant coating according to claim 1 wherein said mechanically alloyed powder mixture is further defined as being applied by means of high-velocity flame (HVOF) spraying.

11. A piston ring for internal combustion engines comprising,

at least one of a flank surface and a bearing surface,

a powder mixture obtainable by mechanical alloying applied to said at least one of said flank surface and said bearing surface, wherein said powder mixture comprises,

a metallic matrix comprising at least one of nickel and iron and at least one of a nickel and iron-alloying element selected from carbon, silicon, chromium, molybdenum, cobalt, nickel and iron, said at least one of said nickel and iron present in a quantity of from 5 to 70% by volume relative to said total powder mixture, whereby said alloying elements do not exceed 70% by weight of said metallic matrix;

and

at least one of a ceramic phase selected from Al₂O₃, Cr₂O₃, TiO₂, ZrO₂, Fe₃O₄, TiC, SiC, CrC, WC, BC or diamond, wherein said ceramic phase has a particle size of up to 10 μ

m and said ceramic is present in an amount of from 30 to 95% by volume relative to said total powder mixture

wherein said powder mixture is applied by means of thermal spraying.

12. A piston ring according to claim 11, wherein said powder mixture has a thickness of from 0.01 to 1.0 mm.

13. A piston ring according to claim 11, wherein said powder mixture is applied by means of high velocity flame (HVOF) spraying.