| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston ring with excellent initial adaptability with an inner circumferential face of a cylinder liner, scuff resistance, and abrasion resistance. SOLUTION: A hard carbon laminated film is formed on at least an outer circumferential sliding face 6 of the piston ring 10. The above problem is solved by the piston ring, in which the hard carbon laminated film 2 is constituted of: a first hard carbon film 11 formed on a surface of the outer circumferential sliding face 6, containing at least Si, with excellent initial adaptability and scuff resistance; and a second hard carbon film 12 formed under the first hard carbon film 11, containing at least W or W and Ni, with excellent abrasion resistance. The second hard carbon film 12 may be additionally formed on upper and lower faces 8, 9 or may be formed on a circumference of the piston ring including an inner circumferential face 7. If required, the first hard carbon film 11 may be formed on the second hard carbon film 12. Further, base layers may be formed to each of the hard carbon films.
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