| 摘要 |
<p>A gas nitrided layer 2 is formed over the entire surface of a piston ring 1 and a hard film 3 with a thickness of 0.5 to 10 micrometers is formed on the gas nitrided layer 2 at the outer circumferential surface. The hard film 3 comprises diamond-like carbon in which are dispersed carbides of one or more elements selected from the group consisting of silicon, titanium, tungsten, chromium, molybdenum, niobium, and vanadium. The diamond-like carbon is configured with any one of an amorphous carbon structure, an amorphous carbon structure having partly a diamond structure, or an amorphous carbon structure having partly a graphite structure. The content of the above elements is 5 to 40 atomic percent, and the hard film 3 has a Vicker's hardness in a range from 700 to 2,000. A chromium plating film or ion plating film may be used instead of the gas nitrided layer 2. The hard film 3 may be formed directly on the outer circumferential surface of the piston ring 1 in a thickness from 10 to 30 micrometers. <IMAGE> <IMAGE> <IMAGE></p> |
