| 摘要 |
PROBLEM TO BE SOLVED: To provide a hard chromium-plated sliding member having high wear resistance, baking resistance and peeling resistance, even at elevated temperature and under a high pressure, a piston ring and a process for manufacturing them. SOLUTION: The piston ring 1 has a hard chromium-plating film 20 made of at least 4 layers comprising an innermost layer 21, middle layers 22, 23 and an outermost layer 24, each comprising a hard chromium-plating layer. The hard chromium-plating film contains 0.1-0.15 mass% (1,000-1,500 ppm) hydrogen and therefore has a distorted crystal lattice. Within each layer, multiple- layer fine cracks 20a, each of which is continuously formed across multiple neighboring hard chromium-plating films, and single-layer fine cracks 20b, each of which is formed within a single layer without extending into other neighboring layers, are formed. COPYRIGHT: (C)2003,JPO
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