| 摘要 |
PROBLEM TO BE SOLVED: To improve sliding performance, particularly peeling resistance of a hard coating. SOLUTION: A nitric layer 2 is formed on a piston ring 1 to have the nitric layer 2 of outside circumferential face coated with the hard coating 3 by ark ion plating. The hard coating 3 has a multi-phase crystal structure of CrN and TiN with [O] dissolved in solid into the CrN/TiN structure, with 40-75 wt.% Cr, 10-40 wt.% Ti, 0.5-15 wt.% O, and the residual N, and each grain size of the crystal is less than 1μm. Vickers hardness of the hard coating 3 is within the range of 1300-2300. The crystal CrN/TiN has a priority orientation of (200) face or (111) face in parallel with the coated face and presents a columnar structure that groves in column from the base material side toward the coating surface. Instead of [O], [C] as well as [O]/[C] may be dissolved in solid. And a base coating 4 in CrN may be formed between the nitric layer 2 and the hard coating 3. |
