| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston ring excellent in initial conformability scuffing resistance and fatigue resistance. SOLUTION: A gas nitriding layer 2 having hardness of more than HV900 is formed on an overall surface of a piston ring 1, and solid Cr plating 3 (2-5μm) is applied on the gas nitriding layer 2 on an outer peripheral sliding surface. Hardness of the solid Cr plating 3 is within a range of HV400-750. Plating bath composition of the solid Cr plating 3 is CrO3 : 250 g/l, H2 SO4 : 1 g/l, H2 SiF6 : 5 g/l, and a plating condition is 60 A/dm<2> for electric current density and 20-30 deg.C for plating bath temperature. It is possible to form hard Cr plating 4 having hardness of more than HV800 in place of the gas nitriding layer 2.
|
