Patent ID: 9644738
Date: 2017-05-09
CPC Classifications: C23C,F02F,F05C,F16J

Claim:
1. A combination of a cylinder and a piston ring for an internal combustion engine, said cylinder being made of an aluminum alloy containing 12-38% by mass of Si; said piston ring comprising, at least on an outer peripheral sliding surface thereof, a laminate coating comprising a metal layer, a metal-containing, hard carbon layer, and a metal-free, hard carbon layer in this order from the substrate side; said laminate coating having Martens' hardness HMs of 5-13 GPa, indentation modulus E of 70-200 GPa, and a deformation ratio Rpe of 0.45 or less, which is expressed by a ratio (Wp/We) of plastic deformation energy Wp to elastic deformation energy We; and a ratio (Tmf/Tm) of the thickness Tmf of said metal-free, hard carbon layer to the thickness Tm of said metal-containing, hard carbon layer being 2-8.