| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston ring for internal-combustion engine which has satisfactory abrasion resistance, crack resistance and exfoliation resistance. SOLUTION: The piston ring 1 for internal-combustion engine has constituent elements Cr, N, Si and has the same crystal structure as that of CrN. Besides, the piston ring has, at least in its peripheral circumference, a hard film layer 2 composed of a crystal phase where Si is subjected to solid solution at a rate of 1% or more and 9.5% or less by atomic ratio in its crystal lattice. The hard film layer is composed of Cr, N, and Si and has the same crystal structure as that of CrN and besides includes a mixed phase comprising a crystal phase where Si is subjected to solid solution in its crystal lattice and an amorphous phase whose constituent elements are Si, N and Cr. The ratio of the amorphous phase in the hard film layer may be 4.5% or less and besides an Si content in the hard film layer may be 1% or more and 9.5% or less. Further, Al, V, Ti, Zr, B, C, O or F may be added thereto. COPYRIGHT: (C)2008,JPO&INPIT
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