comparative test for fast wear of various piston rings(N+ ion implanted
plated with SiNx and ordinary finished product) has been completed. The N+ ion implanted piston rings
among others
demonstrate the best wear resistance and the smallest change of elasticity
which indicates that N+ ion implantation is a fairly well method for improvement of wear resistance of piston rings. The mechanism of raising wear resistance by N+ ion implantation is also discussed.