Combination null with the piston and the piston and the cylinder which improve the abrasion resistance of the contact area of the piston ring

摘要

PROBLEM TO BE SOLVED: To provide a film satisfying the seizure resistance required for a sliding face and the knocked abrasion resistance required for a piston ring insertion groove via one surface treatment by forming a nickel-phosphorus-boron film at least on the face of the piston ring insertion groove to be kept in contact with a piston ring. ;SOLUTION: A nickel film preferably containing phosphorus 1-2 wt.% and boron 0.05-1 wt.% is used for a nickel-phosphorus-boron film. The film thickness is set to 2-50 μm, preferably 5-30 μm. The nickel-phosphorus-boron film is formed by an electroless plating bath containing a phosphorus compound and a boron compound as reducing agents in nickel salt, for example. The plated film improves the adhesiveness to a piston base material and film hardness when it is preferably heat-treated at 200-350°C for 30-120 min, for example.;COPYRIGHT: (C)1999,JPO