Electroless Ni-P-C_g(graphite)-SiC composite coating and its application onto piston rings of a small two stroke utility engine

Abstract

This study presents electroless Ni-P-Cg (graphite)-SiC composite coating deposition onto piston rings of a small two stroke utility engine at 90°C under Cg (10 g/l) and SiC (8 g/l) concentration at agitation speeds of 160 rpm. Coating showed compact embedding of Cg and SiC particles in Ni matrix, uniformly and largely distributed in coating by mechanical stirring. Heat-treatment of coating increased microhardness due to crystallization of a hard Ni3P phase after heat treatment. An average surface roughness of a standard piston ring has improved from 1.095 µm to 0.900 µm, with a lower friction coefficient of coated