The wear response of ceramic matrix nano-composite coatings in simulated piston-ring/cylinder wall test environments

摘要

A series of piston rings with surface coatings of alumina-matrix nano-composite materials have been evaluated in lubricated high-speed sliding contact with cast-iron cylinder liners at 200°C. Comparisons were made with standard CKS-36 (a commercial coating comprising chromium plating reinforced with alumina particles) coated cast-iron piston rings. Two types of wear mechanism were observed for the nano-composite coatings: (ⅰ) micro-scale cohesive failure, and (ⅱ) smooth wear. The latter mechanism resulted in lower wear rates. The predominance of a given wear mechanism was found to depend on the coating composition and type of grinding operation used to finish the nano-composite coated piston rings.