Sliding wear behavior of protective coatings for diesel engine components

The use of heat-insulating ceramic coatings on the cylinder walls of diesel engines is currently being considered for certain advanced engine designs. Since a major consideration in such an application is the wear resistance of the coatings, a series of tests has been carried out to determine the sliding wear behavior of several pairs of candidate materials systems, initially at room temperature. The tests were performed using a washer-on-disc specimen configuration and an oscillatory rotation movement to simulate the motion of a piston ring on a cylinder wall. It was determined that each material tested had a different pattern of sliding wear behavior. Impregnation of plasma-sprayed Y₂O₃-ZrO₂ with chromia markedly improved its wear resistance.