Wear of Sintered Metals

Abstract

A pin-on-disc technique is described which produces a graphical record of the whole duration of a wear experiment. Small changes to the experimental conditions produce large differences in wear rates which are related to oxidative and metallic wear mechanisms. This technique has been used to evaluate materials pressed and sintered under various conditions and to investigate the effect of alloying and oil impregnation. Increases in pressing pressure and sintering temperature improved the wear resistance. The addition of phosphorus in the form of a hard phosphide eutectic brought about an appreciable reduction in wear rate. The presence of lubricant impregnated into the pores of the sintered compact reduced the wear rate to a very low value until all the lubricant had been used up. A correlation is presented between wear of piston rings and cylinder liners in a diesel engine and wear of the same materials investigated on the pin-on-disc machine, on which it was possible to reproduce the wear mechanism observed in service and to study the mechanism of failure. It was also possible to advise on the optimum combination of materials for this application.