Study on Tribology of Silicon Nitride Ceramic Tappet

Abstract

In order to elucidate the tribological behavior of the Si3 N4 ceramic used in automobile engine, a series of tests was carried out to measure the friction coefficient and wear resistance of Si3 N4 during lubricated sliding against metals. A Timken type test machine and a spring loaded wear test machine were used for this study. Tests were also conducted with metal against metal pairs for comparison. The simulation tests of hot-pressed Si3 N4 Ceramic tappet against metal cam pairs were conducted on a single cam-follower test machine. The test results showed that not only that the Si3 N4 ceramic has excellent wear resistance, but also that the wear of the metal parts in contact with the Si3 N4 ceramic decreased. These results were supported by engine bench test results.