Experimental research on the wear performance of Si₃N₄-on-Si₃N₄ and steel-on-Si₃N₄ under the condition of vapor-phase lubrication at high temperature

The tests were carried out by using Si₃N₄ ball as well as M50 tool steel ball on three Si₃N₄ discs at a load of 98N and temperature of 370°C. The results indicate that (1) the mineral oil provides effective lubrication for steel-on-Si₃N₄ system; whereas for the combination of mineral oil with TCP or TMPTH, the wear can even be reduced; (2) in comparison with the steel-on-Si₃N₄ system, the wear of Si₃N₄ discs is greater for the Si₃N₄-on-Si₃N₄ system; (3) the X-ray photoelectron spectroscopy (XPS) analyses on the rubbed surface reveal the existence of transfer of iron or iron compounds to the surface of silicon nitride disc and the formation of a film containing carbonaceous deposits and iron compounds such as iron phosphate.