Effect of selected chemical compounds on the lubrication of silicon carbide

A systematic study has been conducted to investigate the interactions between selected chemical compounds and silicon carbide under boundary lubrication conditions. A modified four-ball wear tester was used to evaluate the additive effectiveness on silicon carbides lubricated with a paraffinic base oil containing one weight percent of additives. Friction, wear and film morphology were observed for a range of chemical compounds containing chlorine, phosphorous, oxygen, and sulfur. Friction reduction was observed for chlorine containing compounds. At weight fraction of one percent under 40 kg lend, wear reduction was obtained by all phosphorous containing compounds, polypropylene glycols, and oleic acid At higher concentration and higher load some sulfur containing compounds also reduced wear significantly In general, all the effective wear reduction compounds generate films in the contact region. The films generated by phosphorous containing compounds appear to involve the iron impurity in the material.