Tribological properties of (Ca, Mg)-sialon lubricated by polyols and polyols water solution

Compared with dry sliding, all water solutions of polyols reduce the friction coefficient, but increase its wear volume. The pure polyols not only reduce the friction coefficient significantly, but also reduce the wear volume of (Ca, Mg)-sialon apparently (1-2 order) and the lowest friction coefficient of 0.06 can be approached, when it is lubricated by ethanediol. The order of wear volume of (Ca, Mg)-sialon in four different polyols is as follows: ethanediol, 1.4-butanediol, 1.3-butanediol, propanetiol. The longer the carbon chains and/or the more the number of hydroxy, the smaller the wear volume of (Ca, Mg)-sialon. The FT-IR analysis shows that the tribochemical reactions between (Ca, Mg)-sialon and polyols lead to the formation of anti-wear and friction-reducing tribo-film, which in turn reduce the wear volume and friction coefficient of (Ca, Mg)-sialon.