Tribological characteristics of silicon nitride-chilled cast iron with oil-less lubrication

Abstract

The friction and wear tests for mated couples of silicon nitride(Si3N4) and chilled cast iron under the oil-less lubrication were carried out by means of block-on-disc with MG-200 wear machine from room temperature to 150°C, the friction coefficients of mated couples and wear rates of Si3N4 were gained, and the friction and wear behaviors were analyzed by the wear rates, friction coefficients, SEM images and percentages of chemical elements on worn surfaces. The results showed that the wear rate of Si3N4 and friction coefficient between Si3N4 and chilled cast iron with oil-less lubrication are much less than those with dry friction condition; the wear rate of Si3N4 increases with the increase of load and temperature, and the effect of sliding speed on wear rate of Si3N4 is not as significant as the effect of load; the friction coefficient between Si3N4 and chilled cast iron decreases with sliding speed, but increases with temperature, and the load has little effect on friction coefficient; the wear of Si3N4 is caused by interaction of chemical wear, abradant wear and particles' peeling off, and chemical wear is the main factor causing other two wears.