The influence of lubrication on tribological properties of Si3iNi4/1045 steel sliding pairs

Compared with cermet cutting tools, ceramic cutting tools have much better thermal stability and higher hardness. Si3N4-based composite ceramics have been used progressively more for machining cast iron at very high speed. However, they have been found to be unsuitable for machining steel. One of the factors influencing this difference in behaviour is thought to be serious chemical wear of the ceramic at the high temperatures reached at the cutting tools. Lubrication could reduce the friction and the high temperature of the cutting tool/workpiece contact zone. A simulation test was carried out on a pin-on-disc tribometer in order to investigate the effect of lubrication on the friction and wear of Si3N4/1045 steel sliding pairs; the effects of load and speed on friction and wear were also investigated. The results show that suitable lubrication could greatly reduce the friction coefficient and wear rate of Si3N4 ceramic. Scanning electron microscopy, Auger electron spectroscopy and X-ray photoelectron spectroscopy were used for examinations of the worn surfaces. A wear mechanism of the Si3N4 ceramic in sliding contact with 1045 steel is proposed.