High temperature friction and wear testing of silicon nitride ceramics

This paper describes the results of unlubricated sliding wear tests carried out on ceramics and composites based on silicon nitride. These were silicon nitride, silicon nitride with titanium carbide, and an electrically conductive silicon nitride with titanium nitride. The tests were carried out from room temperature to 1200 degrees C. For all the materials, there was a small increase in friction from room temperature to 300 degrees C, followed by a small decrease as the temperature increased, until a sharp increase in friction coefficient at 1200 degrees C. There was a maximum in wear as the temperature was varied for all materials, with almost no wear at room temperature and at 1200 degrees C. The wear of the silicon nitride material was significantly higher than that of the composite materials at 900 degrees C.