Environmental effects on wear behaviour of alumina

Abstract

The friction and wear properties of alumina (of purity 92% and 99% respectively) were evaluated at various temperatures (50, 200, 400 and 600 °C) and with an Optimal SRV (Schwingung Reibung Verschleiss) oscillation friction wear tester under loads of 15 and 50 N. In addition to atmospheric tests, dry wear tests were also performed in nitrogen at 600 °C. At 50 °C, the tribological properties of ceramics using water as a lubricant, were studied also. The important results of the present study are as follows: (1) The wear resistance of 99% alumina is better than that of 92% alumina. (2) The wear volume and friction coefficient of wear tests with water as a lubricant are lower than those in dry wear tests. (3) The friction coefficient of self-mated 92% alumina in nitrogen is slightly lower than that in the atmosphere at 600 °C, while the wear of plane specimens in nitrogen is higher than that in the atmosphere. (4) Surface polishing and abrasive wear mechanisms are dominant at lower temperature. Adhesive wear of alumina increases with increasing temperature up to 400 °C, with the exception of alumina softening at 600 °C.