Introduction

The hardness and chemical stability of ceramics should make them ideal materials for tribo-elements that have to function under severe wear and high temperature conditions. Unfortunately, large variations in both friction and wear resistance can occur when ceramics are slid against themselves, or against a metal counterface, in the unlubricated condition. These variations have tended to prevent the widespread use of ceramics in tribo-systems. However, the recent interest in developing the ceramic diesel has tended to bring about an increase in fundamental research into the tribological properties of ceramic/ceramic and ceramic/metal tribo-systems, some of which looks very promising.

Some of the earliest work on the tribology of ceramics was carried out by Seal (1958) on diamond. Other materials include ionic crystals (Steijn, 1963), sapphire (Steijn, 1961), silicon carbide (Miyoshi and Buckley, 1979a), boron nitride (Buckley, 1978), manganese zinc-ferrite (Miyoshi and Buckley, 1981b), titanium (Nutt and Ruff, 1983), silicon nitride (Dalal, Chiu and Rabinowicz, 1975) and many other materials too numerous to mention. Since we are mainly interested in the application of physical analytical techniques to ceramic tribology, we will be very selective and discuss silicon nitride, silicon carbide and sapphire tribo-systems. Other systems may be more relevant to the reader's interest, but at least we know that various physical analytical techniques have been applied to tribo-systems with these materials as tribo-elements.