ABSTRACT
Tribochemical interactions of ceramics with gaseous environments and lubricants determine the wear of these materials. Such interactions can decrease wear or increase it, depending on the particular ceramic and environment. Water decreases wear of silicon nitride and silicon carbide by tribochemical reaction and increases that of zirconia and alumina by chemisorption embrittlement. Lubricants that reduce friction to low values are nevertheless capable of increasing the wear rate of certain ceramics. These phenomena are manifestations of the surface chemistry of ceramics, and the chemical reactions are related to the electronic structure of the materials.
