Ceramic wear maps

Ceramic wear maps have been developed to elucidate the complex interactions of the operating parameters, environments, and wear mechanisms. This paper summarizes these interactions for four ceramics, alumina, yttria-doped zirconia, silicon carbide and silicon nitride. Wear maps of these ceramics are systematically constructed using measured data under dry sliding, water, and paraffin lubricated conditions. For each material, different wear level regions and wear transition zones are identified as a function of operating conditions and lubrication conditions. Wear mechanism studies performed within each wear region give rise to the wear mechanism maps. These maps facilitate material comparison and selection. The knowledge of wear, wear transitions, and wear mechanisms for a material pair enables realistic wear model development. One outcome of this approach is the recognition that a single wear model for a material pair cannot cover all operating conditions and environments. As wear maps are constructed today, they are material pair specific. Within a material pair, there are microstructural dependence and surface properties influence. These parameters can change substantially for a given chemical composition of the material. How to incorporate these factors into the wear map research remains an issue. The search for a universal parameter such as the “asperity temperature” in Ashby's wear map continues in spite of mounting evidence that this may not be practical or feasible. But the hope remains that some parameters can be identified to normalize a large number of materials, operating conditions, and environments for tribological applications. Systematic wear maps are the first steps in this direction.