The importance of microscopy in studying the wear behaviour of ceramic surfaces

This paper demonstrates how careful microscopy of worn ceramic surfaces can be used to provide information on the mechanisms of material removal. This information is necessary as a critical complement to wear‐rate data obtainable from simple wear tests alone (e.g. lapping with diamond grits). Scanning electron microscopy has been extensively used to investigate the changing appearance of worn surfaces as plasticity and fracture processes compete as materials removal and redistribution mechanisms. Examples of the use of secondary electron imaging at different surface tilts, back‐scattered electron imaging and stereo imaging are shown. Further, transmission electron microscopy of samples specially prepared to contain the worn surface layer can reveal the presence of phase changes accompanying wear. Furthermore, observations have been made of instances whereby brittle fracture has unexpectedly occurred as a result of repeated plastic deformation of surfaces at low contact severities. Some conclusions are drawn regarding the influence of specimen microstructure, abrasive grit size and environment of the wear of glass‐bonded (debased) alumina and titania materials. 1985 Blackwell Science Ltd