Erosion of ceramic materials by a sand/water slurry jet

A slurry impingement erosion test rig was constructed and a series of erosi on tests and post-erosion analyses were carried out on four ceramic materia ls, namely alumina, reaction-bonded silicon carbide, sialon and PSZ zirconi a. The effect of sand concentration, erosion time, as well as impact angle, was investigated. Al2O3 was found to have the highest erosion rate, while zirconia has the best erosion resistance at 90 degrees impingement. It was found that the erosion mechanisms for these materials involve both brittle fracture as well as plastic deformation, with ripple patterns found on the surface of some ceramic materials. The dependence of erosion rate on hardne ss and fracture toughness were complicated for the investigated ceramics. T he brittleness, which is defined as a quantity of H-v/K-c, is more convenie nt to describe the erosion process of ceramics. The dependence of erosion r ate on brittleness was followed for SiC, sialon and zirconia but not for Al 2O3. The microstructure of ceramics and a threshold hardness of the target material may be responsible for a change in erosion mechanism. (C) 1999 Pub lished by Elsevier Science S.A. All lights reserved.