The effect of corrosion and erosion on ceramic materials

The effects of corrosion/erosion on the chemical/mechanical properties and microstructures of four engineering ceramic materials, namely alumina, reaction bonded silicon carbide, sialon and PSZ zirconia, were investigated and characterised, using a chemical etch bed (hydrofluoric-hydrochloric acid mixtures, 1.5% HF + 5% HCl) and a sand-water slurry erosion test rig. A series of corrosion and erosion tests were carried out and the morphology, structure and chemical analysis of the samples was investigated using optical microscopy, SEM, XRD and AAS (Atomic absorption spectroscopy). Under the test conditions, SiC shows the best chemical and erosion resistance of the four ceramics; and alumina has the highest corrosion and erosion rate. The erosion and corrosion response, the degeneration of mechanical properties and the micromechanisms of the surface damage for these ceramic materials are presented and discussed. (C) 1997 Elsevier Science Ltd.