Ceramics-Silikáty 51 (1) 30-39 (2007)

The effect of surface finish and cavitating liquid on the  cavitation erosion of alumina and silicon carbide ceramics

W.M.N. Nour, U. Dulias, J. Schneider, K.-H. Zum Gahr

The cavitation erosion of alumina (F 99.7, Friatec) and sintered silicon carbide (SSiC, EKasic F) with different surface finish was investigated at 25°C for up to 6h in distilled water as a cavitating liquid according to ASTM G32-92. The wear progress was followed by measuring the cumulative mass and volume losses. The eroded surfaces were examined for their damaged microstructure using SEM. The wear resistance of the tested ceramics, in terms of the incubation time and mass and volume losses, was improved when decreasing surface roughness. SSiC showed higher wear resistance in comparison with alumina. The results were discussed in terms of the hardness, fracture toughness, grain size, surface roughness and microstructure. In addition, the influence of oils as cavitating liquids on the erosion of tested ceramics was studied. The results indicated that water is highly erosive medium when compared with the used oils as a result of higher water vapour pressure, lower viscosity and higher density.

Keywords: Ceramics; Structural materials; Cavitation