Controlled wet erosive wear of sapphire

Controlled wet erosive wear tests were performed on sapphire specimens. The erosion rates were 5.68 ± 0.67 nm/s, 5.81 ± 0.72 nm/s and 5.85 ± 0.81 nm/s due to impacts produced normal to (0 0 0 1) basal plane and (1 1¯ 0 0), (1 1 2¯ 0) prismatic planes, respectively. On the contrary to wear due abrasion and sliding, the erosion of sapphire did not depend on the crystal orientation. Scanning electron microscopy (SEM) micrographs of worn areas were analysed. The main erosion mechanism of sapphire appears to be by both plastic deformation and brittle fracture.