Controlled wet erosive wear of polycrystalline alumina

Controlled wet erosive wear tests were performed on polycrystalline alumina specimens of mean grain size G = 1.2, 3.8 and 14.1 μm and on sapphire specimens. The tests were performed by using an apparatus consisting of a jet body that rotates immersed in the slurry medium (SiC grits). Impacts are normal to the target surface. The construction and calibration of the apparatus are described. The impacting velocity used was 2.7 m s⁻¹. The weight loss of polycrystalline alumina and sapphire specimens increased linearly with impacting time. The wear rate of polycrystalline alumina specimens increased with grain size. Wear rates of 1.83, 8.36 and 11.3 nm s⁻¹ correspond to G = 1.2, 3.8 and 14.1 μm, respectively. For sapphire specimens the wear rate was 9.56 nm s⁻¹. Worn surfaces of both polycrystalline alumina and sapphire specimens were analysed by scanning electron microscopy.