GRAIN-SIZE EFFECTS ON THE WET EROSIVE WEAR OF HIGH-PURITY POLYCRYSTALLINE ALUMINA

The wet erosive wear of a set of 100% polycrystalline alumina materials of tailored grain sizes in the range 1-12 mum has been studied using a slurry of coarse alumina grit in water. Detailed observations of worn surfaces identify two wear mechanisms: microfracture and grain detachment, and tribochemical wear. Measured wear rates are a function of (grain size)-1/2. and a linear relationship between wear rate and four-point bend strength is also seen. Grain detachment is the dominant wear mechanism for grain sizes >2 mum.