Erosion of alumina ceramics by air- and water-suspended garnet particles

The erosion behaviour of three kinds of commercial alumina ceramics with different microstructures and mechanical properties has been investigated under airborne and slurry erosion conditions. The effect of the angle of impact of the erodent stream on the erosion rate of these materials was determined. A large difference in erosion rates corresponding to shallow angle and normal impact was observed. Such a difference is accounted for by variations in the erosion mechanism. Marked differences were observed in the erosive wear behaviour of the three alumina ceramics. It is concluded that the primary factor controlling the erosion behaviour of alumina ceramics is the microstructure. The effects of varying erodent particle velocity and flux on the erosion rate were also studied. It was found that the erosion rate of alumina ceramics increased with increasing erodent particle velocity and decreasing flux. Finally, a comparison between airborne and slurry erosion of these materials was made. The results indicate that when extrapolated to similar erosion conditions, the slurry erosion rate would be expected to be significantly higher than the airborne erosion rate. Such a difference is attributed to the effects of water on the erosive wear of alumina ceramics. (C) 2000 Elsevier Science S.A. All rights reserved.