Influence of microstructure on the erosive wear behaviour of Ca α-sialon materials

The erosion behaviour of three pressureless sintered Ca α-sialon ceramics with different grain sizes, morphologies and various amounts of grain boundary glass was investigated using a gas-blast type erosion rig. The erodent particles used were SiC grits. The effects of grain size and morphology on the erosion mechanism were studied. It was found that the dominant material removal mechanism for the fine equiaxed-grained sialon was grain dislodgment, while that for the elongate-grained material was transgranular fracture. The effect of different amounts of intergranular glass on the erosion resistance of these materials was also studied. It was found that an optimum amount of grain boundary glass had a beneficial effect on erosion resistance. Finally, the effect of post-sintering heat treatment on the erosion behaviour of these materials was investigated. The results showed that heat-treated samples exhibited a higher erosion rate than their as-sintered counterparts.