Influence of powder, chemistry and intergranular phases on the wear resistance of liquid-phase-sintered Al2O3

Liquid-phase-sintered (LPS) Al2O3 ceramics prepared using different powders of varying particle size, i.e. medium (3.6–7.0 μm), coarse (70–100 μm) and reactive (<2.0 μm) showed a significant difference in wear resistance in different wear test environments, e.g. abrasion and erosion tests with dry silica sand, and wet-milling test with alumina grits. LPS materials derived from the reactive powders yielded a higher wear resistance that was possibly due to dissolution of a higher amount of Al2O3 into the intergranular glassy phase. The wear resistance of 88–94 wt.% LPS Al2O3 increased linearly upon increasing the MgO/(CaO+BaO+Na2O+K2O) ratio in the chemical composition (within the experimental limits) of the sintered material that was derived from the medium and coarse powders. The precipitation of anorthite on the Al2O3 grain boundary led to a lower wear resistance in 91–94 wt.% LPS Al2O3 of medium and coarse powders. Extensive plastic deformation was observed in the high-wear resistant LPS material whereas extensive microcracking was noticed in the low-wear resistant LPS material.