Influence of powder, chemistry and intergranular phases on the wear resistance of liquid-phase-sintered Al 2O 3

Abstract

Liquid-phase-sintered (LPS) Al 2O 3 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 Al 2O 3 into the intergranular glassy phase. The wear resistance of 88–94 wt.% LPS Al 2O 3 increased linearly upon increasing the MgO/(CaO+BaO+Na 2O+K 2O) 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 Al 2O 3 grain boundary led to a lower wear resistance in 91–94 wt.% LPS Al 2O 3 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.