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 mu m), coarse (70-100 mu m) and reactive (<2.0 mu m) showed a significant difference in wear resistanc e in different wear test environments, e.g. abrasion and erosion tests with dry silica sand, and wet-milling test with alumina grits. LPS materials de rived from the reactive powders yielded a highs wear resistance that was po ssibly due to dissolution of a higher amount of Al2O3 into the intergranula r glassy phase. The wear resistance of 88-94 wt.% LPS Al2O3 increased linea rly upon increasing the MgO/(CaO+BaO+Na2O+K2O) ratio in the chemical compos ition (within the experimental limits) of the sintered material that was de rived 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 obser ved in the high-wear resistant LPS material whereas extensive microcracking was noticed in the low-wear resistant LPS material. (C) 2000 Published by Elsevier Science S.A.