Processing high-purity and liquid-phase-sintered alumina ceramics using locally synthesized alumina powders

The feasibility of using locally synthesized powders in the development of high-purity and liquid-phase-sintered (LPS) aluminas, for potential use as ceramics in erosive wear environments, was explored. The principal purpose of the project was the development of processing philosophies for alumina-based ceramics that meet the dual, and usually conflicting needs, for improved properties at lower cost, with special attention to the Western Australian mining industry. The incorporation of glassy grain-boundary phases via sintering additives makes the achievement of low-cost LPS aluminas possible, but also threatens to compromise properties. Sintering behaviour, phase assemblage, microstructural evolution and mechanical properties were explored as key variables in this goal. The results indicate that the locally sourced alumina and mineral additives can be combined to produce LPS aluminas which are comparable in mechanical performance to currently-available commercial LPS alumina ceramics. © 1998 Chapman & Hall