PROCESSING HIGH-PURITY AND LIQUID-PHASE-SINTERED ALUMINA CERAMICS USING LOCALLY SYNTHESIZED ALUMINA POWDERS

The feasibility of using locally synthesized powders in the developmen t of high-purity and liquid-phase-sintered (LPS) aluminas, for potenti al use as ceramics in erosive wear environments, was explored. The pri ncipal purpose of the project was the development of processing philos ophies for alumina-based ceramics that meet the dual, and usually conf licting needs, for improved properties at lower cost, with special att ention to the Western Australian mining industry. The incorporation of glassy grain-boundary phases via sintering additives makes the achiev ement of low-cost LPS aluminas possible, but also threatens to comprom ise 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 co mparable in mechanical performance to currently-available commercial L PS alumina ceramics. (C) 1998 Chapman & Hall.