Lime–Alumina–Silica processing incorporating minerals

Abstract

The use of naturally occurring minerals to enhance the physical and mechanical properties of industrial ceramics such as alumina is an attractive alternative to synthetic materials due to cost, chemical stability and availability. Two systems, have been chosen for investigation, alumina–kyanite to produce an alumina–mullite composite and alumina–wollastonite to produce a lime aluminosilicate. Wet processing conditions were optimised using pH/rheology and microelectrophoresis techniques followed by slip casting. The resulting green compacts were subjected to a variety of sintering regimes to produce the desired composites. Sintered products were characterised by techniques such as electron probe microanalysis, hardness tests and toughness determinations. Results are discussed, both in terms of enhanced properties realised (toughness, wear resistance, dielectric), and with respect to the viability of using natural minerals in this application.