GLASS-CERAMICS - NEW COMPOSITIONS AND USES

Glass ceramics, materials prepared by the controlled crystallisation o f glasses, have a variety of established uses dependent on their unifo rm reproducible fine-grain microstructures, absence of porosity and wi de-ranging properties which can be tailored by changes in composition and heat treatment. Moreover, during manufacture complex shapes may be produced using standard glass-forming techniques prior to crystallisa tion and dimensional changes are small. In recent years, new compositi ons, processing methods and applications have begun to emerge. Among t he recent developments considered are new phosphate-based compositions , the use of sol-gel processing, glass ceramic matrix composites, glas s ceramics in microelectronics packaging, glass ceramics bonded to met als and as joining media, high-strength and high-toughness materials a nd machineable compositions.