The use of microwave heating in advanced ceramics processing

Experiments carried out at IPEN are presented, involving advanced ceramics microwave processing. Drying, binder removal, calcing and sintering of materials such as oxides and other compounds of aluminium, zirconium, uranium, beryllium and rare earths were developed in laboratory scale, 2,42 GHz. Modifications of the available commercial furnaces are described; they permitted to obtain temperatures higher than 400 C. Temperatures over 800 C were reached in quartz chambers surrounded by vermiculite; 1200 C was attained with the utilization of the commercial refractory 'Fiberfrax'. The microwave furnace was operated inside a gas cooled glove-box, with nitrogen, argon and air as heat treatment atmospheres. At the microwave frequency used the experiments, although in a laboratory scale, indicate that uranium compounds microwave drying has competitive potential in relation to other more usual procedures. It is discussed the possibility of using microwave heating in a near future in Brazil, for advanced and traditional ceramics processing. (author)