Sol-gel/co-precipitation method for the preparation and characterization of zirconia-tungsten composite powders

Sol-gel and co-precipitation are interesting processes in view to prepare c eramic-metal composite powder. Using metal salts as starting compounds it i s possible in a first step to synthetise a mixed precipitate and in a secon d reduction step, in a H-2/Ar atmosphere, to obtain such a composite powder . Stabilized zirconia-tungsten composite powder have been prepared by this way without mixing and milling steps. Each step of the synthesis has been c haracterized. Stability of the mixed precipitate suspension and surface are a of the dried powder are largely influenced by the tungsten salts content. The temperature of formation of zirconia changes from 510 degrees C withou t tungsten precursor up to 695 degrees C for a 60% tungsten molar ratio com position. Composite zirconia-tungsten powders, in a large range of composit ion, are obtained at 1100 degrees C with morphologies depending on humidity and thermal treatment conditions. (C) 1999 Kluwer Academic Publishers.