Synthesis of Ceramic Powders from Metal Alkoxides

Abstract

Powders derived from metal alkoxides, irrespective of the specific process, have been demonstrated to possess most of the desirable characteristics for ceramic fabrication and sintering. Particularly impressive gains have been reported for silicates and in the expansion of the compositional range of alkoxide derived powders. While most research has focused on synthesis of simple metal oxide powders, advances in the chemistry of mixed metal alkoxides should pave the way for powder synthesis of more complex, multicomponent oxides.Besides the high chemical costs, a major deterrent for commercial production of powders by controlled hydrolysis of metal alkoxides is the fundamental requirement for dilute solutions, and thus low yield, to obtain monodisperse particles. Continuous processes such as aerosol reactions, spray pyrolysis, seeded growth and, potentially, emulsion processes, may overcome the barrier of low rate of production.A technical impediment for commercial use of alkoxide derived particles stems from their structurally porous character. Although the other physical characteristics allow for lower temperature densification, the large sintering shrinkage associated with porous particles is undesirable and poses a significant barrier to industrial application. As a reasonably mature field, future advances will require the modeling and detailed analysis of the above processes.