Method for making self supporting composite bodies

Abstract

This invention relates generally to a novel directed metal oxidation process which is utilized to produce self-supporting bodies. In some of the more specific aspects of the invention, a parent metal (e.g., a parent metal vapor) is induced to react with at least one solid oxidant-containing material to result in the directed growth of a reaction product which is formed from a reaction between the parent metal and the solid oxidant-containing material. The inventive process can be utilized to form bodies having substantially homogeneous compositions, graded compositions, and macrocomposite bodies. In a preferred embodiment, the reaction product may be chemically modified or a different reaction product may be coated thereon. Specifically, once a first reaction product is formed on a solid oxidant-containing material, the formed body may be exposed to a vapor-phase parent metal different from the first parent metal. Alternatively, the formed body may be exposed to a vapor-phase oxidant having a different chemical composition then the solid oxidant-containing material. Still further, a non-stoichiometric reaction product deficient in the oxidant component may be made more stoichiometric by heating the self-supporting body in the absence of reaction product growth conditions at a temperature and for a time sufficient to effect diffusion of additional oxidant from the solid oxidant-containing material into the sub-stoichiometric reaction product, thereby increasing its stoichiometry.