NONOXIDE CERAMICS WITH NANOCRYSTALLINE LAYERS MADE BY CHEMICAL LIQUIDDEPOSITION

Chemical liquid deposition (CLD) has been used to modify the surface o f non-oxide ceramic powders (silicon nitride, silicon carbide) by mean s of controlled precipitation of inorganic additives and subsequent he at treatment. The processes which occur during the decomposition of th e deposited layers (2-10 nm thickness) are discussed from the results of thermal analysis. The extent of nanolayer formation is considered t o depend on the details of processing methods, the ceramic powder part icle size distribution, the relative densities of the ceramic and of t he deposited material, and the mass concentration of the latter relati ve to the base powder. The preliminary results indicate that CLD can p rovide unconventional ways of surface modification of ceramic powders and hence of their processing properties.