Formation of Refractory Coatings on Carbon-Based Materials by Gas Phase Transport Reactions

Increased oxidation resistance at high temperatures is one of the critical requirements for high-tech application of carbon materials including carbon and silicon carbide fibers, nanotubes, diamonds. Corrosion resistant coatings such as refractory carbides, nitrides, borides and oxides may improve the oxidation behavior of carbon-based materials. The aim of this work is to study theoretical and experimental aspects of the formation of refractory coatings on different carbon materials under chemical transport through the gas phase. The formation of coatings composed from the carbides of metals of IV-V groups (V, Nb, Ta, Ti, Zr, Hf, Cr, Si) on carbon and SiC fibers, diamond and graphite substrates are considered. The coatings were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM). The coatings obtained were found to be uniform and adherent to substrates. Under definite conditions the formation of refractory coatings as needles was observed. Oxidation of coated carbon fibers was studied.