Characterization of a silicon carbide thin layer prepared by a self-propagating high temperature synthesis reaction

Silicon carbide was deposited by a self-propagating high temperature synthe sis reaction between graphite and silicon layers on an oxide substrate. Che mical analyses by Auger electron microscopy and X-ray diffractometry reveal ed that the final product was beta-SiC without an inter-diffusional layer a t the interface between the carbide and graphite layers. Transmission elect ron microscope observation showed that the silicon carbide layer has fine c rystalline structure. Numerical analysis showed that the combustion limit d ecreases with initial reaction temperature, which means that additional hea t is required for the complete reaction. Activation energies between Liquid silicon and carbon fiber or carbon black were 2875 and 1782 kJ/mol, respec tively. The silicon carbide prepared by the combustion reaction between sil icon and carbon was formed by the carbon diffusion at the interface between liquid silicon and silicon carbide. The reaction rate significantly depend ed on the specific surface area of carbon. (C) 2000 Elsevier Science S.A. A ll rights reserved.