Control of functional characteristics of biomorphous carbon matrices, SiC-Si-C composites, and SiC-C ceramics by prepressing wood

Abstract

It is found that the prepressing of wood semiproducts intended for producing carbon and silicon carbide matrices by sequential exposure to pyrolysis and silicization with the targeted adjustment of the pressing parameters makes it possible to control the phase composition, morphology, and functional characteristics of carbon and silicon carbide products over a wide range. It is shown that a significant reduction in the porosity of wood induced by uniform compression results in the extraction of the mineral impurities present in the wood to the outer surfaces of the samples during pyrolysis and thus increases the chemical purity of the resulting carbon. It is revealed that the axial compression of wood leads to the formation of a wavelike profile of the intercellular carbon walls of a micron scale. It is shown that, using inhomogeneous deformation, it is possible to prepare silicon carbide ceramics with large controlled gradients of phase composition, electrical conductivity, and other properties that can significantly improve the functional characteristics of electric heaters and other products based on silicon carbide.