Biomorphic cellular silicon carbide ceramics from wood: I. Processing and microstructure

Processing of cellular ceramics with anisotropic pore structures by infiltr ation of liquid Silicon into carbonized wood and subsequent reaction to SiC was investigated. Natural wood of different pore size distribution and com position was carbonized at 800-1800 degrees C in inert atmosphere resulting in a one-to-one reproduction of the original wood structure. The carbon te mplate was converted to SiC by a rapid liquid infiltration-reaction process at 1600 degrees C. Spontaneous infiltration was achieved by using the cont inous tracheidal cells in wood as a transportation path for liquid silicon. beta-SiC formed by solid-liquid reaction at the pore surface exhibits a cr ystalline texture which may be related to the initial microfibril orientati on in the cell walls of wood. Depending on the initial cellular microstruct ure of the various kinds of wood (ebony, beech, oak, maple, pine, balsa) ce ramic materials of different anisotropic pore structures in the form of pse udomorphs of the original wood were obtained. (C) 1998 Elsevier Science Lim ited. All rights reserved.