Microstructure and properties of porous β-SiC templated from soft woods

Porous beta-SiC with a multimodal porosity preferentially oriented along one direction is obtained by infiltration of pyrolyzed wood with Si at T > T-Si (Melting). Hard woods (obece, poplar and assembled poplar) are used as starting materials. The microstructure of the starting wood, of the wood after pyrolysis and after Si infiltration, is characterised in terms of overall porosity, pore size distribution and of crystallographic phases. The process is optimised for obtaining porous templates of only beta-SiC with a microstructure that replicates the original wood microstructure. Features such as the presence of unreacted carbon, or conversely, of Si within the open pores of the infiltrated materials are minimized by a careful control of the amount of Si in contact with the carbon preform during the infiltration cycle. Compression tests on cubic samples are performed along the axial and longitudinal direction. (C) 2003 Elsevier Ltd. All rights reserved.