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

Porous b-SiC with a multimodal porosity preferentially oriented alongone direction is obtained by infiltration of pyrolyzed wood with Si at T>TSi Melting. Hard woods (obece, poplar and assembled poplar) are used as startingmaterials. 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 b-SiC with a microstructurethat 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 duringthe infiltration cycle. Compression tests on cubic samples are performed alongthe axial and longitudinal direction.