Laminated biomorphous SiC/Si porous ceramics made from wood veneer

Biomorphous SiC/Si porous ceramics with laminated structure are prepared from beech veneer and phenolic resin. The preparation involves carbonization under vacuum and reaction with melted silicon to obtain the biomorphous carbide template. X-ray diffraction confirms that the biomorphous SiC/Si porous ceramics are mainly composed of β-SiC, free silicon and residual carbon. Scanning election microscopy observations indicate a laminated structure and 1–10 μm microporous structures, which suggest retention of the native characteristics of the wood. This paper examines mechanical properties of the final composite in relation to the lamination, porous structure, and free silicon content. The bending strength of the ceramics decreases as the apparent porosity increases. The fracture toughness increases initially with apparent density and then decreases. The fracture toughness load–displacement curve presents a step-like pattern, which suggests that the laminated SiC/Si porous ceramics have high fracture toughness.