Preparation of Biomorphic SiC/C Ceramics from Pine Wood via Supercritical Ethanol Infiltration

Biomorphic（wood derived） carbide ceramics with an overall composition in the SiC/C was produced by supercrifical ethanol infiltration of low viscosity tetraethylorthosilicate/supercritical ethanol into biologically derived carbon templates（C;-templates） and in situ hydrolysis into Si（OH）;-gel,the Si（OH）;-gel was calcined at 1400℃to promote the polycondensation of Si（OH）;-gel into SiO;-phase and then carbonthermal reduction of the SiO;with the biocarbon template into highly porous,biomorphic SiC/C ceramics.The phases and morphology conversion mechanism of resulting porous SiC/C ceramics have been investigated by X-ray diffraction（XRD）,scanning electron microscopy （SEM）,transmission electron microscopy（TEM）,and Fourier transform infrared spectroscopy（FT-IR）.Experimental results showed that the biomorphic cellular morphology of pinewood charcoal was remained in the porous SiC/C ceramic with high precision that consisted ofβ-SiC with minority ofα-SiC and the remain free carbon existed in amorphous phase.