Synthesis of biomorphic Si-based ceramics

Tilia wood was transformed by pyrolysis into carbon preform. This porous carbon preform was infiltrated with TEOS (Si(OC2H5)4), as a source of silica. In situ reaction between the silica and the carbon template occurred in the cellular wall at a hight temperature. Depending on the applied atmosphere, non-oxide (SiC) or oxide (SiO2) ceramics were obtained. Scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared (IR) spectroscopy, mercury porosimetry and BET measurements were employed to characterize the phases and crystal structure of biomorphic ceramics. The experimental results showed that the biomorphic cellular morphology of the wood maintained in both the SiC and SiO2 ceramics, wich consisted of β-SiC with trace of α-SiC and SiO2, respectively