Preparation of biomorphic silicon carbide-mullite ceramics using molten salt synthesis

摘要

Biomorphic silicon carbide-mullite ceramics were prepared from beech wood using liquid Si infiltration and molten salts synthesis. The resulting mullite whiskers coating, as well as the growth mechanism in molten Al-2(SO4)(3)-Na2SO4 environment, have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. The biomorphic SiC ceramics derived from the beech wood template have coarse pore walls consisting of beta-sic grains with diameters ranging from 5 mu m to 20 mu m. After the molten salts reactions between biomorphic SiC substrate and mixture molten salts (Al-2(SO4)(3)-Na2SO4), porous Silicon carbide-mullite ceramics with cilia-like microstructure were obtained. This unique structure has potential application in hot gases filters. An oxidation-dissolution cycle was proposed to explain the mullite whiskers growth in molten salts environment. (C) 2014 Elsevier B.V. All rights reserved.