Effect of different silicon sources on rattan-based silicon carbide ceramic prepared by one-step pyrolysis

Abstract

Rattan-based silicon carbide (R-SiC) ceramics, R-SiCSiO2 and R-SiCSi, were successfully prepared from silica (SiO2) sol and silicon (Si) powder, respectively. The rattan powder was impregnated, respectively, with SiO2 sol at ambient temperature and liquid melt-Si at high temperature. This was followed by one-step direct pyrolysis at 1500 °C under an argon (Ar) atmosphere. The final SiC samples were analyzed using mass analysis, X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX), and nitrogen (N2) physisorption techniques. Experimental results showed that the mass residual of R-SiCSi (42.56 wt%) was almost equal to R-SiCSiO2 (42.45 wt%). However, R-SiCSiO2 had a higher yield of SiC, a higher specific surface area and a more intact porous morphology preserved from the rattan biomass. In addition, some rod-like SiC whiskers and tablet-like SiC particles were found in R-SiCSiO2. By comparison, R-SiCSi had a large amount of unreacted Si, as well as certain amount of SiC and unreacted C. Thus, it can be concluded that SiO2 sols are more appropriate for use in preparation of SiC from rattan, whatever the porous microstructure, yield, and purity of SiC.