关键词: 高粱, 生物形态碳化硅, 微观结构, 液相渗硅

Abstract: Durra was firstly transformed into carbon template by high-temperature pyrolysis and then converted into biomorphic SiC by infiltration of liquid Si in Ar atmosphere at 1600℃. The purified SiC sample was characterized by X-ray diffraction, scanning electron microscope and mercury intrusion. The results suggest that the sample mainly consist of β-SiC and perfectly replicate the microstructure and morphology of the carbon template. The durra-derived SiC has a mean pore diameter of 91.4μm and porosity of 76.6%, and both of them are similar to those of the carbon template, 88.5 μm and 71.2%, respectively. The specific surface area of SiC is 33.7m²/g, which is less than that of the carbon template, 59.4m²/g. The surface fractal dimension is 2.73 for the SiC sample and 2.70 for the template by analyzing the mercury intrusion data. The durra-derived SiC has characteristics of large grain size and high porosity.

Key words: biomorphic silicon carbide, microstructure, infiltration of liquid Si