Preparation of biomorphic SiC-ceramics by the reactive infiltration of Si into carbon template derived from basswood

Basswood was transformed by high-temperature pyrolysis into carbon performs (charcoal) and subsequently converted into cellular SiC-ceramics possessing pseudomorphous microstructure by the reactive-infiltration of Si into C_B-template in Ar atmosphere. Thermogravimetric analysis (TGA) was applied to reveal the pyrolysis behavior of basswood powder. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to characterize and analyze the microstructures and phase identification of C_B-template and final SiC ceramics. The infiltration mechanism of liquid Si into charcoal and the basic properties of cellular SiC were also given. The results showed that C_B-template was amorphous carbon materials. Final cellular SiC was composed of the major phase β-SiC and a little unreacted carbon. Compared to charcoal, cellular SiC possessed higher mechanical properties. The improvement of the mechanical properties of materials was mainly caused by the following factors: one was the conversion of carbon fibres into SiC fibres, and the other was the volume expansion during C_B-template-to-cellular SiC conversion, which inhibited the initiation and propagation of cracks and made cracks deflect.