Synthesis of Si3N4 whiskers in porous SiC bodies

Si3N4 whiskers were synthesized by the carbothermal reduction process in porous SiC bodies. The SiC bodies had a sponge microstructure with pore sizes of approximately 600 μm. The raw materials for the Si3N4 whiskers were powder mixtures of Si3N4, SiO2 and Si for silicon and phenolic resin for carbon. Cobalt was used as a metal catalyst. The carbothermal reaction was performed at 1400 °C or 1500 °C for 1 or 2 h. The α-Si3N4 whiskers grew inside the SiC pores by the VLS process, and their diameters ranged from 0.1 to 1.0 μm. The length of the grown Si3N4 whiskers was over 100 μm and their growth direction was [100].