Sintering of SiC and Si₃N₄ Fine Powders Produced from Rice Husk Char

　Fine powders of β-SiC and α-Si₃N₄ were synthesized from rice husk char (RHC). RHC was prepared by heat treatment of rice husks at 500℃ in a N₂ stream. β-SiC was produced by the heat treatment of RHC at 1550℃ in an Ar stream, and α-Si₃N₄ at 1550℃ in a N₂ stream. Using these powders sintering tests were conducted by hot pressing method. It was possible to compact them by sintering these powders at lower temperature by about 200℃ compared with conventional commercial powders.