高周波熱プラズマによるクロルシラン類からのSiC-Si₃N₄複合微粉体の合成

抄録

Preparation of SiC-Si₃N₄ composite fine powders from chlorosilanes, C₂H₄ and NH₃ by R. F. thermal plasma was studied. SiC-Si₃N₄ composite fine powders were prepared by injecting chlorosilanes (SiCl₄, SiHCl₃, SiH₂Cl₂), C₂H₄ and NH₃ to the tail flame of R. F. plasma. When the powder was prepared from SiH₂Cl₂, C₂H₄ and NH₃, the powder composition depended on the C₂H₄ and NH₃ flow rate. When C₂H₄ flow rate was low, the powder contained SiC, Si, Si₃N₄ and amorphous phases. As the C₂H₄ flow rate increased, crystalline SiC, C and amorphous phases were present. The surface area of the powder was from 46.6 to 100m²/g and the particle size was from 0.02 to 0.2μm. TEM and SAED observation showed that these composite powders contained Si, SiC, Si₃N₄, C and amorphous particles. Si2p XPS spectra of the powder were separated into SiC, Si₃N₄, SiO₂ component. These composite powders were considered to be a mixture of SiC, Si₃N₄, C and amorphous particles. After heat treatment at 1773K for 1h in Ar, amorphous phase disappeared and the crystalline phases in the powder were SiC and Si₃N₄.