Process Control for the Synthesis of Ultrafine Si3N4-SiC Powders by the Hybrid Plasma Processing

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J. Korean Ceram. Soc. > Volume 29(9); 1992 > Article

Journal of the Korean Ceramic Society 1992;29(9): 681.

Hybrid Plasma Processing에 의한 Si3N4-SiC계 미립자의 합성과정 제어

이형직, 吉田禮¹

강릉대학교 재료공학과
¹동경대학 금속공학과

Process Control for the Synthesis of Ultrafine Si3N4-SiC Powders by the Hybrid Plasma Processing

ABSTRACT

Ultrafine Si3N4 and Si3N4+SiC mixed powders were synthesized through thermal plasma chemical vapor deposition(CVD) using a hybrid plasma, which was characterized by the supersposition of a radio-frequency plasma and arc jet. The reactant SiCl4 was injected into an arc jet and completely decomposed in a hybrid plasma, and the second reactant CH4 and/or NH3 mixed with H2 were injected into the tail flame through double stage ring slits. In the case of ultrafine Si3N4 powder synthesis, reaction efficiency increased significantly by double stage injection compared to single stage one, although crystallizing behaviors depended upon injection speed of reactive quenching gas (NH3+N2) and injection method. For the preparation of Si2N4+SiC mixed powders, N/C composition ratio could be controlled by regulating the injection speed of NH3 and/or CH4 reactant and H2 quenching gas mixtures as well as by adjusting the reaction space.