Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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Preparation of α-Si3N4 Powder, in Reaction System Containing Molten Salt, by SHS (Part 3. Reaction Mechanism)

용융염계에서 자전연소합성법에 의한 α-Si3N4 분말의 제조 (Part 3. 반응기구)

  • Yun, Ki-Seok (Rapidly Solidified Materials Research Center, Chungnam National University) ;
  • Yang, Beom-Seok (Rapidly Solidified Materials Research Center, Chungnam National University) ;
  • Park, Young-Cheol (Rapidly Solidified Materials Research Center, Chungnam National University) ;
  • Won, Chang-Whan (Rapidly Solidified Materials Research Center, Chungnam National University)
  • 윤기석 (충남대학교 급속응고센터) ;
  • 양범석 (충남대학교 급속응고센터) ;
  • 박영철 (충남대학교 급속응고센터) ;
  • 원창환 (충남대학교 급속응고센터)
  • Published : 2004.12.01
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Abstract

The nitridation mechanism of Si by SHS at $Si-NaCl-NH_{4}Cl-NaN_3$ system was investigated in this work. It was revealed that NaCl as a diluent was helpful to the perfect nitridation reaction by retarding the growth of Si particle resulted from the melting of Si at the initial stage of the nitridation reaction. And $NH_{4}Cl\;and\;NaN_3$ formed NaCl through decomposition and combination, and the preheating of pellet was helpful to the nitridation reaction in this process. The main nitridation mechanism of this system was liquid-gas reaction. The optimum porosity of the pellet for the nitridation of ${\alpha}-Si_{3}N_4$ was $67-69\%$.

[ $Si-NaCl-NH_4Cl-NaN_3$ ]계에서 자전연소에 의한 Si의 질화반응기구에 대하여 알아보았다. 희석제로서 첨가된 NaCl은 질화반응 초기에 Si의 용융에 따른 Si의 성장을 억제하여 완전한 질화반응에 도움을 주는 것으로 나타났다. 또한 $NH_{4}Cl$과 $NaN_3$는 반응과정 동안 서로 분해하고 결합하여 생성물로서 NaCl을 형성하였고, 이 과정에서의 발열반응은 시편을 예열함으로써 질화반응에 도움을 주었다. 본 반응계에서 주된 질화반응기구는 액상-기상 반응기구였다. 그리고 ${\alpha}-Si_{3}N_4$의 제조를 위한 최적의 펠렛 기공도는 $67-69%\$였다.

Keywords

References

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