Densification Behaviors of Mullite with Addition of Feldspar Formed by Pressureless Powder Packing Forming Method

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J. Korean Ceram. Soc. > Volume 36(2); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(2): 186.

무가압분말충전성형법에 의해 제조된 뮬라이트 성형체의 장석 첨가량에 따른 치밀화 거동

박정현, 황명의, 강민수, 조철구¹

연세대학교 세라믹공학과
¹한양대학교 세라믹소재 연구소

Densification Behaviors of Mullite with Addition of Feldspar Formed by Pressureless Powder Packing Forming Method

ABSTRACT

Dang-Chin feldspar powder with the mean particle size of 9.1 $mutextrm{m}$ was added to the synthesized mullite powder with the particle size of +325∼-200 mesh and the powder compact was prepared by PLPP(pressureless powder packing method). Densification behaviors were observed in sintering temperature range of 1200∼1400$^{circ}C$. The binder solution of 4% PVA was infilterated into packed powder to the suitable strength. The PLPP method makes it possible to form compacts without clay as plasticizer. Therfore there was no defect caused by phase transition after sintering. Additionally, we observed the dense microstructure by the melting of feldspar. When the mullite compacts with feldspar of 30% were sintered at 1300$^{circ}C$-4 hrs, we obtained the dense microstructure with zero water absorption and porosity <1%. When these compacts were sintered longer than 4 hrs at 1300$^{circ}C$ or higher than 1400$^{circ}C$, the examggerated grain growth of mullite was observed.

Key words: Mullite, Feldspar, Sintering tempreature, PLPP, Liquid phase sintering