Attrition Milling and Reaction-sintering of the Oxide-Metal Mixed Powders: II. Reaction-sintering Behavior as the Milling Characteristics of Powders

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J. Korean Ceram. Soc. > Volume 31(4); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(4): 448.

산화물과 금속 복합 분말의 Attrition Milling 및 반응소결: II. 분말의 분쇄특성에 따른 반응소결 거동

황규홍, 김의훈¹

경상대학교 무기재료공학과
¹삼화화성(주) 기술연구소

Attrition Milling and Reaction-sintering of the Oxide-Metal Mixed Powders: II. Reaction-sintering Behavior as the Milling Characteristics of Powders

ABSTRACT

The reaction-sintered alumina and zirconia-alumina ceramics were fabricated from the Al/Al2O3 or Zl/ZrO2(Ca-PSZ) powder mixtures via the attrition milling. And the effects of the milling characteristics of used raw powders on reaction sintering were investigated. After attrition milling and isopressing at 400 MPa the Al/Al2O3 specimen was oxidated at 1200℃ for 8 hours followed by sintering at 1550℃ for 3 hours. Because mixed powders of flake-type Al with coarse alumina was much more effectively comminuted than the globular-type Al with coarse alumina powders, it's sintered body of more than 97% theoretical density was achived, but low contents of Al leads to relatively higher shrinkage of about 8%. And because coarse alumina particles was much more beneficial in cutting and reducing the ductile Al particles, using the coarse alumina powder was much more effective in reaction sintering. Fused Ca-PSZ powder was reaction sintered with Al at 1550℃ for 3 hours and low shrinkage ZrO2-Al2O3 composites were fabricated. But because Al/Ca-PSZ powder mixtures were not effectively milled the reaction sintering and densification was difficult. And the Ca ion in Ca-PSZ grains diffused into alumina grains during sintering so that the unstabilization of Ca-PSZ body was occured which gave the microcracks in the specimens.