Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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Microstructural Evolution of $BaTiO_3$ Ceramics during the Cubin-Hexagonal Phase Transformation

$BaTiO_3$ 요업체에서 Cubic-Hexagonal 상전이에 따른 미세조직 변화

  • 이태헌 (경북대학교 무기재료공학과) ;
  • 이정아 (경북대학교 무기재료공학과)
  • Published : 1996.04.01
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Abstract

The microstructural evolution of BaTiO3 ceramics during cubic-hexagonal phase transformation was investiga-ted. In the case of phase transformation from cubic to hexagonal BaTiO3 the hexagonal phase nucleated at the surface region of specimen. On the other hand in the case of that from hexgonal phase to cubic, cubic phase was initiated at the center region of specimen. And fast grain growth and irregular grain boundary shape could be also observed during these transformation processes. Besides low densified hexagonal BaTiO3 specimen was made with low forming pressure. The phase transformation of these specimens toward cubic phase was relatively retarded comparing with dense hexagonal BaTiO3 specimens. was made low forming pressure.. The phase transformation of these specimens toward cubic phase was relatively retarded comparing with dense hexagonal BaTiO3 specimens. These results were explained that hexagonal BaTiO3 had lowder surface energy than cubic phase.

BaTiO3 세라믹스의 입방정과 육방정간의 상전이에 따른 미세조직 변화를 관찰하였다. 입방정을 육방정영역에서 열처리하는 경우, 시편 표면부터 육방정상이 생성되었고 반대로 육방정을 입방정역에서 열처리하여 상전이 시킬때는 입방정상이 시편이 중심부에서부터 생성되었다. 또한 이러한 상전이 과정 중에는 빠른 입성장과 더불어 불규칙적인 입계형태를 나타내었다. 그 외 낮은 성형압으로 소결체의 밀도가 낮은 육방정 시편을 제조한 경우에는 상대적으로 입방정으로의 상전이가 억제되었다. 이러한 결과들은 육방정의 표면에너지가 입방정보다 상대적으로 낮기 때문으로 해석되었다.

Keywords

References

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