Korean Journal of Crystallography (한국결정학회지)

Korean Crystallographic Association (한국결정학회)
권호 표지

Cation Ordering and Microwave Dielectric Properties of $Ba(Mg_{1/3}Nb_{2/3})O_3$ Ceramics: II. Local Order-Disorder Phase Transition and Second Phase formation

$Ba(Mg_{1/3}Nb_{2/3})O_3$세라믹스의 양이온 규칙구조와 유전특성: II. 국부적 규칙-불규칙 상전이와 이차상 생성 거동

  • 김영웅 (한국과학기술연구원 재료연구부) ;
  • 박재환 (한국과학기술연구원 재료연구부) ;
  • 김긍호 (한국과학기술연구원 재료연구부) ;
  • 김윤호 (한국과학기술연구원 재료연구부) ;
  • 박재관 (한국과학기술연구원 재료연구부)
  • Published : 2001.06.01
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Abstract

We have studied the effect of sintering temperature and time on the cation ordering and second phase formation in Ba(Mg/sub 1/3/Nb/sub 2/3/)O₃(BMN) microwave ceramics by using transmission electron microscopy. The relationship between the structural-chemical behavior arid microwave dielectric properties has also been investigated. It is revealed that according to the sintering conditions the BMN ceramics show very diverse local ordering behavior, such as the development of domain twinning and "core-shell"-structured grains and the formation of local disordered domains, though having 1 : 2 cation ordering structure basically. The disordered structure is found in Mg-excess region. Such local chemical variation seems to be caused by the formation of BaNb₂O/sub 6/-like second phase in its neigh-boring grain boundary. The microwave dielectric quality factor of the ceramics decreases greatly with the increase of the structural-chemical inhomogeneity and diversity.

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References

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