Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Effect of sintering temperature on microstructure and dielectric properties in (Dy, Mg)-doped BaTiO3

Dy 및 Mg가 첨가된 BaTiO3에서 소결 온도가 미세구조와 유전특성에 미치는 영향

  • Woo, Jong-Won (School of Materials Science and Engineering, Changwon National University) ;
  • Kim, Sung-Hyun (School of Materials Science and Engineering, Changwon National University) ;
  • Choi, Moon-Hee (Nanomaterials and Nanotechnology Center, Korea Institute of Ceramic Engineering & Technology) ;
  • Jeon, Sang-Chae (School of Materials Science and Engineering, Changwon National University)
  • 우종원 (창원대학교 신소재공학부) ;
  • 김성현 (창원대학교 신소재공학부) ;
  • 최문희 (한국세라믹기술원 전자융합본부 나노소재.공정센터) ;
  • 전상채 (창원대학교 신소재공학부)
  • Received : 2022.08.25
  • Accepted : 2022.09.14
  • Published : 2022.10.31
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Abstract

Rare-earth elements were doped with Mg to enhance the temperature stability of dielectric properties of BaTiO3 for its application to MLCC (Multi-Layer Ceramic Capacitor). The additives strongly affect both grain growth and densification behaviors during sintering, and hence dielectric properties. The additive effects therefore should be examined in each system with different additives. This study investigated the crystal structure, grain growth and densification behaviors and related variations in dielectric constant with respect to sintering temperature. Dielectric constant appears to be varied with grain size in a temperature range between 1200 and 1300℃, suggesting the importance of grain size control. The temperature dependence of grain size variation was well explained by an established theory correlating the grain growth behavior with grain boundary structure. This accordance provides a basis for sintering technique to control grain growth thus to improve dielectric constant in rare-earth doped BaTiO3.

MLCC(Multi-Layer Ceramic Capacitor)의 유전체 층에 사용되는 BaTiO3는 유전 특성의 온도안정성을 향상시키기 위해 첨가제로서 희토류 및 Mg를 사용한다. 이러한 첨가제는 소결 중 입자성장 및 치밀화 거동, 결국 유전 특성에 지대한 영향을 주게 되므로 조성에 따른 미세구조 발현 양상을 살펴보는 것이 중요하다. 본 연구는 95BaTiO3-1Dy2O3-2MgO-2SiO2(mol%)의 조성에서 온도 변화에 따른 결정구조, 입자성장 및 밀도 변화를 관찰하고 이러한 변화가 유전 상수에 미치는 영향을 관찰하였다. 1200~1300℃의 온도범위에서 소결 온도가 증가함에 따라, 평균 입도는 눈에 띄게 커지는 반면 밀도의 변화는 미미하여 입자크기가 주요한 미세구조적 요소임을 밝혔다. 본 실험에서 관찰된 입자크기의 온도의존성은 기존 입자성장 이론에서 설명한 온도 변화에 따른 입자성장 거동의 변화양상과 잘 부합하였으며, 이러한 이해는 향후 희토류가 첨가된 BaTiO3에서 유전 특성 향상을 위한 소결 미세구조 제어에 유용하게 활용될 수 있을 것이다.

Keywords

Acknowledgement

이 논문은 2021~2022년도 창원대학교 자율연구과제 연구비 지원으로 수행된 연구결과임

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