Preparation of Ferroelectric Barium Titanate Fine Particles by Hydrothermal Method and Their Dielectric Properties -Variation of Dielectric Properties and Phase Transition by Heat Treatment-

강유전성 티탄산바륨 극미립자의 수열합성과 그 유전특성 - 열처리에 의한 상전이 및 유전 특성 변화 -

  • Um, Myeong-Heon (Department of Industrial Chemistry, Cheonan National Technical College) ;
  • Lee, Jin-Sik (Department of Chemical Engineering, Dankook University) ;
  • Lee, Chul-Tae (Department of Chemical Engineering, Dankook University)
  • 엄명헌 (국립천안공업대학 공업화학과) ;
  • 이진식 (단국대학교 공과대학 화학공학과) ;
  • 이철태 (단국대학교 공과대학 화학공학과)
  • Received : 1998.03.19
  • Accepted : 1998.06.16
  • Published : 1998.11.10

Abstract

$BaTiO_3$ particles were prepared using $Ba(OH)_2{\cdot}8H_2O$ and $Ti(OC_2H_5)O_4$ by the hydrothermal method and their characteristics treated at the various temperatures have been investigated. This prepared $BaTiO_3$ powder includes a very small amount of $H_2O$ and $OH^-$. By increasing the treated temperature from $200^{\circ}C$ to $1000^{\circ}C$, the mean particle size was accordingly increased from $0.022{\mu}m$ to $0.072{\mu}m$ and the tetrogonality(c/a)was increased from 1.02 to 1.2 so that the phase transition to tetroganal takes place. $BaTiO_3$ sintered at $1250^{\circ}C$ after heat treatment at $400^{\circ}C$ for 3 hrs showed a specific dielectric constant of 8120 and surface activation energy was 9680 kcal/mol.

Acknowledgement

Supported by : 한국학술진흥재단

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