Dielectric Properties of BaTiO<TEX>$_3$</TEX> Ceramics Having Abnormally Grown Grains

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J. Korean Ceram. Soc. > Volume 36(9); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(9): 965.

비정상 입성장이 일어난 BaTiO$_3$ 세라믹스의 유전특성

조지만, 김병호, 김병국¹, 제해준¹, 이해원¹

고려대학교 재료공학과
¹한국과학기술연구원 재료연구부

Dielectric Properties of BaTiO$_3$ Ceramics Having Abnormally Grown Grains

ABSTRACT

The dielectric properties of BaTiO3 ceramics having abnormally grown grains were investigated. When BaTiO3 were doped by 0-5 mol% of CuO, CuO0.5 CuTi0.33O1.33 and sintered at 1000-130$0^{circ}C$ the abnormal grain growth accelerated as the Cu content or the sintering temperature increased. As area fractions of abnormal grown grains increased the amount of tetragonal phase increased. Also the relative dielectric constant ($varepsilon$r) at room temperature decreased maximum $varepsilon$r at Tc decreased and hence sharper phase transformation occurred at Tc as area fractions of abnormal grown grains increased. The results were interpreted as a process of internal stress relaxation resulting from the increase of 90$^{circ}$ domains induced bythe increase of area fractions of abnormally grown grains

Key words: Barium Titanate Ceramics, Copper Oxide, Copper Titanate, Abnormal Grain Growth, Dielectric Property, internal Stress Model