J. Korean Ceram. Soc. > Volume 28(9); 1991 > Article
 Journal of the Korean Ceramic Society 1991;28(9): 689.
 A-site Sr 및 B-site Ca 첨가 BaTiO$_3$ 세라믹스의 유전특성 박재관, 오태성, 김윤호 한국과학기술연구원 정밀요업연구실 Effects of A-Site Sr and B-Site Substitution on the Dielectric Properties of BaTiO3 Ceramics ABSTRACT Dielectric properties of Ba1-$chi$Sr$chi$Ti1-yCayO3-y ceramics, where Sr and Ca were doped to Ba-site and Ti-site within the range of 0 x 0.24 and 0 y 0.05, respectively, were investigated. The substitution of Ca for Ti, which maintained the high resistivity of these formulations after sintering in a reducing atmosphere, was confirmed. Ca addition decreased the tetragonality c/a, increased the unit cell volume, and lowered Curie temperature, which were attributed to the occupancy of Ca2+ ions on Ti-sites. The lowering of Curie temperature by Ca addition was affected by the substitution of Sr for Ba-site; within 2 mol% of Ca, Curie temperature was lowered at a rate of 2$0^{circ}C$ and 16$^{circ}C$ per mol% of Ca at x=0 and x=0.08, respectively. Whereas the resistivity of the formulations without Ca was reduced to 107 {{{{ OMEGA }}cm, when sintered at low oxygen partial pressure of 10-9 MPa, the resistivity value higher than 1011 {{{{ OMEGA }}cm was maintained for the formulations containing Ca more than 0.5 mol%. Dielectric loss factor, tan$delta$, was about 1% for most formulations.
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