A study on the manufacture of dielectric glass-ceramics

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J. Korean Ceram. Soc. > Volume 19(4); 1982 > Article

Journal of the Korean Ceramic Society 1982;19(4): 281.

유전성 glass-ceramics 제조에 관한 연구

이종근, 박용완, 이병하, 현동석, 이준영

한양대학교 공과대학

A study on the manufacture of dielectric glass-ceramics

ABSTRACT

The composition of glasses to be suitable for crystallisation of $BaTiO_3$ by heat-treatment and the dielectric properties of the glass-ceramics were investigated. The composition of the family of glasses was defined by the formula $chi$ $BaTiO_3 + (100-$chi$)Al_2O_3$.$2SiO_2$ and excess BaO. Data were presented on dielectric constant and loss tangent at various frequencies. The effects of excess BaO on dielectric properties were investigated. The additions of $Na_2O$ and $Nb_2O_5$ shifted the Curite temperature of these glass-ceramics. The glass composition which was able to be melted at 145$0^{circ}C$ and moulded as homogeneous glass phase without devitrification should contain $Al_2O_3$.$2SiO_2$ more than 30 mole %. The more the amount of additive BaO increased, the more dielectric constant increased. When the maximum heat-treatment temperature was 105$0^{circ}C$, we obtained higher dielectric constant than that of 95$0^{circ}C$. The dielectric constant and the dielectric loss were stable at frequencies between 5$times$104 and 107 cycle per second. When $Na_2O$ and $Nb_2O_5$ were added, the Curie temperature, presented at 14$0^{circ}C$ to 15$0^{circ}C$, shifted to lower temperature. Therefore, the glass-ceramics having high dielectric constant at room temperature were obtained.