Influence of Calcination Treatment and Firing Atmosphere on Dielectric Properties of BaTiO₃

Abstract

Influence of controlled rate of cooling after calcination as well as change in furnace atmosphere on the dielectric properties of BaTiO₃ capacitor material prepared by calcination of BaCO₃ and TiO₂ in equimolar composition was studied. Various rates of cooling after calcination were employed to improve the crystalline nature of the powder compacts. Powders were calcined at 1300°C/2 hrs and compacts were sintered in globar furnace up to 1400°C, and in gas fired furnace between 1400° and 1500°C.

It is observed that slower rate of cooling after calcination resulted in decreased dielectric constant for higher temperatures of sintering with lower dissipation. When compacts made from these powders were fired in gas fired furnace, they showed a significant change in K values from 3000 to 7000. The slow rate of cooling resulted in lower K values as well as dissipation factor quite significantly. Wide changes in dielectric constant of gas fired samples have been discussed.