Low Temperature Sintering and Dielectric Properties of 85 Alumina Ceramic

Using multicomponent additives,85 alumina ceramics were sintered at a relatively low temperature.The effects of TiO₂/CaO ratio on the densification,structure and dielectric properties of Al₂O₃ ceramics were investigated.It is found that the appropriate multiomponent additives can reduce the sintering temperature of 85 alumina ceramics to 1 350℃ and the bulk density can be increased by changing TiO₂/CaO ratio where the maximum density reaches at the TiO₂/CaO ratio of 0.5.Besides,by adjusting the ratio of TiO₂/CaO,the dielectric constant can be controlled between 8.0-8.8 and the variation of dielectric constant has the same trend with that of the bulk density.On the other hand,the Q×f values of 85 alumina ceramics are low and their change trend has nothing to do with the dielectric constant,which is probably due to the large amount and complex composition of the sintering additives.