Study Of Medium Temperature Sintering Of Temperature Stable X9R BaTiO3-based Ceramics

In this dissertation, we mainly studied the property and processing of high temperature stable BaTiO₃-based ceramics. Based in the X7R ceramics, started from the crystal structure and dielectric properties of BaTiO₃, ulteriorly studied the system in order to gain better property in high temperature. The range of working temperature was enlarged. And the system was also able to be sintered under intermediate temperature.Firstly, the dissertation introduced the BaTiO₃-based X7R which has been prepared before. The effects of Nb2O5, CoCO₃, MgO, CeO₂ to the dielectric properties of the system was discussed too. A X7R system with the following parameters was gained: sintering temperature 1260℃(6h),ε≈4200 under 1KHz, tanδ≤1.5%, -10%<Δε/ε<10% in the region of -55～125℃.Then effects of Pb(Ti_0.3,Sn_0.7)O₃ and Bi2O₃ were discussed. The Pb(Ti_0.3,Sn_0.7)O₃ can obviously increase the dielectric constant of system in high temperature. A new courier peak was founded. With the doping of Bi2O₃, the system was able to be sintered under intermediate temperature. The reason was that the sintering in liquid state was imported into the process of sintering. The result of Pb(Ti_0.3,Sn_0.7)O₃ together with Bi₂O₃ was that a perfect X9R system with the following parameters was gained: sintering temperature 1140℃,ε≥2300 under 1 kHz , tanδ≤1.5% ,-15%<Δε/ε<15% in the region of -55～210℃.Finally, calcinations of the powder of BaTiO₃ was discussed. And the BaTiO₃ calcined under 1100℃was adopted in this experiment.