Study On Dielectric Properties Of Barium Strontium Titanate Capacitor-Varistor Ceramics Resistor

With the advantages of strontium titanate and Barium titanate, barium strontium titanate has high dielectric constant,low dielectric loss,the adjustable curie temperature,high withstand voltage, it has broad prospects for development.With the simplified batching progress, vacuum sintering method was used in the experiment instead of atmosphere furnace sintering, and then oxidizing sintering was in an atmosphere of air. The ratio of barium and strontium, TiO2, donor doped, acceptor doped, sintering aids, vacuum sintering holding time and the oxidation sintering temperature impact on the dielectric properties of the sample were studied. It was found that the best ratio of barium and strontium was0.1to0.9, the addition of barium carbonate increased the curie temperature and dielectric constant; the appropriate amount of TiO2played the role of a sintering aid, reducing the sintering temperature to1325℃, increasing the sintering success rate; As the acceptor dopant, ZnO increased the nonlinear constant and resistivity and reduced the dielectric loss, MnCO3reduced the dielectric loss; The vacuum sintering temperature can be reduced to1250℃with SiO2as a sintering aid, but the overall dielectric properties of the sample was reduced; The vacuum holding time and the oxidation temperature played important roles in dielectric properties of the sample.The recipe of0.9SrCO3+0.1BaCO3+1.5TiO2+1.1mol%CeO2+0.7mol%ZnO was found, its Vacuum sintering temperature was1325℃, holding time was2h and oxidation temperature was900℃; The nonlinear coefficient of the sample was about15, the dielectric loss was about0.2, the dielectric constant and resistivity were up to105, the varistor voltage was about5V, the functional ceramics with the low varistor voltage, the high dielectric constant and nonlinear constant were got.