Sun Jizhou, Li Xiaotu, Wu Xiawan, Wang Hongru
(School of Electronic Information Engineering, Tianjin University, Tianjin 300072, China)
Abstract:By adding cobalt oxide and calcium titanate to the Mg-Si-Ti system, the effects of ion doping on the system and the way to improve the properties of the material are investigated. The scanning electron microscope and X-ray diffraction analyses indicate the mechanism and the optimum content of additives. Cobalt oxide, a kind of mineralizer, reduces free oxides to improve the bulk densities of the sinterd bodies and lowers the sintering temperature of the ceramics, furthermore, acts as a grain inhibitor to reduce the dielectric loss of the system greatly(from 0.001 13 to 0.000 15). Proper quantities of calcium titanate can compensate the positive temperature coefficient of capacitance and optimize the dielectric properties of the system. Under high frequency the ceramic system has low dielectric coefficient, low dielectric loss, low temperature coefficient of capacitance and high volume resistivity. Multilayer ceramic capacitors made from this system can be widely used in aviation, space flight, national defense and military area.
Keywords:cobalt oxide;calcium titanate;ion doping