Preparation,Characterization And Properties Of BaTiO₃-Based Composite Ceramic Materials

With the development of Electronic Science and technology, the status of the ceramic capacitor in the whole information industry is becoming increasingly prominent. In order to meet the needs of the development of social technology, ceramic capacitor is facing the trend of miniaturization, high portability, network and multimedia, and the high dielectric properties of dielectric ceramic materials must be developed. In all kinds of dielectric materials, lead-free ferroelectric material BaTiO₃ with its excellent performancebecomes the preferred object of many researchers. This paper analyzes and discusses the doped and ferroelectric material compositetwo aspects experimental design and research effect on morphology and dielectric properties and mechanism, aiming at the problems of poor dielectric properties of BaTiO₃, and temperature stability, from improving the dielectric material dielectric properties and temperature stability.Ba_1-1.5xBi_xTiO₃?x=0.01, 0.05, 0.016, 0.01, 0.02? ceramic powders were synthesized by liquid phase method. Amount of Bi dopedeffect on BaTiO₃ was discussed. The bestBaTiO₃ of ferroelectric is obtained by a series of samples of performance test and characterization. The Curie temperature increases, the grain size decreases, the ferroelectric property increases, and the density increases with the increasing Bi content. When Ba_1-1.5xBi_xTiO₃?0.001 < x < 0.02? x = 0.02, the density and dielectric properties of performance is obtained under the condition of1220 oC low temperature sintering. The peak value of dielectric constant is ?=17561, and dielectric strength maximum is E=4.545 kV/mm.The small grain size of Ba_0.97Bi_0.02TiO₃, and thehigh Curie temperature are suitable to high temperature conditions. In order to expand the scope of the material and make the working temperature zone extends moving to the low temperature,this paper discusses the Ba_0.97Bi_0.02TiO₃ and the ferroelectric of low Curie temperature compound,so that realize the purpose of broadening the Curie peak. Sn4+ has the function of improving the dielectric constant and decreasing the Curie temperature, so it is selected as the fixed doping element, and the doping amount is 0.02mol%. The Ba_0.97Bi_0.02TiO₃-Ba_1-xMgxSn_0.02Ti_0.98O₃ system is preparedandamount of Mg doped effect on the microstructure and dielectric properties isdiscussed. The experimental results show that the peak value of the dielectric constant increases gradually, and the temperature stability of the sample increases graduallywith the increasing Mg content. When x=0.007, the peak value of the dielectric constant is 65000.Temperature coefficient of capacitance is-20%-15%range from-55 to 120 oC, and the dielectric strength is E=5.455 kV/mm.Mg can improvetemperature stability of the characteristics, which is based on the study of above composite materials. A series of samples Ba_0.97Bi_0.02TiO₃-Ba0.9-xMgxSr_0.1TiO₃-BaTi_0.98Zr0.02O₃?x=0.004, 0.005, 0.006? are prepared by wet-solid phase method.Amount of Mgand two-preparation method have aneffect on microstructure and dielectric properties of whole system in condition of difference holding temperature. The results show that the dielectric properties of the samples bythree-phase composed one by one is better than the dielectric properties of the samples which are the two-phase combined and then combined with the third phase. A series of samplesare prepared by first method, when x=0.005, the temperature stability of the material is improved obviously, and the ceramic material chemical uniformity has been greatly improved.The dielectric loss is 0.1, and temperature coefficient of capacitance is below 15%range from-55 to 200 oC.