Preparation, Characterization And Properties Of Ceramic Materials

Capacitors are one of the main components used in electronic equipment.They are widely used in industry,agriculture,national defense,scientific research and daily life.For example,low dielectric vessels,mica capacitors,electrolytic capacitors and ceramic capacitors.Ceramic capacitors can not only resist high temperature and corrosion,but also have high dielectric constant.Dielectric ceramic has the advantages of high power density,long life and low cost.As a result,it could be used in hybrid electric vehicles,medical devices,mobile power,electronic equipment and electronic weapons systems.lead-based PbZrO₃ and lead-free ferroelectric material BaTiO₃ with its excellent performance and modification becomes the preferred object of many researchers.In this paper considering the modification by using the method of doping and two phase composite,preparation with dielectric ceramic materials of high stability and low loss.Given the current demand for ceramic material stability,ions-doping BaTiO₃ and PbZrO₃,has been prepared successfully by the solid state reaction method and coprecipitation methods.A broad working temperature dielectric material Pb_0.89La_0.02Sr_0.06{[Zr_0.7Sn_0.25Ti_0.05]_1-x-x Nb_x}O₃?PLSZSTN?was investigated by wet-chemistry methods.The effects of Nb-doping on phase structure,morphology,temperature stability and dielectric properties have been investigated in detail.The XRD results show that the composites are composed of tetragonal perovskite.When the Nb content increases from 0.3 mol%to 0.6 mol%,the average grain size of the PLSZSTN ceramics decreases.As the Nb amout is 0.6 mol%,the dielectric loss of capacitance is below 0.01 and the dielectric constant of the composites is about 318.The temperature coefficient of capacity varied from-11.63%to 6.68%at the temperature range between-55°C and 200°C.The ceramics with the composition of Pb_0.89La_0.02Sr_0.06{[Zr_0.7Sn_0.25Ti_0.05]_0.94Nb_0.06}O₃+x mol%MnO₂?PLSZSTNM?ceramics with broad working temperature are fabricated by a wet-chemistry method.The effects of Mn-doping on morphology,temperature-stability and dielectric properties have been investigated in detail.The ferroelectric behavior of PLSZSTNM ceramics is strongly affected by Mn doping.With increasing Mn-doping,dielectric constant of ceramics increase,followed by a drop.Furthermore,as the Mn amount is 0.2,the dielectric loss of capacitance is below 0.01 and the dielectric constant of the composites is about 577.5.The temperature coefficient of capacity varied from-14.9%to8.3%at the temperature range between-55°C and 200°C.According to the characteristics of rare earth elements can significantly improve the dielectric properties of BaTiO₃,select the Sr,Sn as quantitative elements together with Mg doping NBT-BT,discusses the multiple elements codoping impact on performance.The synthesis of xNa_0.5Bi_0.5TiO₃-?1-x?Ba_0.65Sr_0.3Mg_0.05Sn_0.1Ti_0.9O₃?NBT-BMSST?by the wet solid-phase method was successfully investigated.The microstructure,dielectric properties,and temperature stability of the obtained ceramics were investigated in detail.The crystalline nature of ceramic was studied by XRD which showed that the composites were composed of tetragonal perovskite.The size of the grains was determined by scanning electron microscopy.It was determined that the addition of NBT could enhance the dielectric constant.When the NBT/BMSST ratio is 0.4/0.6,the dielectric loss of capacitance is below0.11 and the dielectric constant of the composites is about 1720.The temperature coefficient of capacity varied from-12.24%to 4.79%at the temperature range between-55°C and 200°C.The temperature-capacitance characteristics meet EIA X9R specifications.