Fabrication And Dielectric Property Research On BNT-SrTiO₃ Based Capacitor Ceramics

As the science and technology and the industry develop rapidly, some electroniccomponentsaremoreandmoreneedforus, butthesecomponentsaremostlyhavetheharmful additives which will hurt human and our environment. Now people urgentlyneed some brand new electronic components can be invent which these components'capability can compare with those old. The materials researches all over the worldhave aimed at devising a new, nonpolluting, high properties, and lead-free dielectricceramics.Strontium titanate and bismuth sodium titanate are investigated in the content.Weoptimizethedielectricproperties tomeet thedemands forpractice applications bydoping. As the dielectric constants of strontium titanate at the Curie temperature isveryhigh, can reach several ten thousand,but at the normal temperature thedielectricconstantsissmall,buttheCurietemperatureofbismuthsodiumtitanate is320℃,andStrontium titanate and bismuth sodium titanate have the same structures (perovskite)and close components, so the composition dependence of dielectric properties ofstrontium titanate and bismuth sodium titanate system is studied, MnCO3(0¹.3wt%),Y2O3(0¹.3wt%),MgCO3(0⁰.5wt%)and CeO2(0⁰.5wt%)doping areperformed.It was found that well-sintered sample in various compositions are obtained atdifferent sinteringtemperature. From those measurements, the dielectric constants areimproved with the increase of additive amount of BNT, If the amount continueincrease,theproperties becomeworse,theoptimum dielectricconstant ofthesamplescanreach 4300.WhendopedMnCO3,Y2O3,MgCO3andCeO2inthe (Bi_0.5Na_0.5)TiO3-SrTiO3ceramics , we can see: the MnCO3doping can move and press the peak at the Curietemperature; the Y2O3 doping can debase ceramics'dielectric loss; the MgCO3 dopingcan move and press the peak at the Curie temperature, and it can repressesthegrowthofthe crystal grain in the meantime; the CeO2 doping can reduce (Bi_0.5Na_0.5)TiO3-SrTiO3ceramics'sintering temperature obviously, and it can narrow down the sinteringtemperature scope, increase the compact degree of theceramics, press and widen the curiepeak equally.