Preparation Properties Of Non-doped And Doped BaTi₂O₅Ferroelectric Ceramic

BaTi2O5is a kind of lead-free ferroelectric material which has high curie temperatureand low dielectric loss at high temperatures. BaTi2O5can work at high temperature due toits good properties and has good potential for widely applications.Because of poorunderstanding of it,the difficulties of its preparation and the high cost of most preparationmethod of it,so BaTi2O5can’t put into production.In this dissertation,we focus on the studyof preparation of BaTi2O5ceramics by conventional solid-state reaction and the effect ofelement doped on its dielectric properties.We found that BaTi2O5can nucleation and growth rapidly through the research of theshortest sintering time to obtain the BaTi2O5ceramics. Shorten the sintering time to0mincan also get pure phase BaTi2O5ceramics. This new preparation technology is not onlysimple, quick and low cost, but also improve the density and the dielectric constant of theBaTi2O5ceramics. But the defect is reduced the Curie temperature about20oC. Sintering inthe O2and Ar atmosphere environment is also beneficial to the improvement of the densityof BaTi2O5ceramics. A certain amount of the deviation of initial raw material compositioncan be permitted to get the pure phase BaTi2O5ceramics and the range of mole ratio of Baand Ti atom is1:1.95to1:2.05. There are two kinds of crystal grain in BaTi2O5ceramics.The grain size of crystal grain are micrometer-scale and nanoscale.The doping element include Ca,Sr,Y,Ho,Fe,Mn and Zr. The maximum content of Caand Sr for doping were6%and4%, respectively. Y and Ho were2%, Fe and Mn werebetween0.5%and1%, while Zr as low as1%. In general, Ca, Fe and Mn doping reducedthe dielectric constant and the ferroelectric phase transition temperature of BaTi2O5ceramics, and broaden the dielectric peak, but there is no relaxation characteristics.Y andHo doping increased the dielectric constant and the ferroelectric phase transitiontemperature of BaTi2O5ceramics. Zr doping made the temperature range ofthermodynamic stability of BaTi2O5ceramics increased10oC in the direction of high temperature.