Ho掺杂对Bi4-xHoxTi3O12陶瓷结构与铁电性能的影响

以Ho为掺杂元素,采用热压烧结方法制备Bi4-xHoxTi3O12陶瓷,重点研究了Ho掺杂量对其物相组成、致密度、微观结构和铁电性能的影响.首先以Bi2O3、TiO2和Ho2O3微粉为原料,利用固相反应在900℃合成出主晶相为Bi4Ti3O12的Bi4-xHoxTi3O12(x=0～0.8)粉体;然后,将合成粉体在850℃、30 MPa条件下热压烧结,当Ho掺杂量x=0～0.4得到了物相单一、整体致密(>99%)的Bi4-xHoxTi3O12陶瓷.随Ho掺杂量的增加,Bi4-xHoxTi3O12陶瓷的剩余极化强度呈现先增大后减小的趋势,主要与氧空位浓度和不同掺杂浓度引起的掺杂位置的不同有关.在Ho掺杂量x=0.4时,其剩余极化强度最大(2Pr=13.92μC/cm2),远大于未掺杂的Bi4Ti3O12陶瓷,说明适量Ho掺杂能有效改善其铁电性能.

Effect of Ho Doping on Structure and Ferroelectric Property of Bi4-xHoxTi3O12 Ceramics

Ho-doped bismuth titanate(Bi4-xHoxTi3O12) ceramics were prepared by hot-press sintering.The effects of Ho doping on the crystalline phase,density,microstructure and ferroelectric property of the ceramics were investigated.At first,Bi4-xHoxTi3O12(x=0 0.8) powders in the main phase of Bi4Ti3O12 were synthesized from Bi2O3,TiO2 and Ho2O3 micro-powders by solid-state reaction at 900℃.The as-synthesized powders were then sintered by hot-press at 850℃ and 30 MPa to prepare Bi4-xHoxTi3O12 ceramics.With the appropriate Ho doping content of x=0 0.4,single-phased and dense(relative density >99%) Bi4-xHoxTi3O12 ceramics were obtained.The remanent polarization(Pr) of the ceramics increased with Ho doping increasing but decreased at x>0.4,mainly due to the oxygen vacancy concentration and different doping sites.The Bi4-xHoxTi3O12 ceramics have the highest value of 2Pr=13.92 μC/cm2 at x=0.4,which is higher that that of the undoped Bi4Ti3O12 ceramics.The result indicates that appropriate Ho doping can improve the ferroelectric property of Bi4Ti3O12ceramics.