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=13.92 μC/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.
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 Bi4Ti3O12 ceramics.
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