铈掺杂对钙铋钛铁电陶瓷取向及性能的影响

Effect of Cerium Doping on Orientation and Properties of Calcium Bismuth Titanium Ferroelectric Ceramics

用固相烧结工艺,制备了不同Ce掺量CaBi4-xCexTi4O15的陶瓷样品。用X射线衍射对其显微结构进行了分析,并测试了样品的介电、铁电性能,研究了烧结温度对样品晶粒取向和铁电性能的影响。结果发现Ce掺杂未改变CaBi4-xCexTi4O15的晶体结构,1150℃烧结所得样品中a轴取向晶粒较多,有利于样品的铁电性能;x=0.2为最佳掺量,样品剩余极化强度最大,2Pr=18.4μC/cm2,对应的矫顽场强度2Ec=99kV/cm,相对介电常数εr=165,介电损耗tanδ=2×10-3。

Ceramic samples CaBi4-xCexTi4O15（x=0, 0.05, 0.1, 0.15, 0.2, 0.25） were prepared by solid-state reaction method. Their structure was analyzed by X-ray diffraction, and their dielectric and ferroelectrics properties were measured. It is found that Ce-doping does not change the crystal structure of CaBi4Ti4O15. The remnant polarization （2Pr） increases at first but then decreases with the increase of Ce content. The 2Pr reaches a maximum value of 18.4 μC /cm^2 when x=0.2. The coercive field of CaBi3.8Ce0.2Ti4O15 is 99 kV/cm. The dielectric and dielectric loss of CaBi3.8Ce0.2Ti4O15 are 165 and 2×10^-3 measured at 100 kHz, respectively. Effects of different sintering temperatures on the crystal orientation of the CaBi3.8Ce0.2Ti4O15 ferroelectric ceramics were also studied. It is found that crystals developed entirely and a-axis orientation was enhanced at 1150 ℃.