La掺杂对(Bi_(1.5)Zn_(0.5))(Ti_(1.5)Nb_(0.5))O_(7)陶瓷组织和介电性能的影响

Effect of La-doped on Microstructure and Dielectric Properties of (Bi_(1.5)Zn_(0.5))(Ti_(1.5)Nb_(0.5))O_7 Ceramics

研究了La3+取代的(Bi1.5Zn0.5)(Ti1.5Nb0.5)O7基陶瓷(Bi1.5-xLaxZn0.5)(Ti1.5Nb0.5)O7(0.0≤x≤1 2,BLZNT)的结构与介电性能。采用传统的固相反应法制备了陶瓷样品,用XRD、SEM分析了样品的组织。在整个取代范围内,La3+取代的样品基本保持单一烧绿石相,稳定范围由容忍因子(RA/RB值)来确定;同时,随着La3+取代量的增加,晶胞常数先增后减。介电性能随结构变化而变化,其中介电性能为:ε=130～170,tanδ=～0.9×10-3(1MHz),并且掺杂La优化了BLZNT x样品高频端(>100kHz)的频谱特性。

The structure and dielectric properties of (Bi_(1.5)Zn_(0.5))(Ti_(1.5)Nb_(0.5))O_7-based ceramics with Bi^(3+) substituted by La^(3+) were investigated. (Bi_(1.5-x)La_xZn_(0.5))(Zn_(0.5)Nb_(1.5))O_7 samples were prepared by conventional method. The X-ray diffraction and SEM were used to analyze the microstructure. The La-doped samples held primarily pyrochlore single-phase on the whole field, and its stable range was determined by the tolerance factor (R_A/R_B values). With the increase of amount of La^(3+) substitution, crystal cell parameters showed a trend from ascent to descent. The dielectric properties varied with the microstructure. The dielectric properties of BLZNT-x samples exhibited as:ε=130～170, tanδ=0.35-0.9×10^(-3) at 1 MHz, and the frequency characteristics at high end (>100kHz) were optimized through the La-doping.