钛酸铋钙和稀土复合掺杂对BaTiO_3陶瓷微结构和介电性能的影响

Effects of CaBi_4Ti_4O_(15) and Rare-earth Oxide Doping on Microstructure and Dielectric Properties of BaTiO_3 Ceramics

研究了稀土及CaBi4Ti4O15(CBT)的复合掺杂对BaTi O3(BT)陶瓷微结构及介电性能的影响。结果表明:单独添加CBT使晶粒细化,促进了陶瓷的烧结致密化,居里温度随着CBT含量的增加(≤0.5mol%)而逐渐移向高温端;当CBT含量由0.3 mol%增加到0.5 mol%时,BT陶瓷的电容量变化率逐渐减小;当CBT含量超过0.5mol%时,电容量变化率又增大。在BaTi O_3CBT(BT_CBT)基础上单独添加1.0mol%La2O3,四方率减小,居里点移向低温端;保持La2O3掺杂量不变,随着CeO2含量的增加,BT_CBT陶瓷的晶胞体积呈现先减小后增大的变化趋势,四方率保持不变;1.0mol%La2O3和0.01mol%CeO2掺杂BT_CBT(0.5 mol%)陶瓷在-55℃和125℃的电容变化率分别为-14.78%和-11.44%,完全符合EIA X7R标准,有望用于X7R型多层陶瓷电容器的制备。

The effects of rare-earth oxide and CaBi4Ti4015（CBT） doping on the microstructure and dielectric properties of BaTiO3（BT） ceramics were investigated. The results showed that the addition of CBT decreased the grain size of BT ceramics and effectively improved sintering densification. The Curie temperature was shifted to a higher level with the increase in CBT addition （≤0.5 mol%）. The variation ratio of dielectric permittivity gradually decreased when CBT content increased from 0.3mol% to 0.5mol%. However, the variation ratio of dielectric permittivity increased when CBT content was more than 0.5mol%. The ratio of c/a decreased and the Curie point was shifted to low temperature with 1.0 mol%La2O3 doping in BT-CBT system. The cell volume of BT-CBT firstly de- creased and then increased and the ratio of c/a remained invariable with increasing CeO2 content when LazOs content was invariable. The variation of dielectric permittivity for BT ceramic doped with 1.0mol%LazO3 and 0.01mol%CeO2 as compared with that at room temperature was about - 14.78% at - 55℃ and - 11.44% at 125 ℃. The asprepared ceramic material is satisfied with the EIA X7R specification and has great potential as EIA XTR-type multilayer ceramic capacitors.