采用Sol-Gel法制备Al^(3+)改性钛酸钡陶瓷

Study on Preparation of BaTiO_3 Ceramics Doped with Al^(3+) by Sol-Gel

采用溶胶凝胶法制备Ba Ti1-xAlxO3(x=0.02,0.04,0.06,0.08)陶瓷样品,借助XRD、SEM和Agilent4284A分别对样品的晶相、显微结构和介电性能进行研究。结果表明:Al3+加入后,主晶相没有变,仍为BaTi O3,但第2相Ba Al2O4出现;随着Al3+的掺杂含量增加,样品的平均晶粒尺寸减小,密度从5.46 g/cm3增加到了5.81 g/cm3,且当x≥0.06时,样品的密度趋于稳定;当测试频率为1 MHz时,随着Al3+掺杂含量的增加,介电常数从4 766减小到1 834,介电常数温度系数从0.001 32/℃增加到0.001 8/℃,介电峰出现展宽现象。同时,采用GULP模拟软件对体系的缺陷能进行计算,缺陷偶极子[2AlTi'+V··O]的稳定性为-1.915 e V。

Ba Ti1-xAlxO3（ x = 0. 02,0. 04,0. 06,0. 08） were prepared by sol-gel methods. The crystal structure,microstructure and dielectric properties were investigated by X-ray diffraction method,scanning electron microscope and Agilent4284 A testing analyzer respectively. The results reveal that BaTiO_3 is the main phase of the samples and the second phase Ba Al2O4 is observed after Al3 ＋doping. With increasing Al3 ＋content,the average grain size decreased gradually; the density of samples increased from 5. 46 g / cm3to5. 81 g / cm3,but tended to stable as x≥0. 06. What＇s more,dielectric constant decreased from 4766 to1834,temperature coefficient increased from 0. 00132 / ℃ to 0. 0018 / ℃ and the dielectric peaks broadened at 1MHz. Meanwhile,the stability of defect cluster[2AlTi＇ ＋ V··O]was-1. 915 e V calculated by General Utility Lattice Program（ GULP）.