铁微量掺杂对二钛酸钡陶瓷介电性能的影响

Influence of light-doped Fe on dielectric properties of barium dititantate ceramics

采用常规固相反应法,以碳酸钡、二氧化钛和三氧化二铁为原料,制备微量铁掺杂的二钛酸钡陶瓷,研究了铁掺杂含量对二钛酸钡陶瓷的相纯度、相对密度和介电性能的影响.采用X射线粉末衍射仪检测二钛酸钡陶瓷的相成分,利用精密阻抗分析仪测量其介电性能.结果表明,微量铁元素进入了二钛酸钡晶格,能够获得单相二钛酸钡陶瓷的最大铁掺杂量在0.5％～1％之间.随着铁含量的增加,铁电相变居里温度快速减小,从未掺杂时的415℃降至铁含量为0.02％时的376℃和铁含量为0.5％时的324℃.同时介电常数逐渐减小,介电峰不断发生宽化,但并没有导致弛豫性铁电体的出现.微量铁元素的掺杂在实验测量误差范围内对陶瓷的密度影响不大.

To investigate the influence of Fe-doping on the dielectric properties,the phase purity and the relative density of BaTi2O5 ceramics,single-phased Fe-doped BaTi2O5 ceramics were synthesized from BaCO3,TiO2 and Fe2 O3 powders by conventional solid-state reaction.The specimens were characterized by powder X-ray diffraction and Fe contents that can yield pure phase BaTi2 O5 were determined.The dielectric properties were measured by precesion impedance analyzer in a wide temperature range.The results show that light amount of Fe element enteres BaTi2 O5 lattice and the solution limit of Fe-doping in BaTi2 O5 ceramics is between 0.5 ％ and 1 ％ ; upon Fe doping,the ferroelectric phase transition temperature of the BaTi2O5 ceramics decrease rapidly,from 415 ℃ at x=0 to 376 ℃ at x=0.02％ and 324 ℃ at x=0.5 ％.The dielectric constant decreased and dielectric peaks became broadened without dielectric relaxation.Fe doping has little effect on the density of BaTi2 O5 ceramics within the limit of the experimental errors.