稀土改性BaTiO_3粉体的制备及其导电性分析  

Preparation and Electrical Properties of Rare Earth Modified BaTiO_3 Powders

作　　者：郝素娥[1] 王威力[1] 王春艳[1] 付东升[1] 李佳龙[1] 

机构地区：[1]哈尔滨工业大学化学系,哈尔滨150001

出　　处：《无机化学学报》2009年第6期1062-1066,共5页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.20571020)资助项目

摘　　要：采用溶胶-凝胶法制备了纯BaTiO3粉体,并以La、Pr、Nd、Sm、Gd和Er等稀土元素通过液相掺杂、气相掺杂和液-气共掺3种不同的方式对其进行改性,以提高BaTiO3粉体的导电性。实验结果表明:各种稀土均可降低BaTiO3粉体的电阻率,效果最好的是Sm。不同掺杂方式中液-气共掺的效果最好,通过液相掺杂、气相掺杂和液-气共掺,BaTiO3粉体的电阻率由4.30×109Ω·m分别降至2.38×105,4.34×104和35.4Ω·m。XRD、SEM、FTIR分析表明,液相掺杂时进入BaTiO3粉体的稀土元素主要集中在晶界处,而气相掺杂后稀土元素主要进入晶格内部,可能取代了Ti4+在晶格中的位置。半径较小的稀土元素更容易迁移而偏离钛氧八面体的中心位置,由此导致稀土掺杂后BaTiO3粉体的电阻率显著降低。Pure BaTiO3 powders were prepared by using sol-gel technology. In order to increase their electrical conductivity, three modifying methods of liquid doping, gas doping and liquid-gas co-doping were adopted to prepare the modified BaTiO3 powders with rare earth elements such as La, Pr, Nd, Sin, Gd and Er. The results show that all of rare earth elements can decrease the resistivity of BaTiO3 powders, especially Sm is the best. Both liquid doping and gas doping can decrease the resistivity of BaTiO3 powders, but liquid-gas co-doping is most effective in decreasing the resistivity of BaTiO3 powders. The resistivity of BaTiO3 powders modified by liquid doping, gas doping and liquid-gas co-doping method are decreased from 4.30×10^9 Ω·m to 2.38×10^5, 4.34×10^4 and 35.4Ω·m respectively. Through XRD, SEM and FTIR analysis, it can be seen that rare earth elements are in the grain boundary of BaTiO3 powders after liquid doping. Rare earth elements enter into the lattice of the BaTiO3 powders during the gas doping process and instead the vacancy of Ti^4＋. Rare earth elements whose radius is smaller than that of Ti^4＋ move more easily to departure from the centre of the octahedron, and leads to the decrease of the resistivity of rare earth modified BaTiO3 powders.

关 键 词：钛酸钡 稀土 导电粉 

分 类 号：O614.233[理学—无机化学] O614.335[理学—化学]