采用溶胶-凝胶法制备了掺杂不同浓度Sm2O3(分别为0.001,0.002,0.003,0.005,0.007mol)的BaTiO3陶瓷,并对其结构与电性能进行了研究.结果表明:Sm2O3掺杂BaTiO3陶瓷的晶型在室温下为四方相,而且随着Sm2O3掺杂浓度的增加,BaTiO3陶瓷的晶粒尺寸变小,说明Sm2O3掺杂对BaTiO3陶瓷晶粒的生长有一定的抑制作用;Sm2O3掺杂BaTiO3陶瓷的电阻率比纯BaTiO3陶瓷明显下降,当添加量为0.001mol时,电阻率最小,.从4.3×109Ω·m下降为6.536×103Ω·m;Sm2O3掺杂BaTiO3陶瓷的晶粒电阻随着温度的变化,呈现NTC效应,而晶界电阻随着温度的变化,呈现PTC效应,且晶界电阻远远大于晶粒电阻,说明该材料的PTC效应是由晶界效应引起的.
BaTiO3 ceramics doped with Sm2O3(the additive contents were 0.001, 0.002, 0.003, 0.005, 0.007 mol respectively) were prepared by the sol-gel method.
The effects of Sm2O3 doping on the structure and electric characteristics of BaTiO_3 ceramics were studied. The results showed that the structure of the
crystal was tetragonal, and with the increasing of Sm2O3 content, the grain size became smaller, which illustrated that Sm2O3 doping could prohibit
the growing of the grain. The resistivity of BaTiO3 ceramics doped with Sm2O3 decreased obviously, when Sm2O3 content was 0.001mol, the resistivity was
the smallest, which changed from 4.3×109Ω·m to 6.536×103Ω·m. The grain resistance of BaTiO3 ceramics doped with Sm2O3 exhibited NTC,
but the grain boundary resistance showed PTC, and the grain boundary resistance was larger than the grain resistance, so the PTC effect originated from the grain boundary.
参考文献
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