Sm2O3掺杂BaTiO3陶瓷的结构与电性能研究

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.

Effects of Sm2O3 Doping on Structure and Electric Characteristics of BaTiO3 Ceramics

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.