BaTi_(1-x)Fe_xO_(3-δ)六方钙钛矿陶瓷材料的NTC特性

NTC characteristic of BaTi_(1-x)Fe_xO_(3-δ) hexagonal perovskite ceramics

采用湿化学合成方法制备BaTi1-xFexO3-δ(x=0.1,0.2,0.3)粉体,经传统烧结工艺得到致密的块体陶瓷材料。利用X线衍射分析材料的相组成,通过电阻-温度特性和交流阻抗谱分析材料的导电性质随温度变化的特性。利用热激活诱导极化子跳跃导电模型对材料的NTC特性进行分析讨论。研究结果表明:BaTi1-xFexO3-δ材料具有六方钙钛矿晶体结构,并体现出优异的电阻负温度系数(NTC)特性;当x=0.1,0.2和0.3时,BaTi1-xFexO3-δ的NTC系数分别为5 497,5 284和4 828 K。

The powders of BaTi1-xFexO3-δ（x=0.1,0.2,0.3） were prepared by a wet chemical process,and the related ceramics were obtained by the conventional sintering technique.X-ray diffraction was used to analyze the crystalline structure.The temperature dependence of electrical conductivity of the ceramics was investigated by using a resistance-temperature measurement system and electrochemical impedance spectroscopy.The electron hopping by thermal activation is supposed to be the NTC mechanism for BaTi1-xFexO3-δ ceramics.The results show that the BaTi1-xFexO3-δ ceramics have hexagonal perovskite crystalline structure and exhibit an excellent characteristic of negative temperature coefficient（NTC） of resistance in the measuring temperature range.The NTC constants of the BaTi1-xFexO3-δ ceramics are 5 497,5 284 and 4 828 K for x as 0.1,0.2 and 0.3,respectively.