钨/氟改性氧化铜陶瓷的导电性质与热敏特性

为了探索开发具有电阻负温度系数(NTC)的新型热敏陶瓷材料，采用湿化学方法合成和制备了W/F掺杂改性的CuO基陶瓷(Cu_1-yW_yO:F_x，x为0.01~0.07，y为0~0.006)。利用X-射线衍射、扫描电子显微镜、电阻-温度测试及电化学交流阻抗等手段对所制备的陶瓷材料的物相组成、微观组织、导电性质及电阻-温度特性进行了测试分析。结果表明，掺杂F能在较大范围内调节CuO陶瓷体的室温电阻率，W/F共掺CuO陶瓷具有优异的NTC特性，适当的W/F掺杂能获得NTC材料常数达5084 K。W/F共掺CuO陶瓷的电子导电性和NTC特性由材料的晶粒（块体）效应和晶界效应共同贡献而成；陶瓷材料的导电模型包含半导体材料的能带理论导电机制和热激活电子跃迁导电模型。 

Electrical conductivity and temperature sensitivity of W/F-modified CuO-based ceramics

I n order to develop new system of thermal sensitive ceramics with negative temperature coefficient (NTC) of resistivity, W/F modified CuO-based ceramics (Cu1-yWyO:Fx, x ranges 0.01~0.07 and y ranges 0~0.006)were prepared by using a wet-chemical synthesis method. The phase component, microstructure, electrical conductivity and resistivity-temperature characteristics of the ceramics were analyzed by using X-ray diffraction, scanning electron microscope, resistance-temperature measurement and electrochemical impedance spectrum, respectively. The results show that the room temperature resistivities of the CuO ceramics can be adjusted obviously by doping with flouorine ions, and the W/F-doped CuO ceramics have excellent NTC feature with the highest materials con-stant of 5084 K. The electrical conductivity and NTC characteristics of the W/F modified CuO ceramics are co-re-sulted from the grain effect (bulk effect) and grain-boundary effect. Conducting model made of ceramics is com-posed of band theory conductive mechanism of semiconductor materials and electron-hopping models.