采用氧化物固相法制备Mn2.25-xNi0.75CoxO4(0.8≤x≤1.2)系列NTC(negative temperature coefficient)热敏电阻粉体材料.利用激光粒度分析、XRD、SEM和电性能测试等手段,表征了煅烧材料的颗粒尺寸、陶瓷体的物相、形貌以及陶瓷材料的电学特性与Co含量的关系.结果表明:在1130～1230℃烧结温度范围内,该材料体系的B值和电阻率ρ25℃随Co含量的变化范围分别为3487～4455 K和1998～203617.cm,B值和电阻率随Co含量的增加先增大后减小.该材料系列电阻率和B值调整范围较大,是一种具有实际应用价值的NTC热敏电阻.
A series of composite of the negative temperature coefficient (NTC) powders of Mn2.25-xNi0.75CoxO4 (0.8&lex&le1.2) materials were prepared via solid-state method. The particle size of calcined powders, ceramics phase structure, morphology and electrical properties were characterized by laser particle size analyzer, XRD, SEM and electrical measurements, respectively. The results show that when the Mn2.25-xNi0.75CoxO4 ceramics sintered at 1130-1230°C, their characteristic parameters B25/50 value are found to be in the range of 3487 K to 4455 K and their electrical resistivities ρ25°C are 1998 Ω·cm to 203617 Ω·cm. The B25/50 value and ρ25°C first increases and then decreases as the Co content increases. This means that electrical resistivity and B value of Mn2.25-xNi0.75CoxO4 ceramics could be adjusted to the desired values and this ternary system can be considered as the advanced semi-conducting materials for NTC thermistor applications.
Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Urumqi 830011, Peoples R China;Xinjiang Key Lab Elect Informat Mat & Devices, Urumqi 830011, Peoples R China;Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China
Peng Chang-Wen,Zhang Hui-Min,Chang Ai-Min,et al. Microstructure and Electrical Properties of Mn2.25-xNi0.75CoxO4 Thermistor Ceramics[J]. JOURNAL OF INORGANIC MATERIALS,2011,26(10):1037-1042.