Fabrication of nano-grained negative temperature coefficient thermistors with high electrical stability  

作　　者：Miao-Miao Cui Xiao Zhang Kuan-Guan Liu Hai-Bo Li Mang-Mang Gao Sen Liang 

机构地区：[1]Ningxia Key Laboratory of Photovoltaic Materials,Ningxia University,Yinchuan 750021,China [2]School of Materials Science and Engineering,North Minzu University,Yinchuan 750021,China

出　　处：《Rare Metals》2021年第4期1014-1019,共6页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51302138 and 21663001);the Western Light Talent Training Program of Chinese Academy of Sciences。

摘　　要：Dense nano-grained Ni_(0.7)Mn_(2.3O4) negative temperature coefficient(NTC) thermistors were fabricated by a novel two-step sintering approach that combines rapid sintering and principle of conventional two-step sintering technique.Samples were sintered at 1042℃ for 30 s in the first rapid step and then at 850-950℃ for 20 h in the second soaking step.Crystal phase,microstructure and electrical properties of sintered samples were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),resistance temperature relationship and aging performance.Sintered samples show a single-phase cubic spinel structure and indicate a high relative density ranging from 84% to 91% of the theoretical density.Moreover,average grain sizes of sintered samples under SEM are distributed between 254 and 570 nm.Meanwhile,the resistivity and the aging coefficient significantly decrease when soaking sintering temperature rises.In addition,the obtained material constant(B) ranges from 3931 to 3981 K.Ni_(0.7)Mn_(2.3)O_(4)-3(soaking at 900℃) and Ni_(0.7)Mn_(2.3O4)-4(soaking at 950℃) present little aging behavior,implying great electrical stability.

关 键 词：Negative temperature coefficient thermistor SINTERING Nano-grain AGING 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TN37[电子电信—物理电子学]