Zr_xNiMn_(1.8-x)Fe_(0.2)O_4系热敏电阻的溶胶-凝胶法制备及热敏特性研究  

Preparation of Zr_xNiMn_(1.8-x)Fe_(0.2)O_(4) Thermistors via Sol-gel Processing and Probing their Thermal Sensitivity

作　　者：章践立[1] 张嗣春[1] 夏海平[1] 

机构地区：[1]宁波大学光电子功能材料研究所

出　　处：《宁波大学学报（理工版）》2008年第2期246-250,共5页Journal of Ningbo University：Natural Science and Engineering Edition

基　　金：浙江省科技厅项目(2007C21121);宁波市科技局项目(2005B100026);宁波市重点实验室开发基金(2007A22010)

摘　　要：用溶胶-凝胶(Sol-gel)技术制备了ZrxNiMn1.8-xFe0.2O4(0<x≤0.8)系列热敏电阻超细粉体,经压片、烧结及封装等后续工艺制得热敏陶瓷电阻.分别用XRD与SEM表征所得陶瓷的结晶相与微观形貌,并详细研究了Zr4+掺杂浓度对该系列热敏电阻特性的影响.实验结果表明:具有正立方尖晶石结构的ZrxNiMn1.8-xFe0.2O4陶瓷随着Zr4+掺杂量的增加(x≤0.6),其电阻率和热敏度(值)都不断增加.并讨论了ZrB4+对该系统热敏特性产生影响的内在机理,认为是具有高势垒的Zr4+离子取代了ZrxNiMn1.8-xFe0.2O4中部分锰离子的格位,增加了微晶的晶界势垒,从而导致B值增高.The nano-ultrafine powders of ZrxNiMn1.8-xFe0.2O4 （0〈x ≤ 0.8） for thermistor application are prepared using sol-gel method. The negative temperature coefficient （NTC） thermistor is fabricated by pressing the powders, sintering the rough, and covering the ceramic by epoxy. The phase and morphologic properties of the ceramic are characterized using X-ray diffraction （XRD） and scanning electron microscopy（SEM）, The effects of Zr^4＋ ion content on the thermal sensitivity are investigated. The results show that the resistivity and sensitivity index B of ceramic with a cubic spinel structure increases along with the increase of the Zr^4＋ content （x≤0.6）. The mechanism of Zr^4＋ composition affecting the thermal sensitivity is discussed. Substitution of Zr^4＋ for the Mn sites of ZrxNiMn1.8-xFe0.2O4 microcrystal result in higher potential barrier of the micro-crystal boundary and higher B value.

关 键 词：Zr^4+离子 NiFeMnO系热敏电阻 溶胶-凝胶法 热敏度 

分 类 号：TM286[一般工业技术—材料科学与工程]