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无机材料学报

无机材料学报

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Mn0.43Ni0.9CuFe0.67O4 NTC热敏材料的Pechini法制备

靳先静1,2， 常爱民1， 张惠敏1,2， 张东炎1,2   

  1. （1. 中国科学院 新疆理化技术研究所， 乌鲁木齐 830011; 2. 中国科学院 研究生院， 北京 100049）
  • 收稿日期:2009-01-19 修回日期:2009-04-19 出版日期:2009-09-20 网络出版日期:2009-09-20

Preparation and Microwave Sinterability of Mn0.43Ni0.9CuFe0.67O4 NTC
Thermistor Materials by Pechini Method

JIN Xian-Jing1, 2, CHANG Ai-Min1, ZHANG Hui-Min1, 2, ZHANG Dong-Yan1, 2   

  1. (1. Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011, China; 2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China)
  • Received:2009-01-19 Revised:2009-04-19 Published:2009-09-20 Online:2009-09-20

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摘要： 为制备材料常数(B值)1900K左右宽温区NTC热敏电阻， 将Pechini方法制备的Mn0.43Ni0.9CuFe0.67O4 粉体置于2.45GHz多模腔微波炉中，经不同温度下微波煅烧压制成型后，于1000℃下微波烧结.采用红外(FT-IR)，X射线衍射（XRD），扫描电镜（SEM），粒度分析分别对样品的晶体结构、相组成、形貌和粒度分布进行了表征.结果表明，不同煅烧和烧结工艺对元件的电学性能有很大的影响；微波最佳煅烧温度为650℃，比常规煅烧所需温度低；微波烧结能够获得微观结构均匀致密的陶瓷体；微波烧结制得元件的B值和电阻率均匀性较好，其B值平均值为1930K，偏差为0.31%，电阻率ρ的平均值为135Ω·cm，偏差为4.55%；而常规烧结制得元件的B值平均值为1720K，偏差为1.47%，电阻率ρ的平均值为78Ω·cm，偏差为25.34%.复阻抗分析表明，微波烧结后样品的晶粒电阻Rb和晶界电阻Rgb分别为255和305Ω，而常规烧结样品的晶粒和晶界电阻分别为200和230Ω.

关键词: 微波烧结, 微波煅烧, NTC, Pechini法

Abstract: In order to obtain the NTC thermistors with small B constant (about 1900K), applied to wide temperature range, Mn0.43Ni0.9CuFe0.67O4 NTC thermistor materials prepared by Pechini method were microwave-calcined at different temperatures (650℃, 750℃ and 850℃). The calcined Mn0.43Ni0.9CuFe0.67O4 powders were pressed and then sintered at 1000℃ in a microwave furnace (multimode cavity, 2.45GHz).The crystal structure, phase compositions, morphology and particle size distribution of the samples were analyzed by FT-IR, X-ray diffraction (XRD), scanning electron microscope (SEM) and a laser particle size analyzer. The experimental results show that the electrical properties of the ceramics are strongly dependent on the calcination and sintering process. The application of microwave leads to a lower calcination temperature (650℃) and densified uniform microstructures. Microwave sintering can obtain the components with well uniformity of B constant and resistivity, of which the Bavg. is 1930K (deviation of 0.31%) and resistivity ρavg. is 135Ω·cm (deviation of 4.55%). However, the Bavg. is 1720K (deviation of 1.47%) and resistivity ρavg. is 78Ω·cm (deviation of 25.34%) for the conventionally sintered components. From complex impedance analysis, the grain resistance (Rb) and grain boundary resistance (Rgb) are respectively 255Ω and 305Ω for the microwavesintered samples. The Rb and Rgb are respectively 200Ω and 230Ω for conventionally sintered samples.

Key words: microwave sintering, microwave calcining, NTC, pechini method

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