%0 Journal Article
%T Preparation and Microwave Sinterability of Mn0.43Ni0.9CuFe0.67O4 NTC Thermistor Materials by Pechini Method
%A JIN Xian-Jing
%A CHANG Ai-Min
%A ZHANG Hui-Min
%A ZHANG Dong-Yan
%J 无机材料学报
%D 2009
%I Science Press
%R 10.3724/sp.j.1077.2009.01013
%X 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  nd 850   The calcined Mn0.43Ni0.9CuFe0.67O4 powders were pressed and then sintered at 1000  n 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 | SUB>avg. is 135|  ¤cm (deviation of 4.55%). However, the Bavg. is 1720K (deviation of 1.47%) and resistivity |Сvg. is 78|  ¤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 255|  and 305|  for the microwavea2sintered samples. The Rb and Rgb are respectively 200|  and 230|  for conventionally sintered samples.
%K microwave sintering
%K microwave calcining
%K NTC
%K pechini method
%U http://www.jim.org.cn/fileup/PDF/20090528.pdf