Microwave sinter of Mn_(0.43)Ni_(0.90)CuFe_(0.67)O_4 thermistor materials prepared by polymerized complex method

In order to obtain NTC thermistor with low B value (2 100 K), high-precision、exchange-type and fine homogeneity, Mn0.43Ni0.90CuFe0.67O4 NTC thermistor material precursors were prepared by the polymerized complex method. The oxide mixtures were attained from calcining of the polymerized gel precursor at 500 ℃ and then were microwave-calcined at different temperatures to determine the optimum temperature. The materials were then microwave and conventionally sintered after forming. The materials were characterized by TGA-DTA, FT-IR, XRD, particle size analyzer, SEM and EDS. The experimental results indicate that the particles microwave calcined at 650 ℃ were small and uniform. The ceramics mainly consist of rich-Cu phase and poor-Cu phase. The homogeneity of components is significantly increased by microwave sinter. Moreover, the rate of finished products is increased to 85% from 30% compared with the one of conventional sinter.