(LaMn_(0.8)Al_(0.2)O_3)_(1-x)(Al_2O_3)_x(0.05≤x≤0.2)NTC热敏陶瓷材料制备及电性能研究

Preparation and Electrical Properties of (LaMn_(0.8)Al_(0.2)O_3)_(1-x)(Al_2O_3)_x(0.05≤x≤0.2) NTC Ceramics

采用氧化物固相法制备(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列负温度系数(Negative Temperature Coefficient,NTC)热敏陶瓷材料。利用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)、阻温特性以及老化性能测试等手段,确定了材料粉体最佳煅烧温度,表征了陶瓷体物相、形貌、元素含量、电学性能、稳定性与Al2O3含量的关系。结果表明:(LaMn0.8Al0.2O3)1-x(Al2O3)x(0.05≤x≤0.2)系列热敏陶瓷材料电阻率随着Al2O3含量增加显著增大,但材料常数B值增加平缓。当x=0.15时,该陶瓷材料呈现出低B(2816.44 K)、高阻(11893.89?·cm)的优良电学特性。热敏电阻经125℃老化500 h,阻值漂移(ΔR/R)均小于0.94%。

（LaMn0.8Al0.2O3）1-x（Al2O3）x （0.05≤x≤0.2） negative temperature coefficient （NTC） ceramics were synthesized through a standard solid-state method. Thermogravimetry-differential scanning calorimetry （TG-DSC）, X-ray diffraction （XRD）, scanning electron microscope （SEM）, energy dispersive spectroscope （EDS）, resistance-temperature measurement and aging test were carried out to characterize the optimal calcined temperature, phase structure, morphology, elements concentration, R-T properties and electrical stability, respectively. The results show that the electrical resistivity of the ceramic samples increases remarkably as Al2O3 content increasing, while the constant B value has just little change. Specially, the ceramics exhibit superior properties of low B value （2816.44 K） and high resistivity （11893.89 Ω？cm） when x=0.15. In addition, the resistance variation （ΔR/R） of samples is less than 0.94% after aging at 125℃ for 500 h.