The NTC thermistor nano-powders of Mn1.05-yCo 1.95-x-z- wNixMgyAlzFewO 4 were prepared by microemulsion method. Scanning electron microscope (SEM) image showed that the particles were well distributed. The mean particle-size was 72 nm. The structure of the precursor was investigated with Fourier infrared spectrometer (FI). The compositions of the powder and the as-sintered ceramic were evaluated by Energy Disperse Spectroscopy (EDS). X-ray diffraction (XRD) result indicated that the sintered samples were in the spinel structure. The room temperature resistivity ρ25, material constant B25/85 and activation energies of the NTC thermistor are in the range of 1173-19,059 Ω cm, 3169-3771 k, 0.2672-0.3136 eV. The room temperature resistivity and B25/85 constant were found to increase with Al2O3 content. The Mn0.9Co 1.2Ni0.21Mg0.15Al0.09Fe 0.45(A2) and Mn0.9Co1.2Ni0.27Mg 0.15Al0.03Fe0.45(A3) specimens both showed a 200 C resistance drift (ΔR/R) within 10% after aging at 910 C for 600 h.
Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Xinjiang Key Lab Elect Informat Mat & Devices, Key Lab Funct Mat & Devices Special Environm, Urumqi 830011, Peoples R China;Univ Chinese Acad Sci, Beijing 100049, Peoples R China
Xia, Junbo,Zhao, Qing,Gao, Bo,et al. Preparation and electrical properties of Mn1.05-yCo1.95-x-z-wNixMgyAlz FewO4 NTC ceramic derived from microemulsion method[J]. Journal of Alloys and Compounds,2014,591(4):207-212.