Characterization of NiO based ceramics modified with Y2O3/BiSbO3 for application of NTC thermistors

Facing the development of electronic information technology, measurement and control technology towards diversity and higher precision, it is interesting to design and fabricate thermistors with effect of negative temperature coefficient (NTC) of resistivity with adjustable room temperature resistivity (ρ25), high thermal sensitivity and electrical stability. Here, NiO-based ceramics doped with Y2O3 and modified by BiSbO3 were prepared by solid state reaction method. Phase component, microstructure, electrical properties and aging performances of the prepared ceramics were investigated. The prepared ceramics have main phase with cubic rock salt structure and present typical NTC characteristics. Doping with Y2O3 and BiSbO3 can effectively adjust the ρ25 of NiO based ceramics, which show high temperature sensitivity with NTC material constants (B25/85 value) larger than 5200 K. The introduction of BiSbO3 into Y-doped NiO ceramics can effectively enhance the electrical stability. The aging-induced resistance change rate of the Y-doped NiO ceramics is − 5.9% after aging for 800 h (treated at 150 °C in air), while the Y-doped NiO ceramics modified with 2 wt% of BiSbO3 have only 0.21% of resistance change rate after aging treatment. The aging mechanism was analyzed by X-ray photoelectron spectroscopies of the ceramics before and after aging.