Microstructure and electrical properties of rare-earth oxides doped ZnO-based linear resistance ceramics

The ZnO-based linear resistance ceramics doped with rare-earth oxides (Y2O3, La2O3) have been prepared by the conventional ceramics method. The effect of the different doping amounts of rare-earth oxides on the microstructure, electrical properties and aging behavior were investigated in detail. The electrical properties analysis shows that the La2O3 addition on ZnO-based linear resistance ceramics has more obviously influence than the addition of Y2O3. The samples with the La2O3 content of 0.25 mol% sintered at 1,320 A degrees C exhibits excellent electrical properties with the resistivity of 253.5 Omega cm and the resistance temperature coefficient of 3.62 x 10(-4)/ A degrees C, which are improved by 60 and 90 %, respectively. The nonlinear coefficient of voltage decreases to 1.16, decreases by 4.3 % and the stability of -1.2 % in the variation rate of the resistivity for aging temperature.