Annealing on the electrical properties of Ni0.75Mn2.25O4 and Zn0.8Ni0.75Mn1.45O4 NTC ceramics

Annealing temperatures on aging of Ni0.75Mn2.25O4 and Zn0.8Ni0.75Mn1.45O4 NTC ceramics were investigated. Zn doping can effectively improve the electrical stability of Ni0.75Mn2.25O4. The aging values for Ni0.75Mn2.25O4 stay almost constant below 300 ∘ C , and then increase sharply from 4.7% to 32% with increasing annealing temperature from 400 to 850 ∘ C . For Zn0.8Ni0.75Mn1.45O4, the aging values are below 10% for all annealing temperatures, 150 to 850 ∘ C . The aging phenomenon is caused by the oxygen uptake/release and the redistribution of cations/vacancies.