Ageing behavior of electrical resistance in manganite NTC ceramics

Experimental results on thermally induced degradation tests, carried out at relatively low ageing temperature (170 °C) in NTC thermistors based on Cu0.1Ni0.8Co0.2Mn1.9O4 spinel-structured ceramics, are discussed. It is shown the kinetics of the observed degradation processes is described mainly by well known DeBast–Gillard or Williams–Watts relaxation function, the deviations from this conclusion being observed only in multiphase ceramic samples. The inhibition effect in ageing of the investigated ceramics is observed at small concentration of additional NiO-enriched rock-salt phase.