Aging of copper-nickel-cobalt manganite NTC thermistors [Cu/sub 0.1/Ni/sub 0.8/Co/sub 0.2/Mn/sub 1.9/O/sub 4/]

Aging phenomenon in copper-nickel-cobalt manganite NTC thermistors under thermal stresses at 125 and 170/spl deg/C during 1000 h was studied. The relative resistance drift observed in NTC thermistors is correlated with the results of Cu/sub 0.1/Ni/sub 0.8/Co/sub 0.2/Mn/sub 1.9/O/sub 4/ ceramic microstructures characterization (obtained by optical microscopy, SEM, electron probe and EDX microanalyses) and thermogravimetric analysis.