Novel NTC ceramics based on pyrochlore-type A2Ti2O7 (A = Sm, Eu, Y) titanates for high-temperature thermistors

In this study, a series of novel negative temperature coefficient thermistor materials based on A 2 Ti 2 O 7 ( A = Sm, Eu, Y) titanate ceramics have been developed for high-temperature applications. The A 2 Ti 2 O 7 ( A = Sm, Eu, Y) ceramics showed cubic pyrochlore structures with dense morphology in X-ray diffraction and scanning electron microscopic analyses. These ceramics showed typical NTC characteristics in a wide temperature range of 673–1473 K, accompanied by resistance drift rates of 2.71%, 1.63%, and 4.95% for 400 h of ageing at 1173 K. The proposed ceramics have high resistivity and thermal constants B that ensure their better sensitivity at high temperatures and also show unique oxygen insensitivity. These properties outperform those of traditional high-temperature NTC materials composed of perovskite-type or scheelite-type ceramics, making A 2 Ti 2 O 7 ( A = Sm, Eu, Y) ceramics promising candidates for fabricating high-temperature NTC thermistors.