High-temperature thermistors using novel double perovskite Ba2ReNbO6 (Re = La, Nd, and Sm) NTC ceramics

High-temperature thermistors face significant challenges in maintaining stability under extreme temperature conditions, meaning that stringent requirements for material selection and structural design are needed. To address this issue, negative temperature coefficient (NTC) thermistor ceramics of Ba 2 ReNbO 6 (Re = La, Nd, and Sm) were successfully prepared using the solid-state reaction method. X-ray diffraction (XRD) analysis revealed that Ba 2 ReNbO 6 (Re = La, Nd, and Sm) had an ordered double perovskite structure. Scanning electron microscopy (SEM) revealed that as the difference in cationic radii between B′/B″ decreased, the porosity of the materials gradually increased. After Ba 2 ReNbO 6 (Re = La, Nd, and Sm) underwent aging tests at 1173 K for 720 h, the resistance drift rates were 1.33, 3.80, and 5.88%, respectively, and the aging mechanism was explained using cation diffusion theory. These ceramics exhibited typical NTC characteristics over a wide temperature range from 773 to 1473 K, with the degree of linearity exceeding 0.999 for all the samples.