Resistance-Temperature Characteristics of Cr Doped Ni<sub>0.7</sub>Mn<sub>2-x</sub>Cu<sub>0.3</sub>Cr<sub>x</sub>O<sub>4</sub> NTC Thermistors

Abstract

Manganese-based solid solution ceramics of transition metal with spinel-type crystal structure have generated much interest as NTC thermistors in various domestic and industrial applications. Doping has been considered as one of the most important method to improve their electrical properties. In this work, Cr doped Mn-based solid solution NTC ceramics Ni0.7Mn2-xCu0.3CrxO4 (x = 0.1, 0.2, 0.3 and 0.4) were prepared by solid-state reaction method. X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray energy dispersive spectrometer (EDS) were applied to study the phase structure, surface morphology and surface element content. The results indicate that the resistance and B value increase as the substituted Cr content increases.