Preparation routes and electrical properties for Ni0.6Mn2.4O4 NTC ceramics

• Published in: Journal of materials science. Materials in electronics Vol. 26; no. 9; pp. 7238 - 7243
• Main Authors: Ma, Chengjian, Liu, Yunfei, Lu, Yinong
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2015
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Optical and Electronic Materials; Spinel Structure; Calcination Temperature; Sinter Temperature; Reaction Powder; Negative Temperature Coefficient
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-015-3350-3

Ni 0.6 Mn 2.4 O 4 negative temperature coefficient ceramics were prepared by using solid-state coordination reaction and traditional solid-state methods, their structures and properties were characterized by using scanning electron microscopy, powder X-ray diffractometer and temperature dependent resistivity test. For solid-state reaction powders, the calcination temperature necessary for formation of the spinel phase was 1000 °C, which is 300 °C higher than that of solid-state coordination reaction powders. Regardless of preparation routes, the ceramics were crystallized in a single cubic spinel structure when the sintering temperature was lower than or equal to 1150 °C, Mn 3 O 4 impurity phase was detected when the sintering temperature raised to 1200 °C. Having higher densities and bigger grain sizes, the solid-state coordination reaction samples had smaller room temperature resistivities and larger B 25/50 values as compared with those of solid-state samples.