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

• DOI: 10.1007/s10854-015-3350-3
• Publication Date: 2015-06-16T16:27:04Z
• Authors: Chengjian Ma; Yunfei Liu; Yinong Lu
• Keywords: Diffractometer; Temperature coefficient

Ni0.6Mn2.4O4 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, Mn3O4 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.