Preparation and characterization of Ni0.6Mn2.4O4 NTC ceramics by solid-state coordination reaction
The impact of synthesis parameters, such as calcination temperature and reaction time, on the microstructure, phase compositions and electrical properties of Ni 0.6 Mn 2.4 O 4 negative temperature coefficient (NTC) ceramics, which were synthesized via solid-state coordination reaction method, was sy...
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Published in | Journal of materials science. Materials in electronics Vol. 24; no. 12; pp. 5183 - 5188 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Boston
Springer US
01.12.2013
Springer |
Subjects | |
Online Access | Get full text |
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Summary: | The impact of synthesis parameters, such as calcination temperature and reaction time, on the microstructure, phase compositions and electrical properties of Ni
0.6
Mn
2.4
O
4
negative temperature coefficient (NTC) ceramics, which were synthesized via solid-state coordination reaction method, was systematically explained. With enhancing calcination temperature and time, the relative densities were raised, while the porosities diminished. A compact single-phase cubic spinel ceramic could be obtained after annealing at 1,100 and 1,150 °C, while a secondary phase Mn
3
O
4
was detected when the annealing temperature raised to 1,200 °C. For the ceramics calcinated at 1,100 or 1,150 °C for 3 h, their resistivities were 2,133 and 2,178 Ω cm, the thermal constant B, which reflects the temperature sensitivity of the NTC ceramics, were 3,820 and 3,857 K. While the ceramic prepared at 1,200 °C for 3 h, the resistivity and the B value reached 2,273 Ω cm and 3,810 K, respectively. This phenomenon was attributed to the increase of lattice parameters and the reduction of Mn
4+
–Mn
3+
at high temperatures. |
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ISSN: | 0957-4522 1573-482X |
DOI: | 10.1007/s10854-013-1542-2 |