• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.7
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• pp.546-551
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• 1998

$Mn{1-X}Fe{2+X}O_4, Mg_{1-X}Fe_{2+X}O_4$ (x=0.0, 0.025, 0.1, 0.2) for negative temperature coefficient (NTC) thermistor was prepared by calcination at $800^{\circ}C$ and sintering at form 1100 to $1250^{\circ}C$ with $50^{\circ}C$ intervals. The best linear property was obtained in the Mn-based sample sintered at $1200^{\circ}C$ with x=0.0 composition. Temperature coefficient of resistance, $\alpha$, was $-5.6%/^{\circ}C$ in the Mn-based sample, $-5.2%/^{\circ}C$ in the MM-based sample, and $-1.6%/^{\circ}C$ in the Mg-based sample. thermistor parameter, B, was in the range of 2665~7780 K. The results show the possibility that Mn-Ni-Co based thermistor could be substituted by the composition used in this study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.407-410
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• 2000

(M $n_{l-x}$M $g_{l-x}$)F $e_{2+x}$ $O_4$(x=0.0, 0.025, 0.1, 0.2) for NTC(negative temperature coefficient) thermistor was prepared by calcining at 80$0^{\circ}C$ and sintering at from 1100 to 130$0^{\circ}C$ with 5$0^{\circ}C$ intervals while x was varied from 0.0 to 0.025, 0.1 and 0.2. The best linear property was obtained in the based specimen sintered at 120$0^{\circ}C$ with x=0.1 composition. Thermistor parameter, $B_{25~85^{\circ}C}$, was in the range of 5000~ 7300 [K]. Temperature coefficient of resistance, $\alpha$$_{25^{\circ}C}$, was -5.2 %/$^{\circ}C$. The results showed the possibility that Mn-Ni-Co based thermistor could be substituted by the composition used in this study was confirmed.med.d.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1855-1857
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• 1999

$Mn_{1-x}Fe_{2+x}O_4$, $Mg_{1-x}Fe_{2+x}O_4$ (x=0.0, 0.025, 0.1, 0.2) for negative temperature coefficient (NTC) thermistor were prepared by calcining at $800^{\circ}C$ and sintering from 1100 to $1250^{\circ}C$ with $50^{\circ}C$ intervals. The best linear property was obtained in the Mn-based sample sintered at $1200^{\circ}C$ with x=0.0 composition. Temperature coefficient of resistance, $\alpha$, was -3.0 %/$^{\circ}C$ in the Mg-based sample at $25^{\circ}C$. Thermistor parameter, B, was in the range of 2500 [K] $\sim$7400 [K]. The results show the possibility that Mn-Ni-Co based thermistor could be substituted by the composition used in this study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.399-402
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• 2000

For improvement of B constant in $CaMnO_3$-$CaTiO_3$ perovskite type thermistors, effect of $Cr_2$$O_3$ addition ranged from 0.0wt% to 5.0wt% on electrical properties were investigated with contents and sintering temperatures in the view of crystal and microstructures. The solubility limit of Cr$_2$O$_3$was up to 0.5wt% judging from the result of lattice parameter. The grain size was decreased and the resistance at room temperature and B constant were increased with the addition of $Cr_2$$O_3$.On particular, B constant of$CaMnO_{3-x}$$Cr_2$$O_3$ system was increased greatly from 1574k to 2598k at 0.5wt% $Cr_2$$O_3$addition. Further addition of $Cr_2$$O_3$, however, resulted in the decrease of the resistance and B constant due to the $Cr_2$$O_3$ precipitation on the grain boundary. As the$CaTiO_3$contents increased in the $CaMnO_3$-$CaTiO_3$ system, the resistance at room temperature and B constant were highly changed.