Microstructural, electrical and reliability aspects of chromium doped Ni–Mn–Fe–O NTC thermistor materials

Varghese, Justin Manjaly; Seema, A.; Dayas, K.R.

doi:10.1016/j.mseb.2007.12.005

Cited by 54 publications

(28 citation statements)

References 15 publications

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“…Dopants facilitate controlled valence semi conduction or dilution by which the conductivity can be adjusted. Recently we have reported the modification of Ni-Mn-O compositions by the addition of Cr 2 O 3 and Fe 2 O 3 [14]. The present study focusing on the development of a reliable NTC material composition based on Ni-Mn-Fe-Cr-O system.…”

Section: Introductionmentioning

confidence: 97%

Ni–Mn–Fe–Cr–O negative temperature coefficient thermistor compositions: Correlation between processing conditions and electrical characteristics

2008

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A study has been carried out to correlate the effect of sintering temperature on the microstructural, electrical and reliability aspects of Ni 0.75 Mn (2.25−x−y) Cr x Fe y O 4 (x=0 to 0.3 and y=0 to 0.3) negative temperature coefficient thermistor compositions prepared by solid-state route. The calcined and sintered compositions were characterized by X-ray diffraction and Scanning Electron Microscopy. The existence of cubic spinel single-phase region was determined by sintering Ni 0.75 Mn (2.25−x−y) Cr x Fe y O 4 samples in air at temperatures 1150 to 1250°C. X-ray diffraction patterns of samples sintered above 1200°C shows additional Bragg reflections of a rock salt structured NiO phase besides normal cubic spinel. A maximum B-value of 4044 K was obtained for Ni 0.75 Mn 1.95 Cr 0.25 Fe 0.05 O 4 composition at a sintering temperature 1250°C/3 h. The reliability of the thermistor compositions were evaluated by performing accelerated ageing based on thermal cycling test. We found that chromium enhances the reliability of Ni 0.75 Mn (2.25−x−y) Cr x Fe y O 4 (x=0 to 0.3 and y=0 to 0.3) based NTC thermistor compositions. A maximum reliability of +0.25% resistance drift was observed at sintering temperature 1200°C for 0.25 mol% chromium content. Excellent reliability of Ni 0.75 Mn (2.25−x−y) Cr x Fe y O 4 NTC thermistor compositions makes it ideal candidates for high-performance thermal sensor applications.

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Section: Introductionmentioning

confidence: 97%

Ni–Mn–Fe–Cr–O negative temperature coefficient thermistor compositions: Correlation between processing conditions and electrical characteristics

2008

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“…All thermistors showed a linear relationship for the ln r with 1/ T in the measured temperature range (room temperature $300 8C), indicating the good agreement of NTC thermistor characteristics as described by the Nernst-Einstein relation [22]. The conductivity mechanism of nickel manganite spinel materials was explained by many researchers [7,12,13,23], and they considered that the conductivity depended on the change in concentration and ordering of hopping charge carriers namely Mn 3+ and Mn 4+ at octahedral site. Table 1 gives the r 25 , B 25/85 constant, activation energy and resistance drift (aging), which are the most important characteristics of technical interest for NTC thermistors.…”

Section: Electrical Measurementmentioning

confidence: 66%

“…In the spinel structure, two sites are available for the cations: the tetrahedral site (A-site) and octahedral site (B-site). It is generally accepted that the exchange of cations between sublattice tetrahedral (A-sites) and octahedral (B-sites) result in the aging of Fe-containing NTC thermistors [4,[7][8][9][10][11][12][13]. Besides, some studies showed that the aging also involves migration of cation vacancies from the grain boundaries to the interior [14].…”

Section: Introductionmentioning

confidence: 99%

An efficient way to improve the electrical stability of Ni0.6Si0.2Al0.6Mn1.6O4 NTC thermistor

Yang

Zhang

et al. 2011

Ceramics International

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“…Clearly, the linear relationship over the measurement temperature range almost coincides with each other. The high aging resistance of the SSZ ceramics should make them useful for the development of high-performance NTC thermistor devices [24].…”

Section: Resistivity-temperature Characteristicsmentioning

confidence: 99%

Zr-substituted SnO2-based NTC thermistors with wide application temperature range and high property stability

Ouyang

Zhang

2015

J Mater Sci: Mater Electron

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Zr-substituted SnO 2 -based ceramics (Sn 0.95-x Sb 0.05 Zr x O 2 , x B 0.1) were prepared by using a wet-chemical synthesis method. The results show that the prepared ceramics have a pure tetragonal phase as that of SnO 2 and have a typical characteristic of negative temperature coefficient (NTC) of resistivity over a wide temperature range from -50 to 300°C. The room-temperature resistivity q 25 and material constant B 25/85 of the NTC thermistors increase from 4.77 X cm to 4.89 9 10 7 X cm and from 641 to 5085 K, respectively, when the content of Zr, x, changes from 0 to 0.1. The NTC thermistors also show high cyclic stability and ageing resistance. The analysis of impedance spectra reveals that the NTC effect mainly resulted from the grain-boundary contribution, and the conduction mechanisms of the Sn 0.95-x Sb 0.05 Zr x O 2 thermistors combine with the electron-hopping conduction and band conduction.

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Microstructural, electrical and reliability aspects of chromium doped Ni–Mn–Fe–O NTC thermistor materials

Cited by 54 publications

References 15 publications

Ni–Mn–Fe–Cr–O negative temperature coefficient thermistor compositions: Correlation between processing conditions and electrical characteristics

Ni–Mn–Fe–Cr–O negative temperature coefficient thermistor compositions: Correlation between processing conditions and electrical characteristics

An efficient way to improve the electrical stability of Ni0.6Si0.2Al0.6Mn1.6O4 NTC thermistor

Zr-substituted SnO2-based NTC thermistors with wide application temperature range and high property stability

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