Effect of Cr2O3 addition on the microstructure and electrical properties of Mn-Ni-Co oxides NTC thermistors

Park, K.; Han, I.

doi:10.1007/s10832-006-8317-6

Cited by 56 publications

(28 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…NTC compositions that have been slowly cooled after sintering are found to be single-phase and free from lattice defects such as dislocations or planar defects [5,7]. Previous studies on Cr-substituted Mn 1.1 Ni 1.4 Co 0.5− x Cr x O 4 showed single phase cubic spinel Mn-Ni-Co-Cr oxide formation, suggesting that the substituted Cr suppressed a loss and transportation of oxygen [13]. The formation of monophase cubic spinel is considered to be very important for the development of stable and reliable NTC thermistor compositions.…”

Section: Resultsmentioning

confidence: 95%

“…Many factors are believed to affect the final characteristics of NTC thermistors, among which the effect due to sintering temperature and cooling rate is of prime importance [10][11][12][13][20][21]. In this study a cooling rate of 2°C per minute applied after sintering.…”

Section: Resultsmentioning

confidence: 99%

“…By varying the types of oxides used, their relative proportions, and the processing conditions, a wide range of resistivity and temperature coefficient characteristics can be obtained [6][7][8][9][10][11][12][13]. The main characteristics of NTC thermistors are their specific resistivity, material constant (B-value) and temperature coefficient of resistance.…”

Section: Introductionmentioning

confidence: 99%

“…Since 1950s Ni-Mn-O based ternary or quaternary transition metal oxide systems are generally used for NTC thermistor manufacturing [7][8][9][10][11][12][13]. The composition range of these systems is often quite narrow, so to extend it the compound is usually doped with impurities.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

2008

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

2008

View full text Add to dashboard Cite

show abstract

“…It is well known that the desired sensitivity coefficient, a 25 , and the activation energy of the NTC thermistors are in the range -2.2 %/K to -5.5 %/K and 0.1-1.5 eV, respectively. 18,19 …”

Section: Discussionmentioning

confidence: 99%

Influence of nano-sized cobalt oxide additions on the structural and electrical properties of nickel-manganite-based NTC thermistors

Hardal¹,

Price²

2016

Mater. Tehnol.

View full text Add to dashboard Cite

The structural and electrical properties of NiMn2O4 and Ni0.5CoxMn2.5-xO4 (where x = 0.5, 0.8 and 1.1) NTC thermistors have been investigated. The samples, prepared by conventional ceramic processing techniques, were calcinated at 900°C for 2 h and then sintered at 1100°C and 1200°C for 5 h. The cubic spinel phase was observed by XRD analysis in the NiMn2O4 and Ni0.5Co0.8Mn1.7O4 samples sintered at 1100°C for 5 h. The sintering at 1200°C resulted in much denser microstructures with a larger grain size. The room-temperature electrical resistivity (r25) and material constant (B) value of the NiMn2O4 sample sintered at 1100°C were 7710 W cm and 3930 K, respectively. The electrical resistivity of the samples decreased significantly with the addition of Co3O4. The B25/85 values of the Ni0.5CoxMn2.5-xO4 (where x = 0.5, 0.8 and 1.1) samples sintered at 1100°C were found to be 3820 K, 3525 K and 3270 K, respectively. Keywords: cobalt oxide, electrical properties, microstructure, NTC thermistor Preiskovana je bila zgradba in elektri~ne lastnosti NiMn2O4 in Ni0.5CoxMn2.5-xO4 (kjer je x = 0,5, 0,8 in 1,1) NTC termistorjev. Vzorci, pripravljeni po obi~ajni tehniki priprave keramike, so bil kalcinirani 2 h na 900°C in potem 5 h sintrani na 1100°C in 1200°C. Kubi~na {pinelna faza je bila opa`ena pri XRD-analizi, v vzorcih NiMn2O4 in Ni0.5Co0.8Mn1.7O4, sintranih 5 h na 1100°C. Sintranje na 1200°C je povzro~ilo mnogo bolj gosto mikrostrukturo z ve~jimi zrni. Vrednosti za elektri~no upornost pri sobni temperaturi (r25) in materialne konstante (B) vzorca NiMn2O4, sintranega na 1100°C, sta bili 7710 W cm in 3930 K. Elektri~na upornost vzorcev se je ob~utno zmanj{ala po dodatku Co3O4. Vrednosti B25/85 pri vzorcih Ni0.5CoxMn2.5-xO4 (kjer je bil x = 0,5, 0,8 in 1,1) sintranih na 1100°C so bile: 3820 K, 3525 K in 3270 K.

show abstract

Aging Behaviour in Ni0.5CoxMn2.5−xO4 (x = 0.5, 0.8 and 1.1) Thermistors

Hardal

Price

2017

The Minerals, Metals &Amp; Materials Series

View full text Add to dashboard Cite

Effect of Cr2O3 addition on the microstructure and electrical properties of Mn-Ni-Co oxides NTC thermistors

Abstract: The as-sintered Mn 1.

Cited by 56 publications

References 19 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

Influence of nano-sized cobalt oxide additions on the structural and electrical properties of nickel-manganite-based NTC thermistors

Aging Behaviour in Ni0.5CoxMn2.5−xO4 (x = 0.5, 0.8 and 1.1) Thermistors

Contact Info

Product

Resources

About