Grain Growth in Nickel Ferrites

Levesque, Pascal; Gerlach, Lawrence; Zneimer, J. E.

doi:10.1111/j.1151-2916.1958.tb12920.x

Cited by 9 publications

(2 citation statements)

References 1 publication

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“…3b) shows a straight line relationship implying the grain growth as Arrhenius-controlled process with activation energy of 64.4 Kcal/mole. The observed values of activation energy for densification and grain growth in the present study are relatively low compared with the values reported by Paulus, 83 Kcal/mole for Mn-Zn and Ni-Zn ferrites [2] and by Levesque, 90 Kcal/mole for Ni ferrites [3]. The deviations and also the related microstructures of these ferrites are explained as follows: Due to volatilization of zinc at higher sintering temperatures, the Ni 0 .…”

Section: Resultscontrasting

confidence: 73%

Densification, Grain Growth and Microstructure of Ni-Zn Ferrites

Rao

1997

J. Phys. IV France

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Nio.6; Zno.35 Fe2 0 4 , with high density and fine grain size, is a desirable composition for applications of high frequency switching power supplies. This composition has been studied under different sintering conditions. Observed changes in density, grain size and microstructure in these ferrites have been correlated to the volatilization of zinc from the samples at elevated sintering temperatures. Densification and grain growth are observed to be Arrhenius controlled rate processes with activation energies of 63.9 and 64.4 Kcal/mole respectively.

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Section: Resultscontrasting

confidence: 73%

Densification, Grain Growth and Microstructure of Ni-Zn Ferrites

Rao

1997

J. Phys. IV France

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“…The higher Fe/Ni atomic ratio in NiFe 2 O 4 phase, the higher oxygen vacancies concentration was. Similarly, the additive of Fe 2 O 3 would promote the abnormal growth of NiFe 2 O 4 grain, the increase of oxygen vacancies concentration would promote the diffusion and growth of NiFe 2 O 4 grain.…”

Section: Resultsmentioning

confidence: 99%

Microstructural Evolution of a Nickel Ferrite–Copper Alloy Cermet During Sintering and High‐Temperature Oxidation

Yuqiang

Zhang

et al. 2012

J. Am. Ceram. Soc.

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The microstructural evolution during sintering and high-temperature oxidation of a cermet comprised of (wt%) a 40/60 ratio of an alloy of composition 80% Cu/20% Ni and a ceramic of composition 90% NiFe 2 O 4 /10% NiO has been studied as a function of processing temperature. The porosity of the cermet reduced significantly without undue coarsening of the microstructure during sintering up to the melting temperature of the alloy phase (T m % 1160°C), whereas at sintering temperatures higher than T m , the ferrite rapidly coarsened with little additional reduction in porosity, and the alloy phase formed a continuous interconnected network while partially extruding from the composite. Upon oxidation in air at temperatures between 850°C and 1000°C, the cermet developed a multilayered oxidized scale, comprising a thin copper-rich outer oxide layer formed via external oxidation and a thicker zone of internal oxidation. The external oxide scale transformed from CuO to Cu 2 O with increasing oxidation temperature. Out-diffusion of the copper to the externally oxidized layer led to significant porosity at the internal interface between oxide and unoxidized cermet. P. Joy-contributing editor

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A comparative study of different sintering routes effects on evolving microstructure and B–H magnetic hysteresis in mechanically-alloyed Ni–Zn ferrite, Ni0.3Zn0.7Fe2O4

Ibrahim

Hashim

Nazlan

et al. 2014

J Mater Sci: Mater Electron

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A comparative study between two sintering routes has been carried out to reveal the parallel evolutions of microstructure and B-H hysteresis in a mechanically-alloyed Ni-Zn ferrite. The starting powders were mixed and crushed via the mechanical alloying technique. Subsequently two portions of the resulting powder were subjected to two respective sintering routes: multi-sample and single-sample. In the multi-sample sintering, the samples were sintered from 600 to 1400 °C with any one sample being subjected to only one sintering temperature. For the single-sample sintering, only a single sample was subjected to repeat sintering from 600 to 1400 °C. In B-H hysteresis measurement, the same trends but with different values were observed for both sintering routes. Saturation induction, Bs, values range from 23.9 to 1076.0 G for multi-sample sintering and from 23.4 to 930.7 G for singlesample sintering. Three distinct behaviour groups could be distinguished which correspond to a particular range of grain sizes and domain state of the samples. The activation energies of grain growth for multi-sample and single-sample sintering show three different ranges of values for each route which are 6.80, 99.31 and 143.39 kJ/mol and 14.60, 29.42 and 162.83 kJ/mol respectively. These different ranges of values characterized the different diffusion mechanisms.

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Grain Growth in Nickel Ferrites

Cited by 9 publications

References 1 publication

Densification, Grain Growth and Microstructure of Ni-Zn Ferrites

Densification, Grain Growth and Microstructure of Ni-Zn Ferrites

Microstructural Evolution of a Nickel Ferrite–Copper Alloy Cermet During Sintering and High‐Temperature Oxidation

A comparative study of different sintering routes effects on evolving microstructure and B–H magnetic hysteresis in mechanically-alloyed Ni–Zn ferrite, Ni0.3Zn0.7Fe2O4

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