Diffusion Coefficient of Hydrogen in Pure Iron between 230 and 300 K

Hagi, Hideki; Hayashi, Yasunori; Ohtani, Namio

doi:10.2320/matertrans1960.20.349

Cited by 93 publications

(27 citation statements)

References 17 publications

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“…6 and 7 due to the depletion of hydrogen in the interstitial lattice sites with the increase of D 0 . Moreover, the value of D 0 , determined by several experiments 19,20) and the theoretical calculation in the ideal bcc lattice, 21) is in the range of 10 Ϫ8 m 2 /s-10 Ϫ7 m 2 /s, and, thus, D 0 is unsuitable for a fitting parameter. Model I by Turnbull et al 13) employed the relation of p 0 /k 0 ϭN I .…”

Section: Numerical Reproduction Of the Experimental Des-mentioning

confidence: 99%

A Numerical Study on the Validity of the Local Equilibrium Hypothesis in Modeling Hydrogen Thermal Desorption Spectra

Ebihara¹,

Kaburaki²,

Suzudo³

et al. 2009

ISIJ Int.

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We present a systematic benchmark study on different numerical models for analyzing hydrogen thermal desorption spectra, by focusing on the adoption of the local equilibrium hypothesis in these models. We find that the direct numerical method of the full set of the extended mass conservation equations is only able to predict the experimental behavior of thermal desorption spectra for pure iron in the thin specimen limit, while other models incorporating the local equilibrium hypothesis fail to predict this behavior.

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Section: Numerical Reproduction Of the Experimental Des-mentioning

confidence: 99%

A Numerical Study on the Validity of the Local Equilibrium Hypothesis in Modeling Hydrogen Thermal Desorption Spectra

Ebihara¹,

Kaburaki²,

Suzudo³

et al. 2009

ISIJ Int.

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“…The observed transient curves of hydrogen permeation were analyzed using the method described in the previous papers(5)(8) (9), which enabled us to obtain reliable values of the diffusion coefficient of hydrogen (DH).…”

Section: Determination Of Diffusion Coefficient Of Hydrogenmentioning

confidence: 99%

Effects of Interstitial Impurities on Dislocation Trapping of Hydrogen in Iron

Hagi

Hayashi

1987

Trans. JIM

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The diffusion coefficient of hydrogen in iron with various interstitial impurity (C, N) contents has been measured at 298 K by an electrochemical permeation method. The diffusivity of hydrogen is significantly reduced by cold-working. In commercially pure iron specimens (high C, N specimens), the diffusivity of hydrogen is slightly restored by aging at room temperature after cold-working. In decarburized-denitrided specimens (low C, N specimens), however, this change by aging is not observed. Annihilation of dislocations by heat treatments causes recovery of the diffusion coefficient. That is, dislocations serve as trapping sites for hydrogen, and the formation of atmosphere of interstitial impurities (C, N) around dislocations weakens the trapping effect of dislocations. The diffusion coefficient of hydrogen has been analyzed on the basis of the trapping theory, and the trap density (i.e., the ratio of the number of the trapping sites to that of total lattice sites) has been calculated. The trap density before the formation of the C, N atmosphere around dislocations is, within experimental error, proportional to the dislocation density.

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“…The electrode potential of the anodic surface of the membrane was maintained at 0 V against a Ag/AgCl reference electrode by a potentiostat. The potentiostatic current, which was proportional to the rate of hydrogen permeation, was recorded(10) (11).…”

Section: Measurement Of Permeation Curvesmentioning

confidence: 99%

Effect of Dislocation Trapping on Hydrogen and Deuterium Diffusion in Iron

Hagi

Hayashi

1987

Trans. JIM

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The diffusion coefficients of hydrogen and deuterium in commercially pure iron deformed and annealed under various conditions have been measured at temperatures between 283 and 318 K by an electrochemical permeation method. The temperature dependence of the diffusion coefficients of hydrogen (DH) and deuterium (DD) is discussed on the basis of the trapping theory by Oriani. Two trapping parameters, the binding energy of hydrogen or deuterium with trapping sites and the trap site density are determined by fitting the diffusion coefficient calculated from the trapping theory to the experimental results. The ratio of the diffusion coefficient of hydrogen to that of deuterium, DH/DD, has been found to be dependent on temperature, but not on the trap site density. This indicates that the trap site density and the binding energy are, within an experimental error, the same for hydrogen and deuterium, although the activation energy of diffusion in a normal lattice is found to be mass dependent. The binding energies with trapping sites (dislocations) for both hydrogen and deuterium are determined as about 27 kJ/mol, which shows a good agreement with those reported by Gibala, Oriani and others.

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Diffusion Coefficient of Hydrogen in Pure Iron between 230 and 300 K

Cited by 93 publications

References 17 publications

A Numerical Study on the Validity of the Local Equilibrium Hypothesis in Modeling Hydrogen Thermal Desorption Spectra

A Numerical Study on the Validity of the Local Equilibrium Hypothesis in Modeling Hydrogen Thermal Desorption Spectra

Effects of Interstitial Impurities on Dislocation Trapping of Hydrogen in Iron

Effect of Dislocation Trapping on Hydrogen and Deuterium Diffusion in Iron

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