Hydrogen Diffusivity and Permeability In Pd50-xTi50(Cr, Fe)x Alloys

Osamu Yoshinari; Daisuke Itoh

doi:10.4028/www.scientific.net/MSF.561-565.2353

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HomeMaterials Science ForumMaterials Science Forum Vols. 561-565Hydrogen Diffusivity and Permeability In...

Hydrogen Diffusivity and Permeability In Pd_50-xTi₅₀(Cr, Fe)_x Alloys

Abstract:

Hydrogen diffusivity (D) and permeability (q) in Pd50-xTi50(Cr, Fe)x alloys were measured at temperature range between 570 and 770 K. During a heating measurement of Pd47Ti50Cr3 alloy, both D and q abruptly increased by factors of 5 and 2, respectively, at 712 K, with a phase transformation from B19 to B2 structures. However, q was far smaller than those in pure bcc metals (eg. V, Nb and Ta), where the hydrogen atoms occupy the tetrahedral interstitial sites. A first-principles calculation revealed that hydrogen atoms occupy the octahedral interstitial sites in Pd50Ti50 with B2 structure. It is concluded that the small hydrogen diffusivity in B2 Pd50-xTi50(Cr, Fe)x alloys is due to the long distance hydrogen jump and the resultant high activation energy for the diffusion.

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Materials Science Forum (Volumes 561-565)

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2353-2356

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https://doi.org/10.4028/www.scientific.net/MSF.561-565.2353

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October 2007

Authors:

Osamu Yoshinari, Daisuke Itoh

Keywords:

Diffusion, First-Principle Calculations, Hydrogen Permeability, Martensitic Transformation (MT), Solubility

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References

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DOI: 10.4028/www.scientific.net/ddf.407.31

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[1] 0.

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