Superabundant vacancy formation in Ni–H alloys

Fukai, Yuh; Shizuku, Y.; Kurokawa, Y.

doi:10.1016/s0925-8388(01)01603-6

Cited by 88 publications

(48 citation statements)

References 16 publications

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“…However, in Pt the complex formation energy mainly comes from distortion energy. 10 Ni, 58 Nb 59 and Cr 51 experimentally. Combined with the slopes of Vac-H n complex and the energy of vacancy reduced by trapping H atoms, we conclude that the SAV is most favorable to form in V, while most unfavorable to form in Ag.…”

Section: Formation Of Sav In Fcc Metalsmentioning

confidence: 93%

Dissolving, trapping and detrapping mechanisms of hydrogen in bcc and fcc transition metals

You¹,

Kong²,

Wu³

et al. 2013

AIP Advances

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First-principles calculations are performed to investigate the dissolving, trapping and detrapping of H in six bcc (V, Nb, Ta, Cr, Mo, W) and six fcc (Ni, Pd, Pt, Cu, Ag, Au) metals. We find that the zero-point vibrations do not change the site-preference order of H at interstitial sites in these metals except Pt. One vacancy could trap a maximum of 4 H atoms in Au and Pt, 6 H atoms in V, Nb, Ta, Cr, Ni, Pd, Cu and Ag, and 12 H atoms in Mo and W. The zero-point vibrations never change the maximum number of H atoms trapped in a single vacancy in these metals. By calculating the formation energy of vacancy-H (Vac-Hn) complex, the superabundant vacancy in V, Nb, Ta, Pd and Ni is demonstrated to be much more easily formed than in the other metals, which has been found in many metals including Pd, Ni and Nb experimentally. Besides, we find that it is most energetically favorable to form Vac-H1 complex in Pt, Cu, Ag and Au, Vac-H4 in Cr, Mo and W, and Vac-H6 in V, Nb, Ta, Pd and Ni. At last, we examine the detrapping behaviors of H atoms in a single vacancy and find that with the heating rate of 10 K/min a vacancy could accommodate 4, 5 and 6 H atoms in Cr, Mo and W at room temperature, respectively. The detrapping temperatures of all H atoms in a single vacancy in V, Nb, Ta, Ni, Pd, Cu and Ag are below room temperature

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Section: Formation Of Sav In Fcc Metalsmentioning

confidence: 93%

Dissolving, trapping and detrapping mechanisms of hydrogen in bcc and fcc transition metals

You¹,

Kong²,

Wu³

et al. 2013

AIP Advances

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“…In contrast, lattice expansion normally occurs in other facecentered-cubic ͑fcc͒ metals. [11][12][13] Thus it will be interesting to investigate defect properties in aluminum exposed to H under weak to aggressive hydrogen charging conditions. In the low-concentration limit, H exists as an impurity defect in Al and interacts with native Al vacancy defects.…”

Section: Introductionmentioning

confidence: 99%

Statistical model of defects in Al-H system

Wang

et al. 2010

Phys. Rev. B

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“…1) A systematic investigation of the phase diagram of transition metalhydrogen (M-H) alloys under extended pressure-temperature conditions (p(H 2 ) 6 GPa, T 400 C) was performed by a Russian group, by combination of in situ resistometry and Xray diffraction (XRD) of recovered specimens, and the results were described in their review papers. 2,3) We have succeeded in taking a step forward by developing techniques of in situ XRD under more extended p(H 2 )-T conditions, and reported the phase diagrams for Cr-H, 4) Mn-H, 5) Fe-H 6) and Ni-H 7) systems. For the Mo-H system at high hydrogen pressures, the Russian group showed that an hcp hydride of a nearly stoichiometric composition [H]/[Mo] % 1 was formed, 8,9) and the bcc ()-hcp (") boundary was located at 250 C, 2 GPa increasing to 450 C, 5 GPa.…”

Section: Introductionmentioning

confidence: 99%

The Phase Diagram of Mo-H Alloys under High Hydrogen Pressures

Fukai

Mizutani

2003

Mater. Trans.

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The phase diagram of the Mo-H system was determined by in situ X-ray diffraction using synchrotron radiation up to 1200 C and the hydrogen pressure to p(H 2 ) = 5.3 GPa. Three phases were found to exist; a bcc phase () of low hydrogen concentrations at low hydrogen pressures, and two high-pressure phases, an hcp (") phase at lower temperatures and an fcc () phase at higher temperatures, both having a nearly stoichiometeric composition of x = [H]/[Mo] $ 1. A gradual lattice contraction observed in the fcc phase indicates the formation of superabundant Mo-atom vacancies (vacancy-hydrogen clusters).

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Superabundant vacancy formation in Ni–H alloys

Cited by 88 publications

References 16 publications

Dissolving, trapping and detrapping mechanisms of hydrogen in bcc and fcc transition metals

Dissolving, trapping and detrapping mechanisms of hydrogen in bcc and fcc transition metals

Statistical model of defects in Al-H system

The Phase Diagram of Mo-H Alloys under High Hydrogen Pressures

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