Deuterium permeation behaviors in tungsten implanted with nitrogen

Liang, Chang-Min; Wang, Dongping; Jin, Wei; Lou, Yuanfu; Wang, Wei; Ye, Xiaoqiu; Chen, Changan; Liu, Kezhao; Xu, Huaping; Wang, Xiaoying; Kleyn, Aart W.

doi:10.1016/j.jnucmat.2018.04.021

Cited by 4 publications

(3 citation statements)

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“…The direct observation of hydrogen transport through the permeation experiments shown in this paper strongly supports our suggestion. The recent permeation results obtained by Zhao et al [47] (green line in Figure 5) on microstructured tungsten samples with elongated grains perpendicular to the surface also support our Zakharov, respectively for samples with grain sizes of several hundreds of nanometres, even few micrometres [48][49][50],…”

Section: Permeation Measurementssupporting

confidence: 81%

“…These calculations have been performed following a standard DFT methodology, thus all processes take place at 0 K. Reaching this huge H occupation at the GB is not expected at higher temperatures, as the binding energy of H decreases when the amount of H atoms that access to Fig. 5 Permeability of H in tungsten obtained by means of the experiments reported in this paper and compared to experiments by Frauenfelder [44], Zakharov [45], Esteban et al [46], Zhao et al [47], Liang et al [48], and Liu et al [49,50]. The continuous lines are fits to the experimental data obtained from samples with different microstructure.…”

Section: Dft Simulationsmentioning

confidence: 73%

“…For comparison purposes, along with our results, Figure 5 contains permeability results obtained by Frauenfelder [44,45], Zakharov [45], Esteban et al [46], Zhao et al [47], Liang et al [48], and Liu et al [49,50]. The results shown in the figure were obtained for samples with different microstructure and defect level; thus, the values shown in the The goodness of the fits, R 2 , is >0.999 in all cases figure are effective permeabilities affected by the details of the samples under study, their microstructure and their defect level.…”

Section: Permeation Measurementsmentioning

confidence: 93%

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Direct observation of hydrogen permeation through grain boundaries in tungsten

et al. 2022

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In this paper, we report on an enhanced hydrogen permeation effect along grain boundaries in tungsten. Sputtered nanocolumnar tungsten layers (column lateral dimensions 100–150 nm and layer thickness 2 μm) were analysed by hydrogen permeation measurements in the temperature range 520–705 K. The experiments constitute a direct observation of this effect, previously postulated by means of a combination of indirect experiments and simulations and considered controversial due to the lack of direct measurements. DFT results support this observation since (i) the hydrogen binding energy to the grain boundary is 1.05 eV and (ii) the migration energies along the grain boundary and along the bulk are 0.12 eV and 0.20 eV, respectively. OKMC simulations, parametrized by DFT data, were used as a supporting tool to attain a better understanding of the involved phenomena. The OKMC results are also compatible with the observations. Indeed, they show that the fraction of hydrogen flux along grain boundaries in the steady-state permeation regime increases when decreasing the ratio of lateral dimensions to length of the nanocolumns, rapidly approaching unity when this ratio is < 2. Therefore, grain boundaries act as preferential migration pathways for H atoms at the studied temperature range in the studied samples. This behaviour has interesting implications to reduce the retention of hydrogen in several applications, in particular, fusion materials exposed to plasma discharges.

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Section: Permeation Measurementssupporting

confidence: 81%