High hydrogen retention in the sub-surfaces of tungsten plasma facing materials: A theoretical insight

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• 作者：Lu Sun^a ; ^b ; Shuo Jin^b ; ^{jinshuo@buaa.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Guang-Hong Lu^b ; Ligen Wang^a ; ^{lg_wang1@yahoo.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Surface vacancies ; Hydrogen ; Tungsten ; First-principles calculations
• 刊名：Scripta Materialia
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：122
• 期：Complete
• 页码：14-17
• 全文大小：483 K

文摘

A high hydrogen concentration at the sub-surface layers of tungsten plasma facing materials has been previously observed by experiments. We have performed the first-principles calculations to understand this experimental phenomenon. The layer-dependent hydrogen dissolution energies, vacancy formation energies and hydrogen trapping energies are calculated for the W(110) surface. Our results show that hydrogen dissolving into the vacancy-free sub-surfaces is energetically unfavorable. A surface tungsten vacancy is easier to form than in the bulk and has a large trapping effect on hydrogen dissolving. The present work demonstrates the important role of surface vacancies on the hydrogen retention in the tungsten sub-surfaces.