Equilibrium concentration of hydrogen at tungsten surface

XS Zhang and K Xu and Y Zhang and YH Li and S Jin and GH Lu, JOURNAL OF NUCLEAR MATERIALS, 541, 152377 (2020).

DOI: 10.1016/j.jnucmat.2020.152377

In this work, numerical calculations have been employed to investigate the adsorption equilibrium state of hydrogen (H) atoms on tungsten (W) surface. The surface energy and relevant surface atomic density of different W surfaces are obtained through the empirical-potential model. The calculations show that the higher surface atomic densities correspond to the more stable surfaces, of which the most stable surface is the W (110) surface. The H adsorption energies are systematically analyzed by density functional theory. The equilibrium concentration dependence for adsorption upon H coverage, a temperature range from 300 K to 1100 K, and a pressure range from 10(-6) Pa to 10(6) Pa is examined by employing a Monte Carlo model. Our results suggest that most of H atoms desorb from 700 K to 1100 K when the pressure region varies from 10(-6) Pa to 10(2) Pa. The monolayer-adsorbed H density is estimated from similar to 1.39 x 10(18) m(-2) to similar to 1.40 x 10(19) m(-2) at the equilibrium state. (C) 2020 Elsevier B.V. All rights reserved.

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