Adsorption and penetration of hydrogen in W: A first principles study

In BCC crystals, such as Tungsten (W), slippage has been observed on the (1 1 0) and (1 1 2) planes. In this work, hydrogen diffusion paths from three different W surfaces ((1 0 0), (1 1 0) and (1 1 2)) have been calculated using first principles density functional theory. Equilibrium sites for H at the surfaces are identified. The energetics for H penetration from the surfaces to the solute site in the bulk is calculated. It is found that for our low surface coverage of H (3.4 × 1014 H/cm2), approximately 2 eV is required for an H atom to penetrate any of the W surfaces considered in this study.

► W as plasma-facing component for next generation fusion reactor. ► Slippage occurs in BCC W on (1 1 0) and (1 1 2) planes. ► H adsorption and penetration energy for these surfaces. ► Around 800 K or higher temperatures H can penetrate W surfaces. ► Reversible migration energy is very small.