Hydrogen exchange with voids in tungsten observed with TDS and PA

• Published in: Journal of nuclear materials 1988-07, Vol.155-157, p.1113-1117
• Main Authors: Van Veen, A., Filius, H.A., De Vries, J., Bijkerk, K.R., Rozing, G.J., Segers, D.
• Format: Article
• Language: English
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(88)90478-3

Hydrogen trapping and dissociation phenomena in single crystalline tungsten with voids have been studied by thermal desorption spectrometry (TDS) and positron annihilation lifetime measurements (PA). The voids were created by MeV electron or proton irradiation and hydrogen decoration of the voids was performed by 2 keV hydrogen ion bombardment. A reduction of the positron lifetime in voids from 500 to 350 ps was observed during the hydrogen bombardment, indicating that hydrogen is transported to voids situated at depths > 10 μm. This implies the saturable character of the voids for hydrogen. The reduction of the positron lifetime and the activation energies derived for the release of hydrogen from voids (1.0–1.4 eV) are explained by the presence of highly pressurised molecular hydrogen inside the saturated voids. The results for tungsten are compared with results obtained by PA for molybdenum.