Deuterium retention in W, W1%La, C-coated W and W2C

This paper reports the results of a systematic investigation into retention of deuterium implanted into various forms of W including: reduction-rolled, powder-metallurgy foil; discs of W1%La alloy; W and W2C prepared by chemical vapor deposition (CVD) and annealed C-coated W discs. Deuterium was implanted at energies of 0.5 keV/D with fluxes of ∼3×1019 D/m2 s and fluences of 3×1023 D/m2, for samples at temperatures from 23°C to 400°C. Retained deuterium quantities were measured using thermal desorption spectroscopy (TDS). Retention in annealed CVD-W and W1%La, for implantation temperatures less than 200°C, is below that in annealed W foil, indicating that trapping may be affected by the different material defect structures. For implantation temperatures less than 300°C, retention in CVD-W2C is somewhat higher than that in CVD-W, indicating trapping could be enhanced by trace carbon impurities, differences in W2C material structure and recoil carbon-induced material damage. Implantation into C-coated W resulted in orders of magnitude more retention than in uncoated material, because of trapping in the carbon coating.