The high-flux effect on deuterium retention in TiC and TaC doped tungsten at high temperatures

Abstract

Samples made of tungsten (W) doped either with titanium carbide (W-1.1TiC) or tantalum carbide (W-3.3TaC) were exposed to a low-energy (40 eV/D), high-flux (1.8-5×10 23 D/m 2 s) deuterium (D) plasma at temperatures of about 800 K, 1050 K, and 1250 K to a fluence of about 1×10 27 D/m 2. The deuterium (D) inventory in the samples was examined by nuclear reaction analysis and thermal desorption spectroscopy. At 800 K the D bulk concentrations and total D inventories in W-1.1TiC and W-3.3TaC were more than one order of magnitude higher compared to that in pure polycrystalline W. At 1050 K and 1250 K the D concentrations in all types of samples were very low (≤10 5 at. fr.); however the D inventories in W-1.1TiC were significantly higher compared to those in W-3.3TaC and pure W. It is suggested that D trapping inside the carbide precipitates and at their boundaries is essential at high temperatures and high incident fluxes, especially in W-1.1TiC.

Influence of surface melting on the deuterium retention in pure and lanthanum oxide doped tungsten

“…However, the oxide and carbide dopants (e.g. La 2 O 3 , Y 2 O 3 and TiC) have been widely reported to significantly increase the D retention in advanced tungsten-based materials [23,29,[33][34][35]. Moreover, similar with La, metal elements Y and Ti also have the ability to form high temperature hydrides [25].…”

Surface blistering and deuterium retention behaviors in pure and ZrC-doped tungsten exposed to deuterium plasma

“…It is reported that the carbide precipitates in W can be served as the trapping sites of D, and the implanted D can be captured not only in the interior of the carbide precipitates (e.g. vacant sites in the carbon sublattice) but also at the boundary of the carbide precipitates [52,53]. The vacant sites in the carbide are considered to be the high-energy trapping sites of D. Density function theory calculations indicate that the binding energy of H with carbon vacancies in TiC is 2.12 eV, which is higher than that of experimentally determined D with vacancies and vacancy clusters in W [54][55][56].…”

“…The reason should be that the exposure temperature used in this study is too low to allow the implanted D atoms to be trapped in the carbides. Compared with the vacant site in the carbide, the implanted D is easier to capture by the carbide boundary at moderate temperatures [52]. It is necessary to point out that the content of ZrC used in this work is very low, and thus the effect of their boundaries on the D retention can be ignored.…”

Hydrogen Retention in Doped Tungsten Materials Developed for Fusion

“…Интегральный захват также растёт. Однако при высокодозном облучении дейтерием энергией 40 эВ/D до более высокой дозы 110 27 D/м 2 при температуре 800 K оказалось, что и W-TiC, и W-TaC захватывают на порядок большее количество дейтерия, чем чистый вольфрам [56].…”