München 2019 – scientific programme
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P: Fachverband Plasmaphysik
P 12: Plasma Surface Interaction II - Helmholtz Graduate School IV
P 12.3: Talk
Tuesday, March 19, 2019, 17:15–17:30, HS 20
Impact of fusion-relevant plasmas on WCrY Smart Alloys — •Janina Schmitz1,2, Andrey Litnovsky1, Felix Klein1, Karen De Lannoye1, and Christian Linsmeier1 — 1Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich, Germany — 2Department of Applied Physics, Ghent University, 9000 Ghent, Belgium
Only few materials are suitable to withstand the high heat and particle loads of the first wall of future fusion devices such as DEMO. While advantageous properties like, among others, low tritium retention and low sputter yields make tungsten (W) a suitable plasma-facing material, its disadvantageous property of fast oxidation in oxygen-containing environment may disqualify it. For this reason self-passivating chromium(Cr)-containg smart alloys (WCrY) are developed aiming at suppressing W oxidation in case of accidental scenarios in DEMO. Exposure to steady-state deuterium (D) plasma at low ion energies of around 120 eV up to a fluence of 1*1026 ions/m2 has proven W-like erosion yields for the smart alloys [1]. In order to estimate the lifetime of plasma-facing materials like WCrY in more fusion-relevant conditions plasma exposure to different gas mixtures and moreover higher fluences is necessary. Results of a recent D exposure with increased fluence are presented in this contribution. Further, the results of oxidation in dry atmosphere at 1000 ∘C of plasma-exposed WCrY samples is discussed.
[1] J. Schmitz et al., Nuclear Materials and Energy 15 (2018) 220-225