Mainz 2022 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 14: Plasma Wall Interaction II / HEPP III
P 14.1: Vortrag
Mittwoch, 30. März 2022, 16:00–16:15, P-H12
Surface Segregation of Cr in the WCrY SMART Alloy — •Pawel Bittner1, Hans Rudolf Koslowski1, Andrey Litnovsky1,2, and Christian Linsmeier1 — 1Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich, Germany — 2Institute of Laser and Plasma Technologies, National Research Nuclear University MEPhI, 115409 Moscow, Russia
Self-passivating Metal Alloys with Reduced Thermo-oxidation (SMART) are promising candidates for the first wall of the DEMOnstration power plant (DEMO). These materials aim at having an increased oxidation resistance during accidental conditions and acceptable plasma performance during regular operation of the power plant. In this work, the effects of surface segregation, diffusion and sputter erosion on the Cr concentration of a tungsten-chromium-yttrium SMART alloy (WCrY) with a composition of 68 at% of W, 31 at% of Cr and 1 at% of Y are studied with low energy ion scattering (LEIS) measurements and numerical calculations.
A three-parameter phenomenological model to describe the time and temperature dependent surface concentration of Cr is proposed. Further, temporally resolved ion scattering measurements during thermal annealing between 800 K and 1100 K were conducted. The parameters of the model were changed in consecutive numerical calculations to fit these measurements best. The calibrated model is applied to conditions in which the samples were sputtered during annealing and the similarities and differences between theoretical prediction and experimental results are discussed.