Bremen 2017 – scientific programme
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P: Fachverband Plasmaphysik
P 24: Plasma Wall Interaction
P 24.4: Talk
Thursday, March 16, 2017, 09:30–09:45, HS 1010
Oxidation resistance of plasma-facing tungsten alloys — •Felix Klein1, Andrey Litnovsky1, Tobias Wegener1, Marcin Rasinski1, Christian Linsmeier1, Jesus Gonzalez2, Martin Bram2, Uwe Breuer3, Hongchu Du4, and Joachim Mayer4 — 1Forschungszentrum Jülich, Institut für Energie- und Klimaforschung (IEK) - Plasmaphysik — 2Forschungszentrum Jülich, IEK - Werkstoffsynthese und Herstellungsverfahren — 3Forschungszentrum Jülich, Zentralinstitut für Engineering, Elektronik und Analytik, Analytik — 4Ernst Ruska-Centrum, 52425 Jülich
Tungsten (W) is the prime candidate as plasma-facing material for the first wall of future fusion power plants like DEMO. Advantages of W include the high melting temperature and the low sputtering rate. A problem is oxidation and sublimation of radioactive oxide in case of an accident featuring a loss of active cooling and air ingress. Therefore, new alloys are developed. On the one hand the alloys exhibit the advantages of W and on the other hand they passively develop corrosion resistance in case of an accident. Using W-Cr-Y thin films, prepared by magnetron sputtering, the suppression of tungsten oxide formation was shown for up to 9 h at 1273 K. Cr continuously formed a protective oxide layer. In contrast, the problem of WO3 formation/sublimation occurred during studies of first powder-metallurgically prepared bulk samples. A key difference was the distribution of Y: Homogeneous within the thin films versus nano-particles at the grain boundaries of the bulk samples. Microstructure and oxidation behaviour are analysed and approaches for further development are presented.