Bremen 2017 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

P: Fachverband Plasmaphysik

P 6: Helmholtz Graduate School I

P 6.4: Poster

Montag, 13. März 2017, 16:30–18:30, HS Foyer

Dependence of Oxidation on the Grain Orientation of Tungsten — •Karsten Schlüter and Martin Balden — Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching, Germany

Tungsten (W) is planned to be a plasma facing material of future fusion reactors. It can be oxidized in case of a loss of coolant with simultaneous air ingress. In such an incident, activated tungsten oxide could sublimate leading to a potential safety issue if the tungsten oxide is released into atmosphere. Oxidation processes are complex and for a deeper understanding, this study focuses on oxidation in relation to the grain orientations.

The grain orientations on a W sample were analyzed using electron backscatter diffraction. Subsequently, the sample was oxidized in a thermobalance, measuring the time dependent weight increase. The grain dependent oxidation rates were determined by measuring the thickness of the oxide layer of single grains by scanning electron microscope and confocal laser scanning microscope. W grains with {100} orientation have the highest and a two times higher oxidation rate in a range of 720 K to 870 K than to the lowest oxidation rates, e.g. like the oxidation rate of the {111} orientation. The derived oxidation rates are consistent with gravimetric measurements.