%0 Journal Article
%A Wegener, Tobias
%A Klein, Felix
%A Litnovsky, Andrey
%A Rasinski, Marcin
%A Brinkmann, Jens
%A Koch, Freimut
%A Linsmeier, Christian
%T Development and analyses of self-passivating tungsten alloys for DEMO accidental conditions
%J Fusion engineering and design
%V 124
%@ 0920-3796
%C New York, NY [u.a.]
%I Elsevier
%M FZJ-2017-05136
%P 183-186
%D 2017
%X Tungsten is considered the main candidate material for the first-wall in DEMO due to its high melting point, low erosion yield and low tritium retention. Nevertheless, it can cause a substantial safety issue in a loss-of-coolant accident (LOCA) in combination with air ingress into the plasma vessel, due to the formation and sublimation of volatile neutron activated tungsten oxide. Self-passivating tungsten alloys introduce a passive safety mechanism by forming a stable chromic oxide scale on the surface acting as a diffusion barrier for oxygen and preventing the formation of tungsten oxide. Self-passivating tungsten alloys optimized for oxidation resistance containing ∼12 wt.% Cr and ∼0.6 wt.% Y are investigated under conditions of argon–oxygen, humid argon and humid air atmospheres at different partial pressures and temperatures ranging from 1073 to 1273 K. Thin films with ∼3.5 μm thickness produced by magnetron sputter deposition are used as a model system. The oxidation resistance of these films in an argon–20 vol.% oxygen atmosphere is sufficient to prevent formation and release of tungsten oxide at temperatures of from 1073 to 1273 K. The sublimation of Cr in nitrogen–oxygen–water atmosphere at T ≥ 1273 K is discussed. A deeper understanding of the governing processes for oxygen/Cr diffusion under different atmospheres is gained, supported by SEM/EDX in combination with FIB cross-section and TGA measurements.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000419411900039
%R 10.1016/j.fusengdes.2017.03.072
%U https://juser.fz-juelich.de/record/836011