TY  - JOUR
AU  - Wegener, Tobias
AU  - Klein, Felix
AU  - Litnovsky, Andrey
AU  - Rasinski, Marcin
AU  - Brinkmann, Jens
AU  - Koch, Freimut
AU  - Linsmeier, Christian
TI  - Development and analyses of self-passivating tungsten alloys for DEMO accidental conditions
JO  - Fusion engineering and design
VL  - 124
SN  - 0920-3796
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2017-05136
SP  - 183-186
PY  - 2017
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000419411900039
DO  - DOI:10.1016/j.fusengdes.2017.03.072
UR  - https://juser.fz-juelich.de/record/836011
ER  -