TY  - CONF
AU  - Unterberg, B.
AU  - Zlobinski, Miroslaw
AU  - De Temmerman, G.
AU  - Porosnicu, C.
AU  - Matveev, D.
AU  - Sergienko, G.
AU  - Brezinsek, S.
AU  - Nicolai, D.
AU  - Rasinski, M.
AU  - Spilker, B.
AU  - Freisinger, M.
AU  - Möller, S.
AU  - Linsmeier, Ch.
AU  - Lungu, C. P.
AU  - Dinca, P.
TI  - Stability of deuterated beryllium layers on tungsten substrates during transient heat loads by laser irradiation
M1  - FZJ-2021-01671
PY  - 2021
AB  - 24th Int. Conf. on Plasma Surface Interaction in Fusion Devices (PSI-24) in Jeju, Korea, May 31st to June 5th, 2020 Stability of deuterated beryllium layers on tungsten substrates during transient heat loads by laser irradiationB. Unterberga, M. Zlobinskia,*, G. De Temmermanb, C. Porosnicuc, D. Matveeva, G. Sergienkoa, S. Brezinseka, D. Nicolaia,  M. Rasinskia, B. Spilkera, M. Freisingera, S. Möllera, Ch. Linsmeiera, C. P. Lunguc,   P. Dincac aInstitute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich GmbH (FZJ), Partner in the Trilateral Euregio Cluster, D-52425 Jülich, GermanybITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex, FrancecNational Institute for Laser, Plasma and Radiation Physics (INFLPR), Atomistilor 409, Magurele, Jud Ilfov, 077125, Bucharest, Romaniab.unterberg@fz-juelich.deA major contribution to long-term hydrogen retention in ITER is expected in Be layers on W divertor components [1]. Therefore, for ITER an in-situ and spatially resolved diagnostic of in-vessel retention has been qualified based on laser induced desorption (LID) of tritium out of Be co-deposits [2]. In this context, the stability of such layers is important in view of possible dust production and flaking.Homogeneous   Be   layers   with   different   deuterium   content   (0.01-0.3   D/Be)   and   layer   thicknesses  (1-20  μm)  were  deposited  on  W  substrates  by  HiPIMS  (High  Power  Impulse  Magnetron Sputtering) [3]. The laser irradiation parameters have been varied between 0.5 and 5.0 MJ/m2 (diameter of the laser beam at the sample of 3 mm) with pulse lengths between 1 and 20 ms. Such loading parameters also cover the power load densities during ELMs in ITER. The surface temperature was monitored by a pyrometer and ranged between 900 and 2300 K.Overall, the stability of the Be layer is mostly governed by the operational conditions during the  coating  process  within  the  magnetron.  Best  adhesion  has  been  obtained  for  a  surface  roughness of 150 nm of the substrate, chemical surface cleaning and in-situ cleaning via GDC, and layer deposition at a rate of 0.2 nm/s. These layers withstand the strongest laser pulses even above melting onset without significant detachment of layer fragments. Crack networks can be observed below  melting  which  are  connected  to  tension  during  the  cool-down  phase  of  the  layer.  When  the  deposition  was  performed  on  less  rough  substrates  (10-15  nm)  with  DC  deposition either the layer is fragmented in microscopic parts,   which are delaminated to a large extent, or even complete macroscopic lamination is observed with a clear separation into mm-sized delaminated areas with no remaining layer fragments and remaining layer. SEM pictures show hill-like structures on the μm scale with local delamination surrounded by cracks. The different damage categories can also be distinguished via the temperature increase during the  laser  pulse:  for macroscopic  delamination  the  pyrometer  shows  a steep temperature increase until delamination, for microscopic delamination the temperature still increases fasterthan on the best, most adhesive layer, governed by the heat contact between layer and substrateas described for plasma deposited carbon layers in [4]. [1] S. Brezinsek, et al., Nucl. Fusion 55, 063021 (2015)[2] M. Zlobinski et al., Nuclear Materials and Energy, Volume 19, May 2019, Pages 503-509[3] P. Dinca, et al., Surface & Coatings Tech. 321 (2017) 397-402[4] A. Herrmann, Phys. Scr. T128 (2007) 234–238
T2  - 24th International Conference on Plasma Surface Interactions in Controlled Fusion Devices (PSI 2020)
CY  - 25 Jan 2021 - 29 Jan 2021, virtuell (virtuell)
Y2  - 25 Jan 2021 - 29 Jan 2021
M2  - virtuell, virtuell
LB  - PUB:(DE-HGF)1
UR  - https://juser.fz-juelich.de/record/891688
ER  -