Göttingen 2025 – scientific programme

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P: Fachverband Plasmaphysik

P 17: Poster Session II

P 17.20: Poster

Wednesday, April 2, 2025, 16:15–18:15, ZHG Foyer 1. OG

Temperature-dependent grain boundary permeation in tungsten investigated by hydrogenography — •Fahrudin Delic, Armin Manhard, and Udo von Toussaint — Max Planck Insti tute for Plasma Physics, 85748 Garching, Germany

The temperature-dependent permeation of deuterium through grain boundaries in tungsten has been studied using a newly developed hydrogenography technique, which employs patterned films to laterally resolve hydrogen fluence density on the back side of the permeation samples. Primarily, a tungsten oxide layer was developed as a hydrogen indicator that could withstand greater temperatures than previously used yttrium, and a method for reliably quantifying the results was established. Ion-driven permeation with constant deuterium fluence was conducted using 50 µm thick recrystallized tungsten samples at various exposure temperatures. The temperature-dependent permeation indicated that the permeation fluence density of hydrogen isotopes in grain boundaries is dominant up to 660 K, with an increasing number of grain boundaries favorable for hydrogen transport as the temperature rises. At 660 K, a halo of hydrogen fluence density forms around several permeating grain boundaries, suggesting a desorption of hydrogen isotopes from grain boundaries and the initial signs of the transition towards predominant bulk permeation

Keywords: Grain boundary; Deuterium; Tungsten; Permeation; Hydrogenography