Berlin 2018 – wissenschaftliches Programm

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

MM: Fachverband Metall- und Materialphysik

MM 16: Topical session (Symposium MM): Hydrogen in Materials

MM 16.3: Vortrag

Montag, 12. März 2018, 18:15–18:30, H 0107

Grain Boundary Diffusion in the Magnesium-Hydrogen system - Harrison regimes C in action — •Magnus Hamm and Astrid Pundt — Institute for Material Physics, Georg-August University, Göttingen, Germany

Magnesium acts as storage material for hydrogen in a future hydrogen energy based economy because of its high reversible hydrogen capacity of up to 7,6 wt% [1]. However the slow kinetics its high desorption temperature provide a significant barrier to it's commercial use [2]. This kinetic limitation may be improved by the presence of grain boundaries. Grain boundary (GB) diffusion differs from bulk diffusion in crystals. For interstitial diffusion it can be either slower or faster, depending on the solvent concentration [4][5]. Magnesium seems to offers an ideal model system to study the dominant influence of the GBs in diffusion measurements as discussed in a recent publication [6]. The knowledge gained from finite-element-(FEM) simulations [6] will be used to evaluate diffusion coefficients of hydrogen in magnesium. The diffusion coefficients were measured by gasvolumetry and resistivity measurements. Combining experimental with FEM and analytical models results allows to show how grain boundaries can influence the kinetics in the Mg-H system.

Financial support provided via the projects PU131/10-1 and PU131/10-2 is gratefully acknowledged.

[1] Dornheim, R. et al., Scr. Mat. 56 (2007) [2] Bogdanović, B. et al., J. Alloys Compd. 282 (1999) [3] [4] T. Muetschele and R. Kirchheim, Scr. Metall. 21, (1987) [5] M. Hamm and A. Pundt, IJHE 42(2017)