Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7721351 | International Journal of Hydrogen Energy | 2013 | 9 Pages |
Abstract
Hydrogen absorption in thin metal films clamped to rigid substrates results in mechanical stress that changes the hydrogen's chemical potential by ÎμH(Ï) = â1.124Ï kJ/molH for Ï measured in [GPa]. In this paper we show that local stress relaxation by the detachment of niobium hydrogen thin films from the substrate affects the chemical potential on the local scale: using coincident proton-proton scattering at a proton microprobe, the hydrogen concentration is determined with μm resolution, revealing that hydrogen is not homogenously distributed in the film. The local hydrogen solubility of the film changes with its local stress state, mapping the buckled film fraction. In niobium hydrogen thin films loaded up to nominal concentrations in the two-phase coexistence region, the clamped film fraction remains in the solid solution phase, while the buckles represent the hydride phase. These results are compared to a simple model taking the stress impact on the chemical potential into account.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Stefan Wagner, Marcus Moser, Christoph Greubel, Katrin Peeper, Patrick Reichart, Astrid Pundt, Günther Dollinger,