C03 – Cathodic hydrogen uptake and permeation of passivated Ni-Nb Intermetallics

PI: Daniela Zander (RWTH Aachen University, KKS)

SFB researcher: Alexander Lutz (RWTH Aachen University, KKS)

Project C03 will focus on investigating the cathodic hydrogen uptake and permeation of passivated Ni-Nb intermetallics compared to Ni. Mechanisms determining the passivation, hydrogen evolution, adsorption and absorption at the passivated surface as well as transport properties of hydrogen through the passive layer and within the Ni-Nb intermetallics (e.g. Nb₇Ni₆) in comparison to Ni will be investigated. For this, growth, faceting and crystallinity of the oxide layer as key factors for the stability of passivity will be considered. This should enable to identify, the influence of the surface condition, e.g. of the passivated surfaces, on the cathodic hydrogen reactions and, the limiting factors for the permeation in simplified electrolytes. Moreover, the role of Nb on the ability to form surface defect phases, e.g. an oxidic passivation layer, will be investigated and related to the hydrogen evolution, adsorption and absorption.Furthermore, the kinetics of permeation will be studied, e.g. in correlation with the theoretically possible formation of hydrogen induced nanocrystalline phases.

Methods: Electrochemical methods for hydrogen charging and mechanism characterisation, ICP-MS, SVET/SIET, EC-STM, SEM/EDS/EBSD, TDS, XRD/XRR, TEM/STEM/EELS, (B01) XPS and APT (B03 and B08N). Further exchange with B02, B04 and C04 are foreseen in the working program.