Stress in Aluminum Induced by Hydrogen Absorption during Cathodic Polarization

Published

September 16, 2015

Author(s)

Gery R. Stafford, Jae W. Shin, Kurt Hebert

Abstract

The hydrogen concentration in metals during aqueous corrosion is influenced by the kinetics of hydrogen absorption. Measurements of absorption kinetics are challenged by competing gas evolution and corrosion processes. However, in situ measurements of hydrogen- induced stress in metal films can be used to determine absorption rates during electrochemical experiments. An exploratory study of stress generation in aluminum thin films in sulfuric acid is reported, during cathodic polarization in the potential region of vigorous hydrogen evolution. Absorption-induced compressive stress increased at more negative potentials. The potential dependence of stress was similar, but shifted cathodically by about 0.2 V, to that expected from literature hydrogen solubility data. This discrepancy could be reconciled through consideration of the cathodic reaction overpotential. The stress measured during cathodic potential scans did not depend on scan rate, indicating rapid diffusion of H atoms within the thin film. The close approach to equilibrium of the hydrogen concentration is explained by slow kinetics of recombination cathodically formed hydrogen to H2 gas, on the oxide-covered aluminum surface.

Citation

Corrosion Science

Pub Type

Journals

Citation

Stafford, G. , Shin, J. and Hebert, K. (2015), Stress in Aluminum Induced by Hydrogen Absorption during Cathodic Polarization, Corrosion Science (Accessed April 25, 2024)