Hydrogen detection in high strength dual phase steel using scanning Kelvin probe technique and XPS analyses

Hydrogen permeation through high strength DP1180 steel was studied by Scanning Kelvin Probe (SKP) and X-ray photoelectron spectroscopy (XPS). The XPS analyses showed that hydrogen desorption from the steel increased the ratio Fe(II)/Fe(III) related to oxide film reduction. In parallel, a drop of the electrochemical potential in the oxide film was measured by SKP. Analyses of the composition and potential of the surface were correlated based on Nernst red-ox thermodynamic equilibrium. From this approach, it was shown that the SKP potential can be a measure of hydrogen affecting the surface oxide, but additional contributions should be considered.