The effect of hydrogen permeation on the corrosion performance of Alloy 22 was investigated.
50µm thick Alloy 22 membranes were permeated with Hydrogen under a cathodic charging
current density of 1mA/cm2 in a Devanathan-Stachurski cell at 60ºC in pH 12.5, 0.1M NaOH
solution. Anodic polarization scans of permeated and unpermeated samples were performed,
under conditions with and without the addition of 0.1M sodium chloride in order to investigate
the effect of a detrimental synergistic effect of hydrogen and chloride on the critical pitting
potential (CPP) as reported in type 304 and 310 stainless steels. The thickness of the passive
film before during and after hydrogen permeation was estimated using a parallel plate
capacitor method. The diffusivity of hydrogen in Alloy 22 was estimated in the method outlined
by ASTM standard G148-97.