Characterization of Hydrogen Permeation Through Zinc‐Nickel Alloys under Corroding Conditions: Mathematical Model and Experimental Study

A mathematical model was developed for the characterization of hydrogen permeation into metals and alloys under corroding conditions. The model requires a knowledge of the corrosion rate of the given metal or alloy in solutions of various H + concentrations. It provides quantitative values of rate constants of the hydrogen discharge, recombination, and adsorption reactions. This model can serve as a diagnostic criterion for determining the effectiveness of various metals and alloys as hydrogen permeation inhibitors and can be used for evaluation of hydrogen entry inhibition efficiency. Experiments were carried out to study the effectiveness of thin layers of electrodeposited Zn-Ni alloys to inhibit hydrogen permeation into iron. The experimental permeation data obtained for Zn-Ni-coated iron were analyzed using the model and the results were compared with the hydrogen permeation characteristics of bare iron.