Effect of corrosion inhibitors on hydrogen uptake by Al from NaOH solution

Corrosion rate, hydrogen permeation rate (hydrogen uptake) and stress corrosion cracking of Al were studied in NaOH solutions, pure and with the addition of H3BO3, EDTA, KMnO4 and As2O3. The presence of the studied species in electrolyte and the implantation of Al surface with B+ ions inhibited corrosion. Hydrogen uptake was found to be promoted or inhibited by means of studied species, depending on the method of their introduction into the base solution and on the applied polarization. The observed different influence of corrosion inhibitors on the hydrogen uptake was associated with the different chemical composition and structure (revealed by XPS analysis) of the surface films, formed on Al under the various conditions. Under similar polarization conditions, the presence of H3BO3 in the base solution similarly affected the hydrogen uptake by Al and the susceptibility to stress corrosion cracking of the metal.