Characterization of hydrogen permeation through a corrosion-resistant zinc-nickel-phosphorus alloy

Hydrogen permeation characteristics of a new Zn-Ni-P alloy were studied and compared with that of a Zn-Ni alloy. The Zn-Ni-P alloy was deposited from an acid sulfate bath containing 0.5 M nickel sulfate (NiSO4), 0.2 M zinc sulfate (ZnSO4), 0.5 M sodium sulfate (Na2SO4), and 100 g/L sodium hypophosphite (NaH2PO2) at pH 3. The permeation characteristics of the alloy were studied and compared qualitatively with that of Zn-Ni alloy under cathodically polarized and corroding conditions. The Zn-Ni-P alloy had better permeation inhibition characteristics in terms of permeation efficiency through the alloy. The lyer-Pickering-Zamanzadeh (IPZ) model was used to quantitatively estimate the various kinetic parameters associated with hydrogen permeation for Zn-Ni-P alloy under polarized conditions. The Zn-Ni-P alloy had superior permeation inhibition properties compared to the Zn-Ni alloy. © 2000, NACE International.