The application of electrochemical methods to the study of the electroless nickel deposition from hypophosphite solutions
Résumé
The rotating disk electrode has been used for the study of the electroless nickel plating from an acid bath strongly buffered by acetate. The variations of the mixed potential with the temperature have been investigated, and explained by means of polarization curves. These latter present an anodic peak which is typical of the electroless nickel deposition. The polarization resistance measurements allow a direct determination of the plating rate. All these experiments, related to mechanical measurements of plating rate, show the important inhibitor effect of the dissolved oxygen on the deposition reaction. The preliminary study of the faradaic impedance of the metal-electrolyte interface shows that the deposit occurs with not less than two heterogeneous steps, involving an adsorbed intermediate species, which could be NiOHads.