Influence of pH Galvanic Baths on the Nickel Deposits

Résumé

The influence of pH on cathodic and anodic current efficiency, surface quality and morphology of nickel deposit in the electrolyte solutions of the Watts bath type was investigated. Cathodic current efficiency of nickel deposit is maximum for electrolytic bath whose pH value is about 4 and decreases for an electrolytic bath with a higher pH. The deposited thickness is a significant parameter because the thickness determining may establish if the deposition corresponds to the destination application deposition or not; and the measurements were made by non-destructive physical methods. The properties of nickel deposits, brightness and hardness are influenced by the pH of the bath electrolyte. The surface morphology of nickel deposit was analyzed by scanning electronic microscopy (SEM). The results showed that the structure of nickel deposits is influenced by pH of the bath. The pH increasing causes structural changes on the deposits in fine to coarse, while the electrodeposited nickel at pH 6.21 has a compact morphology with many cracks.