Prediction of morphology development from nucleation and plating overpotentials in nickel electrodeposition

• Published in: Canadian metallurgical quarterly Vol. 56; no. 4; pp. 393 - 400
• Main Authors: Schoeman, L., Sole, K. C.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 02.10.2017
• Subjects: Electrocrystallisation; electrowinning; morphology; nickel; nucleation; polarisation; sulphate
• ISSN: 0008-4433; 1879-1395
• DOI: 10.1080/00084433.2017.1361179

Evaluation and measurement of the influence of changes in conditions and electrolyte composition during early stages of a growing metal electrodeposit are crucial to predict changes in developing morphology. A galvanodynamic polarisation technique was developed to reliably measure overpotentials for nickel electrodeposition from sulphate electrolyte. The validity of these polarisation parameters as indicators of the relationships between changes in the electrolyte and resulting deposit morphology was evaluated for electrolytes of varying composition. Findings indicate that nucleation and plating overpotentials measured by the described technique can be used as indicative tools for monitoring, evaluating and ultimately improving control of the electrodeposition of nickel from sulphate electrolytes. The results predict that nickel deposits of desirable quality and morphology are obtained when plating overpotentials are higher than 700 mV vs. Ag/AgCl and nucleation overpotential is less negative than plating overpotential.