Importance of anions in electrodeposition of nickel from gluconate solutions

Abstract

AbstractElectrodeposition of nickel from slightly acidic gluconate solutions containing chloride or/and sulfate ions was investigated. Electrochemical measurements correlated with bath speciations showed nickel chloride complex and nickel sulfate complexes as crucial species affecting cathodic reactions in a potential range up to −1.3V. At more negative potentials, nickel deposition was governed by a release of nickel cation from nickel-gluconate complex. This was further evidenced by differences in nucleation modes, morphology, and structure of the deposits. Wettability of as-plated and chemically modified nickel layers were determined and correlated with their morphology and corrosion resistance.