Electroplating of Iron Films: Microstructural Effects of Alkaline Baths
Several alkaline baths based on different complexing agents were examined for iron electroplating. The resultant films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that adherent and smooth iron coatings with uniform microstructure can be obtained using alkaline Fe (II) baths containing pyrophosphate and tartrate ions as complexing agents. The average grain size can be substantially decreased by glycine additions in the pyrophosphate bath. The faradaic efficiency in these electrolytes may achieve up to 40-50%. The tartrate-containing baths are characterized with a higher throwing power and an increased buffer capacity with respect to the pyrophosphate-based electrolytes. The resultant Fe coatings are single-phase, whilst substantial broadening of the XRD peaks indicates nano-scale grain size. The alkaline baths based on EDTA complexes of iron (III) give black dull iron deposits and are characterized by rather low cathodic current efficiencies, especially at low current densities.
Paula Maria Vilarinho
S. K. Poznyak, V. V. Kharton, J. R. Frade, M. G.S. Ferreira, "Electroplating of Iron Films: Microstructural Effects of Alkaline Baths", Materials Science Forum, Vols. 514-516, pp. 88-92, 2006