A Study of Zn-Co Alloy Electrodeposits by Auger Spectroscopy and XPS

SUMMARY

AES and XPS techniques have been used to analyse thin Zn-Co films obtained by electrodeposition at different potentials and to characterise the interface between the substrate and the deposits. Measurement of depth profiles of the thin films has been carried out by Auger spectroscopy to determine the homogeneity of the deposit and to explore the influence of the substrate on the alloy composition. It was found that the composition of the thin film is affected by the deposition potential as well as by the substrate.

XPS has been used to determine the chemical states of Zn and Co at the surface, in the bulk and at the interface with the substrate. The results showed that zinc occurs as zinc oxide and zinc metal at the surface, however in the bulk and at the interface only zinc and cobalt metals have been detected. The analyses do not provide evidence for the inclusion of zinc hydroxide in the deposit by precipitation during the deposition process. This may be significant in considering the mechanism of deposition.

Keywords:

• electrodeposition
• zinc-cobalt alloys
• corrosion protection
• thin films
• Auger spectroscopy
• XPS spectroscopy
• interface