Thermal stability of electrodeposited nickel on vanadium: evidence for oxygen diffusion and intermetallic phase formation

• Published in: Surface science 2004-03, Vol.552 (1), p.215-228
• Main Authors: Zafeiratos, S., Paloukis, F.E., Jaksic, M.M., Neophytides, S.G.
• Format: Article
• Language: English
• Subjects: Alloys; Cross-disciplinary physics: materials science; rheology; Electrodeposition, electroplating; Exact sciences and technology; Materials science; Metal–electrolyte interfaces; Methods of deposition of films and coatings; film growth and epitaxy; Nickel oxides; Photoelectron spectroscopy; Physics; Vanadium oxide
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2004.01.021

The thermal stability of Ni overlayers electrochemically prepared on a polycrystalline vanadium (V) surface, was studied by means of X-ray and UV photoelectron spectroscopies (XPS, UPS). The results showed that upon cathodic polarization, a mixed Ni–Ni(OH) 2 adlayer is formed, while V surface becomes partially oxidized into vanadium oxide (V 2O x ). The applied potential during nickel electrodeposition is crucial for both Ni–Ni(OH) 2 composition and V 2O x film thickness. Annealing the Ni–Ni(OH) 2/V 2O x interface under UHV conditions leads to the gradual reduction of the films and the formation of a new Ni–V intermetallic phase. A solid state reaction accompanies the decomposition of nickel and vanadium oxides resulting in oxygen migration from the Ni adlayer to the V support. The electronic structure of Ni–V intermetallic phase formed after oxide decomposition is compared to previously reported results for Ni alloys and intermetallic compounds.