Cobalt-vanadium coating deposition via programmed electrolysis mode

Abstract

In the current work, the co-deposition of cobalt with vanadium from a complex citrate electrolyte via stationary and pulse electrolysis modes was investigated. The process was carried out at a current density of 1–15 A⋅dm–2 in stationary electrolysis mode and 2–10 A⋅dm–2 in pulse electrolysis mode, with variable ratio of pulse time to pause time at a temperature range of 35–400Ñ and pH 3.0–3.5. According to the results of X-ray fluorescence spectrometry, the maximum content of vanadium in the coating obtained via the programmed electrolysis mode is 1.20–1.45%, which is tens of times higher than in the coating deposited by the stationary electrolysis mode (vanadium content of 0.007–0.017%) under similar conditions. The obtained results may confirm the hypothesis of additional vanadium reduction from oxo-anions by adsorbed hydrogen atoms formed on the cathode surface during the pause period. Based on the results of the analysis of 3D graphs, the optimal parameters of the process for fabricating a cobalt-vanadium coating with the maximum vanadium content in the alloy and a coating current efficiency of 80% have been established.