Electrodeposition of Zn-V oxide composite from strong agitated solution without dispersed particles

Electrodeposition of Zn-V oxide composite was examined from an agitated sulfate solution without dispersed particles containing Zn²⁺ and VO²⁺ at pH 2 and 40 °C under galvanostatic conditions. Although V content in deposits decreased for the moment with increasing current density regardless of flow rate of electrolyte, the further increase in current density brought about the increase in V content in deposits. The curves, which shows the relationship between the V content in deposits and current density, shifted to the higher current density region with increasing flow rate of electrolyte. Agitation of the electrolyte decreased the V content of the deposits but reduced the segregation of V oxide. EDX point analysis of cross section of deposits revealed that the V oxide concentrated at the surface of deposits. It was found from the polarization curves in 3% NaCl solution that the corrosion potential of deposited Zn-V oxide films depended on the V content in deposits regardless of the flow rate of electrolyte and it shifted to more noble direction with codeposition of V oxide at V contents in deposits below 2 mass%. At V contents of < 4 mass%, the corrosion current density of deposits decreased with increasing V contents in deposits. The corrosion current densities of deposits obtained from agitated solutions were smaller than that from un-agitated solutions.