Effect of polyethylene glycol on electrodeposition of zn active metal oxide composites from a particle-free solution

Electrodeposition of ZnZr and ZnVoxide composites was performed under galvanostatic conditions at 313K on unagitated pH 2 sulfate solutions containing Zn2+ and Zr4+ or VO2+ ions and an additive such as polyethylene glycol (PEG). The effects of PEG addition on the codeposition of Zr and V oxides and their polarization behavior, and on the microstructure of the deposits, were investigated. Although the Zr content in the deposits obtained from the ZnZr solution in the absence of PEG was approximately zero, it increased significantly at a current density of above 1000 A m 2 following the addition of PEG. In the ZnV solution, the V content in the deposits obtained from 100 to 2000 A m 2 was higher with PEG than without it. In the presence of PEG, the cathode potential polarized, the rate of hydrogen evolution increased, and the hydrolysis reaction of Zr4+ and VO2+ ions proceeded smoothly, resulting in an increase in the Zr and V content in the deposits. Additionally, the crystal platelets of Zn in the ZnZr and the ZnVoxide films became fine, and the surface coverage of the spongiform Zr and film-like Voxides increased. Furthermore, the corrosion current densities of the ZnZr and ZnVoxide films obtained from the solution with PEG were lower than those from the solution without it.