Electrodeposition of Composite Ni-TiO2 Coatings from Aqueous Acetate Baths

In this paper, results concerning electrochemical deposition of Ni-TiO2 composite coatings are presented. The influence of electrode potential, concentration of TiO2 in the electrolyte, as well as the influence of magnetohydrodynamic effect (MHD) on deposition rate, composition, current efficiency, structure, surface states, and coatings surface morphology is described. Electrochemical studies were preceded by thermodynamic analysis of the system. In addition, the electrokinetic potential (ZP) of TiO2 particles in applied electrolyte was determined. Electrodeposited composites contained up to 2.15 wt. pct of TiO2. Depending on the applied electrolysis conditions, the current efficiency recorded up to 31.7 pct for B = 0 T and up to 34.2 for B = 1 T. Electrochemical studies as well as further material characterizations indicated the strong influence of the magnetic field on processes taking place at the electrode surface. Several results indicated that the synthesis process is accompanied by precipitation of nickel hydroxides and nickel hydrides as well as by hydrogen evolution reaction (HER). The obtained coatings were also characterized in order to determine their photoelectrochemical properties.