Influence of CeO[sub.2] and TiO[sub.2] Particles on Physicochemical Properties of Composite Nickel Coatings Electrodeposited at Ambient Temperature

The Ni-TiO[sub.2] and Ni-CeO[sub.2] composite coatings with varying hydrophilic/hydrophobic characteristics were fabricated by the electrodeposition method from a tartrate electrolyte at ambient temperature. To meet the requirements of tight regulation by the European Chemicals Agency classifying H[sub.3] BO[sub.3] as a substance of very high concern, Rochelle salt was utilized as a buffer solution instead. The novelty of this study was to implement a simple one-step galvanostatic electrodeposition from the low-temperature electrolyte based on a greener buffer compared to traditionally used, aiming to obtain new types of soft-matrix Ni, Ni-CeO[sub.2] , and Ni-TiO[sub.2] coatings onto steel or copper substrates. The surface characteristics of electrodeposited nickel composites were evaluated by SEM, EDS, surface contact angle measurements, and XPS. Physiochemical properties of pure Ni, Ni-CeO[sub.2,] and Ni-TiO[sub.2] composites, namely, wear resistance, microhardness, microroughness, and photocatalytic activity, were studied. Potentiodynamic polarization, EIS, and ICP-MS analyses were employed to study the long-term corrosion behavior of coatings in a 0.5 M NaCl solution. Superior photocatalytic degradation of methylene blue, 96.2% after 6 h of illumination, was achieved in the case of Ni-TiO[sub.2] composite, while no substantial change in the photocatalytic behavior of the Ni-CeO[sub.2] compared to pure Ni was observed. Both composites demonstrated higher hardness and wear resistance than pure Ni. This study investigates the feasibility of utilizing TiO[sub.2] as a photocatalytic hydrophilicity promoter in the fabrication of composite coatings for various applications.