Hierarchically coupled multiscale structure-property correlations in electrodeposited Zn-TiO₂-graphene oxide...

Electrochemically deposited zinc (Zn)-based composite coatings have multifunctional applications in corrosion prevention, mechanical strengthening, photocatalysis, biomedical implants, energy storage, and optoelectronics. In the present study, titanium dioxide (TiO₂) nanoparticles and graphene oxide (GrO) sheets were co-electrodeposited within a Zn matrix on copper substrates to produce pristine Zn, Zn-TiO₂, Zn-GrO, and Zn-TiO₂-GrO coatings. The morphology, composition, crystal structure, wettability, surface roughness, and mechanical properties of the coatings were systematically investigated. The Zn-TiO₂-GrO hybrid coating exhibited the best overall performance, with improved hydrophilicity (44.2°), lowest surface roughness (0.157 ± 0.06 µm), refined crystallite size (18 ± 2 nm), and the highest hardness values (29 HV). Chen model calculations indicated enhanced elastic modulus values for the composite coatings (up to 12.70 GPa) compared with pristine Zn (3.25 GPa). The improved performance of the hybrid coating is attributed to the synergistic effect of TiO₂ nanoparticles and graphene oxide, which promotes grain refinement, improves interfacial bonding, and enhances load transfer within the Zn matrix. Thus, this study reveals that the Zn-TiO₂-GrO composite coating provides an effective strategy for multifunctional applications with enhanced surface and mechanical properties.