Annealed Zn–TiO2 nanocomposites electrodeposited: Effect of the substrate

Zn–TiO2 coatings were successfully prepared by the co-deposition method on titanium and steel substrates using an acidic zinc sulphate solution with TiO2 nanoparticles in suspension. The filmʹs surface is rough and the TiO2 agglomerates are randomly distributed on the metallic matrix formed by staked hexagonal plates oriented in different directions. From the structural study it was concluded that although some Tc values are slightly above 1, this may not be indicative of the preferred orientations because the crystals grow randomly, as observed by scanning electron microscopy (SEM). After electrodeposition, samples were heated in air at 450 °C for 3 h. The X-ray diffraction analysis of the deposits points to the metal matrix modification from Zn to ZnO, and the formation of intermetallic phases. In addition, the SEM results indicate that the films have a high surface area, with a rich morphology, due to the appearance of ZnO hollow structures, porous microdiscs, porous flaky nanosheets and needle-shaped grains. These are highly dependent on the characteristics of as-deposited films, which are tightly correlated to the substrate nature/type.