Enhanced interfacial adhesion of TiO2 nanotubes (TiO2-NTs) decorated with Ag Silver nanoparticles (Ag-NPs) prepared by photo-reduction process

In the present study, the adhesion of TiO2 nanotubes (TiO2-NTs) to thicker substrates was improved by decorating them with metallic Ag nanoparticles (NPs) using the photo-reduction process. The obtained coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM). X-ray diffraction (XRD) confirmed that all TiO2-NTs crystallized in anatase after annealing at 400°C regardless of the anodization potential. The scanning electron microscopy (SEM) indicated that the TiO2-NTs were uniformly distributed on the substrate with an ordered and vertically aligned morphology. It also revealed that the diameter of the TiO2-NTs reached~100 nm. The decoration of TiO2-NTs surface with silver nanoparticles was assessed by transmission electron microscopy (TEM). Moreover, a new scratch test mode called ‘wear mode’ was performed to evaluate the wear resistance of the coatings. Results obtained by the scratch tests proved that the decorated coating with Ag nanoparticles improved the interfacial adhesion. The friction coefficient decreased from 0.65 to 0.45 when pure TiO2 was decorated with 10 min-Ag-NPs.The wear behavior was studied using a multi-pass scratch test. It was found that the wear volume reduced with the incorporation of Ag nanoparticles. The study of the damage mechanisms showed visco-elastic plastic deformation in the pure TiO2 coating.