Characterization and fabrication of titanium oxide coated titanium via anodization technique

Titanium surfaces were modified in order to obtain nanosized grains, rough surfaces and nanotubes for the future applications in medicine and engineering by changing anodization parameters. Conventional microscopical techniques SEM (scanning electron microscopy), EDX (energy-dispersive X-ray spectroscopy) and AFM (atomic force microscopy) were applied to study morphological structures. Nanoindentations and nanotribological methods were applied to get informations on the effect of altered anodization parameters on mechanical behaviour of the oxide surfaces. Depending on chemical composition of the anodization solution either rough surfaces, nanograins or nanotubes were obtained. In case of the condition where rough surfaces were obtained roughness was increased with the increase in applied voltage and anodization time. In the same time other than obtaining rough surfaces inhomogeneous morphological structures in terms of chemistry and crystallographic differences were obtained. The thicknesses of the nanorough coatings were ranged roughly between 50-100 nm according to the nanoindentation tests. These tests also show that thickness of the coating varies and so does the hardness values. Among the samples, nanotube has the lowest hardness value due to its brittle nature. According to contact angle studies on the samples, it was found that titanium surfaces became more hydrophilic after anodization coating. The efficiency of the surfaces in preventing bacteria attachment were tested by seeding S. aureus on the titanium surface, which is the most common bacteria species causing biomaterial centered infections. After leaving the bacteria for a while to form biofilms, anti bacterial property of the surfaces were tested by visualizing the bacteria on the surfaces via SEM. Nanotube has the highest bacteria attachment on its surface, which may be resulted due to porosity and/or the feature of the surface of the nanotube. In this study, it was found that surfaces having different surface morphology and crystallography by altering the anodization parameters were obtained and these surfaces had different mechanical and antibacterial properties due to these changes.