Effect on the Electrochemical Properties of PEO Films Produced on Commercially Pure Titanium Using Multicomponent Oxide Coatings

Titanium has specific uses due to its cost, which is counterbalanced by its extraordinary chemical and physical properties. Submarine hulls and nuclear power plant pipes have been made of titanium since the last century due to its high corrosion resistance, and the aircraft industry has also exploited its remarkable properties, such as lightness and high melting point. Surface modifications by plasma electrolytic oxidation (PEO) may increase its corrosion resistance, roughness and wettability. Furthermore, greater corrosion resistance is a rather attractive property in nuclear power plant pipes, although the increased roughness and wettability are disadvantageous downsides as they favor the attachment of marine organisms. Nonetheless these new features are particularly interesting for biomedical applications. In this study, PEO films were produced on commercially pure titanium substrates using different electrolytes, one of which contains zirconium dioxide and the other consisting of tantalum pentoxide, in addition to a third one composed of a combination of the former two. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses were performed in addition to contact angle and roughness measurements, and electrochemical tests were carried out to comparatively characterize the different film compositions. The results revealed that excellent corrosion resistance was achieved by mixing oxides in the electrolyte.