Raman spectroscopy of TiO2 thin films formed by hybrid treatment for biomedical applications

The paper presents the results of the investigations of the surface layer obtained after application of the combined hybrid method of oxidation in a fluidized bed (FB) and deposition of the oxide coating by PVD technique. The material used in the study was Ti Grade 2. The process of diffusive saturation was carried out in a fluidized-bed reactor at the temperature of 640°C for 8h in air while the top oxide layer was obtained through PVD method - magnetron sputtering using TiO2 target and argon atmosphere with the pressure of 3×10(-2)mbar and the distance between the substrate to the target of 60mm. In order to determine changes in the properties that occur as a result of modification of the Ti surface, the following examinations were carried out by SEM-EDX, X-ray diffraction methods, Raman spectroscopy, Glow Discharge Optical Spectroscopy (GDOS) and Secondary Ion Mass Spectrometry (SIMS). The coatings obtained were characterized by zonal structure comprising the solution zone of Tiα(O) and oxide zone of TiO2 with modifications of rutile and anatase, depending on the oxidation method. It was found that formation of oxide layers using the hybrid method (FB+PVD) leads to limitation of defects in the oxide layer after fluidized-bed thermal treatment and obtaining a uniform, tight coating with improved corrosion properties which are important from the biomedical standpoint.