Study of microparticles incorporation in coatings on titanium produced by plasma electrolytic oxidation (PEO)

This research is focused on the analysis of the influence of rutile (TiO2) and anatase (TiO2) microparticles (d < 5 mu m) on the morphology, structure, and anticorrosive properties of PEO coatings on titanium produced in alkaline based solution containing sodium hydroxide and sodium metasilicates or nanoclay particles (hydrophilic bentonite, H2Al2O6Si, d < 25 mu m). PEO coatings are characterized by scanning electron microscope (SEM), energy dispersive spectroscopy ( EDS) and X-ray diffraction (XRD). In addition, the samples are electrochemically investigated by electrochemical impedance spectroscopy analysis. The tests carried out have shown that the incorporation of TiO2 microparticles in the coating leads to the formation of thick oxide layers characterized by a fine porosity. These coatings provide good corrosion protection when samples are exposed to an aggressive sulfuric acid solution.