In the paper, the Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) results of the surface layer formed on pure titanium after plasma electrolytic oxidation (micro arc oxidation) at the voltage of 450 V are shown. As an electrolyte, the mixture of copper nitrate Cu(NO₃)₂ (10-600 g/L) in concentrated phosphoric acid H₃PO₄ (98 g/mol) was used. The thickness of the obtained porous surface layer equals about 10 μm, and it consists mainly of titanium phosphates and oxygen with embedded copper ions as a bactericidal agent. The maximum percent of copper in the PEO surface layer was equal to 12.2 ± 0.7 wt % (7.6 ± 0.5 at %), which is the best result that the authors obtained. The top surface layer of all obtained plasma electrolytic oxidation (PEO) coatings consisted most likely mainly of Ti₃(PO₄)₄∙nH₃PO₄ and Cu₃(PO₄)₂∙nH₃PO₄ with a small addition of CuP₂, CuO and Cu₂O.

Department of Physics Norwegian University of Science and Technology Realfagbygget E3 124 Høgskoleringen 5 NO 7491 Trondheim Norway

Division of Surface Electrochemistry and Technology Faculty of Mechanical Engineering Koszalin University of Technology Racławicka 15 17 PL 75 620 Koszalin Poland

Institute of Clean Technologies for Mining and Utilization of Raw Materials for Energy Use Faculty of Mining and Geology VŠB Technical University of Ostrava 708 33 Ostrava Czech Republic

Institute of Geological Engineering Faculty of Mining and Geology ŠB Technical University of Ostrava 708 33 Ostrava Czech Republic

Institute of Physics Faculty of Mining and Geology VŠB Technical University of Ostrava 708 33 Ostrava Czech Republic

Regional Materials Science and Technology Centre Faculty of Metallurgy and Materials Engineering VŠB Technical University of Ostrava 708 33 Ostrava Czech Republic

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Novel Porous Phosphorus⁻Calcium⁻Magnesium Coatings on Titanium with Copper or Zinc Obtained by DC Plasma Electrolytic Oxidation: Fabrication and Characterization