SEM, EDS and XPS Analysis of the Coatings Obtained on Titanium after Plasma Electrolytic Oxidation in Electrolytes Containing Copper Nitrate

Krzysztof Rokosz; Tadeusz Hryniewicz; Dalibor Matýsek; Steinar Raaen; Jan Valíček; Łukasz Dudek; Marta Harničárová

doi:10.3390/ma9050318

SEM, EDS and XPS Analysis of the Coatings Obtained on Titanium after Plasma Electrolytic Oxidation in Electrolytes Containing Copper Nitrate

Materials (Basel). 2016 Apr 27;9(5):318. doi: 10.3390/ma9050318.

Authors

Krzysztof Rokosz¹, Tadeusz Hryniewicz², Dalibor Matýsek³, Steinar Raaen⁴, Jan Valíček^{5

6

7}, Łukasz Dudek⁸, Marta Harničárová⁹

Affiliations

¹ Division of Surface Electrochemistry & Technology, Faculty of Mechanical Engineering, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland. rokosz@tu.koszalin.pl.
² Division of Surface Electrochemistry & Technology, Faculty of Mechanical Engineering, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland. Tadeusz.Hryniewicz@tu.koszalin.pl.
³ Institute of Geological Engineering, Faculty of Mining and Geology, ŠB-Technical University of Ostrava, 708 33 Ostrava, Czech Republic. dalibor.matysek@vsb.cz.
⁴ Department of Physics, Norwegian University of Science and Technology (NTNU), Realfagbygget E3-124 Høgskoleringen 5, NO 7491 Trondheim, Norway. steinar.raaen@ntnu.no.
⁵ Institute of Physics, Faculty of Mining and Geology, VŠB-Technical University of Ostrava, 708 33 Ostrava, Czech Republic. jan.valicek@vsb.cz.
⁶ 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. jan.valicek@vsb.cz.
⁷ Regional Materials Science and Technology Centre, Faculty of Metallurgy and Materials Engineering, VŠB-Technical University of Ostrava, 708 33 Ostrava, Czech Republic. jan.valicek@vsb.cz.
⁸ Division of Surface Electrochemistry & Technology, Faculty of Mechanical Engineering, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland. Lukasz.Dudek@tu.koszalin.pl.
⁹ Institute of Physics, Faculty of Mining and Geology, VŠB-Technical University of Ostrava, 708 33 Ostrava, Czech Republic. marta.harnicarova@vsb.cz.

Abstract

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.

Keywords: Energy Dispersive X-ray Spectroscopy (EDS); Scanning Electron Microscopy (SEM); X-ray Photoelectron Spectroscopy (XPS); copper nitrate; micro arc oxidation (MAO); plasma electrolytic oxidation (PEO); titanium.