Development of Porous Coatings Enriched with Magnesium and Zinc Obtained by DC Plasma Electrolytic Oxidation
Krzysztof Rokosz,
Tadeusz Hryniewicz,
Sofia Gaiaschi,
Patrick Chapon,
Steinar Raaen,
Winfried Malorny,
Dalibor Matýsek,
Kornel Pietrzak
Affiliations
Krzysztof Rokosz
Division of BioEngineering and Surface Electrochemistry, Department of Engineering and Informatics Systems, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland
Tadeusz Hryniewicz
Division of BioEngineering and Surface Electrochemistry, Department of Engineering and Informatics Systems, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland
Sofia Gaiaschi
HORIBA France S.A.S., Avenue de la Vauve-Passage Jobin Yvon, 91120 Palaiseau, France
Patrick Chapon
HORIBA France S.A.S., Avenue de la Vauve-Passage Jobin Yvon, 91120 Palaiseau, France
Steinar Raaen
Department of Physics, Norwegian University of Science and Technology (NTNU), Realfagbygget, E3-124 Høgskoleringen 5, 7491 NO Trondheim, Norway
Winfried Malorny
Faculty of Engineering, Hochschule Wismar-University of Applied Sciences Technology, Business and Design, DE 23966 Wismar, Germany
Dalibor Matýsek
Institute of Geological Engineering, Faculty of Mining and Geology, VŠB—Technical University of Ostrava, 708 33 Ostrava, Czech Republic
Kornel Pietrzak
Division of BioEngineering and Surface Electrochemistry, Department of Engineering and Informatics Systems, Koszalin University of Technology, Racławicka 15-17, PL 75-620 Koszalin, Poland
Coatings with developed surface stereometry, being based on a porous system, may be obtained by plasma electrolytic oxidation, PEO (micro arc oxidation, MAO). In this paper, we present novel porous coatings, which may be used, e.g., in micromachine’s biocompatible sensors’ housing, obtained in electrolytes containing magnesium nitrate hexahydrate Mg(NO3)2·6H2O and/or zinc nitrate hexahydrate Zn(NO3)2·6H2O in concentrated phosphoric acid H3PO4 (85% w/w). Complementary techniques are used for coatings’ surface characterization, such as scanning electron microscopy (SEM), for surface imaging as well as for chemical semi-quantitative analysis via energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), and X-ray powder diffraction (XRD). The results have shown that increasing contents of salts (here, 250 g/L Mg(NO3)2·6H2O and 250 g/L Zn(NO3)2·6H2O) in electrolyte result in increasing of Mg/P and Zn/P ratios, as well as coating thickness. It was also found that by increasing the PEO voltage, the Zn/P and Mg/P ratios increase as well. In addition, the analysis of XPS spectra revealed the existence in 10 nm top of coating magnesium (Mg2+), zinc (Zn2+), titanium (Ti4+), and phosphorus compounds (PO43−, or HPO42−, or H2PO4−, or P2O74−).
