Krzysztof Rokosz1, Tadeusz Hryniewicz1, Wojciech Kacalak1, Katarzyna Tandecka1, Steinar Raaen2, Sofia Gaiaschi3, Patrick Chapon3, Winfried Malorny4, Dalibor Matýsek5, Kornel Pietrzak1, Łukasz Dudek1. 1. Department of Engineering and Informatics Systems, Faculty of Mechanical Engineering, Koszalin University of Technology, 75620 Koszalin, Poland. 2. Department of Physics, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway. 3. HORIBA FRANCE S.A.S., Boulevard Thomas Gobert - Passage Jobin Yvon, 91120 Palaiseau, France. 4. Hochschule Wismar-University of Applied Sciences Technology, Business and Design, Faculty of Engineering, 23966 Wismar, Germany. 5. Institute of Geological Engineering, Faculty of Mining and Geology, VŠB-Technical University of Ostrava, 70833 Ostrava, Czech Republic.
Abstract
The present paper covers the possible ways to fabricate advanced porous coatings that are enriched in copper on a titanium substrate through Direct Current Plasma Electrolytic Oxidation (DC-PEO) with voltage control, in electrolytes made of concentrated orthophosphoric acid with the addition of copper(II) nitrate(V) trihydrate. In these studies, solutions containing from 0 to 650 g salt per 1 dm3 of acid and anodic voltages from 450 V up to 650 V were used. The obtained coatings featuring variable porosity could be best defined by the three-dimensional (3D) parameter Sz, which lies in the range 9.72 to 45.18 μm. The use of copper(II) nitrate(V) trihydrate in the electrolyte, resulted, for all cases, in the incorporation of the two oxidation forms, i.e., Cu+ and Cu2+ into the coatings. Detailed X-Ray Photoelectron Spectroscopy (XPS) studies layers allowed for stating that the percentage of copper in the surface layer of the obtained coatings was in the range of 0.24 at% to 2.59 at%. The X-Ray Diffraction (XRD) studies showed the presence of copper (α-Cu2P2O7, and Cu3(PO4)2) and titanium (TiO2-anatase, TiO3, TiP2O7, and Ti0.73O0.91) compounds in coatings. From Energy-Dispersive X-Ray Spectroscopy (EDS) and XPS studies, it was found that the Cu/P ratio increases with the increase of voltage and the amount of salt in the electrolyte. The depth profile analysis by Glow-Discharge Optical Emission Spectroscopy (GDOES) method showed that a three-layer model consisting of a top porous layer, a semi-porous layer, and a transient/barrier layer might describe the fabricated coatings.
The present paper n class="Chemical">covers the possible ways to fabricate advanced porous coatings that are enriched in <span class="Chemical">copper on a <class="Chemical">span class="Chemical">titanium substrate through Direct Current Plasma Electrolytic Oxidation (DC-PEO) with voltage control, in electrolytes made of concentrated orthophosphoric acid with the addition of copper(II) nitrate(V) trihydrate. In these studies, solutions containing from 0 to 650 g salt per 1 dm3 of acid and anodic voltages from 450 V up to 650 V were used. The obtained coatings featuring variable porosity could be best defined by the three-dimensional (3D) parameter Sz, which lies in the range 9.72 to 45.18 μm. The use of copper(II) nitrate(V) trihydrate in the electrolyte, resulted, for all cases, in the incorporation of the two oxidation forms, i.e., Cu+ and Cu2+ into the coatings. Detailed X-Ray Photoelectron Spectroscopy (XPS) studies layers allowed for stating that the percentage of copper in the surface layer of the obtained coatings was in the range of 0.24 at% to 2.59 at%. The X-Ray Diffraction (XRD) studies showed the presence of copper (α-Cu2P2O7, and Cu3(PO4)2) and titanium (TiO2-anatase, TiO3, TiP2O7, and Ti0.73O0.91) compounds in coatings. From Energy-Dispersive X-Ray Spectroscopy (EDS) and XPS studies, it was found that the Cu/P ratio increases with the increase of voltage and the amount of salt in the electrolyte. The depth profile analysis by Glow-Discharge Optical Emission Spectroscopy (GDOES) method showed that a three-layer model consisting of a top porous layer, a semi-porous layer, and a transient/barrier layer might describe the fabricated coatings.