scholarly journals SEM and EDS Characterization of Porous Coatings Obtained On Titaniumby Plasma Electrolytic Oxidation in Electrolyte Containing Concentrated Phosphoric Acid with Zinc Nitrate

2017 ◽  
Vol 17 (2) ◽  
pp. 41-54 ◽  
Author(s):  
K. Rokosz ◽  
T. Hryniewicz ◽  
K. Pietrzak ◽  
W. Malorny
Keyword(s):  
Phosphoric Acid ◽  
Plasma Electrolytic Oxidation ◽  
Pure Titanium ◽  
Zinc Nitrate ◽  
Porous Coatings ◽  
Electrolytic Oxidation ◽  
Micro Arc Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

AbstractThe SEM and EDS results of porous coatings formed on pure titanium by Plasma Electrolytic Oxidation (Micro Arc Oxidation) under DC regime of voltage in the electrolytes containing of 500 g zinc nitrate Zn(NO3)2·6H2O in 1000 mL of concentrated phosphoric acid H3PO4at three voltages, i.e. 450 V, 550 V, 650 V for 3 minutes, are presented. The PEO coatings with pores, which have different shapes and the diameters, consist mainly of phosphorus, titanium and zinc. The maximum of zinc-to-phosphorus (Zn/P) ratio was found for treatment at 650 V and it equals 0.43 (wt%) | 0.20 (at%), while the minimum of that coefficient was recorded for the voltage of 450 V and equaling 0.26 (wt%) | 0.12 (at%). Performed studies have shown a possible way to form the porous coatings enriched with zinc by Plasma Electrolytic Oxidation in electrolyte containing concentrated phosphoric acid H3PO4with zinc nitrate Zn(NO3)2·6H2O.

scholarly journals XPS and GDOES Characterization of Porous Coating Enriched with Copper and Calcium Obtained on Tantalum via Plasma Electrolytic Oxidation

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Patrick Chapon ◽  
Steinar Raaen ◽  
Hugo Ricardo Zschommler Sandim
Keyword(s):  
Phosphoric Acid ◽  
Plasma Electrolytic Oxidation ◽  
Calcium Nitrate ◽  
Porous Coating ◽  
Porous Coatings ◽  
New Model ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

XPS and GDOES characterizations of porous coatings on tantalum after Plasma Electrolytic Oxidation (PEO) at 450 V for 3 minutes in electrolyte containing concentrated (85%) phosphoric acid with calcium nitrate and copper (II) nitrate are described. Based on the obtained data, it may be concluded that the PEO coating consists of tantalum (Ta5+), calcium (Ca2+), copper (Cu2+  and Cu+), and phosphates (PO43-). It has to be pointed out that copper and calcium are distributed throughout the volume. The authors also propose a new model of PEO, based on the derivative of GDOES signals with sputtering time.

Characterization of Porous Coatings Obtained on Materials by Plasma Electrolytic Oxidation

2016 ◽  
Vol 862 ◽  
pp. 86-95 ◽  
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Winfried Malorny
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Niti Alloy ◽  
Pure Titanium ◽  
Copper Nitrate ◽  
Porous Coatings ◽  
Average Value ◽  
Pure Niobium ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

The main goal of present paper is to obtain porous coatings enriched in copper by Plasma Electrolytic Oxidation on titanium and niobium as well as on NiTi and Ti6Al4V alloys. Performed SEM and EDS studies confirmed the hypothesis that it is possible to create the porous surfaces with pores, which shapes and size are different. In order to show the copper enrichment inside the surface layers, the copper-to-phosphorus ratios were used. Based on these ratios it may be concluded that average value of Cu/P is maximal for NiTi alloy after oxidation in electrolyte containing 300 g of copper nitrate in 1 liter of phosphoric acid and equals 0.26. The minimum of Cu/P ratio equaling to 0.12 was recorded for pure titanium and pure niobium treated in electrolyte containing 300 g of Cu (NO3)2 in 1 L H3PO4.

scholarly journals Comparison of Biocompatible Coatings Produced by Plasma Electrolytic Oxidation on cp-Ti and Ti-Zr-Nb Superelastic Alloy

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Ruzil Farrakhov ◽  
Olga Melnichuk ◽  
Evgeny Parfenov ◽  
Veta Mukaeva ◽  
Arseniy Raab ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
X Ray ◽  
Kinetic Coefficients ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Cp Ti ◽  
Peo Coatings

The paper compares the coatings produced by plasma electrolytic oxidation (PEO) on commercially pure titanium and a novel superelastic alloy Ti-18Zr-15Nb (at. %) for implant applications. The PEO coatings were produced on both alloys in the identical pulsed bipolar regime. The properties of the coatings were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The PEO process kinetics was modeled based on the Avrami theorem and Cottrell equation using a relaxation method. The resultant coatings contain TiO2, for both alloys, and NbO2, Nb2O5, ZrO2 for Ti-18Zr-15Nb alloy. The coating on the Ti-18Zr-15Nb alloy has a higher thickness, porosity, and roughness compared to that on cp-Ti. The values of the kinetic coefficients of the PEO process—higher diffusion coefficient and lower time constant for the processing of Ti-18Zr-15Nb—explain this effect. According to the electrochemical studies, PEO coatings on Ti-18Zr-15Nb alloy provide better corrosion protection. Higher corrosion resistance, porosity, and roughness contribute to better biocompatibility of the PEO coating on Ti-18Zr-15Nb alloy compared to cp-Ti.

Characterization of porous coatings obtained via plasma electrolytic oxidation

2019 ◽  
pp. 163-214
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Antje Schütz ◽  
Jan Heeg ◽  
Marion Wienecke ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Porous Coatings ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

scholarly journals Characterization of Coatings Created on Selected Titanium Alloys by Plasma Electrolytic Oxidation

2016 ◽  
Vol 16 (1) ◽  
pp. 5-16 ◽  
Author(s):  
K. Rokosz ◽  
T. Hryniewicz ◽  
W. Malorny
Keyword(s):  
Phosphoric Acid ◽  
Titanium Alloys ◽  
Plasma Electrolytic Oxidation ◽  
Copper Nitrate ◽  
Ti6al4v Alloy ◽  
Pure Niobium ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Abstract The SEM and EDS results of coatings obtained on pure niobium and titanium alloys (NiTi and Ti6Al4V) by Plasma Electrolytic Oxidation in the electrolytes containing of 300 g and 600 g copper nitrate in 1 litre of concentrated phosphoric acid at 450 V for 3 minutes, are presented. The obtained coatings are porous and consist mainly of phosphorus within titanium and copper. For each coating, the Cu/P ratios were calculated. The maximum of that coefficient was found for niobium and Ti6Al4V alloy oxidised in the electrolyte containing 600 g of Cu(NO3)2 in 1 dm3 of H3PO4 and equaling to 0.22 (wt%) | 0.11 (at%). The minimum of Cu/P ratio was recorded for NiTi and Ti6Al4V alloys oxidised by PEO in electrolyte consisting of 300 g of copper nitrate in 1 dm3 of concentrated phosphoric acid and equals to 0.12 (wt%) | 0.06 (at%). The middle value of that ratio was recorded for NiTi and it equals to 0.16 (wt%) | 0.08 (at%).

scholarly journals Improvement of Mechanical and Corrosion Properties of Commercially Pure Titanium Using Alumina PEO Coatings

Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 29
Author(s):  
Viorel Malinovschi ◽  
Alexandru Horia Marin ◽  
Catalin Ducu ◽  
Sorin Moga ◽  
Victor Andrei ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Corrosion Properties ◽  
Commercially Pure ◽  
Electrolytic Oxidation ◽  
Aluminum Oxide Layer ◽  
Plasma Electrolytic ◽  
Cp Ti ◽  
Peo Coatings

In this study, the surface of commercially pure titanium (Cp-Ti) was covered by a 21–95 µm-thick aluminum oxide layer using plasma electrolytic oxidation. Coating characterization revealed the formation of nodular and granular α- and γ-Al2O3 phases with minor amounts of TiAl2O5 and Na2Ti4O9 which yielded a maximum 49.0 GPa hardness and 50 N adhesive critical load. The corrosion resistance behavior in 3.5 wt.% NaCl solution of all plasma electrolytic oxidation (PEO) coatings was found to be two orders of magnitude higher compared to bare Ti substrate.

scholarly journals Phosphate Porous Coatings Enriched with Selected Elements via PEO Treatment on Titanium and Its Alloys: A Review

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2468 ◽  
Author(s):  
Krzysztof Rokosz ◽  
Tadeusz Hryniewicz ◽  
Łukasz Dudek
Keyword(s):  
Vapor Deposition ◽  
Plasma Electrolytic Oxidation ◽  
Physical Vapor Deposition ◽  
Sol Gel ◽  
Chemical Vapor ◽  
Porous Coatings ◽  
High Durability ◽  
Electrolytic Oxidation ◽  
Micro Arc Oxidation ◽  
Plasma Electrolytic

This paper shows that the subject of porous coatings fabrication by Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation (MAO), is still current, inter alia because metals and alloys, which can be treated by the PEO method, for example, titanium, niobium, tantalum and their alloys, are increasingly available for sale. On the international market, apart from scientific works/activity developed at universities, scientific research on the PEO coatings is also underway in companies such as Keronite (Great Britain), Magoxid-Coat (Germany), Mofratech (France), Machaon (Russia), as well as CeraFuse, Tagnite, Microplasmic (USA). In addition, it should be noted that the development of the space industry and implantology will force the production of trouble-free micro- and macro-machines with very high durability. Another aspect in favor of this technique is the rate of part treatment, which does not exceed several dozen minutes, and usually only lasts a few minutes. Another advantage is functionalization of fabricated surface through thermal or hydrothermal modification of fabricated coatings, or other methods (Physical vapor deposition (PVD), chemical vapor deposition (CVD), sol-gel), including also reoxidation by PEO treatment in another electrolyte. In the following chapters, coatings obtained both in aqueous solutions and electrolytes based on orthophosphoric acid will be presented; therein, dependent on the PEO treatment and the electrolyte used, they are characterized by different properties associated with their subsequent use. The possibilities for using coatings produced by means of plasma electrolytic oxidation are very wide, beginning from various types of catalysts, gas sensors, to biocompatible and antibacterial coatings, as well as hard wear coatings used in machine parts, among others, used in the aviation and aerospace industries.

scholarly journals Fabrication and characterisation of porous, calcium enriched coatings on titanium after plasma electrolytic oxidation under DC regime

2017 ◽  
Vol 17 (4) ◽  
pp. 55-67 ◽  
Author(s):  
K. Rokosz ◽  
T. Hryniewicz ◽  
K. Pietrzak ◽  
P. Sadlak ◽  
J. Valíček
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Plasma Electrolytic Oxidation ◽  
Calcium Nitrate ◽  
Roughness Parameters ◽  
Porous Coatings ◽  
Electrolytic Oxidation ◽  
Titanium Grade ◽  
Plasma Electrolytic ◽  
Peo Coatings

Abstract The purpose of this work is to produce and characterize (chemical composition and roughness parameters) porous coatings enriched in calcium and phosphorus on the titanium (CP Titanium Grade 2) by plasma electrolytic oxidation. As an electrolyte, a mixture of phosphoric acid H3PO4 and calcium nitrate Ca(NO3)2·4H2O was used. Based on obtained EDS and roughness results of PEO coatings, the effect of PEO voltages on the chemical composition and surface roughness of porous coatings was determined. With voltage increasing from 450 V to 650 V, the calcium in PEO coatings obtained in freshly prepared electrolyte was also found to increase. In addition, the Ca/P ratio increased linearly with voltage increasing according to the formula Ca/P = 0.035·U+0.176 (by wt%) and Ca/P = 0.03·U+0.13 (by at%). It was also noticed that the surface roughness increases with the voltage increasing, what is related to the change in coating porosity, i.e. the higher is the surface roughness, the bigger are pores sizes obtained.

scholarly journals SEM And EDS Analysis Of Nitinol Surfaces Treated By Plasma Electrolytic Oxidation

2015 ◽  
Vol 15 (3) ◽  
pp. 41-47 ◽  
Author(s):  
K. Rokosz ◽  
T. Hryniewicz ◽  
Ł. Dudek ◽  
W. Malorny
Keyword(s):  
Surface Layer ◽  
Phosphoric Acid ◽  
Plasma Electrolytic Oxidation ◽  
Copper Nitrate ◽  
Layer Versus ◽  
Surface Layers ◽  
Electrochemical Processes ◽  
Electrolytic Oxidation ◽  
Micro Arc Oxidation ◽  
Plasma Electrolytic

Abstract In the paper, the surface layers formed on nickel-titanium alloy during Plasma Electrolytic Oxidation (PEO), known also as Micro Arc Oxidation (MAO), are described. The mixture of phosphoric acid and copper nitrate as the electrolyte for all plasma electrochemical processes was used. Nitinol biomaterial was used for the studies. All the experiments were performed under the voltage of 450 V and current density of 0.3 A/dm2. The main purpose of the studies was to achieve the highest amount of copper in the surface layer versus amount of the copper nitrate in phosphoric acid. The highest copper concentration was found in the surface layer after the PEO treatment in the electrolyte consisting of 150g Cu(NO3)2 in 0.5 dm3 H3PO4. The worst results, in case of the amount of copper in the NiTi surface layer, were recorded after oxidizing in the solution with 5 g Cu(NO3)2.

scholarly journals Plasma electrolytic oxidation of tantalum

2012 ◽  
Vol 9 (1) ◽  
pp. 81-94 ◽  
Author(s):  
Marija Petkovic ◽  
Stevan Stojadinovic ◽  
Rastko Vasilic ◽  
Ivan Belca ◽  
Becko Kasalica ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Optical Emission ◽  
Oxide Coating ◽  
Oxide Coatings ◽  
Tungstosilicic Acid ◽  
Coating Morphology ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

This paper is a review of our research on the plasma electrolytic oxidation (PEO) process of tantalum in 12-tungstosilicic acid. For the characterization of microdischarges during PEO, real-time imaging and optical emission spectroscopy (OES) were used. The surface morphology, chemical and phase composition of oxide coatings were investigated by AFM, SEM-EDS and XRD. Oxide coating morphology is strongly dependent on PEO time. The elemental components of PEO coatings are Ta, O, Si and W. The oxide coatings are partly crystallized and mainly composed of WO3, Ta2O5 and SiO2.

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