Composition, Surface Structure and Catalytic Properties of Manganese- and Cobalt-Containing Oxide Layers on Titanium

2014 ◽  
Vol 875-877 ◽  
pp. 351-355 ◽  
Author(s):  
M.S. Vasilyeva ◽  
V.S. Rudnev
Keyword(s):  
Surface Structure ◽  
Plasma Electrolytic Oxidation ◽  
Catalytic Properties ◽  
Oxidation Of Co ◽  
Oxide Layers ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Catalytically Active ◽  
Plasma Electrolytic ◽  
Scanning Electron

Silicon-containing oxide layers deposited on titanium using the plasma electrolytic oxidation (PEO) method were modified with manganese and cobalt compound through impregnation followed by annealing. The obtained manganese composites are catalytically active in the process of oxidation of CO at 100 оС, while cobalt-containing structures demonstrate this type of activity at temperatures above 200оС. The composition and surface structure of the obtained systems were investigated by means of X-ray phase and energy dispersive analyses and by high resolution scanning electron microscopy (SEM). Granule-like particles with diameters of a few dozens of nanometers were observed on the surface of oxide-cobalt layers on titanium, whereas the surface of oxide-manganese layers was coated by nano-whiskers of diameters <50 nm and length <1 μm. The presence of manganese-containing nano-whiskers substantially increases the catalyst specific surface, thus facilitating the attainment of higher degree of transformation of initial gaseous substances.

scholarly journals Nanodesigned coatings obtained by plasma electrolytic oxidation of titanium implant and their cytotoxicity

2021 ◽  
Vol 19 ◽  
pp. 228080001882225
Author(s):  
Marko Magić ◽  
Božana Čolović ◽  
Saša Vasilijić ◽  
Nenad Tadić ◽  
Stevan Stojadinović ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Cell Attachment ◽  
Titanium Implant ◽  
Ionic Exchange ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
The Given ◽  
Scanning Electron

The titanium implant was treated with plasma electrolytic oxidation and subsequent ionic exchange and thermal treatment in order to obtain bioactive layer consisting of titanium oxide, calcium and sodium titanates and hydroxyapatite, as confirmed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed that the given method, besides corresponding phase composition, enables suitable nanotopology for cell attachment and proliferation. Cytotoxicity investigations by MTT, LDH and propidium iodide assays and light microscopy showed that these coatings were not toxic to L929 cells.

MICROSTRUCTURE AND WEARING PROPERTIES OF PEO COATINGS: EFFECTS OF Al2O3 AND TiO2

2018 ◽  
Vol 25 (05) ◽  
pp. 1850102 ◽  
Author(s):  
Y. ZHANG ◽  
W. FAN ◽  
H. Q. DU ◽  
Y. W. ZHAO
Keyword(s):  
Photoelectron Spectroscopy ◽  
Plasma Electrolytic Oxidation ◽  
Xps Analysis ◽  
X Ray Diffraction ◽  
Properties Of Coatings ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings ◽  
Scanning Electron

Plasma electrolytic oxidation (PEO) coatings were formed on aluminium alloy in additive Al2O3- and TiO2-containing Na2SiO3-based electrolytes, respectively. The effect of these additives on morphology, composition and wearing properties of coatings was investigated. The morphology and composition of coatings were studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS). Analysis of wearing properties of coatings were done by friction and wearing experiment. It was found that the use of additives greatly affects the surface morphology of coatings. It is shown that the content of [Formula: see text]-Al2O3 in coatings formed in Al2O3-containing electrolytes increased with the addition of Al2O3. However, the content of [Formula: see text]-Al2O3 in coatings formed in TiO2-containing electrolytes first increased and then decreased. Among these coatings, the coating formed in silicate-based electrolytes system containing 7[Formula: see text]g/L Al2O3 showed the most superior wearing properties.

INCORPORATION OF MULTI-WALLED CARBON NANOTUBES INTO OXIDE LAYER FORMED ON AL ALLOY BY PLASMA ELECTROLYTIC OXIDATION

2020 ◽  
Vol 27 (11) ◽  
pp. 2050007
Author(s):  
KOANGYONG HYUN ◽  
JUNG-HYUNG LEE ◽  
SEONG-JONG KIM
Keyword(s):  
Carbon Nanotubes ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Aqueous Suspension ◽  
Al Alloy ◽  
Time Curve ◽  
Oxide Layers ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Plasma electrolytic oxidation (PEO) is an electrochemical-based surface modification technique that produces oxide layers on valve metals. The PEO process is performed in an electrolyte solution, which offers the possibility of particles’ incorporation into the growing oxide layer. In this study, we employed a PEO technique on a commercial Al alloy in an aqueous suspension of carbon nanotubes (CNTs) to fabricate CNT-incorporated oxide layer. The voltage–time response was recorded during the process. The surface of the resulting oxide layer was characterized by means of a scanning electron microscope (SEM), an energy-dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD). It was found from the SEM observation that the CNTs were successfully incorporated into the oxide layer. The PEO with the addition of CNTs led to a delay in time to breakdown (50[Formula: see text][Formula: see text][Formula: see text]s) and a decrease in breakdown voltage (442[Formula: see text][Formula: see text][Formula: see text]V) in the voltage–time curve. The microstructural feature was clearly distinguishable between the oxide layers produced with and without CNTs: a pancake-like structure for PEO without CNTs, and a doughnut-like structure for PEO with CNTs. However, neither the results of the structure analysis nor the elemental analysis provides a clear indication of carbon, even though the presence of CNTs in the oxide layer is evident, suggesting that further optimization of CNT concentration is required.

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.

scholarly journals Effects of a Carbon Nanotube Additive on the Corrosion-Resistance and Heat-Dissipation Properties of Plasma Electrolytic Oxidation on AZ31 Magnesium Alloy

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2438 ◽  
Author(s):  
Myungwon Hwang ◽  
Wonsub Chung
Keyword(s):  
Corrosion Resistance ◽  
Carbon Nanotube ◽  
Plasma Electrolytic Oxidation ◽  
Heat Dissipation ◽  
X Ray ◽  
Steady State Method ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Dissipation Property ◽  
Peo Coatings

Plasma electrolytic oxidation (PEO) coating was obtained on AZ31 Mg alloy using a direct current in a sodium silicate-based electrolyte with and without a carbon nanotube (CNT) additive. The surface morphology and phase composition of the PEO coatings were investigated through field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The corrosion-resistance properties of the PEO coatings were evaluated using potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. Furthermore, the heat-dissipation property was evaluated by a heat-flux measurement setup using a modified steady-state method and Fourier transform infrared spectroscopy (FT-IR). The results demonstrate that, by increasing the concentration of CNT additive in the electrolyte, the micropores and cracks of the PEO coatings are greatly decreased. In addition, the anticorrosion performance of the PEO coatings that incorporated CNT for the protection of the Mg substrate was improved. Finally, the coating’s heat-dissipation property was improved by the incorporation of CNT with high thermal conductivity and high thermal emissivity.

Plasma Electrolytic Oxidation on Ti–xNb–2Ag–2Pt Alloys for Nano- and Micro-Pore Formation in Electrolyte with Ca and P Ions for Dental Implant Use

2021 ◽  
Vol 21 (7) ◽  
pp. 3753-3758
Author(s):  
Hyun-Jun Kim ◽  
Han-Cheol Choe
Keyword(s):  
Dental Implant ◽  
Plasma Electrolytic Oxidation ◽  
Pore Formation ◽  
Melting Furnace ◽  
Vacuum Arc ◽  
X Ray ◽  
Arc Melting ◽  
Electrolytic Oxidation ◽  
Nb Content ◽  
Plasma Electrolytic

In this study, plasma electrolytic oxidation (PEO) on Ti–xNb–2Ag–2Pt alloys for nano- and micro-pore formation in electrolyte with Ca and P ions for dental implant use was studied using various experimental equipment. The Ti–xNb–2Ag–2Pt alloys were fabricated using a vacuum arc melting furnace, and micro-pores were created through PEO-treatment in an electrolyte containing Ca and P ions. The PEO-treated surface was observed by X-ray diffractometer (XRD), field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy (EDS). The microstructure of Ti– xNb–2Ag–2Pt alloys showed the transformation of needle-like structure to equiaxed structure, as Nb content increased. Adding small amounts of Ag and Pt to Ti–xNb alloys, microstructure was not observed the significantly difference compared to Ti–xNb. The nano- and micro-pore sizes increased as the Nb content increased after PEO-treatment of Ti-xNb. In the case of Ti–50Nb–2Ag–2Pt, groove structure was observed, also the Ca/P ratio increased as the Nb content increased. The oxide layer thickness of Ti–xNb–2Ag–2Pt alloys was increased, as the Nb content increased.

Sn-Containing Oxide Coatings: Formation, Composition, Electroanalytical and Catalytic Properties

2019 ◽  
Vol 806 ◽  
pp. 70-75
Author(s):  
Marina S. Vasilyeva ◽  
Vladimir S. Rudnev ◽  
Irina V. Lukiyanchuk ◽  
N.E. Zabudskaya ◽  
I.V. Chasovnikov
Keyword(s):  
Redox Reactions ◽  
Oxide Coatings ◽  
Oxidation Of Co ◽  
Direct Potentiometry ◽  
Oxide Electrodes ◽  
Electrolytic Oxidation ◽  
Catalytically Active ◽  
Plasma Electrolytic ◽  
Complex Anions ◽  
Potentiometric Tests

Sn-containing oxide coatings were prepared via plasma electrolytic oxidation (PEO) of Ti plate in the electrolytes with [SnII-EDTA]2- complex anions or SnO2 particles in the anode and anodic-cathodic modes. The coatings formed in electrolyte with SnO2 particles stabilized by SAS contain SnO2 and Sn0. In the electrolyte with [Sn-EDTA]2- complex anions, the SnO2-containing coatings were formed in the anodic mode while Sn0-containing ones were obtained in the anodic-cathodic mode. SnO2-containing structures formed in the electrolytes with [Sn-EDTA]2- anions are shown to be active in catalytic oxidation of CO into CO2 at temperatures above 350 °C. They can be the basis for the preparation of both carriers of catalytically active compounds and catalysts for redox reactions. Potentiometric tests showed that the Sn-containing PEO layers on titanium exhibit the most characteristic pH function for the metal oxide electrodes in the direct potentiometry and acid-base titration.

scholarly journals Plasma Electrolytic Oxidation of Titanium in H2SO4–H3PO4 Mixtures

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 116 ◽  
Author(s):  
Bernd Engelkamp ◽  
Björn Fischer ◽  
Klaus Schierbaum
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Phase Changes ◽  
Crystal Phase ◽  
Plasma Discharges ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Oxide layers on titanium foils were produced by galvanostatically controlled plasma electrolytic oxidation in 12.9 M sulfuric acid with small amounts of phosphoric acid added up to a 3% mole fraction. In pure sulfuric acid, the oxide layer is distinctly modified by plasma discharges. As the time of the process increases, rough surfaces with typical circular pores evolve. The predominant crystal phase of the titanium dioxide material is rutile. With the addition of phosphoric acid, discharge effects become less pronounced, and the predominant crystal phase changes to anatase. Furthermore, the oxide layer thickness and mass gain both increase. Already small amounts of phosphoric acid induce these effects. Our findings suggest that anions of phosphoric acid preferentially adsorb to the anodic area and suppress plasma discharges, and conventional anodization is promoted. The process was systematically investigated at different stages, and voltage and oxide formation efficiency were determined. Oxide surfaces and their cross-sections were studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase composition was determined by X-ray diffraction and confocal Raman microscopy.

scholarly journals Plasma electrolytic oxidation of metals

2013 ◽  
Vol 78 (5) ◽  
pp. 713-716 ◽  
Author(s):  
Stevan Stojadinovic
Keyword(s):  
Photoelectron Spectroscopy ◽  
Plasma Electrolytic Oxidation ◽  
Dielectric Breakdown ◽  
Optical Emission ◽  
Active Surface ◽  
Spatial Density ◽  
Oxide Coatings ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

In this lecture results of the investigation of plasma electrolytic oxidation (PEO) process on some metals (aluminum, titanium, tantalum, magnesium, and zirconium) were presented. Whole process involves anodizing metals above the dielectric breakdown voltage where numerous micro-discharges are generated continuously over the coating surface. For the characterization of PEO process optical emission spectroscopy and real-time imaging were used. These investigations enabled the determination of electron temperature, electron number density, spatial density of micro-discharges, the active surface covered by micro-discharges, and dimensional distribution of micro-discharges at various stages of PEO process. Special attention was focused on the results of the study of the morphology, chemical, and phase composition of oxide layers obtained by PEO process on aluminum, tantalum, and titanium in electrolytes containing tungsten. Physicochemical methodes: atomic force microscopy (AFM), scanning electron microscopy (SEM-EDS), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy served as tools for examining obtained oxide coatings. Also, the application of the obtained oxide coatings, especially the application of TiO2/WO3 coatings in photocatalysis, were discussed.

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