scholarly journals Study of Coatings Formed on Zirconium Alloy by Plasma Electrolytic Oxidation in Electrolyte with Submicron Yttria Powder Additives

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1392
Author(s):  
Svetlana Savushkina ◽  
Mikhail Gerasimov ◽  
Andrey Apelfeld ◽  
Igor Suminov
Keyword(s):  
Current Density ◽  
Plasma Electrolytic Oxidation ◽  
Zirconium Alloy ◽  
Protective Ability ◽  
Electrolytic Oxidation ◽  
Current Densities ◽  
Polarization Studies ◽  
Plasma Electrolytic ◽  
Peo Coatings ◽  
Yttria Powder

Coatings with thickness 40 to 150 μm were formed by plasma electrolytic oxidation (PEO) on the zirconium alloy Zr-1Nb (Zr-1% Nb) in the slurry electrolyte containing 9 g/L Na2SiO3 5H2O, 5 g/L Na(PH2O2) and 6 g/L submicron Y2O3 yttria powder during 60 min under the AC electrical mode at current densities 20; 30 and 40 A/dm2. The surface morphology, structure, composition, and corrosion-protective ability of the formed coatings have been analyzed. At PEO current density 30 A/dm2, a predominantly tetragonal phase of zirconia was formed in coatings. Increasing the PEO current density up to 40 A/dm2 promoted the formation of the coating surface layer containing submicron yttria particles. Electrochemical polarization studies in 0.5% LiOH solution showed that PEO coatings demonstrated high corrosion-protective ability. The dependence of the polarization currents on the PEO current density was found to be inconsequential.

Correlation between the Properties of PEO-Layer and Coating Formation Current Density

2020 ◽  
Vol 312 ◽  
pp. 361-365
Author(s):  
Sergey N. Suchkov ◽  
Mariia S. Gerasimenko ◽  
Konstantine V. Nadaraia ◽  
Igor M. Imshinetsky ◽  
Dmitry V. Mashtalyar ◽  
...  
Keyword(s):  
Cross Section ◽  
Current Density ◽  
Plasma Electrolytic Oxidation ◽  
Protective Coatings ◽  
Corrosion Properties ◽  
Electrolytic Oxidation ◽  
Coating Formation ◽  
Current Densities ◽  
Plasma Electrolytic ◽  
Peo Coatings

Presented paper considers the formation of protective coatings on MA8 magnesium alloy by plasma-electrolytic oxidation (PEO). The influence of current densities formation on the structure, corrosion properties of PEO-coatings was studied. Electrochemical and scanning electron microscopy of the surface and cross-section of the samples were carried out. The effect of changing the formation current density on the functional parameters of coatings, such as corrosion resistance, thickness and porosity was investigated.

scholarly journals Effect of Applied Current Density of Plasma Electrolytic Oxidation Process on Corrosion Resistance of AZ31 Magnesium Alloy

2019 ◽  
Vol 21 (2) ◽  
pp. 32-36 ◽  
Author(s):  
Daniel Kajanek ◽  
Branislav Hadzima ◽  
Matej Brezina ◽  
Martina Jackova
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Current Density ◽  
Plasma Electrolytic Oxidation ◽  
Az31 Magnesium Alloy ◽  
Applied Current ◽  
Applied Current Density ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Peo Coatings

Impact of applied current density during the plasma electrolytic oxidation (PEO) process on corrosion resistance of AZ31 magnesium alloy was studied. The PEO coatings were prepared using four different current densities with values of 0.025 A/cm2, 0.05 A/cm2, 0.1 A/cm2 and 0.15 A/cm2 in electrolyte consisting of 10 g/l Na 3PO4.12H2O and 1 g/l KOH. Morphology and chemical composition of the coatings was examined using the scanning electron microscopy and EDS analysis respectively. Electrochemical characteristics of ground and coated samples were measured by means of electrochemical impedance spectroscopy (EIS) in 0.1M NaCl solution. Obtained data in form of Nyquist diagrams were analysed by equivalent circuit method. Results of experiments showed that value of applied current density had significant effect on protective performance of the PEO coatings prepared on AZ31 magnesium alloy surface.

Characterization of Graphite Containing Ceramic Coating Prepared on Carbon Steel by Plasma Electrolytic Oxidation

2012 ◽  
Vol 271-272 ◽  
pp. 46-49 ◽  
Author(s):  
Yun Long Wang ◽  
Miao Wang ◽  
Ming Zhou ◽  
Zhao Hua Jiang
Keyword(s):  
Carbon Steel ◽  
Current Density ◽  
Bonding Strength ◽  
Plasma Electrolytic Oxidation ◽  
Substrate Surface ◽  
Ceramic Coatings ◽  
Electrolytic Oxidation ◽  
Q235 Carbon Steel ◽  
Current Densities ◽  
Plasma Electrolytic

Ceramic coatings containing graphite were prepared on Q235 carbon steel by plasma electrolytic oxidation (PEO) in aluminate electrolyte with graphite dispersed in electrolyte. The microstructure and properties of the coatings including phase composition, surface and cross section morphology, thickness and bonding strength were characterized. The results showed that the coating consisted of FeAl2O4, Fe3O4 and a certain amount of graphite. The coating was typically characterized by micro pores and ball-shaped round grains distributed on the surface. With increasing the treating current density, the pores became bigger and the ball-shaped round grains became more. Coatings obtained with various current densities showed a good interface between the coating and substrate. The bonding strength of the coatings decreased a little when increasing the current densities, the values of which were all above 20MPa. The coating grew both inwards and outwards to the substrate surface. With increasing the treating current density, the consumption of substrate gradually increased but the whole thickness was not strongly affected by the current density and the value was about 115 μm.

Influences of Current Density on Tribological Characteristics of Ceramic Coatings on 6061 Al Alloy by Plasma Electrolytic Oxidation

2011 ◽  
Vol 239-242 ◽  
pp. 1892-1895
Author(s):  
Xiao Dong Wang ◽  
Xiao Hong Wu ◽  
Rui Wang ◽  
Song Tao Lu
Keyword(s):  
Current Density ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coatings ◽  
Tribological Characteristics ◽  
Al Alloy ◽  
Friction Testing ◽  
Electrolytic Oxidation ◽  
Current Densities ◽  
Plasma Electrolytic ◽  
6061 Al Alloy

Plasma electrolytic oxidation (PEO) of an 6061 Al alloy was accomplished in an electrolyte with sodium hexametaphosphate (10 g/L) and sodium silicate (10 g/L) Coatings were produced at four different current densities (4, 6, 8 and 10 A/dm2). Phase composition, morphology and tribological characteristics of the coatings were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and ball-on-disk friction testing. The results show that among the four ceramic coatings which were produced under four current densities, the coating produced under the current density of 8 A/dm2 got the lowest wear rate with the value of 4.5 × 10-5 g/m.

scholarly journals Plasma Electrolytic Oxidation (PEO) Process—Processing, Properties, and Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1375
Author(s):  
Soumya Sikdar ◽  
Pramod V. Menezes ◽  
Raven Maccione ◽  
Timo Jacob ◽  
Pradeep L. Menezes
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Nanocomposite Coatings ◽  
Mechanical And Tribological Properties ◽  
Electrolytic Oxidation ◽  
Recent Developments ◽  
Coating Formation ◽  
Wear And Corrosion Resistance ◽  
Plasma Electrolytic ◽  
Peo Coatings ◽  
Future Work

Plasma electrolytic oxidation (PEO) is a novel surface treatment process to produce thick, dense metal oxide coatings, especially on light metals, primarily to improve their wear and corrosion resistance. The coating manufactured from the PEO process is relatively superior to normal anodic oxidation. It is widely employed in the fields of mechanical, petrochemical, and biomedical industries, to name a few. Several investigations have been carried out to study the coating performance developed through the PEO process in the past. This review attempts to summarize and explain some of the fundamental aspects of the PEO process, mechanism of coating formation, the processing conditions that impact the process, the main characteristics of the process, the microstructures evolved in the coating, the mechanical and tribological properties of the coating, and the influence of environmental conditions on the coating process. Recently, the PEO process has also been employed to produce nanocomposite coatings by incorporating nanoparticles in the electrolyte. This review also narrates some of the recent developments in the field of nanocomposite coatings with examples and their applications. Additionally, some of the applications of the PEO coatings have been demonstrated. Moreover, the significance of the PEO process, its current trends, and its scope of future work are highlighted.

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 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.

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