scholarly journals EFFECT OF CURRENT MODE ON THE PLASMA DISCHARGE, MICROSTRUCTURE AND CORROSION RESISTANCE OF OXIDE COATINGS PRODUCED ON 1100 ALUMINUM ALLOY BY PLASMA ELECTROLYTIC OXIDATION

2019 ◽  
Author(s):  
RIYAD O. HUSSEIN ◽  
XUEYUAN NIE ◽  
DEREK O. NORTHWOOD
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Current Mode ◽  
Plasma Discharge ◽  
Oxide Coatings ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

scholarly journals Surface Modification of Aluminum 6061-O Alloy by Plasma Electrolytic Oxidation to Improve Corrosion Resistance Properties

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
High Strength ◽  
Electrolytic Oxidation ◽  
Coating Layers ◽  
Plasma Electrolytic ◽  
High Strength Aluminum Alloys

In the present investigation, the plasma electrolytic oxidation (PEO) process was employed to form aluminum oxide coating layers to enhance corrosion resistance properties of high-strength aluminum alloys. The formed protective coating layers were examined by means of scanning electron microscopy (SEM) and characterized by several electrochemical techniques, including open circuit potential (OCP), linear potentiodynamic polarization (LP) and electrochemical impedance spectroscopy (EIS). The results were reported in comparison with the bare 6061-O aluminum alloy to determine the corrosion performance of the coated 6061-O alloy. The PEO-treated aluminum alloy showed substantially higher corrosion resistance in comparison with the untreated substrate material. A relationship was found between the coating formation stage, process parameters and the thickness of the oxide-formed layers, which has a measurable influence on enhancing corrosion resistance properties. This study demonstrates promising results of utilizing PEO process to enhance corrosion resistance properties of high-strength aluminum alloys and could be recommended as a method used in industrial applications.

Corrosion Properties of Plasma Electrolytic Oxidation Ceramic Coatings on an A356 Alloy Tested in an Ethanol-Gasoline Fuel (E85) Medium

2011 ◽  
Vol 282-283 ◽  
pp. 774-778
Author(s):  
Zhi Jing Peng ◽  
Ying Chen ◽  
Xue Yuan Nie
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
A356 Alloy ◽  
Current Mode ◽  
Ceramic Coatings ◽  
Corrosion Properties ◽  
Cross Sectional ◽  
Electrolytic Oxidation ◽  
Zero Resistance ◽  
Plasma Electrolytic

Ceramic oxide coatings were prepared on an aluminum A356 alloy by a plasma electrolytic oxidation (PEO) technique under unipolar, bipolar and duplex unipolar/bipolar current modes. Cross-sectional morphologies of the coatings were studied using a scanning electron microscope (SEM). The corrosion behavior of the coated and uncoated samples was evaluated in ethanol-gasoline E85 fuels through potentiodynamic polarization and zero resistance ammeter (ZRA) testing methods. The results indicated that all the coatings had a better corrosion resistance compared to the uncoated substrate. The unipolar current mode created the PEO coating with a thicker coating microstructure and thus a better corrosion resistance, compared to a bipolar current mode. The duplex treatments of unipolar/bipolar or bipolar/unipolar current modes produced the best performance of the coatings against galvanic corrosions caused by a steel/Al coupling in the E85 fuel medium.

scholarly journals Corrosion Inhibitor-Modified Plasma Electrolytic Oxidation Coatings on 6061 Aluminum Alloy

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 619
Author(s):  
Maciej Sowa ◽  
Marta Wala ◽  
Agata Blacha-Grzechnik ◽  
Artur Maciej ◽  
Alicja Kazek-Kęsik ◽  
...  
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Photoelectron Spectroscopy ◽  
Plasma Electrolytic Oxidation ◽  
Step Method ◽  
Corrosion Properties ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

There are many methods for incorporating organic corrosion inhibitors to oxide coatings formed on aluminum alloys. However, typically they require relatively concentrated solutions of inhibitors, possibly generating a problematic waste and/or are time-/energy-consuming (elevated temperature is usually needed). The authors propose a three-step method of oxide layer formation on 6061-T651 aluminum alloy (AAs) via alternating current (AC) plasma electrolytic oxidation (PEO), impregnation with an 8-hydroxyquinoline (8-HQ) solution, and final sealing by an additional direct current (DC) polarization in the original PEO electrolyte. The obtained coatings were characterized by scanning electron microscopy, roughness tests, contact angle measurements, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Additionally, corrosion resistance was assessed by potentiodynamic polarization in a NaCl solution. Two types of the coating were formed (A—thicker, more porous at 440 mA cm−2; B—thinner, more compact at 220 mA cm−2) on the AA substrate. The 8-HQ impregnation was successful as evidenced by XPS. It increased the contact angle only for the B coatings and improved the corrosion resistance of both coating systems. Additional DC treatment destroyed superficially adsorbed 8-HQ. However, it served to block the coating pores (contact angle ≈ 80°) which improved the corrosion resistance of the coating systems. DC sealing alone did not bring about the same anti-corrosion properties as the combined 8-HQ impregnation and DC treatment which dispels the notion that the provision of the inhibitor was a needless step in the procedure. The proposed method of AA surface treatment suffered from unsatisfactory uniformity of the sealing for the thicker coatings, which needs to be amended in future efforts for optimization of the procedure.

Effect of Electrolyte Chemistry on the Structural, Morphological and Corrosion Characteristics of Titania Films Developed on Ti-6Al-4V Implant Material by Plasma Electrolytic Oxidation

2011 ◽  
Vol 493-494 ◽  
pp. 436-441 ◽  
Author(s):  
K. Venkateswarlu ◽  
S. Suresh ◽  
N. Rameshbabu ◽  
Arumugam Chandra Bose ◽  
S. Subramanian
Keyword(s):  
Corrosion Resistance ◽  
Pore Size ◽  
Plasma Electrolytic Oxidation ◽  
Constant Current ◽  
Oxide Coatings ◽  
Electrolyte System ◽  
Physiological Conditions ◽  
Implant Material ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

The present work is aimed at the optimisation of an electrolyte system for the development of an oxide layer on Ti-6Al-4V implant material by plasma electrolytic oxidation (PEO) process, to improve its corrosion resistance under 4.5 pH osteoclast bioresorption and 7.4 pH simulated body fluid physiological conditions. All the PEO experiments were conducted for 12 min in constant current mode by a DC power supply unit with 7 different electrolyte systems consisting of methodically varied concentrations of tri-sodium ortho phosphate (Na3PO4.12H2O), sodium meta silicate (Na2SiO3.9H2O) and potassium hydroxide (KOH). The phase composition of the fabricated oxide coatings was analyzed by X-ray diffraction (XRD) technique. The morphology and thickness of the coatings were determined by scanning electron microscopy (SEM) and the corrosion characteristics were assessed by potentiodynamic polarization and electrochemical impedance spectroscopic techniques. The XRD results demonstrated that the oxide coatings mainly consisted of anatase and rutile phases with different proportions. While the average surface pore size was in the range of 3 to 6 µm, the thickness of the coating varied from 5 to 20 µm. A significant improvement in the corrosion resistance and an added capacitive nature was observed for the PEO treated Ti-6Al-4V implant material compared to that of the untreated. The variation in the proportions of anatase and rutile phases, the surface pore size distribution, the thickness of the coating and the corrosion characteristics of the developed coatings were correlated with the composition and concentration of the electrolyte system. Of the seven different electrolyte systems employed in the present study, the one consisting of 10 g Na3PO4.12H2O, 2 g Na2SiO3.9H2O and 2 g of KOH was established to be an optimized electrolyte system for developing oxide coatings on Ti-6Al-4V to minimise corrosion and thereby reduce the metal ion release under physiological conditions.

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