scholarly journals TiO2Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Leon White ◽  
Youngmi Koo ◽  
Yeoheung Yun ◽  
Jagannathan Sankar
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Protective Layer ◽  
Az31 Magnesium Alloy ◽  
Treatment Technique ◽  
Functional Coating ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Plasma electrolytic oxidation (PEO) has been used in the past as a useful surface treatment technique to improve the anticorrosion properties of Mg alloys by forming protective layer. Coatings were prepared on AZ31 magnesium alloy in phosphate electrolyte with the addition of TiO2nanoparticles using plasma electrolytic oxidation (PEO). This present work focuses on developing a TiO2functional coating to create a novel electrophotocatalyst while observing the surface morphology, structure, composition, and corrosion resistance of the PEO coating. Microstructural characterization of the coating was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) followed by image analysis and energy dispersive spectroscopy (EDX). The corrosion resistance of the PEO treated samples was evaluated with electrochemical impedance spectroscopy (EIS) and DC polarization tests in 3.5 wt.% NaCl. The XRD pattern shows that the components of the oxide film include Mg from the substrate as well as MgO and Mg2TiO4due to the TiO2nanoparticle addition. The results show that the PEO coating with TiO2nanoparticles did improve the corrosion resistance when compared to the AZ31 substrate alloy.

scholarly journals Corrosion resistance of AZ31 magnesium alloy treated by plasma electrolytic oxidation

2019 ◽  
Vol 63 (2) ◽  
pp. 65-71
Author(s):  
D. Kajánek ◽  
B. Hadzima ◽  
J. Tkacz ◽  
J. Pastorková ◽  
M. Jacková ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Az31 Magnesium Alloy ◽  
Potentiodynamic Curves ◽  
Coating Morphology ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Dc Current

Abstract The coating prepared by plasma electrolytic oxidation (PEO) was created on AZ31 magnesium alloy surface with the aim to evaluate its effect on corrosion resistance. The DC current was applied on the sample in solution consisted of 10 g/l Na3PO4·12H2O and 1 g/l KOH. Additional samples were prepared with 2 and 4 minutes of preparation to observe evolution of the PEO coating. Morphology of the coatings was evaluated by scanning electron microscopy and chemical composition was examined by EDX analysis. Electrochemical characteristic were measured by potentiodynamic polarization tests and electrochemical impedance spectroscopy in 0.1 M NaCl at the laboratory temperature. Obtained data were presented in form of potentiodynamic curves and Nyquist diagrams. Results of analysis showed that plasma electrolytic oxidation coating positively influence corrosion resistance of AZ31 magnesium alloy in chosen corrosive environment.

scholarly journals Influence of Different Electrolyte Additives and Structural Characteristics of Plasma Electrolytic Oxidation Coatings on AZ31 Magnesium Alloy

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 817
Author(s):  
Zhiquan Huang ◽  
Ruiqiang Wang ◽  
Xintong Liu ◽  
Dongdong Wang ◽  
Heng Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Ceramic Layer ◽  
Az31 Magnesium Alloy ◽  
Electrolyte Additives ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Coatings prepared by different electrolyte additives were investigated on AZ31 magnesium alloy by plasma electrolytic oxidation. In this study, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were employed to assess the morphologies, chemical and phase compositions of the plasma electrolytic oxidation (PEO) coatings, respectively. Furthermore, electrochemical impedance spectroscopy was used to evaluate the corrosion behavior of the composite coating. The investigation of the effect of electrolyte additives in the base electrolyte showed that the PEO specimens exhibit different surface and cross-sectional morphologies, and phase compositions. The results showed that SiO32− was conducive to the growth of the ceramic layer, and the ceramic layer developing in the electrolyte which contained AlO2− showed a typical double-layer structure. The corrosion resistance of coating formed in a phosphate bath was higher than that of the coating formed in silicate bath and coating formed in an aluminate bath. Moreover, the corrosion resistance of the coating formed in the fluoride bath was the highest.

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.

scholarly journals Impact of Processing Parameters in Plasma Electrolytic Oxidation (PEM) on Corrosion Resistance of Magnesium Alloy Type AZ91

2021 ◽  
Author(s):  
Talal Aljohani ◽  
Sami Aljadaan ◽  
Meteb Bin Rubayan ◽  
Fuad Khoshnaw
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Duty Cycle ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Processing Parameters ◽  
Coated Sample ◽  
Alloy Type ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

This study aims to investigate the effect of the processing parameters in plasma electrolytic oxidation (PEO) on the corrosion resistance of magnesium alloy type AZ91. The PEO coatings were prepared on the samples using alkaline-based electrolyte. Both unipolar and bipolar, different frequencies and duty cycles were applied. Corrosion tests, using potentiodynamic polarisation (PDP), linear and cyclic, and electrochemical impedance spectroscopy (EIS) techniques, were applied on the as-received and PEO coated samples. Scanning electron microscopy was used to investigate the surface morphology, e.g. micropores, as well as to measure the thickness of the coated layer with changing the processing parameters. The results show that the size of micropores is interrelated to the duty cycle percentage and current polarities, as the higher frequency causes thinner coating layers, with fewer micropores, consequently higher corrosion resistance. In addition, increasing the duty cycle, a denser and more compact coating was obtained. The XRD results showed missing peak of the α-Mg phase in a PEO coated sample using Bipolar, the highest frequency (1666 Hz) and the highest duty cycle (66.6%). The mils per year calculations showed that the PEO coated have lower corrosion rate by at least 8 times than the as-received alloy.

scholarly journals Comparison of Corrosion Resistance and Cytocompatibility of MgO and ZrO2 Coatings on AZ31 Magnesium Alloy Formed via Plasma Electrolytic Oxidation

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 441 ◽  
Author(s):  
Shimeng Wang ◽  
Lingxia Fu ◽  
Zhenggang Nai ◽  
Jun Liang ◽  
Baocheng Cao
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Mg Alloy ◽  
Az31 Magnesium Alloy ◽  
Corrosion Properties ◽  
Az31 Mg Alloy ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

In this work, one coating is comprised of ZrO2 and the other consists of MgO as main phase composition was produced on AZ31 magnesium alloy using one-step plasma electrolytic oxidation (PEO). The purpose of this work was to study the corrosion resistance and cytocompatibility of the above-coated AZ31 magnesium alloys in order to provide a basis for AZ31 Mg alloy’s clinical applications of biomedical use. The morphology and phase composition of the coatings were studied using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion properties were examined using electrochemical testing, hydrogen evolution measurements, and immersion tests in a simulated body fluid (SBF). Compared with bare magnesium and the MgO coating, the ZrO2-containing coating exhibited an improved corrosion resistance. Cell proliferation assays and cell morphology observations showed that the ZrO2-containing coating was not toxic to the L-929 cells. The ZrO2 coating was much denser and more homogeneous than the MgO coating, hence the corrosion resistance of the ZrO2-coated AZ31 Mg alloy was superior and more stable than the MgO-coated AZ31 Mg alloy, and ZrO2/AZ31 did not induce a cytotoxic reaction to L-929 cells and promote cell growth.

scholarly journals Preparation and Characterization of Fluoride-Incorporated Plasma Electrolytic Oxidation Coatings on the AZ31 Magnesium Alloy

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 826
Author(s):  
Lingxia Fu ◽  
Yanxia Yang ◽  
Longlong Zhang ◽  
Yuanzhi Wu ◽  
Jun Liang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Chemical Elements ◽  
Az31 Magnesium Alloy ◽  
Cell Counting ◽  
Fluoride Ions ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

In this study, films with different fluorine contents were prepared on an AZ31 magnesium alloy by using plasma electrolytic oxidation to study the corrosion resistance and cytocompatibility of the alloy. The morphology of the coating surface, phase, and chemical elements were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectrometry (EDS). The changes in the corrosion resistance with different fluorine contents were investigated by electrochemical experiments, hydrogen evolution, and long-term immersion tests. In addition, murine fibroblast L-929 cells were adopted for in vitro cytotoxicity tests using the cell counting kit (CCK)-8 assay, and the morphology of the cells was observed simultaneously by inverted microscopy. The results showed that the main form of the fluorine ions in the plasma electrolytic oxidation coatings was magnesium fluoride (MgF2). In addition, the corrosion resistance and cytocompatibilities of the coatings were improved by the addition of fluoride ions. When the content of potassium fluoride reached 10 g/L, the cell compatibility and corrosion resistance were the best, a finding which provides a basis for the clinical applications of the AZ31 magnesium alloy in the biomedical field.

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