scholarly journals Electrochemical Characterization of Az31 Magnesium Alloy Treated by Ultrasonic Impact Peening (Uip)

2018 ◽  
Vol 20 (3) ◽  
pp. 24-29
Author(s):  
Daniel Kajanek ◽  
Branislav Hadzima ◽  
Filip Pastorek
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Az31 Alloy ◽  
Az31 Magnesium Alloy ◽  
Electrochemical Characteristics ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Testing Solution

Electrochemical characteristics of AZ31 magnesium alloy after impacting by ultrasonic impact peening (UIP) were measured in order to evaluate its effect on corrosion resistance of mentioned alloy. For this purpose, potentio-dynamic polarization (PD) tests and electrochemical impedance spectroscopy (EIS) of ground and impacted samples were performed in 0.1 M NaCl solution at the temperature of 22±2 °C after 5 minutes of potential stabilization. The obtained PD curves were analysed using the Tafel extrapolation method and data from EIS measurements in form of Nyquist plots were quantified by the equivalent circuit method. The results showed clearly that application of the UIP significantly deteriorated corrosion resistance of AZ31 alloy in the chosen testing solution.

scholarly journals ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY CHARACTERIZATION OF ZW3 MAGNESIUM ALLOY COATED BY DCPD USING LASV DEPOSITION TECHNIQUE

2017 ◽  
Vol 23 (2) ◽  
pp. 147 ◽  
Author(s):  
Daniel Kajánek ◽  
Branislav Hadzima ◽  
Filip Pastorek ◽  
Martina Neslušan Jacková
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Magnesium Alloy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Water Solution ◽  
Electrochemical Characteristics ◽  
Phosphate Dihydrate ◽  
Nyquist Plots ◽  
Eis Measurements

<p class="AMSmaintext"><span lang="EN-GB">The contribution deals with the preparation of the dicalcium phosphate-dihydrate (DCPD) coating on ZW3 magnesium alloy surface. The coating was prepared using large amplitude sinusoidal voltammetry (LASV) electrodeposition technique in water solution of </span><span lang="SK">0.1M Ca(NO<sub>3</sub>)<sub>2</sub>.4H<sub>2</sub>O + 0.06M NH<sub>4</sub>HPO<sub>4 </sub>+ 10 ml.dm<sup>-3</sup> of 50 vol.% H<sub>2</sub>O<sub>2</sub>. </span><span lang="EN-GB">The influence of the DCPD coating on electrochemical characteristics was examined using potentiodynamic polarization (PD) tests and electrochemical impedance spectroscopy (EIS) at the temperature <br /> </span><span lang="EN-GB">22 ± 2 °C in 0.1M NaCl. The obtained PD curves were analysed using Tafel extrapolation method and the data obtained by EIS measurements in a form of Nyquist plots were analysed quantitatively by equivalent circuit method. The results showed the increase of corrosion resistance after application of DCPD coating on ZW3 Mg alloy in sodium chloride solution. </span></p>

scholarly journals INFLUENCE OF A PREFABRICATED-CROWN ROLLING PROCESS ON THE CORROSION BEHAVIOUR OF AZ31 MAGNESIUM ALLOY

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Zhiquan Huang ◽  
Jinchao Zou ◽  
Junpeng Wang ◽  
Yanjie Pei ◽  
Renyao Huang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Plate Thickness ◽  
Az31 Alloy ◽  
Rolling Process ◽  
Charge Transfer Resistance ◽  
Az31 Magnesium Alloy ◽  
Transfer Resistance

The present study aims to investigate the effect of a prefabricated-crown rolling process on the corrosion characteristic of the AZ31 magnesium alloy. Specimens made of the AZ31 alloy were rolled under various crown conditions, and their microstructure evolution and corrosion behavior were analyzed. The corrosion behavior was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion-current density of the AZ31 alloy with a side pressure of 37.5 % of the plate thickness of the precast convexity decreased from 3.79 × 10–6 A/cm2 to 1.80 × 10–6 A/cm2, and the difference between the edge and the middle of the AZ31 alloy was shortened from 2.05 × 10–6 A/cm2 to 1.14 × 10–6 A/cm2. The charge-transfer resistance also increased from 507.1 Ω·cm2 to 581.2 Ω·cm2. The improvement in the corrosion resistance is a result of the more stable corrosion products and microstructure refinement formed after the prefabricated-crown rolling process.

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.

Corrosion Behavior of AZ31 Magnesium Alloy with Microarc Oxidation Film Irradiated by High-Intensity Pulsed Ion Beam

2008 ◽  
Vol 373-374 ◽  
pp. 460-463 ◽  
Author(s):  
X.G. Han ◽  
P. Li ◽  
X.P. Zhu ◽  
M.K. Lei
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
High Intensity ◽  
Electrochemical Impedance ◽  
Ion Beam ◽  
Microarc Oxidation ◽  
Az31 Magnesium Alloy ◽  
Noticeable Improvement ◽  
Original Films ◽  
Sealing Layer

The microarc oxidation (MAO) films on AZ31 magnesium alloy were modified by high-intensity pulsed ion beam (HIPIB) at an ion current density of 200 A/cm2 with 1-5 shots. The modified MAO films presented a corrosion resistance superior to that of the original films. Scanning electron microscopy (SEM) observation revealed that a sealing layer was formed on the MAO films by HIPIB irradiation. The corrosion behaviors of the MAO films in 3.5 % NaCl solution were characterized by using electrochemical impedance spectroscopy (EIS). The noticeable improvement in the corrosion resistance of MAO films is attributed to the blocking effect of the sealing layer that hinders the process of electrolyte penetrating the MAO films to the magnesium alloy.

Corrosion Resistance of Modified Silane Films Formed on AZ31 Magnesium Alloys

2011 ◽  
Vol 686 ◽  
pp. 21-25
Author(s):  
Xian Long Cao ◽  
Fu Sheng Pan ◽  
Hong Da Deng ◽  
Wei Cai
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Chloride Ions ◽  
Cerium Nitrate ◽  
Az31 Magnesium Alloy ◽  
Sodium Chloride Solutions

This present work investigated the corrosion behavior of AZ31 magnesium alloy substrates pre-treated with bis-[triethoxysilylpropyl] tetrasulfide silane modified with cerium nitrate. The corrosion behavior of the pre-treated substrates in 0.005M sodium chloride solutions was assessed by potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy (EIS). The results showed that the silane pre-treatments improved the corrosion resistance of the AZ31 magnesium alloy substrates in the presence of chloride ions. Especially the addition of cerium nitrate played an important role in reducing the corrosion activity.

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 Characterization and Corrosion Properties of Fluoride Conversion Coating Prepared on AZ31 Magnesium Alloy

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 675
Author(s):  
Juliána Dziková ◽  
Stanislava Fintová ◽  
Daniel Kajánek ◽  
Zuzana Florková ◽  
Jaromír Wasserbauer ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Molten Salt ◽  
Electrochemical Impedance ◽  
Intermetallic Phase ◽  
Negative Influence ◽  
Conversion Coating ◽  
Az31 Magnesium Alloy ◽  
Corrosion Properties ◽  
Coating Temperature

Wrought AZ31 magnesium alloy was used as the experimental material for fluoride conversion coating preparation in Na[BF4] molten salt. Two coating temperatures, 430 °C and 450 °C, and three coating times, 0.5, 2, and 8 h, were used for the coating preparation. A scanning electron microscope and energy-dispersive X-ray spectroscopy were used for an investigation of the surface morphology and the cross-sections of the prepared coatings including chemical composition determination. The corrosion resistance of the prepared specimens was investigated in terms of the potentiodynamic tests, electrochemical impedance spectroscopy and immersion tests in the environment of simulated body fluids at 37 ± 2 °C. The increase in the coating temperature and coating time resulted in higher coatings thicknesses and better corrosion resistance. Higher coating temperature was accompanied by smaller defects uniformly distributed on the coating surface. The defects were most probably created due to the reaction of the AlxMny intermetallic phase with Na[BF4] molten salt and/or with the product of its decomposition, BF3 compound, resulting in the creation of soluble Na3[AlF6] and AlF3 compounds, which were removed from the coating during the removal of the secondary Na[MgF3] layer. The negative influence of the AlxMny intermetallic phase was correlated to the particle size and thus the size of created defects.

scholarly journals Facile Fabrication and Properties of Super-hydrophobic MgAl-LDH Films With Excellent Corrosion Resistance on AZ31 Magnesium Alloy

2021 ◽  
Vol 8 ◽  
Author(s):  
Xing Han ◽  
Jia Hu ◽  
Yong-Qin Wang ◽  
Tian-Bing Xiao ◽  
Wei Xia ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Immersion Test ◽  
Contact Angles ◽  
Az31 Magnesium Alloy ◽  
Water Contact ◽  
Double Hydroxides

A super-hydrophobic anti-corrosion film was facilely prepared via in situ growth of layered double hydroxides (LDHs) on the etched AZ31 magnesium alloy and then modification by 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane (PFOTMS) in this work. The morphology, structure, composition, surface roughness and water contact angles (WCA), and the anti-corrosion performance of the samples were investigated. The results revealed that the micro/nano hierarchical surface morphology of the films was composed of island structures obtained after chemical etching and MgAl-LDH nanowalls grown in situ. The best hydrophobicity (CA = 163°) was obtained on the MgAl-LDHs with the maximum surface roughness. Additionally, the potentiodynamic polarization, electrochemical impedance spectroscopy, and immersion test indicated that the super-hydrophobic LDH films provided better corrosion resistance to AZ31 magnesium alloy due to the double-protection derived from the LDHs and super-hydrophobic properties. Furthermore, the contact angle could be kept at above 140° after dipped in 3.5 wt% NaCl solution for 6 days.

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