Evaluation of Corrosion Protection of Sol-Gel Coatings on AZ31B Magnesium Alloy

2008 ◽  
Vol 587-588 ◽  
pp. 390-394 ◽  
Author(s):  
Alexandre Ferreira Galio ◽  
Sviatlana V. Lamaka ◽  
Mikhail L. Zheludkevich ◽  
L.F. Dick ◽  
Iduvirges Lourdes Müller ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Weight Ratio ◽  
Hybrid Coatings ◽  
Magnesium Alloy Az31b ◽  
Excellent Adhesion ◽  
Sol Gel Films

Magnesium is one of the lightest metals and magnesium alloys have good strength to weight ratio making them very attractive for many particular applications [1]. The main drawback of magnesium alloys is their high corrosion susceptibility. Improving the corrosion protection by deposition of thin hybrid films can expand the areas of applications of relatively cheap magnesium alloys. This work aims at investigation of new anticorrosion coating systems for magnesium alloy AZ31B using hybrid sol-gel films. The sol-gels were prepared by copolymerization of 3- glycidoxypropyltrimethoxysilane (GPTMS), titanium alcoxides and special additives which provide corrosion protection of magnesium alloy. Different compositions of sol-gel systems show enhanced long-term corrosion protection of magnesium alloy. The sol-gel coatings exhibit excellent adhesion to the substrate and protect against the corrosion attack. Corrosion behavior of AZ31B substrates pre-treated with sol–gel derived hybrid coatings was tested by Electrochemical Impedance Spectroscopy (EIS). The morphology and the structure of sol-gel films under study were characterized with SEM/EDS techniques.

Microstructural and Mechanical Properties of a Solid-State Additive Manufactured Magnesium Alloy

2021 ◽  
pp. 1-21
Author(s):  
Thomas Robinson ◽  
Malcolm Williams ◽  
Harish Rao ◽  
Ryan P. Kinser ◽  
Paul Allison ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Solid State ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Process Parameters ◽  
Weight Ratio ◽  
Structural Components ◽  
Friction Stir ◽  
Magnesium Alloy Az31b

Abstract In recent years, additive manufacturing (AM) has gained prominence in rapid prototyping and production of structural components with complex geometries. Magnesium alloys, whose strength-to-weight ratio is superior compared to steel and aluminum alloys, have shown potential in lightweighting applications. However, commercial beam-based AM technologies have limited success with magnesium alloys due to vaporization and hot cracking. Therefore, as an alternative approach, we propose the use of a near net-shape solid-state additive manufacturing process, Additive Friction Stir Deposition (AFSD), to fabricate magnesium alloys in bulk. In this study, a parametric investigation was performed to quantify the effect of process parameters on AFSD build quality including volumetric defects and surface quality in magnesium alloy AZ31B. In order to understand the effect of the AFSD process on structural integrity in the magnesium alloy AZ31B, in-depth microstructure and mechanical property characterization was conducted on a bulk AFSD build fabricated with a set of acceptable process parameters. Results of the microstructure analysis of the as-deposited AFSD build revealed bulk microstructure similar to wrought magnesium alloy AZ31 plate. Additionally, similar hardness measurements were found in AFSD build compared to control wrought specimens. While tensile test results of the as-deposited AFSD build exhibited a 20 percent drop in yield strength, nearly identical ultimate strength was observed compared to the wrought control. The experimental results of this study illustrate the potential of using the AFSD process to additively manufacture Mg alloys for load bearing structural components with achieving wrought-like microstructure and mechanical properties.

Impedance Behavior of the Composite Coatings Prepared on Magnesium Alloy AZ91 in Simulated Seawater Solution

2014 ◽  
Vol 900 ◽  
pp. 526-530
Author(s):  
Wei Shang ◽  
Zhou Lan Yin ◽  
Yu Qing Wen ◽  
Xu Feng Wang
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Protection ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Sol Gel ◽  
Soaking Time ◽  
Magnesium Alloy Az91 ◽  
Micro Arc Oxidation ◽  
Simulated Seawater

The composite coatings were obtained on a magnesium alloy by micro-arc oxidation and sol-gel technique. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion behavior of MAO coating and composite coatings in a simulated seawater solution. The results show that corrosion behavior of the MAO coating and composite coatings are different at different immersion times. Corrosion protection of the MAO coating gradually weaken with the extension of soaking time, but corrosion protection of the composite coatings become stronger first and then weaken.

Comparison of Electrochemical and Chemical Corrosion Behavior of MRI 230D Magnesium Alloy with and without Plasma Electrolytic Oxidation Treatment

2015 ◽  
Vol 364 ◽  
pp. 27-34
Author(s):  
Barbara Kazanski ◽  
Alex Lugovskoy ◽  
Ohad Gaon ◽  
Michael Zinigrad
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Corrosion Behavior ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Weight Ratio ◽  
Open Circuit ◽  
Chemical Corrosion ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Magnesium is one of the lightest metals and magnesium alloys have quite special properties, interest to which is continuously growing. In particular, their high strength-to-weight ratio makes magnesium alloys attractive for various applications, such as transportation, aerospace industryetc. However, magnesium alloys are still not as popular as aluminum alloys, and a major issue is their corrosion behavior.The present research investigated the influence of the PEO treatment on the corrosion behavior of MRI 230M magnesium alloy. Plasma electrolytic oxidation (PEO) of an MRI 230M alloy was accomplished in a silicate-base electrolyte with KF addition using an AC power source.The corrosion behavior of both treated and untreated samples was evaluated by open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear polarization tests, linear sweep voltammetry (Tafel extrapolation) and chemical methods, such as mass loss and hydrogen evolution, in neutral 3.0 wt% NaCl solution.According to the tests results, PEO process can affect the corrosion resistance of MRI 230M magnesium alloy, though its action is not always unambiguous. An attempt to explain the influence of the PEO treatment on the corrosion behavior of the alloy is presented.

Anti-corrosion performances of hybrid silane coatings on AZ31 alloy

2018 ◽  
Vol 65 (3) ◽  
pp. 317-324 ◽  
Author(s):  
Luigi Calabrese ◽  
Angela Caprì ◽  
Edoardo Proverbio
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Electrochemical Impedance ◽  
Direct Synthesis ◽  
Sol Gel ◽  
Corrosion Properties ◽  
Surface Pretreatment ◽  
Content Type ◽  
Zeolite Content ◽  
Zeolite Coating

Purpose This paper aims to evaluate the efficacy of a zeolite-filled silane sol–gel coating as protective layer on pretreated AZ31 magnesium alloy substrates. Design/methodology/approach Anti-corrosion properties of a silane–zeolite composite coating, at various zeolite content, have been investigated on AZ31 magnesium substrates subjected to different surface pretreatment procedures before coating deposition. A short time etching by hydrofluoric acid (HF) and an anodic polarization in NaOH solution were used as surface pretreatments. Findings High hydrophobicity and good adhesion performances of coatings have been observed. Corrosion protection performance, during immersion in 3.5 per cent NaCl solution, was evaluated by means of electrochemical impedance spectroscopy tests. All coating formulations evidenced good barrier properties. Better durability properties have been shown by coating obtained on HF pretreated magnesium substrate and with a 60 per cent of zeolite content. Originality/value High electrochemical reactivity of magnesium alloys represents the mayor limit of its application in many different fields. In this concern, zeolite-based coatings are emerging as potentially effective environmentally friendly coating for metallic substrates. Despite aluminum and stainless steel substrates, in the literature, only expensive direct synthesis zeolite coating was investigated for its application on magnesium alloys protection. For this reason, this paper fulfills the need to assess the adhesion and anti-corrosion behavior of sol–gel silane–zeolite coating in magnesium alloy substrates.

scholarly journals Evaluation of the Corrosion Resistance and Cytocompatibility of a Bioactive Micro-Arc Oxidation Coating on AZ31 Mg Alloy

Coatings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 396 ◽  
Author(s):  
Shun-Yi Jian ◽  
Mei-Ling Ho ◽  
Bing-Ci Shih ◽  
Yue-Jun Wang ◽  
Li-Wen Weng ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Corrosion Protection ◽  
Treatment Time ◽  
Electrochemical Impedance ◽  
Oxide Coating ◽  
Constant Current ◽  
Micro Arc Oxidation

Magnesium alloys have recently been attracting attention as a degradable biomaterial. They have advantages including non-toxicity, biocompatibility, and biodegradability. To develop magnesium alloys into biodegradable medical materials, previous research has quantitatively analyzed magnesium alloy corrosion by focusing on the overall changes in the alloy. Therefore, the objective of this study is to develop a bioactive material by applying a ceramic oxide coating (magnesia) on AZ31 magnesium alloy through micro-arc oxidation (MAO) process. This MAO process is conducted under pulsed bipolar constant current conditions in a Si- and P-containing electrolyte and the optimal processing parameters in corrosion protection are obtained by the Taguchi method to design a coating with good anti-corrosion performance. The negative duty cycle and treatment time are two deciding factors of the coating’s capability in corrosion protection. Microstructure characterizations are investigated by means of SEM and XRD. The simulation body-fluid solution is utilized for testing the corrosion resistance with the potentiodynamic polarization and the electrochemical impedance test data. Finally, an in vivo testing shows that the MAO-coated AZ31 has good cytocompatibility and anticorrosive properties.

Synthesis of Oxide Nanoparticles in Hybrid Nanocomposite Coatings as Nanoreservoirs of Corrosion Inhibitors

2012 ◽  
Vol 05 ◽  
pp. 234-241 ◽  
Author(s):  
NAHID PIRHADY TAVANDASHTI ◽  
SOHRAB SANJABI
Keyword(s):  
Corrosion Protection ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Oxide Nanoparticles ◽  
Prolonged Release ◽  
Self Healing ◽  
Boehmite Nanoparticles ◽  
Healing Property ◽  
Sol Gel Films

Nanostructured hybrid silica/epoxy films containing boehmite nanoparticles were investigated in the present work as pretreatments for AA2024 alloy. To produce the nanocomposite sol-gel films, boehmite nanoparticles prepared from hydrolysis/condensation of aluminum isopropoxide ( AlI ) were doped into another hybrid organosiloxane sol. The produced oxide nanoparticles have the capability to act as nanoreservoirs of corrosion inhibitors, releasing them controllably to protect the metallic substrate from corrosion. For this purpose the corrosion inhibitor, cerium nitrate, was introduced into the sol-gel system via loading the nanoparticles. The morphology and the structure of the hybrid sol-gel films were studied by Scanning Electron Microscopy (SEM). The corrosion protection properties of the films were investigated by Potentiodynamic Scanning (PDS) and Electrochemical Impedance Spectroscopy (EIS). The results show that the presence of boehmite nanoparticles highly improved the corrosion protection performance of the silica/epoxy coatings. Moreover, they can act as nanoreservoirs of corrosion inhibitors and provide prolonged release of cerium ions, offering a self-healing property to the film.

scholarly journals Hybrid Sol-Gel Coatings Doped with Non-Toxic Corrosion Inhibitors for Corrosion Protection on AZ61 Magnesium Alloy

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 34
Author(s):  
Luis Rodríguez-Alonso ◽  
Jesús López-Sánchez ◽  
Aida Serrano ◽  
Oscar Rodríguez de la Fuente ◽  
Juan Carlos Galván ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Biomedical Applications ◽  
Corrosion Inhibitors ◽  
Sol Gel ◽  
Hybrid Coatings ◽  
Al Alloy ◽  
Ph Measurements ◽  
Sol Gel Process ◽  
Sol Gel Films ◽  
Human Fluid

Physiological human fluid is a natural corrosive environment and can lead to serious corrosion and mechanical damages to light Mg–Al alloys used in prosthetics for biomedical applications. In this work, organic–inorganic hybrid coatings doped with various environmentally friendly and non-toxic corrosion inhibitors have been prepared by the sol-gel process for the corrosion protection of AZ61 magnesium alloys. Effectiveness has been evaluated by pH measurements, optical microscopy, and SEM during a standard corrosion test in a Hanks’ Balanced Salt Solution. The results showed that the addition of an inhibitor to the sol-gel coating can improve significantly the corrosion performance, being an excellent barrier for the L-cysteine-doped hybrid sol-gel films. The incorporation of TiO2 nanoparticles, 2-Aminopyridine and quinine organic molecules slowed down the corrosion rate of the Mg–Al alloy. Graphene oxide seemed to have the same response to corrosion as the hybrid sol-gel coating without inhibitors.

scholarly journals Enhancing the Corrosion Protection of AA2024-T3 Alloy by Surface Treatments Based on Piperazine-Modified Hybrid Sol–Gel Films

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 539
Author(s):  
Diógenes J. Carbonell ◽  
Rodrigo Montoya ◽  
Victoria J. Gelling ◽  
Juan Carlos Galván ◽  
Antonia Jiménez-Morales
Keyword(s):  
Corrosion Inhibitor ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Condensation Reaction ◽  
Sol Gel ◽  
Resonance Spectroscopy ◽  
29Si Nmr ◽  
Crosslinking Degree ◽  
Molar Ratios ◽  
Sol Gel Films

The aim of this study was to develop new chrome-free surface pretreatments for AA2024-T3 aluminum alloy. These pretreatments were based on hybrid organic–inorganic sol–gel thin films prepared from mixtures of γ-methacryloxypropyltrimethoxysilane (MAPTMS) and tetramethylorthosilicate (TMOS). Different MAPTMS/TMOS molar ratios were used for optimizing the physical–chemical characteristics of the sol–gel films. The formulation of a set of these sols was modified by incorporating piperazine (1,4-diazacyclohexane) as a corrosion inhibitor. The resulting sol–gel films were characterized by using Fourier transform infrared spectroscopy (FTIR), liquid-state 29Si nuclear magnetic resonance spectroscopy (29Si-NMR) and viscosity measurements. The corrosion performance of the sol–gel films was analyzed by using electrochemical impedance spectroscopy (EIS) and local electrochemical impedance mapping (LEIM). The characterization techniques indicated that piperazine behaved as a catalyst for the condensation reaction during the formation of the MAPTMS/TMOS organopolysiloxane network and produces an increase of the crosslinking degree of the sol–gel films. EIS and LEIM results showed that piperazine is an effective corrosion inhibitor, which can be used to enhance the active corrosion protection performance of sol–gel films.

scholarly journals Effect of Inorganic Content on the Performance of Anticorrosive Hybrid Sol-Gel Coated EN AW-6063 Alloy

2012 ◽  
Vol 730-732 ◽  
pp. 745-750
Author(s):  
Rute I. Fontinha ◽  
Manuela M. Salta ◽  
Mikhail L. Zheludkevich ◽  
Mário G.S. Ferreira
Keyword(s):  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Hybrid Coatings ◽  
Molar Ratio ◽  
Gravimetric Analysis ◽  
Inorganic Content ◽  
Pre Treatment ◽  
Sol Gel Films

The organic-inorganic hybrid sol-gel films have been reported as an effective anti-corrosion and environmentally friendly alternative to Cr(VI) pre-treatment for aluminium alloys. The sol-gel process used to obtain these coatings allows the variation of the different synthesis parameters to achieve coatings with optimized properties. In this work, hybrid films with different Zr/Si ratios were synthesized from glycidoxypropyltrimethoxysilane (GPTMS) and zirconium n-propoxide (TPOZ) precursors. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate the corrosion behaviour of coated aluminium specimens in 0.5 M NaCl solution. The morphology and chemical structure of the hybrid coatings prepared were studied by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), Fourier Transformed Infrared Spectroscopy (FTIR) and Thermo Gravimetric Analysis (TGA). It was found that increasing Zr/Si ratio leads to a more cross linked inorganic network, resulting in higher initial coatings resistance, but may turn coatings more hydrophilic, prone to rapid degradation in water, due to a less connected organic network. Consequently, the best anticorrosive performance derives from the balance between the two opposite trends and it was achieved with Zr/Si molar ratio of 0.25.

Controlled release and corrosion protection by self-assembled colloidal particles electrodeposited onto magnesium alloys

2015 ◽  
Vol 3 (8) ◽  
pp. 1667-1676 ◽  
Author(s):  
Jiadi Sun ◽  
Ye Zhu ◽  
Long Meng ◽  
Wei Wei ◽  
Yang Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Controlled Release ◽  
Magnesium Alloys ◽  
Corrosion Protection ◽  
Colloidal Particles ◽  
Self Assembled ◽  
Bioactive Agents

Self-assembled nanoparticles loaded with bioactive agents were electrodeposited to provide the magnesium alloy with controlled release and corrosion resistance properties.

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