scholarly journals Corrosion protection of AZ91D magnesium alloy by a duplex coating

2020 ◽  
Vol 85 (10) ◽  
pp. 1317-1328
Author(s):  
López Forero ◽  
Ana Loperena ◽  
Ivana Lehr ◽  
Lorena Brugnoni ◽  
Silvana Saidman
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Antibacterial Properties ◽  
Silver Ions ◽  
Ringer Solution ◽  
Open Circuit ◽  
Duplex Coating ◽  
Alloy Az91d

A duplex coating was formed under potentiostatic conditions on magnesium alloy AZ91D in order to improve its corrosion resistance in a simulated physiological environment. The first layer was formed by anodization at low potentials in molybdate solution. The outer layer was a PPy film electrosynthesized in sodium salicylate solution. The conditions of the formation were determined to obtain a layer with globular morphology. The bilayer was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion protection properties of the coatings were examined in Ringer solution by monitoring the open circuit potential (OCP), polarization techniques, and electrochemical impedance spectroscopy (EIS). The obtained results showed that the bilayer improves the corrosion resistance of the substrate. Moreover, the duplex coating presented better anticorrosive properties than a single PPy film. Afterwards, the bilayer was modified by cementation of silver ions from a solution containing AgNO3. The modified electrode exhibited good antibacterial properties.

scholarly journals Corrosion Resistance of Mg72Zn24Ca4 and Zn87Mg9Ca4 Alloys for Application in Medicine

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3515
Author(s):  
Andrzej Fijołek ◽  
Janusz Lelito ◽  
Halina Krawiec ◽  
Jagoda Ryba ◽  
Łukasz Rogal
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Melt Spinning ◽  
Electrochemical Impedance ◽  
Cast Alloy ◽  
Ringer Solution ◽  
Open Circuit ◽  
Chloride Ions ◽  
Zinc Alloy ◽  
Corrosion Tests

The aim of this work was to monitor the corrosion rate of the Mg72Zn24Ca4 and Zn87Mg9Ca4 alloys. The purity of the alloying elements was 99.9%. The melt process was carried out in an induction furnace. The melting process took place under the cover of an inert gas (argon). The copper form was flooded by liquid alloy. Then, in order to obtain ribbons, the cast alloy, in rod shape, was re-melted on the melt spinning machine. The corrosion resistance of both alloys has been determined on the basis of the following experiments: measurements of the evolution of OCP (open circuit potential), LSV (linear sweep voltamperometry) and EIS (electrochemical impedance spectroscopy). All corrosion tests were carried out in Ringer’s solution at 37 °C and pH 7.2. The corrosion tests have revealed that the zinc alloy, Zn87Mg9Ca4, exhibits significantly higher corrosion resistance in the Ringer solution compared to the magnesium alloy, Mg72Zn24Ca4. Moreover, it has been shown that the cathodic reaction proceeds faster on the surface of ribbons. EIS measurements show that the dissolution of Mg alloy proceeds with two steps: transfer of Mg2+ ions to the Ringer solution and then the formation of the corrosion products, which are deposited on the surface of magnesium alloy. It has been revealed, too, that for both bulk materials, diffusion of chloride ions through the corrosion product’s layer takes place.

scholarly journals Corrosion behavior in Ringer solution of several commercially used metal alloys

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Carmen Marina Garcia-Falcon ◽  
Tomas Gil-Lopez ◽  
Amparo Verdu-Vazquez ◽  
Julia Claudia Mirza-Rosca
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Dental Materials ◽  
Ringer Solution ◽  
Open Circuit ◽  
Metal Alloys ◽  
Cylindrical Shape ◽  
Content Type ◽  
Biological Safety

Purpose This paper aims to analyze the corrosion behavior in Ringer solution of six commercially used Ni-based alloys that are present and commonly used as metallic biomaterials. Design/methodology/approach The specimens were received in the form of cylindrical ingots and were cut to get five samples of each brand with a cylindrical shape of 2 mm height to conduct the study. In this scientific research, the following techniques were used: open circuit potential, potentiodynamic polarization studies, and electrochemical impedance spectroscopy. Findings The study findings revealed the passivation tendency of the different specimens. Additionally, when the materials were compared, it was discovered that the decisive factor for high corrosion resistance was the chromium concentration. However, with similar chromium content, the stronger concentration in molybdenum increased the resistance. According to the results obtained in this investigation, the biological safety of the dental materials studied in Ringer solution was considered very high for specimens 1 and 2, and adequate for the other samples. Originality/value Metal alloys used as biomaterials in contact with the human body should be deeply investigated to make sure they are biocompatible and do not cause any harm. The corrosion resistance of an alloy is the most important characteristic for its biological safety, as all problems arise because of the corrosion process. There is scarce investigation in these Ni-based dental biomaterials, and none found in these commercially used dental materials in Ringer solution.

Corrosion of an Active Antibacterial Nanostructured Coating on Titanium

2018 ◽  
Vol 69 (5) ◽  
pp. 1115-1121 ◽  
Author(s):  
Daniela Ionita ◽  
Luiza Necula ◽  
Mariana Prodana ◽  
Georgeta Totea ◽  
Ioana Demetrescu
Keyword(s):  
Corrosion Resistance ◽  
Tio2 Nanotubes ◽  
Electrochemical Impedance ◽  
Antibacterial Properties ◽  
Barrier Properties ◽  
Ringer Solution ◽  
Contact Method ◽  
Properties Of Coatings ◽  
Stable Domain ◽  
Ha Coating

This study aims on antibacterial and corrosion characterization of a complex ceramic coating based on titania (TiO2) nanotubes, hydroxyapatite (HA) and single walled carbon nanotubes (SWCNTs), in physiological environment. Hybrid materials structure was identified by Fourier transformed infrared spectroscopy (FTIR) and their surface analysed by scanning electron microscopy (SEM) and contact angle analysis. The most hydrophilic sample was the one with TiO2-HA coating. The electrochemical behavior of materials has been investigated in Ringer solution performing potentiodiynamic polarization and electrochemical impedance spectroscopy. Antibacterial properties of coatings were determined by contact method using two types of strains, one of them Staphylococus aureus (S. aureus) is a positive gram bacteria and another one Pseudomonas aureoginosa (P. aureoginosa) a negative gram bacteria. The corrosion rates are in the perfect stable domain of corrosion resistance and no breakdown phenomena were observed. A range of stability in tested bioliquid has been established from electrochemical and ICP-MS measurements. TiO2-HA-SWCNTs coating has the best corrosion resistance and the best barrier properties for ions release. Antibacterial effect of TiO2-HA-SWCNTs coating seems to be synergistic being higher compared to TiO2 nanotubes and TiO2-HA coating.

Corrosion resistance of ZrO2–Zr-coated biodegradable surgical magnesium alloy

2008 ◽  
Vol 23 (2) ◽  
pp. 312-319 ◽  
Author(s):  
Yunchang Xin ◽  
Chenglong Liu ◽  
Wenjun Zhang ◽  
Kaifu Huo ◽  
Guoyi Tang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Surface Hardness ◽  
Hardness Measurement ◽  
Open Circuit ◽  
Coated Sample ◽  
Az91 Magnesium Alloy ◽  
Coated Alloy

Magnesium alloys are potential biodegradable biomaterials in hard tissue implants. However, the fast degradation rate in the biological environment has hampered widespread applications. We propose to use a ZrO2 coating in conjunction with a Zr transition layer to improve the corrosion resistance of AZ91 magnesium alloy. X-ray photoelectron spectroscopy discloses that the coating is composed of ZrO2. The Vickers hardness measurement demonstrates that the surface hardness of the alloy is significantly enhanced. The electrochemical behavior of the coated sample is systematically evaluated by means of potentiodynamic polarization, open-circuit potential evolution, and electrochemical impedance spectroscopy. The electrochemical results indicate that the corrosion resistance of the coated alloy is enhanced significantly, and the electrode-controlled processes in a coated alloy–solution system are discussed.

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 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.

Electrosynthesis of a Duplex Coating Consisting of a Cerium-Based Layer and a Polypyrrole Film for the Corrosion Protection of AISI 304 Stainless Steel

2021 ◽  
Vol 8 ◽  
pp. 1-11
Author(s):  
A.P. Loperena ◽  
I.L. Lehr ◽  
S.B. Saidman
Keyword(s):  
Stainless Steel ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
304 Stainless Steel ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Protection Efficiency ◽  
Duplex Coating ◽  
Polypyrrole Film

Duplex coating consisting of an inner cerium-based layer and polypyrrole (PPy) film topcoat was electrodeposited onto AISI 304 stainless steel. The cerium-based coating was electrodeposited in solutions containing cerium nitrate at 50 ºC. The polymeric outer layer was electropolymerized in the presence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT). The electrosynthesis was done under potentiostat conditions. The coatings were characterized by scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDX). The morphology of the double-layered cerium polypyrrole film shows a granular structure with the presence of agglomerates of small grains. The anticorrosive performance of the coatings was evaluated in sodium chloride solution by linear polarization, open circuit measurements, and electrochemical impedance spectroscopy (EIS). Single films, cerium layer and PPy coating, and the duplex film all reduce the corrosion rate of AISI 304 stainless steel in NaCl solution. The duplex coating presents an improved corrosion resistance concerning the single films. The combination of the characteristics of the single layers is responsible for the superior corrosion protection efficiency of the double-layered cerium polypyrrole coating.

scholarly journals Role of Surface Preparation in Corrosion Resistance due to Silane Coatings on a Magnesium Alloy

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6663
Author(s):  
Abhishek Saxena ◽  
R. K. Singh Raman
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Alkali Treatment ◽  
Surface Preparation ◽  
Alloy Az91d ◽  
Silane Coating ◽  
Different Types ◽  
Coated Alloy

Coating of an organo-silane (Bis-1,2-(TriethoxySilyl)Ethane (BTSE)) has been observed to improve the corrosion resistance of magnesium alloy AZ91D. Three different types of surface preparations have been employed before condensing the silane coating on to the substrate. Corrosion resistance was investigated using electrochemical impedance spectroscopy (EIS). A specific alkali treatment of the substrate prior to the coating has been found to improve the corrosion resistance of the coated alloy, which has been attributed to the ability of the treatment in facilitating the condensation of a relatively compact siloxane film.

Improvement of Adhesion Strength of Electroless Nickel Coating on AZ91D by Anodized Oxide Interlayer

2012 ◽  
Vol 509 ◽  
pp. 90-95
Author(s):  
Hsien Ta Hsu ◽  
Tsong Jen Yang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Adhesion Strength ◽  
Electroless Nickel ◽  
Anodic Oxide ◽  
Duplex Coating ◽  
Az91d Magnesium Alloy ◽  
Alloy Az91d ◽  
Surface Morphologies ◽  
Electroless Ni

Nickel-oxide duplex coatings were successfully deposited on magnesium alloy (AZ91D) by anodizing and electroless nickel-phosphorus plating processes. The anodizing interlayer was used to increase the adhesion strength of Ni-P layer. The electroless Ni-P coating enhances the corrosion resistance of the anodic oxide layer. Specimen of AZ91D magnesium alloy was polished firstly. The anodizing process was preceded in alkaline anodizing solution at 24 °C, and the bath voltage maintained at 70 volts for 2 hours. Successive electroless Ni-P plating was used to achieve the sandwich structure. The surface morphologies of the coatings were observed by field-emission scanning electron microscopy (FE-SEM). The adhesion strength was measured by pull-off tester. The electrochemical behavior of coatings with corrosion resistance in 3.5 wt.% NaCl solution was evaluated by potential polarization curve. The experimental results showed that the adhesion strength of directly deposited coating and duplex coating were 115.4 kgf/cm2 and 142.2 kgf/cm2, respectively. The adhesion strength of coatings on AZ91D magnesium alloy was improved by the synergistic effect between anodized magnesium oxide and Ni-P layer in duplex coating.

The Characteristic of the Coating Prepared on Magnesium Alloy AZ91D by Micro-Arc Oxidization

2011 ◽  
Vol 418-420 ◽  
pp. 751-755
Author(s):  
Wei Shang ◽  
Yu Qing Wen ◽  
Yan Yun Qin ◽  
Fang He ◽  
Ji Yun Fang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Protection ◽  
Electrolyte Solution ◽  
Phase Component ◽  
Az91d Magnesium Alloy ◽  
Acacia Gum ◽  
Alloy Az91d ◽  
Micro Arc Oxidation ◽  
Electric Parameters

Micro-arc oxidation coating on AZ91D magnesium alloy is prepared in a NaAlO2-NaOH-montmorillonite-acacia gum electrolyte solution with adaptive electric parameters. The morphologies, composition, phase component of the coatings are analyzed by SEM, EDS and XRD. And CHI600B electrochemistry workstation is employed to investigate the corrosion resistance of the coatings. The results show that the MAO coating has the relatively uniform in thickness. The coating is mainly composed of MgO and MgAl2O4 phases. It provides corrosion protection by acting as a barrier. The MAO coating enhances the corrosion resistance of the magnesium alloy AZ91D to some extent.

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