Anodic Oxidation and Silane Treatment for Corrosion Protection of AM60B Magnesium Alloy

2011 ◽  
Vol 690 ◽  
pp. 413-416 ◽  
Author(s):  
Anna da Forno ◽  
Massimiliano Bestetti ◽  
Nora Lecis ◽  
Stefano Paolo Trasatti ◽  
Monica Trueba
Keyword(s):  
Magnesium Alloy ◽  
Anodic Polarization ◽  
Oxidation Process ◽  
Composite Coatings ◽  
Silane Treatment ◽  
Nacl Solution ◽  
Corrosion Resistant ◽  
Micro Arc Oxidation ◽  
Corrosion Resistant Coatings ◽  
Scratch Tests

Oxide films have been produced on AM60B magnesium alloy using micro-arc oxidation process in an environmentally friendly alkaline solution with and without addition of different oxides nanoparticles (TiO2, ZrO2 and Al2O3). In order to seal the oxides porosity generated in the sparking process, a silane-based top coat has been applied. The surface morphology of samples was analyzed by Scanning Electron Microscopy (SEM). Scratch tests were performed for evaluating the adhesion strength of the anodic oxides. The corrosion resistance of the oxide- silane- based topcoat composite coatings was evaluated in 3.5% NaCl solution using anodic polarization tests. The anodizing in oxides nanoparticles rich solutions (ZrO2 or Al2O3), followed by a silane top coat treatment performed using OSi as precursor, is an interesting way to synthesize adherent corrosion resistant coatings on magnesium alloy AM60B.

Microstructure and Corrosion Resistance of Black Microarc Oxidation Ceramic Coatings on Magnesium Alloy

2012 ◽  
Vol 581-582 ◽  
pp. 427-430
Author(s):  
Sheng Xue Yu ◽  
Rui Jun Zhang ◽  
Qiao Yan Lv
Keyword(s):  
Aqueous Solution ◽  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Microarc Oxidation ◽  
Ceramic Coatings ◽  
Nacl Solution ◽  
Corrosion Resistant ◽  
Before And After ◽  
Micro Arc Oxidation ◽  
Immersion Experiment

Black micro-arc oxidation (MAO) ceramic coatings were prepared on magnesium alloy in a silicate electrolyte; SEM, EDS and XRD were tested to analyze surface morphology, chemical composition and phase composition of ceramic coatings, Corrosion resistant in 3.5％ NaCl aqueous solution of magnesium alloy before and after MAO treatment was evaluated by polarization curves and electrochemical impedance spectroscopy (EIS); the weight loss of magnesium alloy with black MAO ceramic coatings in 3.5％ NaCl aqueous solution was studied through immersion experiment. The results indicated that, the black MAO ceramic coatings was composed by Mg、Al、Si、Cu and O; black MAO ceramic coatings could protect magnesium alloy substrate effectively; the corrosion resistant of black MAO ceramic coatings in neutral 3.5% NaCl solution was favorable.

Calcium and Phosphate Biocoatings on Magnesium Alloy Fabricated by Micro-Arc Oxidation

2010 ◽  
Vol 105-106 ◽  
pp. 565-568 ◽  
Author(s):  
Chen Ma ◽  
Xiang Yu Zhang ◽  
Li Jie Qu ◽  
Mu Qin Li
Keyword(s):  
Magnesium Alloy ◽  
Friction Coefficient ◽  
Composite Coatings ◽  
Pulse Frequency ◽  
Test Machine ◽  
Anode Polarization ◽  
Corrosion Resistant ◽  
Alloy Substrate ◽  
Phosphate Ions ◽  
Micro Arc Oxidation

Calcium phosphate biocoatings were fabricated on the surface of magnesium alloy by micro-arc oxidation (MAO) technique. The properties of biocoatings related with MAO technics parameters and the electrolyte constitute. The surface morphology, constitute and friction coefficient were studied by SEM XRD and fret test machine. The results indicated that the optimum electrolyte was CaCO3-Na3PO4 contained 20g/L phosphate ions and 1.5 Ca/P ratio, and the optimum technics parameters was 350V oxidation voltage for10min, 500HZ pulse frequency and 1:10 in duty cycle. The main phase constitutes of the porous biocoatings contained were Mg, MgO, Mg3(PO4)2 and CaNaPO4. The anode polarization potential of the coating was -1.36V and enhanced about 0.29V compared with that of magnesium alloy substrate, which indicated that the biocoatings had better corrosion resistant properties. The friction coefficient of the biocoatings was 0.23 and decreased 0.15 compared with that of magnesium alloy substrate, which indicated that the biocoatings had better wear resistant properties. The biocoatings could induce hydroxyapatite to form on its surface after soaked in body fluid, which showed that the composite coatings owned good bioactivity.

Corrosion resistant metal-ceramic composite coatings for tribological applications

2021 ◽  
pp. 1-34
Author(s):  
Peter Renner ◽  
Swarn Jha ◽  
Yan Chen ◽  
Tariq Chagouri ◽  
Serge Kazadi ◽  
...  
Keyword(s):  
Ceramic Composite ◽  
Low Cost ◽  
Composite Coatings ◽  
Salt Spray ◽  
Extreme Environments ◽  
Safe Procedure ◽  
Corrosion Resistant ◽  
Wide Range ◽  
Metal Ceramic ◽  
Corrosion Resistant Coatings

Abstract Effective design of corrosion-resistant coatings is critical for the protection of metals and alloys. Many state-of-the-art corrosion-resistant coatings are unable to satisfy the challenges in extreme environments for tribological applications, such as elevated or cryogenic temperatures, high mechanical loads and impacts, severe wear, chemical attack, or a combination of these. The nature of challenging conditions demands that coatings have high corrosion and wear resistance, sustained friction control, and maintain surface integrity. In this research, multi-performance metal-ceramic composite coatings were developed for applications in harsh environments. These coatings were developed with an easy to fabricate, low-cost, and safe procedure. The coating consisted of boron nitride, graphite, silicon carbide, and transition metals such as chromium or nickel using epoxy as vehicle and bonding agent. Salt spray corrosion tests showed that 1010 carbon steel (1/4 hard temper) substrates lost 20-100× more mass than the coatings. The potentiodynamic polarization study showed better performance of the coatings by seven orders of magnitude in terms of corrosion relative to the substrate. Additionally, the corrosion rates of the coatings with Ni as an additive were five orders of magnitude lower than reported. The coefficient of friction of coatings was as low as 0.1, five to six times lower than that of epoxy and lower than a wide range of epoxy resin-based coatings found in literature. Coatings developed here exhibited potential in applications in challenging environments for tribological applications.

Bioactivity, Wear and Corrosion Resistant Properties of Rare Earth/Calcium Phosphate Composite Coatings

2008 ◽  
Vol 368-372 ◽  
pp. 1194-1197 ◽  
Author(s):  
Chen Ma ◽  
Ying Hui Wang ◽  
Mu Qin Li ◽  
Li Jie Qu
Keyword(s):  
Rare Earth ◽  
Calcium Phosphate ◽  
Composite Coatings ◽  
Xrd Analysis ◽  
Wear Properties ◽  
Corrosion Resistant ◽  
Phosphate Coatings ◽  
Wear And Corrosion ◽  
Micro Arc Oxidation ◽  
Calcium Phosphate Coatings

Rare earth/calcium phosphate composite coatings were fabricated on the surface of Ti-6Al-4V by micro-arc oxidation (MAO) technique. The wear properties and corrosion resistant of rare earth/ calcium phosphate composite coatings in the simulated body fluid (SBF) have been investigated and the bioactivity of the composite coatings were evaluated. The results show that the friction coefficient of the composite coatings in the SBF is only 0.15~0.18 and the anode polarization potential of the coating has been obviously enhanced about 0.18V compared with that of coatings of calcium phosphate coatings. So the composite coatings have excellent wear and corrosion resistant properties. XRD analysis indicates that the composite coatings can induce hydroxyapatite to form on its surface after soaked in SBF for 9d, which shows that the composite coatings own good bioactivity.

The Characteristic of Ceramic Coatings Prepared on Magnesium Alloy AZ91D by Micro-Arc Oxidization in Silicate Electrolyte

2010 ◽  
Vol 146-147 ◽  
pp. 941-947
Author(s):  
Xi Chang Shi ◽  
Xiang Xiao ◽  
Bai Zhen Chen ◽  
Wei Shang
Keyword(s):  
Magnesium Alloy ◽  
Outer Region ◽  
Ceramic Coatings ◽  
Nacl Solution ◽  
Acacia Gum ◽  
Alloy Az91d ◽  
Micro Arc Oxidation ◽  
Distribution Phase ◽  
Magnesium Surface ◽  
Better Than

A novel process of micro-arc oxidation (MAO) on AZ91D magnesium alloy is investigated in a Na2SiO3-NaOH-montmorillonite-EDTA-acacia gum electrolyte solution. The morphologies, elements distribution, phase components of the coatings are characterized by SEM, EDS and XRD. And CHI600 electrochemistry corrosion workstation is employed to investigate the property of corrosion resistance of the coatings. Furthermore, the anti-corrosion behavior is analyzed immersed in 3.5 wt. % NaCl solution. The results reveal that the ceramic coatings have the relatively dense and uniform in thickness and the silicon element tends to present primarily in the outer region of the coatings. The XRD results indicate that the oxide films are mainly composed of Mg2SiO4 and MgAl2O4 phases. The immersion results show that the corrosion resistances of the ceramic coatings on AZ91D magnesium surface are better than the magnesium substrate.

Laser Cladding of Zr55Al10Ni5Cu30/SiC Amorphous Composite Coatings on AZ91D Magnesium Alloy for Improvement of Corrosion Resistance

2011 ◽  
Vol 179-180 ◽  
pp. 757-761 ◽  
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Rong Zhou
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Laser Cladding ◽  
Composite Coatings ◽  
Corrosion Property ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Corrosion Resistance ◽  
Az91d Magnesium Alloy

To improve the corrosion property of magnesium alloys, Zr-based amorphous composite coatings have been fabricated on AZ91D magnesium alloy by laser cladding using mixed powders Zr55Al10Ni5Cu30/SiC. The microstructure of the coating was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The corrosion resistance of the coatings was tested in 3.5wt.% NaCl solution. The results show that the coatings mainly consist of amorphous and different crystalline phases. The coatings compared with AZ91D magnesium alloy exhibit good corrosion resistance because of the presence of the amorphous phase in the coatings.

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.

Enhancing Conductivity and Corrosion Resistance by Organic Coatings on AZ31 Magnesium Alloy Treated by Micro-Arc Oxidation

2019 ◽  
Author(s):  
Xiuping Zhang ◽  
Lei Li ◽  
Yaozhao Mu ◽  
Yanxiang Xie ◽  
Jun Dai ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Carbon Black ◽  
Composite Coatings ◽  
Electrochemical Corrosion ◽  
Organic Coating ◽  
Organic Coatings ◽  
Micro Arc Oxidation ◽  
Conductive Particles

Abstract In this study, an organic coating, in combination of a micro-arc oxidation ceramic layer, was prepared on the surface of a magnesium alloy (AZ31) to achieve both functions of corrosion resistance and electrical conductivity. By using carbon black as conductive particles and epoxy resin as matrix, organic coatings of various weight fractions were applied on the AZ31 surface treated by micro-arc oxidation through adjusting the contents of the conductive particles and non-conductive matrix. Electrical conductivity and corrosion resistance of organic coatings were measured. The results show that the organic coatings can improve the electrical conductivity of the AZ31 material treated by micro-arc oxidation, and the conductivity changes with the ratio between the carbon black particles and non-conductive matrix. The smallest resistance value of the organic coatings reached 130Ω. Also, the organic coating can further improve the corrosion resistance of the AZ31 material. The electrochemical corrosion tests show that the corrosion potential of the AZ31 material with composite coatings was at least 0.6V higher than that of AZ31 only with micro-arc oxidation treatment.

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