FORMATION OF HA-CONTAINING COATING ON AZ31 MAGNESIUM ALLOY BY MICRO-ARC OXIDATION

2013 ◽  
Vol 20 (03n04) ◽  
pp. 1350026 ◽  
Author(s):  
HUI TANG ◽  
DEYU LI ◽  
XIUPING CHEN ◽  
CHAO WU ◽  
FUPING WANG
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Channel Model ◽  
Optical Emission ◽  
Biological Properties ◽  
Az31 Magnesium Alloy ◽  
Apatite Formation ◽  
Biodegradable Implant ◽  
Electrochemical Tests ◽  
Micro Arc Oxidation

Magnesium and its alloys are potential biodegradable implant materials due to their attractive biological properties. But the use of magnesium is still hampered by its poor corrosion resistance in physiological fluids. In this study, a HA-containing coating was fabricated by micro-arc oxidation (MAO). The active plasma species of micro-discharge was studied by optical emission spectroscopy (OES). The microstructure and composition were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion behavior and apatite-forming ability were studied by electrochemical tests and immersed samples in simulated body fluids (SBF). The results show that the microdischarge channel model is gas discharges and oxide layer discharges. The elements from the substrate and electrolyte take part in the formation of the coating. The MAO coating significantly improves the corrosion resistance of AZ31 magnesium alloy and enhances the apatite formation ability.

scholarly journals Preparation and Characterization of a Sol–Gel AHEC Pore-Sealing Film Prepared on Micro Arc Oxidized AZ31 Magnesium Alloy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 784
Author(s):  
Longlong Zhang ◽  
Yuanzhi Wu ◽  
Tian Zeng ◽  
Yu Wei ◽  
Guorui Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Sol Gel ◽  
Oxide Coating ◽  
Az31 Magnesium Alloy ◽  
Hydroxyethyl Cellulose ◽  
Gel Spinning ◽  
Test Analysis ◽  
Pore Sealing ◽  
Micro Arc Oxidation

The purpose of this study was to improve the cellular compatibility and corrosion resistance of AZ31 magnesium alloy and to prepare a biodegradable medical material. An aminated hydroxyethyl cellulose (AHEC) coating was successfully prepared on the surface of a micro-arc oxide +AZ31 magnesium alloy by sol–gel spinning. The pores of the micro-arc oxide coating were sealed. A polarization potential test analysis showed that compared to the single micro-arc oxidation coating, the coating after sealing with AHEC significantly improved the corrosion resistance of the AZ31 magnesium alloy and reduced its degradation rate in simulated body fluid (SBF). The CCK-8 method and cell morphology experiments showed that the AHEC + MAO coating prepared on the AZ31 magnesium alloy had good cytocompatibility and bioactivity.

scholarly journals Corrosion Behaviour of Preserved PEO Coating on AZ31 Magnesium Alloy

2020 ◽  
Vol 23 (2) ◽  
pp. B76-B88
Author(s):  
Filip Pastorek ◽  
Milan Štrbák ◽  
Daniel Kajánek ◽  
Martina Jacková ◽  
Jana Pastorková ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Treatment Process ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Az31 Magnesium Alloy ◽  
Electrochemical Tests ◽  
Marine Transport ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

A surface treatment process, composed of plasma electrolytic oxidation (PEO) and sealing by temporary oil preservation system containing corrosion inhibitors, was performed on AZ31 magnesium alloy in order to improve its corrosion resistance in environments containing chlorides. Both atmospheric and immersion conditions were evaluated by electrochemical tests in 0.1M NaCl solution together with salt spray test according to STN EN ISO 9227 standard. The obtained results confirmed significant improvement of corrosion resistance reached by the PEO sealing in aggressive environments compared to the pure PEO coating on AZ31 surface. Hence, such a duplex coating is a very perspective alternative for magnesium alloy applications in severe conditions or for temporary protection of magnesium products coated by the PEO during marine transport.

PREPARATION OF GRAYISH BLACK FILM ON AM50 MAGNESIUM ALLOY BY CHEMICAL CONVERSION–MICRO-ARC OXIDATION

2016 ◽  
Vol 24 (01) ◽  
pp. 1750012 ◽  
Author(s):  
ZHONGCAI SHAO ◽  
FEIFEI ZHANG ◽  
QINGFANG ZHANG ◽  
LI YANG ◽  
XIAOYI SHEN
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Composite Film ◽  
Chemical Conversion ◽  
X Ray Diffraction ◽  
Black Film ◽  
X Ray ◽  
Electrochemical Tests ◽  
Micro Arc Oxidation ◽  
Optimum Formula

The grayish black film was prepared on AM50 magnesium alloy with a new method which combined chemical conversion with micro-arc oxidation (MAO). The optimum formula of chemical conversion was obtained by L9(34) orthogonal test. Meanwhile, the morphology, structure, composition and corrosion resistance of films were analyzed by scanning electron microscopy (SEM), energy spectrum analysis (energy dispersive X-ray spectroscopy (EDS)), X-ray diffraction (XRD), electrochemical tests and CuSO4 drip experiment. The results indicated that Mo element was introduced into the MAO film by chemical conversion pretreatment. The surface of composite film was smooth and compact. The main phase composition of the composite film were SiO2, Mo9O[Formula: see text], MgSiO[Formula: see text] Mg2SiO4 and Mo9O[Formula: see text] was identified to be responsible for giving color to the film. The corrosion resistance of the grayish black film was improved obviously.

Influence of Current Density on Structure and Performance of Micro-Arc Oxidation Coatings on AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 562-566 ◽  
Author(s):  
Mei Yang ◽  
Zheng Lei ◽  
Xiao Hong Wang ◽  
Ping Wang ◽  
Jun Yang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Current Density ◽  
Adhesion Force ◽  
Water Solution ◽  
Corrosion Current ◽  
Az31 Magnesium Alloy ◽  
Positive Direction ◽  
Micro Arc Oxidation ◽  
And Performance

In the Na2SiO3-NaOH-C3H8O3electrolyte system,the micro-arc oxidation (MAO) coatings were prepared on AZ31 magnesium alloy when J=2A/dm2,4A/dm2,8A/dm2and 12A/dm2.The relations of current density with microstructure and performance of the MAO coatings on AZ31 were studied by means of SEM, XRD, HVS-1000 micro Vicker, MFT-4000 Scratch Tester and electro-chemical method. The results show that when current density increases,the thickness,growth rate,micro-hardness and the contents of MgO and Mg2SiO4of MAO coatings increase,but the adhesion force between MAO coating and substrate decreases, the millipores and the roughness become larger.The corrosion resistance of MAO coatings increases firstly and then decreases with the increasing current density.The corrosion resistance of MAO coating,which J=6 A/dm2,is the best in 4.5% NaCl water solution,whose corrosion current density reduces by 3 orders of magnitude, and corrosion potential increases 1078mV in positive direction.

Corrosion Characteristics of Friction Stir Welded AZ31 Magnesium Alloy

2013 ◽  
Vol 785-786 ◽  
pp. 97-100 ◽  
Author(s):  
Chang Bin Shen
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Comparative Evaluation ◽  
Research Work ◽  
Az31 Magnesium Alloy ◽  
Corrosive Media ◽  
Electrochemical Tests ◽  
Friction Stir ◽  
Corrosion Rates ◽  
Ph Values

A comparative evaluation of the corrosion behavior of friction stir welded AZ31 weldments under immersion and electrochemical tests was revealed. Extruded Mg alloy plates of 6 mm thick of AZ31 grade were butt welded using friction stir welding (FSW) process. The specimens were exposed to immersion and polarization environments in order to evaluate their corrosion rates at the corrosive media containing Cl-with different pH values. This research work proves a better corrosion resistance of AZ31 magnesium alloy welds at the alkaline solution than the acidic and the neutral solutions.

A Preliminary Study of Anodization and Electroless Ni–P Plating on AZ80 Magnesium Alloy

2011 ◽  
Vol 299-300 ◽  
pp. 663-666 ◽  
Author(s):  
Ping Shi ◽  
Xue Dong Han
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Weight Ratio ◽  
High Strength ◽  
Surface Modifications ◽  
Atomic Ratio ◽  
Az80 Magnesium Alloy ◽  
Micro Arc Oxidation ◽  
Preliminary Study ◽  
Electroless Ni

Magnesium alloys are being used as structural components in industry because of their high strength to weight ratio. But their high electrochemical activity and poor corrosion resistance limited their applications. Therefore, surface modifications are needed for protection purpose. This paper studied the anodic micro-arc oxidation and electroless Ni-P plating surface modifications on AZ80 magnesium alloy. The SEM, XRD and EDS were used to characterize the surface coating. It shows that a micro-porous MgO layer with the pores size 5 – 20 μm was fabricated on the bare magnesium alloy. The nodule Ni-P deposition could be prepared on the out layer of MgO with Ni/P atomic ratio being 1.4. The pores in MgO layer could be sealed by the following Ni-P deposition. Therefore the corrosion resistance of the magnesium alloy could be further improved.

Al–AlN composite coatings on AZ31 magnesium alloy for surface hardening and corrosion resistance

Vacuum ◽  
2021 ◽  
pp. 110146
Author(s):  
Wenling Xie ◽  
Yiman Zhao ◽  
Bin Liao ◽  
Pan Pang ◽  
Dongsing Wuu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Surface Hardening ◽  
Composite Coatings ◽  
Az31 Magnesium Alloy

Phosphate film free of chromate, fluoride and nitrite on AZ31 magnesium alloy and its corrosion resistance

2012 ◽  
Vol 22 (11) ◽  
pp. 2713-2718 ◽  
Author(s):  
Xue-jun CUI ◽  
Chun-hai LIU ◽  
Rui-song YANG ◽  
Ming-tian LI ◽  
Xiu-zhou LIN ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Az31 Magnesium Alloy ◽  
Phosphate Film
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