Optimized Micro-Arc Oxidation Coating Thickness on ALZ Magnesium Lithium Alloy

2020 ◽  
Vol 975 ◽  
pp. 37-42
Author(s):  
Le Hung Toan Do ◽  
Shuo Jen Lee ◽  
Duc Binh Luu ◽  
Quang Bang Tao ◽  
Nhu Thanh Vo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Coating Thickness ◽  
Thickness Measurement ◽  
High Voltage Power Supply ◽  
Lithium Alloy ◽  
Coating Uniformity ◽  
Valve Metal ◽  
Micro Arc Oxidation ◽  
Predicted Values ◽  
Corrosive Environments

Micro-arc oxidation (MAO) is known as a novel technique to use for the modifying the surface of valve metal, which improve mechanical and corrosion resistance properties. In this study, MAO coatings are fabricated on ALZ magnesium lithium alloy to protect the substrate from corrosion using environmentally friendly electrolytes under a high voltage power supply. The Taguchi method is used to identify the effects of current density, coating time and electrical frequency on the thickest coating uniformity. The optimum coating properties are characterized by coating thickness measurement, Scanning electron microscopy (SEM), Potentiodynamic polarization analysis. It was found that the processing time is the main factor affecting the thickest coating uniformity (tu). Coatings fabricated under optimum conditions are in close agreement with the predicted values of Taguchi analysis. The corrosion resistance of MAO coated on ALZ magnesium lithium alloy are greatly improved compare to the bare alloy in corrosive environments.

scholarly journals Thickness and corrosion resistance optimization of Micro-ARC oxidation coating on Mg-Al-Li-Zn alloy using Taguchi approach

2020 ◽  
pp. 62-66
Author(s):  
Do Le Hung Toan, Shuo-Jen Lee Do
Keyword(s):  
Corrosion Resistance ◽  
Processing Time ◽  
Electrical Potential ◽  
Surface Protection ◽  
Alkaline Electrolytes ◽  
Micro Arc Oxidation ◽  
Corrosive Environments ◽  
Zn Alloy ◽  
Main Factor

Micro arc oxidation method has been developed in the field of surface protection of magnesium alloys and considered as a simple, highly effective, commercial and environmentally friendly method in industry. MAO coatings are fabricated on novel Mg-Al-Li-Zn alloy to improve the anti-corrosion performance of surface by using friendly alkaline electrolytes under a high electrical potential. The Taguchi method and optimal analysis are used to identify the effects of the three factors including current density, processing time and electrical frequency on coating’s characteristics. The results have shown that the main factor that affects coating thickness and corrosion resistance of coating is the processing time. The results obtained by optimal conditions are consistent with prediction values of Taguchi analysis. The thickness of the coating can help to improve the long-term corrosion protection of a MAO coating in corrosive environments.

Effect of Plasma Electrolytic Surface Treatment on the Corrosion Characteristics of the Ti-6Al-4V in Acidic, Industrial and Marine Environments

2012 ◽  
Vol 710 ◽  
pp. 677-682 ◽  
Author(s):  
S. Suresh ◽  
K. Pavankumar ◽  
N. Rameshbabu ◽  
K. Venkateswarlu
Keyword(s):  
Corrosion Resistance ◽  
Surface Treatment ◽  
Coating Thickness ◽  
Potentiodynamic Polarization ◽  
Ceramic Coatings ◽  
Test Results ◽  
Wide Range ◽  
Structural Parts ◽  
Plasma Electrolytic ◽  
Corrosive Environments

Titanium and its alloys find wide range of applications in aerospace, marine and automobile industries due to their excellent properties like high strength to weight ratio and good mechanical behaviour. Accordingly, the structural parts made of these alloys are being exposed to different corrosive environments. Therefore, the electrochemical stability of these structural parts needs to be significantly improved for their extended life time and effective functioning. The objective of the present work is to examine the effect of plasma electrolytic surface treatment in improving the corrosion resistance of Ti-6Al-4V in simulated acidic (0.5M H2SO4), marine (3.5% NaCl) and sulphur containing industrial (0.5M Na2SO4) environments. PEO is a relatively new technique for producing ceramic coatings on light metal alloys by employing higher voltage and current than anodizing. The Ti-6Al-4V was surface treated by plasma electrolytic oxidation (PEO) technique for 12 min under optimized conditions of electrical processing parameters and electrolyte chemistry. The logically selected electrolyte system consisting of 10 g of tri-sodium ortho phosphate (Na3PO4.12H2O), 2 g of sodium meta silicate (Na2SiO3.9H2O) and 2 g of potassium hydroxide (KOH) in 1 L of double distilled water was employed. The decisively optimized electrical parameters were fixed as 75% for the duty cycle, 1500 Hz for the pulse frequency and 0.1 A/cm2 for the current density. The phase composition of the resulted coating was analyzed by the X-ray diffraction (XRD) technique. The coating thickness and the elemental composition of the coating were assessed using a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS). The corrosion characteristics were determined by potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements. The XRD results demonstrated that the resulted coatings consisted of both anatase and rutile phases. The SEM results showed a coating thickness of about 15 µm and a canal like surface morphology with inter-connected open pores over the coating surface. The potentiodynamic polarization test results, in general, showed a minimum of about two orders of magnitude improvement in the corrosion resistance of the treated Ti-6Al-4V compared to that of the untreated in all the three corrosive environments. The EIS test results exhibit comparatively higher AC impedance and higher bode angle over the entire frequency range indicating an improved corrosion resistance of the surface treated Ti-6Al-4V. Thus the plasma electrolytic surface treatment with optimized process parameters, made the Ti-6Al-4V electrochemically stable by significantly improving its corrosion resistance in all the three environmental conditions.

Micro Arc Oxidation of AZ91 Magnesium Alloy – Effect of Organic Compounds in the Electrolyte

2014 ◽  
Vol 353 ◽  
pp. 217-222 ◽  
Author(s):  
Namik Kemal Gozuacik ◽  
Mert Altay ◽  
Murat Baydogan
Keyword(s):  
Corrosion Resistance ◽  
Coating Thickness ◽  
Electrochemical Corrosion ◽  
Organic Chemicals ◽  
X Ray Diffraction ◽  
Az91 Magnesium Alloy ◽  
Micro Arc Oxidation ◽  
Az91 Magnesium ◽  
Alloy Effect ◽  
Thickness Measurements

AZ91 Mg alloy was micro arc oxidized under constant electrical parameters in silicate based and phosphate based electrolytes with and without addition of organic chemicals, namely Hexamethylenetetramine (HMTA), TRIS (hydroxymethyl) aminomethane (THAM) and Glycerol in two different concentrations. Following oxidation, samples were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), coating thickness measurements, hardness measurements and electrochemical corrosion tests. Results showed that coating layers mainly consisted of MgO, Mg2SiO4 and MgF2 for silicate based electrolytes, and MgO for phosphate based electrolytes. Incorporation of organic chemicals into electrolyte composition did not change the type of the phases in the coating. However, when they are added in silicate based electrolytes, pore density and coating thickness are reduced and pore size is increased. On the other hand, there is no significant change in surface morphology when organic chemicals are added in phosphate based electrolyte. In the view point of corrosion resistance, organic chemicals did not enhance corrosion resistance of the samples oxidized in silicate based electrolytes, but exhibited some increment in corrosion resistance of the samples oxidized in phosphate based electrolytes.

Effect of Time Voltage and Voltage of 1100 Aluminum Coating Using Chitosan Using Electrodeposition Method

2020 ◽  
Vol 844 ◽  
pp. 32-37
Author(s):  
Puth H. Setyarini ◽  
Femiana Gapsari ◽  
Agil Setyawan
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Layer Thickness ◽  
Coating Thickness ◽  
Thickness Measurement ◽  
Thickness Gauge ◽  
Electrodeposition Process ◽  
Electrodeposition Method ◽  
Coating Thickness Measurement

Aluminum has mechanical properties such as light, easy to form, and the ability to conduct heat and electricity, but has less corrosion resistance properties. One effort to improve corrosion resistance in aluminum is by electrodeposition method. The electrodeposition process was carried out with a variation of time 10, 20, and 30 minutes and variations in voltage of 5 V, 10 V, and 15 V using AA 1100. The electrolyte used was a mixture of acetic acid and chitosan. Coating thickness measurement was carried out using NOVOTEST TP-1M coating thickness gauge, the corrosion rate was measured with 128N Autolab PGSTAT Potentiodynamic and surface roughness measurements using Mitutoyo SJ-210 Surface Roughness Tester. Based on the research data, it was found that the results of optimum layer thickness were obtained at 10 Volt variation of 20 minutes at 11 μm ± 0.04%. Specimens without treatment had the highest corrosion rate of 0.25541 mpy while the lowest corrosion rate was in the 10 variations of 20 minutes which produced 0.0078935 mpy. The surface roughness data of the specimen without treatment was 1.034 μm. The results of the smallest surface roughness were obtained at 10 V 20 minutes variation of 0.725 μm, while the largest surface roughness results in a variation of 15 V 30 minutes which was 2.529 μm. In this stud, it is known that the higher the time and stress used in the electrodeposition process results in greater corrosion rates, because it produces a higher layer thickness but results in higher surface roughness as well.

scholarly journals Investigation on Corrosion Resistance and Formation Mechanism of a P–F–Zr Contained Micro-Arc Oxidation Coating on AZ31B Magnesium Alloy Using an Orthogonal Method

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 197 ◽  
Author(s):  
Yuanyuan Zhu ◽  
Wenhui Chang ◽  
Shufang Zhang ◽  
Yingwei Song ◽  
Huade Huang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Coating Thickness ◽  
Treatment Time ◽  
Synergistic Effects ◽  
Main Role ◽  
Orthogonal Method ◽  
Micro Arc Oxidation ◽  
Coating Formation ◽  
Coating Characteristics

In this study, the synergistic effects of NH4HF2, sodium phytate (Na12Phy), K2ZrF6, and treatment time on corrosion resistance of a micro-arc oxidation (MAO) treated magnesium alloy and the entrance mechanism of P, F, and Zr into anodic coatings were investigated using an orthogonal method. In addition, the roles of NH4HF2, Na12Phy, and K2ZrF6 on coating development were separately studied. The results show that NH4HF2 and Na12Phy, the corrosion inhibitors of magnesium alloys, are beneficial but K2ZrF6 is harmful to developing anodic coatings. The corrosion resistance of MAO coatings is synergistically determined by coating characteristics, though the coating thickness plays a main role. Na12Phy significantly improves but NH4HF2 decreases the corrosion resistance of MAO coatings, while excess high K2ZrF6 is harmful to the coating corrosion resistance. Treatment time can increase the coating thickness but is the least important factor in corrosion resistance. During MAO, NH4HF2, Na12Phy, and K2ZrF6 take part in coating formation, causing P, F, and Zr to compete with each other to enter into anodic coatings.

ALLEGHENY STAINLESS TYPE 434

Alloy Digest ◽  
1974 ◽  
Vol 23 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Heat Treating ◽  
Low Carbon ◽  
Good Corrosion Resistance ◽  
Temperature Performance ◽  
Continuous Service ◽  
Oxidation Resistant ◽  
Corrosive Environments

Abstract ALLEGHENY STAINLESS TYPE 434 is a low-carbon ferritic stainless steel with good corrosion resistance to mildly corrosive environments and the atmosphere. It is oxidation resistant at temperatures up to 1600 F for intermittent service and up to 1450-1500 F for continuous service. It is used for automotive trim and other exterior environments. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-292. Producer or source: Allegheny Ludlum Corporation.

OUTOKUMPU MODA 410L/4003

Alloy Digest ◽  
2020 ◽  
Vol 69 (12) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Ferritic Stainless Steel ◽  
Low Cost ◽  
Heat Treating ◽  
Low Carbon ◽  
Alloy Steels ◽  
Corrosive Environments

Abstract Outokumpu Moda 410L/4003 is a weldable, extra low carbon, Cr-Ni, ferritic stainless steel that is best suited for mildly corrosive environments such as indoors, where the material is either not exposed to contact with water or gets regularly wiped dry, or outdoors, where some discoloration and superficial rusting are acceptable. It is a low-cost alternative to low-carbon non-alloy steels in certain applications. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1330. Producer or source: Outokumpu Oyj.

OUTOKUMPU MODA 410S/4000

Alloy Digest ◽  
2020 ◽  
Vol 69 (11) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Low Carbon ◽  
Good Resistance ◽  
Temperature Performance ◽  
Corrosive Environments

Abstract Outokumpu Moda 410S/4000 is a 13% Cr, ferritic stainless steel that is used in applications requiring good resistance to mildly corrosive environments. It is a low carbon, non-hardening modification of Type 410 stainless steel. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on low and high temperature performance, corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1329. Producer or source: Outokumpu Oyj.

scholarly journals Evaluation of Coating Thickness Using Lift-Off Insensitivity of Eddy Current Sensor

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 419
Author(s):  
Xiaobai Meng ◽  
Mingyang Lu ◽  
Wuliang Yin ◽  
Abdeldjalil Bennecer ◽  
Katherine J. Kirk
Keyword(s):  
Eddy Current ◽  
Coating Thickness ◽  
Thickness Measurement ◽  
Eddy Current Testing ◽  
Thickness Variation ◽  
Testing Technique ◽  
Current Testing ◽  
Thin Skin ◽  
Embedded Algorithms ◽  
Lift Off

Defect detection in ferromagnetic substrates is often hampered by nonmagnetic coating thickness variation when using conventional eddy current testing technique. The lift-off distance between the sample and the sensor is one of the main obstacles for the thickness measurement of nonmagnetic coatings on ferromagnetic substrates when using the eddy current testing technique. Based on the eddy current thin-skin effect and the lift-off insensitive inductance (LII), a simplified iterative algorithm is proposed for reducing the lift-off variation effect using a multifrequency sensor. Compared to the previous techniques on compensating the lift-off error (e.g., the lift-off point of intersection) while retrieving the thickness, the simplified inductance algorithms avoid the computation burden of integration, which are used as embedded algorithms for the online retrieval of lift-offs via each frequency channel. The LII is determined by the dimension and geometry of the sensor, thus eliminating the need for empirical calibration. The method is validated by means of experimental measurements of the inductance of coatings with different materials and thicknesses on ferrous substrates (dual-phase alloy). The error of the calculated coating thickness has been controlled to within 3% for an extended lift-off range of up to 10 mm.

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