Effect of Current Density on Morphology and Corrosion Resistance of Anodized Coating on SiCp/2024 Al Composite

2007 ◽  
pp. 661-666
Author(s):  
Chun Lin He ◽  
Qing Kui Cai
Keyword(s):  
Corrosion Resistance ◽  
Current Density ◽  
Al Composite

Effect of Current Density on Morphology and Corrosion Resistance of Anodized Coating on SiCp/2024 Al Composite

2007 ◽  
Vol 546-549 ◽  
pp. 661-666 ◽  
Author(s):  
Chun Lin He ◽  
Qing Kui Cai
Keyword(s):  
Corrosion Resistance ◽  
Current Density ◽  
Energy Dispersive Spectrometry ◽  
Surface Cracks ◽  
Sic Particles ◽  
Al Composite ◽  
Oxide Substrate ◽  
Current Densities ◽  
Reduced Rate ◽  
Sic Particle

The effects of current densities on the morphology and corrosion resistance of anodized coating formed on a SiCp/2024 Al metal matrix composite (MMC) in sulfuric acid solution were investigated by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and polarization curve. The results showed that the surface of the coating was not flat, and cracks existed when the current density increased to 20mA/cm2. The SiC particles could be oxidized during anodizing of the MMC. And the SiC particle anodized at a significantly reduced rate compared with the adjacent Al matrix. This gave rise to alumina film encroachment beneath the particle and occlusion of the partly anodized particle in the coating. As a consequence, the oxide/substrate interface became locally scalloped, and the anodized coating was non-uniform in thickness. Further, oxidation of SiC appeared to be associated with gas-filled cavities in the coating material. The size of cavities above the SiC particles increased obviously and the surface cracks developed when the current density increased. This shows that the anodized coating formed at higher current density has a structural feature with lower corrosion resistance. The polarization results indicated that the corrosion resistance of the coating decreases when the current density increases.

scholarly journals Structure, Corrosion Resistance, Mechanical and Tribological Properties of ZrB2 and Zr-B-N Coatings

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1194
Author(s):  
Philipp Kiryukhantsev-Korneev ◽  
Alina Sytchenko ◽  
Yuriy Kaplanskii ◽  
Alexander Sheveyko ◽  
Stepan Vorotilo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Tribological Properties ◽  
Current Density ◽  
Corrosion Current Density ◽  
Elastic Recovery ◽  
Optical Emission ◽  
Corrosion Current ◽  
Impact Testing ◽  
Total Oxidation ◽  
Mechanical And Tribological Properties

The coatings ZrB2 and Zr-B-N were deposited by magnetron sputtering of ZrB2 target in Ar and Ar–15%N2 atmospheres. The structure and properties of the coatings were investigated via scanning and transmission electron microscopy, energy dispersion analysis, optical profilometry, glowing discharge optical emission spectroscopy and X-ray diffraction analysis. Mechanical and tribological properties of the coatings were investigated using nanoindentation, “pin-on-disc” tribological testing and “ball-on-plate” impact testing. Free corrosion potential and corrosion current density were measured by electrochemical testing in 1N H2SO4 and 3.5%NaCl solutions. The oxidation resistance of the coatings was investigated in the 600–800 °С temperature interval. The coatings deposited in Ar contained 4–11 nm grains of the h-ZrB2 phase along with free boron. Nitrogen-containing coatings consisted of finer crystals (1–4 nm) of h-ZrB2, separated by interlayers of amorphous a-BN. Both types of coatings featured hardness of 22–23 GPa; however, the introduction of nitrogen decreased the coating’s elastic modulus from 342 to 266 GPa and increased the elastic recovery from 62 to 72%, which enhanced the wear resistance of the coatings. N-doped coatings demonstrated a relatively low friction coefficient of 0.4 and a specific wear rate of ~1.3 × 10−6 mm3N−1m−1. Electrochemical investigations revealed that the introduction of nitrogen into the coatings resulted in the decrease of corrosion current density in 3.5% NaCl and 1N H2SO4 solution up to 3.5 and 5 times, correspondingly. The superior corrosion resistance of Zr-В-N coatings was related to the finer grains size and increased volume of the BN phase. The samples ZrB2 and Zr-B-N resisted oxidation at 600 °C. N-free coatings resisted oxidation (up to 800 °С) and the diffusion of metallic elements from the substrate better. In contrast, Zr-B-N coatings experienced total oxidation and formed loose oxide layers, which could be easily removed from the substrate.

scholarly journals Corrosion Behavior of AA 1100 Anodized in Gallic-Sulfuric Acid Solution

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 405
Author(s):  
Marlon L. Mopon ◽  
Jayson S. Garcia ◽  
Dexter M. Manguerra ◽  
Cyril John C. Narisma
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Gallic Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Solution ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Anodized Aluminum ◽  
The Common

Sulfuric acid anodization is one of the common methods used to improve corrosion resistance of aluminum alloys. Organic acids can be added to the sulfuric acid electrolyte in order to improve the properties of the anodized aluminum produced. In this study, the use of gallic acid as an additive to the sulfuric acid anodization of AA1100 was explored. The effect of varying anodization current density and gallic acid concentration on the properties of anodized aluminum samples was observed using electrochemical impedance spectroscopy, linear polarization, and scanning electron microscopy. It was observed that the corrosion resistance of samples anodized in gallic-sulfuric acid solution at 10 mA·cm−2 is lower than samples anodized in sulfuric acid. It was also observed that higher anodization current density can lead to lower corrosion resistances for aluminum samples anodized in gallic-sulfuric acid solution. However, samples anodized at 5 mA·cm−2 and at a gallic acid concentration of 5 g·L−1 showed better corrosion performance than the samples anodized in sulfuric acid only. This suggests that the use of low amounts of gallic acid as an additive for sulfuric acid anodization can lead to better corrosion resistances for anodized aluminum.

scholarly journals Microstructural and Corrosion Behavior of High Velocity Arc Sprayed FeCrAl/Al Composite Coating on Q235 Steel Substrate

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 542 ◽  
Author(s):  
Ndumia Joseph Ndiithi ◽  
Min Kang ◽  
Jiping Zhu ◽  
Jinran Lin ◽  
Samuel Mbugua Nyambura ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
High Velocity ◽  
Steel Substrate ◽  
Arc Spraying ◽  
Spray Parameters ◽  
Q235 Steel ◽  
Electrochemical Tests ◽  
Al Composite ◽  
Al Coating

High velocity arc spraying was used to prepare FeCrAl/Al composite coating on Q235 steel substrate by simultaneously spraying FeCrAl wire as the anode and Al wire as the cathode. The composite coating was sprayed with varying voltage and current to obtain optimum coating characteristics. FeCrAl coating was also prepared for comparison purposes. The surface microstructure of the coatings was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The average microhardness of the coatings and the substrate was analyzed and compared. Corrosion resistance was investigated by means of electrochemical tests. The image results showed that a lamellar structure consisted of interwoven layers of FeCrAl and Al. Al and FeCr constituted the main phases with traces of oxides and AlFe intermetallic compounds. The average porosity was reduced and microhardness of the coatings was improved with increasing voltage and current. The FeCrAl/Al coating formed alternating layers of hard and ductile phases; the corrosion resistance of the coatings in the sodium chloride (NaCl) solution depended on the increase in Al content and spray parameters. The corrosion resistance tests indicated that FeCrAl/Al coating had a better corrosion resistance than the FeCrAl coating. FeCrAl/Al can be used to coat steel substrates and increase their corrosion resistance.

The effect of electroplating current density on microstructure, corrosion, and wear behavior of Ni–P–W–TiO2 coating

2021 ◽  
Vol 112 (6) ◽  
pp. 474-485
Author(s):  
Sajjad Sadeghi ◽  
Hadi Ebrahimifar
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Wear Behavior ◽  
Micro Hardness ◽  
Aisi 304L

Abstract The use of ceramic particles in the matrix of alloy coatings during the electroplating process has received considerable attention. These particles can create properties such as high corrosion resistance, insolubility, high-temperature stability, strong hardness, and self-lubrication capability. Herein, an Ni–P–W–TiO2 coating was deposited on an AISI 304L steel substrate using the electroplating method. Electroplating was performed at current densities of 10, 15, 20, and 25 mA · cm–2, and the effect of current density on microstructure, corrosion behavior, and wear behavior was investigated. The coatings were characterized by means of scanning electron microscopy. To investigate corrosion resistance, potentiodynamic polarization and electrochemical impedance spectroscopy tests were performed in a 3.5% NaCl aqueous solution. A pin-on-disk test was conducted to test the wear resistance of uncoated and coated samples. Sample micro-hardness was also measured by Vickers hardness testing. Examination of the microstructure revealed that the best coating was produced at a current density of 20 mA · cm–2. The results of potentiodynamic polarization and electrochemical impedance spectroscopy tests were consistent with microscopic images. The coating created at the current density of 20 mA · cm–2 had the highest corrosion resistance compared to other coated and non-coated samples. Furthermore, the results of the wear test showed that increasing the current density of the electroplating path up to 20 mA · cm–2 enhances micro-hardness and wear resistance.

scholarly journals Preparation of Ti–Zr-Based Conversion Coating on 5052 Aluminum Alloy, and Its Corrosion Resistance and Antifouling Performance

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 397 ◽  
Author(s):  
Hehong Zhang ◽  
Xiaofeng Zhang ◽  
Xuhui Zhao ◽  
Yuming Tang ◽  
Yu Zuo
Keyword(s):  
Corrosion Resistance ◽  
Surface Modification ◽  
Aluminum Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Salt Water ◽  
Water Immersion ◽  
Chemical Conversion ◽  
Corrosion Current ◽  
Conversion Coating

A chemical conversion coating on 5052 aluminum alloy was prepared by using K2ZrF6 and K2TiF6 as the main salts, KMnO4 as the oxidant and NaF as the accelerant. The surface morphology, structure and composition were analyzed by SEM, EDS, FT–IR and XPS. The corrosion resistance of the conversion coating was studied by salt water immersion and polarization curve analysis. The influence of fluorosilane (FAS-17) surface modification on its antifouling property was also discussed. The results showed that the prepared conversion coating mainly consisted of AlF3·3H2O, Al2O3, MnO2 and TiO2, and exhibited good corrosion resistance. Its corrosion potential in 3.5 wt % NaCl solution was positively shifted about 590 mV and the corrosion current density was dropped from 1.10 to 0.48 μA cm−2. By sealing treatment in NiF2 solution, its corrosion resistance was further improved yielding a corrosion current density drop of 0.04 μA cm−2. By fluorosilane (FAS-17) surface modification, the conversion coating became hydrophobic due to low-surface-energy groups such as CF2 and CF3, and the contact angle reached 136.8°. Moreover, by FAS-17 modification, the corrosion resistance was enhanced significantly and its corrosion rate decreased by about 25 times.

Effect on Corrosion Resistance of Ce-Rich-Sealed Ni-P Coatings on Cf/Al Composite Surface

2012 ◽  
Vol 22 (2) ◽  
pp. 624-631 ◽  
Author(s):  
Chunyu Wang ◽  
Huanran Li ◽  
Peng Zhang ◽  
Hongyun Zhao
Keyword(s):  
Corrosion Resistance ◽  
Composite Surface ◽  
Al Composite

scholarly journals Low Temperature Sealing of Anodized Aluminum Alloy for Enhancing Corrosion Resistance

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4904
Author(s):  
Hyunbin Jo ◽  
Soomin Lee ◽  
Donghyun Kim ◽  
Junghoon Lee
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Anodic Oxide ◽  
Nickel Acetate ◽  
Anodized Aluminum ◽  
Corrosive Media ◽  
Nickel Fluoride

Sealing as a post treatment of anodized aluminum is required to enhance the corrosion resistance by filling nanopores, which allow the penetration of corrosive media toward the base aluminum. We designed a mixed sealing solution with nickel acetate and ammonium fluoride by modifying traditional nickel fluoride cold sealing. The concentration of mixed sealing solution affected the reaction rate of sealing and corrosion current density of anodized aluminum alloy. The higher concentration of mixed sealing solution improved the sealing rate, which was represented by a decrease of corrosion current density of anodized aluminum alloy. However, a mixed sealing solution with 2/3 concentration of general nickel fluoride sealing solution operated at room temperature showed the lowest corrosion current density compared to traditional methods (e.g., nickel fluoride cold sealing (NFCS) and nickel acetate hot sealing) and other mixed sealing solutions. Moreover, the mixed sealing solution with 2/3 concentration of general NFCS had a lower risk for over sealing, which increases the corrosion current density by excessive dissolution of anodic oxide. Therefore, the mixed sealing solution with optimized conditions designed in this work possibly provides a new method for enhancing the corrosion resistance of anodized aluminum alloys.

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