scholarly journals Protection of Aluminum Alloy 3003 in Sodium Chloride and Simulated Acid Rain Solutions by Commercial Conversion Coatings Containing Zr and Cr

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 563 ◽  
Author(s):  
Kim ◽  
Kapun ◽  
Tiringer ◽  
Šekularac ◽  
Milošev
Keyword(s):  
Aluminum Alloy ◽  
Acid Rain ◽  
Photoelectron Spectroscopy ◽  
Simulated Acid Rain ◽  
Conversion Coatings ◽  
Manganese Alloy ◽  
Corrosion Properties ◽  
Alloy Matrix ◽  
X Ray ◽  
Intermetallic Particles

The morphology, composition and corrosion properties of commercial hexafluoro-zirconate trivalent chromium coatings (SurTec® 650) deposited on chemically cleaned aluminum alloy 3003 were studied. The coatings were deposited at room temperature using different concentrations of SurTec® 650 (10, 25 and 50 vol.%) and different conversion times (90 s, 11 min and 18 min). Scanning electron microscopy with energy dispersive X-ray spectrometry, X-ray photoelectron spectroscopy and time-of-flight secondary ion spectrometry were employed to investigate the surface morphology, composition and thickness of uncoated and coated AA3003 samples. The morphology of the coating varied from uniform nodular to non-uniform and cracked; coatings were deposited at intermetallic particles and at the alloy matrix. The main constituents of conversion coatings were Zr(IV) and Cr(III) oxides; in addition to oxides, fluorides were also formed. The corrosion properties were investigated in two solutions: more aggressive sodium NaCl and less aggressive simulated acid rain. These commercial conversion coatings exhibited a good corrosion resistance but only after longer immersion in solution, i.e., 24 h. The results reveal an interesting behavior of zirconate-based coatings on aluminum-manganese alloy.

scholarly journals Corrosion Inhibitor-Modified Plasma Electrolytic Oxidation Coatings on 6061 Aluminum Alloy

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 619
Author(s):  
Maciej Sowa ◽  
Marta Wala ◽  
Agata Blacha-Grzechnik ◽  
Artur Maciej ◽  
Alicja Kazek-Kęsik ◽  
...  
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Photoelectron Spectroscopy ◽  
Plasma Electrolytic Oxidation ◽  
Step Method ◽  
Corrosion Properties ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

There are many methods for incorporating organic corrosion inhibitors to oxide coatings formed on aluminum alloys. However, typically they require relatively concentrated solutions of inhibitors, possibly generating a problematic waste and/or are time-/energy-consuming (elevated temperature is usually needed). The authors propose a three-step method of oxide layer formation on 6061-T651 aluminum alloy (AAs) via alternating current (AC) plasma electrolytic oxidation (PEO), impregnation with an 8-hydroxyquinoline (8-HQ) solution, and final sealing by an additional direct current (DC) polarization in the original PEO electrolyte. The obtained coatings were characterized by scanning electron microscopy, roughness tests, contact angle measurements, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Additionally, corrosion resistance was assessed by potentiodynamic polarization in a NaCl solution. Two types of the coating were formed (A—thicker, more porous at 440 mA cm−2; B—thinner, more compact at 220 mA cm−2) on the AA substrate. The 8-HQ impregnation was successful as evidenced by XPS. It increased the contact angle only for the B coatings and improved the corrosion resistance of both coating systems. Additional DC treatment destroyed superficially adsorbed 8-HQ. However, it served to block the coating pores (contact angle ≈ 80°) which improved the corrosion resistance of the coating systems. DC sealing alone did not bring about the same anti-corrosion properties as the combined 8-HQ impregnation and DC treatment which dispels the notion that the provision of the inhibitor was a needless step in the procedure. The proposed method of AA surface treatment suffered from unsatisfactory uniformity of the sealing for the thicker coatings, which needs to be amended in future efforts for optimization of the procedure.

The Effect of Deposition Parameters on the Properties of CeCl3 and LaCl3 Conversion Coatings Deposited on Three Al-Based Substrates

CORROSION ◽  
10.5006/3303 ◽  
2019 ◽  
Vol 76 (1) ◽  
pp. 18-38
Author(s):  
Barbara Volarič ◽  
Anca Mazare ◽  
Sannakaisa Virtanen ◽  
Ingrid Milošev
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Photoelectron Spectroscopy ◽  
Conversion Coatings ◽  
Corrosion Properties ◽  
X Ray ◽  
Deposition Parameters ◽  
Conversion Time ◽  
Conversion Temperature ◽  
Scanning Electron

Cerium and lanthanum conversion coatings were deposited from solution of CeCl3 and LaCl3 salts on three aluminum-based substrates: Al, AA2024-T3, and AA7075-T6 to investigate the effect of conversion temperature, conversion time, and addition of hydrogen peroxide. Coatings prepared under different conditions were then analyzed in terms of corrosion properties in 0.1 M NaCl, morphology, topography, and composition. Morphology and composition of the coatings were analyzed using scanning electron microscopy with energy dispersive x-ray spectrometry and x-ray photoelectron spectroscopy. Corrosion resistance, morphology, composition, and homogeneity of coatings were largely dependent on parameters of conversion treatment and type of substrates. Most corrosion resistants were Ce-based coatings produced at 60°C for 1 h in a bath containing CeCl3 and H2O2. La-based coating did not reach comparative resistance when deposited under the same conditions. Morphology of coatings ranged between individual deposits to thick, cracked coatings with nodular morphology. Ce-based coatings predominantly contained Ce(IV) hydroxide when formed with added H2O2. La-based coatings contained La(III) hydroxide mixed with Al(III) hydroxide.

Cerium Chemical Conversion Coating for Aluminum Alloy 2024-T3 and Its Corrosion Resistance

CORROSION ◽  
2004 ◽  
Vol 60 (3) ◽  
pp. 237-243 ◽  
Author(s):  
C. Wang ◽  
F. Jiang ◽  
F. Wang
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Photoelectron Spectroscopy ◽  
Chemical Conversion ◽  
Spherical Particles ◽  
Conversion Coatings ◽  
Nacl Solution ◽  
X Ray ◽  
Golden Yellow ◽  
Aluminum Alloy 2024

Abstract New golden, yellow-colored cerium chemical conversion coatings on aluminum alloy 2024-T3 (AA2024-T3 [UNS A92024]) surface at room temperature were obtained by immersing the alloy into a cerium solution containing zinc chloride (ZnCl2) and hydrogen peroxide (H2O2). Electrochemical methods and immersion tests were used to study the dynamics of the coatings formation and their corrosion resistance in 3.5% sodium chloride (NaCl) solution. The morphologies of the coatings were recorded by scanning electronic microscopy (SEM). Energy-dispersive x-ray (EDX) analysis and x-ray photoelectron spectroscopy (XPS) were used to analyze the chemical composition and the oxidation state of the elements in the coatings. Polarization experiments and immersion tests in 3.5% NaCl solution showed that the sensitivity to pitting corrosion for the conversion-coated AA2024-T3 was greatly lower than that of the untreated specimens, and the corrosion resistance improved markedly. SEM photographs showed that the coatings consisted of a lot of spherical particles. EDX and XPS experimental results showed that the coatings were made up of oxygen, cerium, and aluminum, and the spherical particles contained higher contents of cerium and oxygen than the other sites. Cerium was mainly in the form of Ce4+. The mechanisms of conversion coatings formation and improvement on corrosion resistance also are discussed.

scholarly journals Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 666
Author(s):  
Xinchuan Fan ◽  
Yue Hu ◽  
Yijun Zhang ◽  
Jiachen Lu ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Scanning Electron

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

Electrochemical noise study on 2024-T3 Aluminum alloy corrosion in simulated acid rain under cyclic wet–dry condition

2006 ◽  
Vol 51 (23) ◽  
pp. 4977-4986 ◽  
Author(s):  
Yanyan Shi ◽  
Zhao Zhang ◽  
Jingxin Su ◽  
Fahe Cao ◽  
Jianqing Zhang
Keyword(s):  
Aluminum Alloy ◽  
Acid Rain ◽  
Electrochemical Noise ◽  
Simulated Acid Rain

NANOMECHANICAL AND CORROSION PROPERTIES OF ZK60 MAGNESIUM ALLOY IMPROVED BY GD ION IMPLANTATION

2014 ◽  
Vol 21 (06) ◽  
pp. 1450085 ◽  
Author(s):  
XUE WEI TAO ◽  
ZHANG ZHONG WANG ◽  
XIAO BO ZHANG ◽  
ZHI XIN BA ◽  
YA MEI WANG
Keyword(s):  
Magnesium Alloy ◽  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Surface Hardness ◽  
Protective Layer ◽  
Hybrid Structure ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
X Ray ◽  
Zk60 Magnesium Alloy

Gadolinium ( Gd ) ion implantation with doses from 2.5 × 1016 to 1 × 1017 ions/cm2 into ZK60 magnesium alloy was carried out to improve its surface properties. X-ray photoelectron spectroscopy (XPS), nanoindenter, electrochemical workstation and scanning electron microscope (SEM) were applied to analyze the chemical composition, nanomechanical properties and corrosion characteristics of the implanted layer. The results indicate that Gd ion implantation produces a hybrid-structure protective layer composed of MgO , Gd 2 O 3 and metallic Gd in ZK60 magnesium alloy. The surface hardness and modulus of the Gd implanted magnesium alloy are improved by about 300% and 100%, respectively with the dose of 1 × 1017 ions/cm2, while the slowest corrosion rate of the magnesium alloy in 3.5 wt.% NaCl solution is obtained with the dose of 5 × 1016 ions/cm2.

scholarly journals Investigation of Protective Performance of a Mg-Rich Primer Containing Aluminum Tri-Polyphosphate on AZ91D Magnesium Alloy in Simulated Acid Rain

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 649 ◽  
Author(s):  
Xiangyu Lu ◽  
Sichen Sun ◽  
Qiqi Fan ◽  
Xiangjun Pei ◽  
Yuchao Dun ◽  
...  
Keyword(s):  
Acid Rain ◽  
Cathodic Protection ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Simulated Acid Rain ◽  
Protective Film ◽  
Az91d Alloy ◽  
Testing Environment ◽  
Protective Performance

Mg-rich primer (MRP) containing aluminum tri-polyphosphate functions via a galvanic mechanism to protect AZ91D alloy from corrosion in the 3 wt % NaCl solution. However, its protective performance can be strongly affected by the testing environment. Therefore, it is important to investigate the performance of the primer on magnesium alloys in an acid rain environment. In the present study, the protective performance of MRP with or without aluminum tri-polyphosphate was investigated via open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), scanning electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) in the simulated acid rain. Compared to the primer without aluminum tri-polyphosphate, the MRP containing aluminum tri-polyphosphate pigments exhibited better protective performance in the simulated acid rain condition. In the initial stage, the acidic condition prompted the aluminum tri-polyphosphate pigments to release phosphates and H+ to form magnesium phosphates on Mg particles, retarding their consumption rate. The Mg-rich primer with aluminum tri-polyphosphate can provide cathodic protection to AZ91D alloy for about 49 days in the simulated acid rain solution. Simultaneously, the corrosion products of Mg particles, magnesium oxides and phosphates, precipitated on the Mg particles and improved the stability of the primer. In addition, a protective film, consisting of magnesium oxides and phosphates, formed on the AZ91D substrate. Consequently, all these factors contributed to the long cathodic protection and improved corrosion resistance of MRP containing aluminum tri-polyphosphate in the simulated acid rain.

scholarly journals Influence of Cu2+ Ions on the Corrosion Resistance of AZ31 Magnesium Alloy with Microarc Oxidation

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2647
Author(s):  
Madiha Ahmed ◽  
Yuming Qi ◽  
Longlong Zhang ◽  
Yanxia Yang ◽  
Asim Abas ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Microarc Oxidation ◽  
Mg Alloy ◽  
Cell Counting ◽  
Cytotoxicity Test ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Az31 Mg Alloy

The objectives of this study were to reduce the corrosion rate and increase the cytocompatibility of AZ31 Mg alloy. Two coatings were considered. One coating contained MgO (MAO/AZ31). The other coating contained Cu2+ (Cu/MAO/AZ31), and it was produced on the AZ31 Mg alloy via microarc oxidation (MAO). Coating characterization was conducted using a set of methods, including scanning electron microscopy, energy-dispersive spectrometry, X-ray photoelectron spectroscopy, and X-ray diffraction. Corrosion properties were investigated through an electrochemical test, and a H2 evolution measurement. The AZ31 Mg alloy with the Cu2+-containing coating showed an improved and more stable corrosion resistance compared with the MgO-containing coating and AZ31 Mg alloy specimen. Cell morphology observation and cytotoxicity test via Cell Counting Kit-8 assay showed that the Cu2+-containing coating enhanced the proliferation of L-929 cells and did not induce a toxic effect, thus resulting in excellent cytocompatibility and biological activity. In summary, adding Cu ions to MAO coating improved the corrosion resistance and cytocompatibility of the coating.

Effect of Additives on Structure and Corrosion Resistance of Molybdate Conversion Coatings Deposited on AZ31B Mg Alloy

2011 ◽  
Vol 308-310 ◽  
pp. 2458-2462 ◽  
Author(s):  
Li Hui Yang ◽  
Mi Lin Zhang ◽  
Cun Guo Lin ◽  
Jian Hua Wu
Keyword(s):  
Corrosion Resistance ◽  
Photoelectron Spectroscopy ◽  
Corrosion Current ◽  
Mg Alloy ◽  
Spherical Particles ◽  
Polarization Analysis ◽  
Conversion Coatings ◽  
X Ray ◽  
Effect Of Additives ◽  
Additive Solution

Molybdate conversion coatings were prepared on AZ31B Mg alloy in a molybdate based solution with additives of sodium fluoride (NaF) or lanthanum nitrate (La(NO3)3). The effects of F- and La3+ additives on the morphology and on the corrosion resistance of the molybdate coatings were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and potentiodynamic polarization analysis. The results revealed that these additives could accelerate the deposition of molybdenum on the surface of AZ31B magnesium alloy. It can be seen that the composite conversion coatings consist of many spherical particles. It is also found that the corrosion resistance is greatly improved after molybdate treatment. The films formed in F- additive solution showed lower corrosion current density than in La3+ additive solution.

Study of corrosion behavior of virgin and recycled Pb anodes used in zinc electrowinning industry

2020 ◽  
Vol 67 (6) ◽  
pp. 529-536
Author(s):  
Shima Nakisa ◽  
Naghi Parvini Ahmadi ◽  
Javad Moghaddam ◽  
Habib Ashassi-Sorkhabi
Keyword(s):  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Electrochemical Impedance ◽  
Zinc Electrowinning ◽  
Composition Analysis ◽  
Corrosion Properties ◽  
Content Type ◽  
X Ray ◽  
Galvanostatic Polarization

Purpose The composition and corrosion behaviors of recycled and virgin Pb anode were investigated in industrial zinc electrowinning solution with different methods. The purpose of this study is the illustration of good anticorrosion activity of virgin Pb anodes compared to recycled one in industrial operation, while the compositions of both of them are the same which obtained from quantmetry method. Design/methodology/approach Its corrosion properties and electrocatalytic activity toward oxygen evolution reaction were appraised using potentiodynamic polarization, electrochemical impedance spectroscopy, galvanostatic polarization and ionic equilibrium methods. In addition, composition of anodes investigated with X-ray photoelectron spectroscopy (XPS) method. The surface composition of samples was studied via X-ray diffractogram (XRD). Findings The results indicate that the anodes display different anodic behaviors during the galvanostatic polarization. Virgin Pb anode shows a “potential reduction” about 320 mV lower than recycled Pb anode after 6 h of polarization; also, the stable potential after 72 h for virgin Pb anode is 100 mV lower than recycled Pb anode. Also, The XPS results show a trace amount of Cl in recycled anodes which cause the more corrosion activity. XRD results indicate that virgin Pb anodes have been covered by more oxides than recycled anodes after 72 h of electrowinning. Originality/value The treatment of corrosion behavior by virginity has not been detected by any researchers yet. Therefore, it is imperative to study the corrosion behavior and exact composition analysis of virgin and recycled Pb anodes to comprehension of them. This paper fulfills this need.

Sign in / Sign up

Export Citation Format

Share Document