Preparation of Molybdate Conversion Coatings on the Anodizing Surface of Aluminum Alloy

2008 ◽  
Vol 368-372 ◽  
pp. 1287-1290
Author(s):  
Shi Guo Du ◽  
Jun Yan ◽  
Hai Ping Cui ◽  
Bin Wang
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Chemical Composition ◽  
Polarization Curve ◽  
Pitting Corrosion ◽  
Main Element ◽  
Conversion Coatings ◽  
Nacl Solution ◽  
Eds Analysis

Molybdate conversion coatings were prepared on the anodized surfaces of aluminum alloy substrates, and the corrosion resistance in 3.5% NaCl solution was also investigated. The effects of the main parameters on the quality of the coatings were discussed. The morphology and chemical composition of the conversion coatings was examined by SEM and EDS. SEM observation showed that the coatings were composed of small sheet grains with tiny cracks between them. EDS analysis showed that the main element of the coatings was molybdenum. The results of polarization curve showed that the coatings effectively inhabited the pitting corrosion of aluminum alloy substrates. In the end the possible conversion mechanism was discussed.

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 Effect of Temperature on Corrosion Resistance of Layered Double Hydroxides Conversion Coatings on Magnesium Alloys Based on a Closed-Cycle System

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1658
Author(s):  
Xiaochen Zhang ◽  
Zhijuan Yin ◽  
Bateer Buhe ◽  
Jiajie Wang ◽  
Lin Mao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Conversion Coating ◽  
Effect Of Temperature ◽  
Conversion Coatings ◽  
Closed Cycle ◽  
Cycle System ◽  
Double Hydroxide ◽  
Double Hydroxides

The effect of temperature on the corrosion resistance of layered double hydroxide (LDH) conversion coatings on AZ91D magnesium alloy, based on a closed-cycle system, was investigated. Scanning electron microscopy (SEM), photoelectron spectroscopy (XPS), and X-ray diffractometry (GAXRD) were used to study the surface morphology, chemical composition, and phase composition of the conversion coating. The corrosion resistance of the LDH conversion coating was determined through electropotentiometric polarisation curve and hydrogen evolution and immersion tests. The results showed that the conversion coating has the highest density and a more uniform, complete, and effective corrosion resistance at 50 °C. The chemical composition of the LDH conversion coating mainly comprises C, O, Mg, and Al, and the main phase is Mg6Al2(OH)16CO3·4H2O.

scholarly journals A microstructural and corrosion resistance study of (Zr, Si, Ti)N-Ni coatings produced through co-sputtering

DYNA ◽  
2018 ◽  
Vol 85 (207) ◽  
pp. 192-197 ◽  
Author(s):  
Estrella Natali Borja-Goyeneche ◽  
Jhon Jairo Olaya-Florez
Keyword(s):  
Corrosion Resistance ◽  
Nickel Content ◽  
Corrosion Current ◽  
Nacl Solution ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Current Densities ◽  
Fcc Phase

This work researches the influence of the nickel content on the structural and anticorrosive properties of ZrSiTiN films deposited by means of reactive co-sputtering on alloys of Ti6Al4V. The morphology and structure were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the chemical composition was identified via X-ray scattering spectroscopy (EDS). The corrosion resistance was studied using potentiodynamic polarization (PP) tests employing a 3.5% by weight NaCl solution. In the films, an increase of Ni up to 6.97 at% was observed, while in XRD the FCC phase of (Zr, Ti) N was identified, with a mixed orientation in planes (111) and (200), which tended to diminish with the increase of Ni. Finally, with the addition of Ni, the corrosion current densities were reduced from 5.56 𝑥 10−8 to 2.64 𝑥 10−9 𝐴/𝑐m2. The improvement in the corrosion resistance is due to the effect of the Ni on the microstructure of the system (Zr, Ti) N, which can improve the quality of the passive film and prevent crystalline defects and corrosion zones.

scholarly journals Investigation on the Surface Properties of 5A12 Aluminum Alloy after Nd: YAG Laser Cleaning

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 578 ◽  
Author(s):  
Guodong Zhu ◽  
Shouren Wang ◽  
Wei Cheng ◽  
Gaoqi Wang ◽  
Wentao Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Laser Cleaning ◽  
Alloy Surface ◽  
Residual Tensile Stress ◽  
Yag Laser ◽  
Diode Pumped ◽  
Aluminum Alloy Surface ◽  
Diode Pumped Nd:Yag Laser

The surface of the aluminum alloy is prone to oxidation, which in turn affects the quality of the weld. The 5A12 aluminum alloy was cleaned by acousto-optic Q-switched diode-pumped Nd:YAG laser and the effects of different laser powers and different cleaning speeds on the surface roughness, microstructure, element content, microhardness, residual stress and corrosion resistance of aluminum alloy were investigated. The results show that when the power is 98W and the cleaning speed is 4.1 mm/s, the effect of Nd: YAG laser on the removal of oxide film on 5A12 aluminum alloy surface is the most effective. After laser cleaning, the smoothness and strength of aluminum alloy surface can be effectively improved. However, as a major element in 5A12 aluminum alloy, the content of magnesium decreased. At the same time, the residual tensile stress was generated on the surface of the aluminum alloy after cleaning, and the corrosion resistance slightly decreased.

Effect of tempering treatment on pitting corrosion resistance of modified cast CA6NM stainless steel in 3.5 % NaCl solution

2021 ◽  
Author(s):  
Vinda Puspasari ◽  
Mukhlis Agung Prasetyo ◽  
Arini Nikitasari ◽  
Efendi Mabruri ◽  
Moch. Syaiful Anwar
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Nacl Solution ◽  
Pitting Corrosion Resistance ◽  
Tempering Treatment

Investigation of Corrosion Resistant of Al-Zn-Si-Re-Mg Coating

2013 ◽  
Vol 652-654 ◽  
pp. 1775-1779
Author(s):  
Dong Bo Wei ◽  
Jun Huang ◽  
Ping Ze Zhang ◽  
Zheng Jun Yao ◽  
Qiang Miao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Passive Film ◽  
Polarization Curve ◽  
Steel Sheet ◽  
Indentation Test ◽  
Nacl Solution ◽  
Corrosion Resistant ◽  
Nano Indentation ◽  
Dipping Process

A dense hot-dipping Al-Zn-Si-Re-Mg coating was prepared on the surface of steel sheet. The microstructure and toughness of coating were investigated by SEM and Nano-indentation test. The polarization curve of coating was acquired in static 3.5 wt.% NaCl solution in air at 25°C. The results show that Re and Mg improve the corrosion resistance and toughness of Al-Zn-Si coating. The formation of passive film on surface of Al-Zn-Si-Re-Mg coating is easier than that of Al-Zn-Si coating. Re decreases the number of oxygen existed in the coating. Mg3Al2(SiO4)3 depresses the porosity of coating, which is a glassy compound and formed in hot-dipping process.

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