Technical and Performance Study of Ti-W Composite Chemical Conversion Coating on Aluminum Alloy

2010 ◽  
Vol 129-131 ◽  
pp. 819-823
Author(s):  
Yan Bo Wu ◽  
Si Si Zeng ◽  
Peng Sun

Ti-W composite coating was made by chemical conversion method on aluminum alloy. By orthogonal experiment, the optimal coating-forming conditions were the concentration ratio of TiOSO4 and Na2WO4 was 0.3 g/L:0.3 g/L、KMnO4 1.0 g/L、NaF 1.0 g/L、reaction temperature 40°C、reaction time 2min. The morphology of the coating was observed by scanning electron microscopy (SEM). Coating composition and the microcosmic phase structure were characterized using energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) respectively. Electrochemical test was used to study the coatings corrosion resistance. The results indicated that the composite chemical conversion coating is a crystal structure material that composites with Al、Mn、W、Ti et al., its surface appears as a accumulation of fibroid spherical particles, the crystallinity of conversion coating is better than uncoated sample obviously. The corrosion potential of the coating is improved to -0.440V, they were both prove the corrosion resistance has improved.

2010 ◽  
Vol 129-131 ◽  
pp. 467-471
Author(s):  
Yan Bo Wu ◽  
Si Si Zeng ◽  
Peng Sun

A chrome-free chemical conversion coating was prepared using stannous sulfate as the main salt. The morphology of the chemical conversion surface layer was observed by scanning electron microscopy (SEM). Coating composition and the microcosmic phase structure were characterized using energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) respectively. Electrochemical method and dropping test were used to study the coatings corrosion resistance. The results indicated that the tin salts conversion coating is a crystal structure material that composites with Sn-F-O-Al et al., the surface appears as a accumulation of spherical particles, the crystallinity of conversion coating is better than uncoated sample obviously, the corrosion resistance has improved too.


2010 ◽  
Vol 146-147 ◽  
pp. 208-211
Author(s):  
Yan Bo Wu ◽  
Si Si Zeng ◽  
Peng Sun

In this paper, we made two different chemical conversion coatings on aluminum alloy by TiOSO4 and Na2WO4. The morphology of the chemical conversion surface layers were observed by scanning electron microscopy (SEM). The microcosmic phase structures were characterized using X-ray diffraction (XRD). Electrochemical method was used to study the coatings corrosion resistance. The results indicated that the two conversion coatings were crystal structure material, the surface of coating were both show pothole structure. TiOSO4 coating have better corrosion resistance than Na2WO4 coating.


CORROSION ◽  
2004 ◽  
Vol 60 (3) ◽  
pp. 237-243 ◽  
Author(s):  
C. Wang ◽  
F. Jiang ◽  
F. Wang

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.


2012 ◽  
Vol 512-515 ◽  
pp. 2191-2194
Author(s):  
Yan Bo Wu ◽  
Xiao Xi Wang ◽  
Ting Lou ◽  
Tie Ben Song

SnSO4 and TiOSO4 were chosen in this paper as the main salts for preparing composite chemical conversion coating on aluminum alloy. The scope of this paper is to find out the optimal experiment process, the performance of Ti-Sn composite chemical conversion coating and tentative to analysis the microstructure of this chemical conversion coating. The optimal conditions of the concentration ratio of TiOSO4 and SnSO4 was 0.4g/L, 0.4g/L, KMnO4 1.0g/L, NaF 1.0g/L, reaction temperature 50°C、reaction time was 3min. And then different methods were used to study the performance and microstructure of the conversion coating.


Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 397 ◽  
Author(s):  
Hehong Zhang ◽  
Xiaofeng Zhang ◽  
Xuhui Zhao ◽  
Yuming Tang ◽  
Yu Zuo

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.


2019 ◽  
Vol 19 (6) ◽  
pp. 3487-3494 ◽  
Author(s):  
Bin Liu ◽  
Yi Zhao ◽  
Liang Li ◽  
Yafei Feng ◽  
Zhigang Fang ◽  
...  

An environment-friendly non-chromium chemical conversion coating was obtained from fluozirconate/fluotitanate acidic solution for the corrosion protection of AA 5083. The surface morphology, composition, electrochemical behavior and corrosion resistance of this coating were investigated. The coating was found to be a homogeneous and dense layer consisting of nano-size particles, of which the major component was compound oxides consisted by Al, Mg, Zr, Ti, F and O. The results of electrochemical measurements, immersion and natural salt spray (NSS) tests demonstrated that the corrosion resistance of the AA 5083 H-116 was improved by the nano-sized non-chromium chemical conversion coating considerably, which was most attributed to the great inhibitive action on the anodic dissolution by acting as a protective barrier layer.


2016 ◽  
Vol 40 (2) ◽  
pp. 1347-1353 ◽  
Author(s):  
Cong-cong Jiang ◽  
Gui-yong Xiao ◽  
Xian Zhang ◽  
Rui-fu Zhu ◽  
Yu-peng Lu

A uniform fine-crystalline structure is obtained upon PCC coating on 35CrMnSi with Fe2+ curing (b).


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