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

Coatings

Yu Zuo¹  Xiaofeng Zhang¹  Yuming Tang¹  Hehong Zhang¹  Xuhui Zhao¹ 

[1] Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, China;

关键词: conversion coating;    aluminum alloy;    fluorosilane modification;    corrosion resistance;    antifouling performance;   

DOI  :  10.3390/coatings8110397

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown