| ZHAO Bi-fang,ZOU De-ning,TONG Li-bo.Effect of Modified Nano-SiO2/Epoxy Resin Hybrid Coating on Corrosion Resistance of Magnesium Alloy[J],50(10):322-329, 336 |
| Effect of Modified Nano-SiO2/Epoxy Resin Hybrid Coating on Corrosion Resistance of Magnesium Alloy |
| Received:November 20, 2020 Revised:February 27, 2021 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.10.033 |
| KeyWord:Mg alloy silane nano silica epoxy resin corrosion resistance long-term service |
| Author | Institution |
| ZHAO Bi-fang |
Xi’an University of Architecture and Technology, Xi’an , China |
| ZOU De-ning |
Xi’an University of Architecture and Technology, Xi’an , China |
| TONG Li-bo |
Xi’an University of Architecture and Technology, Xi’an , China |
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| Abstract: |
| To study the corrosion protection effect of silane-modified nano-SiO2/EP (epoxy resin) hybrid coating for Mg alloy substrate and its long-term service performance. The nano-SiO2 was modified by γ-(2,3-epoxy propoxy) propytrimethoxysilane, and then the nano-SiO2/EP composite protective coating was prepared on the surface of Mg-6.0Zn-0.5Ca-0.6Zr (wt.%) alloy by spin-coating technology. The scanning electron microscope (SEM) was used to observe the coating surface and cross-sectional morphology, and the atomic force microscope (AFM) was carried out to characterize the three-dimensional morphology of the coating surface, and the attenuated total reflectance infrared spectroscopy (ATR-FIIR) was applied to analyze the chemical composition of the coating. The barrier effect of composite coating to corrosive media and the influence on the corrosion resistance of magnesium alloy was measured through electrochemical tests. A dense three-dimensional network structure was formed within the nano-SiO2/EP composite coating, which exhibited high compactness. According to the results of polarization curves, the self-corrosion current of the magnesium alloy substrate of the composite coating decreased from 1.31×10−5 A/cm2 to 2.40×10−9 A/cm2, which reduced by four orders of magnitude. The corrosion rate was decreased from 1.61 mm/a to 1.32×10−5 mm/a, which exhibited a reduction of 5 orders of magnitude. The strong interaction between SiO2 and EP conferred the coating an outstanding barrier effect and remarkably improved the corrosion resistance of the Mg alloy substrate. In terms of the long-term serviceability of the coating, the SiO2/EP coating immersed in a 3.5 wt% NaCl solution for 336 h, and there was no diffusion phenomenon of the corrosive medium in the coating. The SiO2/EP hybrid coating significantly improves the corrosion resistance of the Mg alloy substrate, and the dense three-dimensional network structure effectively blocks the diffusion of H2O, Cl−, and other corrosive media in the coating. |
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