Study of the Protection of Aluminum Alloy Surfaces by a Graphene-Modified Fluorocarbon Anticorrosive Coating

Peng Wang,Dayong Cai,Yimin Wu

doi:10.1155/2020/8835737

Abstract

Graphene-modified anticorrosion coatings have become a hot spot in the field of metal protection due to the large-scale promotion of aluminum alloys, which are prone to corrosion in marine and atmospheric environments. The protection of aluminum alloy surfaces by a graphene-modified anticorrosive coating was explored in this study by applying a graphene-modified anticorrosive coating to an aluminum alloy surface to test its resistance to corrosion. Dispersion-treated reduced graphene oxide (rGO) was used to modify the epoxy resin and fluorocarbon resin. It was found, by using a scanning electron microscopy (SEM) and the microstructure of the coating made by the Raman Spectroscopy Institute, that the addition of rGO could effectively improve the porosity of the epoxy primer, and the electrochemical workstation was able to resist the graphene-modified anticorrosive coating. The corrosion performance was quickly characterized, the polarization curve and the AC impedance curve were fitted, and it was found that the self-corrosion current density ( J corr ) of the graphene-modified anticorrosive coating was the smallest ( 1.190 × 10 − 7 A / c m 2 ) when 0.6% of rGO was added; the impedance modulus ( ∣ Z ∣ ) was the largest (104), the capacitive reactance arc radius was the largest, and the coating resistance was the largest after fitting (15517 Ω). When 0.8% of rGO was added, the dispersion coefficient was large, and it had a good physical insulation performance. The main reason for the reduction of the corrosion resistance was that the agglomeration of rGO made the aluminum alloy matrix and the external corrosive environment form a highly conductive circuit, thereby accelerating the corrosion of the aluminum alloy matrix.

Highlights

In a space shuttle, the most serious corrosion is found in the structure of the aircraft body
When the relative humidity of the atmosphere in the external environment exceeds 65%, a film of water about 0.001 μm thick is deposited on the surface of the aircraft body and structural parts [1]
The thickness of the water film gradually increases with the increase of the external relative humidity, and when the humidity of the external environment reaches 100%, condensation forms on the surface of the aircraft body

Summary

Introduction

The most serious corrosion is found in the structure of the aircraft body. It is often used as a topcoat in the field of heavy anticorrosion to protect the substrate due to its mechanical properties, but its UV resistance is poor, and its anticorrosion performance is greatly reduced after ultraviolet aging; (3) fluorocarbon coatings that contain a large amount of C, with a bond energy of up to 485.6 kJ/mol F-bonded fluorocarbon resin, have excellent chemical and UV resistance. They are widely used in ships, pipelines, and aerospace fields, but their adhesion and pigment wetting are poor [3, 4]. The corrosion resistance mechanism of the anticorrosive coating is explored by fitting an equivalent circuit to explore its ability to resist the corrosion of aviation aluminum alloy

Experimental Section

Results and Discussion

Conclusions