| The corrosion of metal not only leads to a decrease in material properties,but also indirectly causes failure of parts and materials,and resulting in a large number of economic losses and engineering accidents.Epoxy coatings are widely used in corrosion protection field.However,due to the permeability of the epoxy coatings,it is easy to fail under long-term corrosion,and forming a corrosion channel to erosion the coating substrate.In this paper,the two-dimensional materials of graphene and nano-h-BN are used to enhance the penetration resistance of the coatings,and thereby improving the corrosion resistance of the coating.Based on the reading of the literature and experimental exploration,the following research work was carried out:(1)A high-quality,6-15 layer lamellar of graphene was prepared by a modified redox process,and a sheet structure with a complete structure and a layer number of 5-10 layers nano h-BN was prepared by liquid phase stripping method.(2)Added the graphene oxide and graphene before and after modification to the epoxy Zn-Al system,it was found that the corrosion resistance of the modified graphene oxide coating(coating resistance is 9.00 MΩ)was better than unmodified graphene oxide coating(6.526 MΩ);The corrosion resistance of the modified graphene coating(coating resistance is 32.13 MΩ)was better than the unmodified graphene coating(13.11 MΩ).Moreover,it can be seen that the modified graphene had an obvious improvement in the corrosion resistance of the coating.Therefore,it was determined that the modified Zn-Al coating was modified by solution blending with modified graphene,and the effects of different modified graphene additions on the corrosion resistance of the coatings were investigated.The results showed that with the increase of modified graphene content,the corrosion resistance first rised and then decreased.The composite coating with 0.15% graphene had the best corrosion resistance perforence,with minimal corrosion current density(1.31×10-7 A cm-2)and maximum coating resistance(159.7 MΩ).(3)The modified nano-h-BN composite epoxy Zn-Al coating was prepared by solution blending method,and the effect of nano-h-BN addition on the corrosion resistance of the coating was investigated.It was found that the effect of modified nano-h-BN on the corrosion resistance of the coating was similar to that of modified graphene,which was also increased first and then decreased.The composite coating with 0.1% nano-h-BN had the best anti-corrosion performance,and its coating resistance was 34.97 KΩ,which was higher than that of the coating without added nano-h-BN(1.708 KΩ).Overall,the corrosion resistance performance of graphene composite coatings were better than nano-h-BN composite coatings.(4)The layered structure and hydrophobic barrier of graphene and nano-h-BN two-dimensional materials can slow the corrosion of the coating matrix and improve the corrosion resistance performance of the matrix.In addition,since graphene had excellent electrical conductivity compared to nano-h-BN,it can enhance the conductive path between Zn-Al powder and the matrix,improve the protection of the cathode matrix of Zn-Al powder,and improved the corrosion resistance of the coatings. |
