| At present,the commonly used protection technology of transmission and transformation equipment is mainly coating protection technology and hot dip zinc protection technology.However,the development of epoxy zinc-rich coatings is limited by the defects of low adhesion,poor compatibility with topcoat and environmental pollution,complex processing,high energy consumption and non-in-situ repair of hot dip zinc coating.Against the above,this paper uses a new protective coating material and process,using thermal spraying technology with the cold spraying process on the 45 steel substrate preparation of zinc coating and zinc coating on aluminum,aluminum zinc,hot to cold galvanized,hot-dip zinc and epoxy zinc rich primer-alkyd enamel coating as the research object,analyzes the structure of the coating adhesion and,The structural characteristics and adhesion of the coating were investigated.The electrochemical analysis of the coating was carried out to explore the electrochemical characteristics and corrosion tendency of the coating.In order to explore the corrosion resistance of the coating,the structure characterization,adhesion analysis and weight loss detection of the coating samples after the neutral salt spray test,outdoor hanging test and acid immersion test were carried out.The results show that the surface of hot-dip zinc coating is rough and the smoothness is poor,while the hot-spray zinc coating and cold-spray aluminum zinc coating are smooth and have no obvious defects,and the adhesion property is good.Epoxy Zn-rich primer-alkyd enamel（black/blue）The surface of these two coatings is uniform and smooth,without foaming holes and other defects,the coating has good compactness,and the adhesion grade meets the requirements of test and practical application.The results show that the corrosion current density of hot dip zinc,hot spray zinc and cold spray aluminum-zinc coatings are 1.58×10-4A/cm2,9.33×10-5A/cm2and 5.75×10-5A/cm2,respectively.The Zf=0.01Hzvalue and capacitance-resistance arc diameter of hot-dip zinc coating and hot-spray zinc coating are both smaller than those of cold-spray aluminum zinc coating,and the resistance value of cold-spray aluminum zinc coating is greater than that of hot-dip zinc coating and hot-spray zinc coating by EIS fitting equivalent circuit.Therefore,the corrosion resistance of cold-spray aluminum zinc coating is better than that of hot-dip zinc coating and hot-spray zinc coating.This is because the aluminum-zinc coating has the protective effect of both aluminum and zinc,so that the corrosion resistance of the coating is more excellent.By analyzing the protective coatings after three corrosion aging tests:neutral salt spray test,outdoor hanging test,and acid immersion test,the corrosion resistance of the coating in different environments was explored.The results show that hot dipping zinc coating,hot spraying zinc coating and cold spraying aluminum zinc coating have good protective properties to the substrate after 264 h neutral salt spray test and 6 months outdoor air hanging sheet test.The spalling area ratio of hot dip zinc coating,hot spray zinc coating and cold spray aluminum zinc coating are 80.30%,87.18%and 7.14%respectively in 264 h acid immersion test.Epoxy Zn-rich primer--alkyd enamel（black/blue）coating appeared serious powdery and blistering at the edge of the coating surface after 192 h salt spray test and 6 months outdoor air test.The adhesion grade was grade 3,and the adhesion performance of the coating was poor,which did not meet the requirements of the test and application.The results of weight loss detection and electrochemical analysis after corrosion aging test show that the cold-sprayed Al-Zn coating has a slower corrosion process and a lighter corrosion degree compared with the hot-dipped and hot-sprayed zinc coating,and its corrosion resistance is better than that of the hot-dipped and hot-sprayed zinc coating,which can provide a longer service time for the substrate.At the same time,it can also provide experimental support and scientific basis for the selection of protective coating materials and preparation technology of transmission and transformation equipment. |
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