Experimental Study on Neutral Salt Spray Accelerated Corrosion of Metal Protective Coatings for Power-Transmission and Transformation Equipment

At present, the common protection technology of power-transmission and transformation equipment is mainly coating protection and hot-dip zinc protection. However, due to the low adhesion of epoxy zinc-rich coating, and the poor compatibility with top paint, environmental pollution, complex processing, high energy consumption and other defects of the hot-dip zinc process, its development is limited. In view of the above deficiencies, new anti-corrosion coating materials and processes were investigated in this study. Zinc coatings and Al-Zn coatings were prepared on the C45 steel matrix by hot-spraying and cold-spraying processes. The macro appearance, micromorphology and phase composition analysis of the coatings were evaluated. The adhesion of the coating to the substrate after the salt-spray test was tested. The results showed that the hot dip zinc coating and hot spray zinc coating had obvious cracking after the salt-spray test. The surface structure of cold-sprayed Al-Zn coating was relatively dense after the salt-spray test. The critical load of the cold-sprayed Al-Zn coating after the salt-spray test was higher than that of the other two coatings. The corrosion resistance to salt spray of cold-sprayed Al-Zn coating was demonstrated to be better than the hot-dip zinc coating, and thus has great application prospects.