Understanding Corrosion Behavior of Hot-Dipped Galvanized Steel and Cold Sprayed Zinc Steel in Urban Atmosphere
摘要
In this paper, the short-term corrosion behavior of the hot-dipped galvanized steel and cold sprayed zinc steel in urban atmosphere was investigated using scanning electron microscope, 3D microscopic and electrochemical measurements. The results showed that the corrosion rate values of hot-dipped galvanized steel decreased from 1.013 μm·y−1 in the first year to 0.891 μm·y−1 after two years of exposure, whereas the corrosion rate values of cold sprayed zinc steel increased from 1.645 μm·y−1 in the first year to 1.882 μm·y−1 after two years of exposure. Electrochemical measurements corroborated these trends, revealing a substantially higher corrosion current density of cold sprayed zinc steel (from 24.46 μA·cm−2 to 47.40 μA·cm−2) compared to hot-dipped galvanized steel (from 10.40 μA·cm−2 to 6.186 μA·cm−2). During the field exposure, the corrosion rate values of the cold sprayed zinc steel were always higher than that of the hot-dipped galvanized steel. The localized corrosion degree for the hot-dipped galvanized steel was relatively high, and the zinc coating was perforated after one year of exposure. General corrosion dominated the surface of the cold sprayed zinc steel, with a low sensitivity of localized corrosion.