Category: Other, Science & Nature, Technology

White rust is not iron oxide red rust produced by corrosion of basic steel; It mainly consists of zinc hydroxide, basic zinc carbonate, and basic zinc chloride produced via electrochemical reaction between zinc coating, ambient moisture, and carbon dioxide in a sealed low-airflow environment. Standard hot-dip galvanized steel grades DX51D Z and DC51D Z use pure zinc coating as a sacrificial anticorrosive coating. When condensation water or rainwater trapped between layers is tightly piled up, the enclosed space hinders free air circulation, hinders the formation of natural and stable zinc carbonate patina, and accelerates the local electrochemical corrosion on the zinc surface, resulting in thick white powder deposits, namely white rust.