In high-temperature environments, the corrosion resistance of galvanized coatings significantly decreases due to accelerated oxidation, zinc-iron diffusion, and damage to the passivation film. When the temperature exceeds 60°C, zinc becomes more reactive, reacting with oxygen and water vapor to form a loose mixture of zinc hydroxide and zinc oxide, leading to increased porosity in the protective layer. Especially in humid environments, this reaction creates electrolyte channels, accelerating the electrochemical corrosion of the base metal.
High-temperature hot-dip galvanizing causes the zinc layer to become brittle because the chemical reaction between zinc and steel becomes more intense at high temperatures, resulting in more unstable compounds that are prone to porosity and cracks. These defects affect surface quality and corrosion resistance, and can even lead to product failure.

Time：11/05/2026 04:18:31

Under high temperature conditions, the hot-dip galvanized layer will undergo a series of changes, which will affect its performance as follows: Appearance changes: High temperature may cause the color of the hot-dip galvanized layer to change, turning yellow, gray, or even black. This is because high temperatures cause the zinc layer to oxidize, generating different zinc oxides, which in turn affect the appearance and color of the coating.
Changes in microstructure: The microstructure of the hot-dip galvanized layer changes at high temperatures. Zinc grains grow, and grain boundaries become blurred. This change in organizational structure alters the mechanical properties of the zinc layer, typically resulting in decreased hardness and increased toughness.
Changes in corrosion resistance: Generally speaking, within a certain temperature range, the corrosion rate of hot-dip galvanized layers will accelerate as the temperature increases. This is because high temperatures accelerate the chemical reaction between zinc and oxygen, moisture, and other corrosive media in the air, and may also damage the passivation film on the zinc layer surface, reducing its protective effect on the substrate. When the temperature exceeds a certain limit, the zinc layer may peel or flake off, further losing its protective properties.

Time：08/05/2026 16:44:12

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