The protective mechanism of galvanized coils is predicated upon the electrochemical properties of zinc. Since zinc is more electrochemically active than iron, it preferentially undergoes oxidation in humid environments, thereby forming a dense protective layer of zinc oxide that effectively prevents corrosion from propagating into the underlying substrate.
Depending on the specific manufacturing process, galvanized coils can be broadly categorized into two types: hot-dip galvanized and electro-galvanized. Hot-dip galvanizing involves immersing the material in a bath of molten zinc at high temperatures, resulting in a relatively thick zinc coating (typically ≥ 20 μm) that is well-suited for outdoor environments characterized by high corrosivity. In contrast, electro-galvanizing applies the zinc coating through electrolytic deposition; while the resulting layer is thinner (3–15 μm), it features a smoother surface finish, making it ideal for applications requiring precision processing. Furthermore, certain products incorporate an anti-fingerprint coating-achieved through a composite treatment utilizing organic resins and silanes-which creates a microporous surface structure that not only prevents fingerprint residue but also enhances the adhesion of the coating.