Hot-dip galvanizing is the application of a metallic zinc layer to iron or steel by dipping it into molten zinc (with a temperature of approx. 450 °C). By this process, a resistant alloy layer consisting of iron and zinc and thereon a highly adherent layer of pure zinc is built up. Hot-dip galvanizing is one of several methods to build up a zinc coat. Difference is made between (discontinuous) piece galvanizing and (continuous) strip galvanizing.

When just applied, the zinc coat is bright and glossy, then it has for some time a metallic-crystalline appearance, and over time it becomes dark grey due to corrosion of the zinc which, when exposed to atmospheric oxygen, yields a relatively weatherproof protective layer of zinc oxide and zinc carbonate.

When applied to more noble metals such as iron (see electromotive series) zinc serves as a sacrificial anode, which protects the iron underneath from corrosion until it is itself fully corroded. Because of these two material properties such a think zinc coat can provide an economical rust prevention for decades without maintenance.

The term of protection of hot-dip galvanization can be further improved by an additional coat of paint ("duplex system").

Please select from the subnavigation the process about which you want to know more or click on the link in the text: Normal-temperature galvanizing, high-temperature galvanizing,  Duplex-Coating systems, Anodizing & Zinc-flake.