Galvanizar

Galvanizar, or galvanización, is the process of applying a protective zinc coating to iron or steel to prevent corrosion. The zinc coating provides protection primarily through galvanic action: zinc acts as a sacrificial anode, corroding before the iron or steel, and also forms a protective layer of zinc compounds that slows further rust. This combination extends the service life of metal parts exposed to moisture and salts.

The two main methods are hot-dip galvanizing and electrogalvanizing. In hot-dip galvanizing, parts are cleaned, fluxed, and immersed in molten zinc at temperatures around 450°C, resulting in a relatively thick coating that adheres well to complex shapes. The coating thickness is typically tens of micrometers, varying with part type and environment. Electrogalvanizing deposits zinc electrochemically from a solution, producing thinner, more uniform coatings suitable for precision parts and components requiring tight tolerances.

Other related processes include coatings of zinc alloys (such as zinc-nickel), and sherardizing, a semi-dry diffusion process. Galvanized coatings are widely used on structural steel, pipelines, automotive components, appliances, fencing, and street furniture due to durability and reduced maintenance.

Standards governing galvanization include ISO 1461 and EN 1461 for hot-dip coatings on iron and steel, and ASTM A123/A123M in the United States. Limitations include potential white rust if stored improperly, mechanical damage exposing the substrate, and environmental considerations related to coating disposal and recyclability.