The process of coating iron or steel with zinc, most commonly by immersion in a bath of molten zinc, to protect the base metal from corrosion. It works by sacrificial (cathodic) protection: because zinc is more chemically reactive than iron, it corrodes preferentially, including at cut edges and scratches where bare steel is exposed, sparing the steel underneath far longer than a barrier coating like paint would. Notably, the process's name is a documented misnomer: it is named after Luigi Galvani, an 18th-century physician and physiologist whose actual work concerned bioelectricity, the twitching of dissected frogs' legs under electrical stimulus, and had no direct connection to zinc coating or corrosion; the modern hot-dip process was patented decades after Galvani's death by a different man entirely, Stanislas Sorel. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/
Facts
Core PrincipleSacrificial (cathodic) protection: a more chemically reactive zinc coating corrodes preferentially, protecting the iron or steel beneath it, including at cut or scratched edges where bare metal is exposed. 1 Origin YearStanislas Sorel's French patent for both a molten-zinc immersion process and a "galvanic paint" (an early cold-galvanizing variant). Two Wikipedia articles disagree on the exact day, 10 May versus 10 June 1837; the atlas records year-precision only here, so the disagreement does not affect this fact, but is flagged for anyone sourcing a specific day. FAQs
How long does a galvanized coating protect steel?
Many decades when supplementary measures such as paint and sacrificial anodes are maintained.
Galvanized steel can last for many decades, but the source ties that long life to supplementary measures being maintained, such as paint coatings and additional sacrificial anodes. The zinc alone does not guarantee a fixed lifespan, because how long the protection holds depends on the conditions the steel faces and how it is looked after.
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Source Hot-dip Galvanization (Wikipedia)Wikipedia contributors
In Field
Source Galvanization (Wikipedia)Wikipedia contributors
Sources
1. Galvanization (Wikipedia)
Wikipedia contributors, Wikimedia FoundationHistory section
Galvanic paint, a precursor to hot-dip galvanizing, was patented by Stanislas Sorel, of Paris, on June 10, 1837... The process is named after the Italian physician, physicist, biologist and philosopher Luigi Galvani.
In Group: Steel Heat Treating and Finishing, Lead paragraph
is the process of applying a protective zinc coating to steel or iron
View the Source Hot-dip Galvanization (Wikipedia)
Wikipedia contributors, Wikimedia FoundationAssociated With: Steel, lead sectionQuote, Associated With: Steel, lead section
a usually dull grey, fairly strong material that protects the steel underneath from further corrosion in many circumstances.
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