Eventual corrosion Galvanization

rusted corrugated steel roof

although galvanizing inhibit attack of underlying steel, rusting inevitable after decades of exposure weather, if exposed acidic conditions. example, corrugated iron sheet roofing start degrade within few years despite protective action of zinc coating. marine , salty environments lower lifetime of galvanized iron because high electrical conductivity of sea water increases rate of corrosion, through converting solid zinc soluble zinc chloride washes away. galvanized car frames exemplify this; corrode faster in cold environments due road salt, though last longer unprotected steel.

galvanized steel can last many decades if other supplementary measures maintained, such paint coatings , additional sacrificial anodes. rate of corrosion in non-salty environments caused levels of sulfur dioxide in air. in benign natural environments, such inland low population areas, galvanized steel can last without rust on 100 years.