The process of galvanizing simply involves coating a given material with zinc. Galvanizing a metal makes it more resistant to corrosion because zinc has the natural ability to resist corrosion. The process of galvanizing metal has been in practice for well over a century. Galvanizing metals has countless modern-day practical applications. Galvanized sheet metal is used in the manufacturing of pipes, pipe fittings, nails and gutter systems, according to the sources at the United States General Services Administration.
According to Haverford College, water is the necessary component for corrosion to take place. Oxidation (the loss of electrons) is the deleterious process behind corrosion. Since there are traces of water in the air, a material can eventually corrode even under the driest conditions. The process of corrosion compromises the structural integrity of metals. When a droplet of water comes in contact with iron, for example, the oxygen in the air near the droplet diffuses into the droplet. The liquid then brings the dissolved gases onto the metal enabling corrosion, according to Chem Topics.
According to the U.S. General Services Administration, to galvanize a material like pipes and pipe fittings, the metal they are constructed of must undergo one of a number of processes. "Hot-dip" galvanizing involves immersing a given amount of metal into a bath of molten zinc. "Electro-galvanizing" a metal involves dipping it into an electrolyte solution which coats the material with zinc. Placing a given amount of a metal in a vacuum, encompassing it with zinc dust and heating it is referred to as, "sherardizing." The heat bonds zinc to the metal. It should also be noted that a zinc coating can be painted on a given material to galvanize it. The U.S. General Services Administration claims that zinc thickness is the easiest to control under electro-galvanizing.
There are several limitations with the technology behind galvanizing. Regardless of how well a zinc coating is applied to a material, abrasion can wear off a material's zinc coating, making it more prone to corrode. Continuous expansion and contraction of a galvanized material can lead to the premature deterioration of a material's zinc coating.
Corroding steel costs this country around 3 percent of its gross domestic product every year, according to the American Galvanizers Association. Literally billions of dollars are spent each year on dealing with corroded metals. This is the main reason that galvanized products like galvanized pipes and pipe fittings are widely employed throughout the country. Galvanized stainless steel can last for well over a hundred years even under corrosive conditions.