Galvanized iron is iron ore that has been refined and coated with zinc.
Galvanized iron is iron ore that has been refined, shaped, and coated with a layer of zinc. Zinc provides the galvanizing as zinc resists corrosion typical of ungalvanized cast or wrought iron. Galvanized iron is made and used for a wide variety of purposes, but its primary use is for sheet metal roofing and other building materials such as metal framing, metal shingles, and fencing. Other uses include wire mesh, pipes, crown molding and other decorative exterior architectural products, gutters, flashing, metal buckets, and connectors such as screws and nails. The material resists rust and is therefore a very common material for outdoor projects.
Galvanized iron can be used for sheet metal roofing.
The term galvanized originates from Luigi Galvani, an 18th-century Italian physician and physicist who experimented in bioelectricity and electrochemistry. His experiments and research, focused on chemical and electrical reactions, did not lead directly to galvanized iron, but rather prompted the investigation of chemical reactions between metals. Zinc-coated iron, it was later discovered, resists rust that turns pure iron into a red powder in a matter of years. Galvanized iron revolutionized metallurgy and spawned the modern galvanized iron industry.
Electroplating is the process of immersing the cast iron product in an electrolyte solution of zinc sulfate.
Iron is galvanized by several different processes. The most common is electroplating, the process of immersing the cast iron product in an electrolyte solution of zinc sulfate. Hot-dip galvanizing, another common process, involves dipping iron into molten zinc or zinc alloys. In sherardizing, the iron is placed in an airtight vault and dusted heavily with zinc dust particles. The fourth process, less effective than the others, is to paint or spray molten zinc or zinc pigments onto the metal.
Galvanized iron comes in wire, sheet, and many other forms.
The types of iron galvanizing differ for various uses. For example, sheet metal roofs exposed to the harshest outdoor elements year-round are often galvanized or hot-dipped. The bottom cover is painted with zinc. Gutters and pipes can be painted or sprayed.
Galvanized iron is not completely resistant to corrosion. Products exposed to concrete, acid rain, tannic acids from certain trees, and excessive moisture will rust over time. Abrasions or slip and twist iron can open up the zinc coating, allowing moisture to enter the cracks and rust the iron below. Despite their vulnerabilities, galvanized iron products are extremely strong and remain the only corrosion-resistant metal products available.