Why Iron Rusts (And How to Prevent It)

Iron is arguably one of the world’s most important metals. It’s relatively strong, lightweight and malleable, making it an effective material for countless products. In its natural state, however, iron is highly susceptible to rusting. Over time, the versatile metal will become corrode, resulting in the formation of iron oxide, which is more commonly known as rust.

The Science Behind Rusting

Iron, as well as iron alloys, rusts because of a chemical reaction known as oxidation. When iron is exposed to moisture or oxygen, oxidation occurs. During this chemical reaction, iron is converted into iron oxide. The iron oxide typically has a reddish, flaky appearance that becomes progressively worse over time. If left unaddressed, the iron oxide will spread, thereby jeopardizing the physical integrity of the iron.

Iron can rust from either exposure to air or exposure to moisture. Both oxygen and moisture are catalysts for rusting. When iron is exposed to air or moisture, oxidation will convert it into iron oxide.

Anti-Corrosion Treatments for Iron

There are ways for metalworking and manufacturing companies to protect their iron workpieces from rusting. Galvanization, for example, is a common anti-corrosion treatment process for iron. It involves the application of a protective coating over the surface of a metal workpiece. With galvanization, zinc is applied over the surface of iron. The zinc layer acts as a barrier between the iron and its surrounding environment. As a result, the iron doesn’t come into contact with air or moisture. Assuming the zinc layer remains intact, galvanized iron shouldn’t rust.

Another common anti-corrosion treatment for iron is surface plating. Surface plating involves the deposition of nickel or chrome. Because nickel and chrome don’t contain iron, they aren’t susceptible to rusting. Surface plating is a more complex anti-corrosion treatment, but it’s highly effective at protecting iron from rusting.

Something as simple as painting the surface of iron can protect it from rusting. Like with galvanization, painting creates a barrier over the surface of iron. The presence of the paint creates a barrier between the iron and its surrounding environment. The downside to painting iron, however, is that it doesn’t last as long as other surface treatments.

Using wrought iron instead of pure iron can also protect against rusting. Wrought iron has a higher carbon content than pure iron, and with more carbon, it’s naturally better protected against rusting. With that said, pure iron, wrought iron and cast iron can all rust when exposed to moisture or air.

No tags for this post.