Process of Corrosion
The process of corrosion is where metals progressively decline through chemical reactions, usually with moisture and oxygen.
The harsh climate in Australia, particularly along the coastline creates a powerful process of corrosion for metal.
What is Corrosion?
Corrosion is a natural process when metals and similar materials undergo a chemical reaction to the environment. This chemical reaction which is driven by corrosive substances such as moisture and oxygen causes the metal to eventually degrade.
The visible signs of corrosion are tarnishing and rusting, which eats away at the metal. Understanding the degradation that corrosion can have to metal means knowing its environmental, safety, and economic impact.
The most seen effect of metal corrosion is rust. Although rust occurs in different types of metals, iron is arguably the most common.
Iron and metals made from iron such as steel will start the corrosion process in the presence of oxygen and moisture.
Copper and Aluminium are metals that are less vulnerable to the corrosive process, but it can still occur under specific conditions. For copper, a green patina forms on the surface in the presence of moisture and airborne pollutants.
The patina creates a protective barrier and is often left on copper surfaces such as the Statue of Liberty.
Aluminium is highly resistant to natural corrosive processes. But one exception occurs in the presence of chloride ions.
The result is the creation of a protective layer of aluminium hydroxide. Thence it will cover the metal, not unlike the green patina of copper.
Different Types of Corrosion
There are several types of corrosion, each of which has unique characteristics. The seven basic types include the following.
– Erosion: Caused by exposure to corrosive environment
– Galvanic: When two or more dissimilar metals meet each other
– Intergranular: Metal with distinct grain boundary
– Localised: Corrosion on specific area as opposed to across the metal
– Selective Leaching: The dissolution of one or more alloy components
– Stress or Cracking: Created by tensile stress that causes cracking
– Uniform: Corrosion that occurs across the surface of the metal
Some types of corrosion are more common than others. For the most part, all of them can be prevented by taking the proper precautions.
Metal Corrosion Prevention
There are ways to slow down and even prevent corrosion from occurring in metal. It begins by cleaning the surface and removing any traces of rusting or contaminants that might be present.
Followed by application of a coating such as varnish, sealant, or paint. Hence, this creates a barrier between the metal and corrosive agents.
Once applied, the surface will need to be periodically inspected and maintained to ensure that the metal is protected. It also helps if the environmental conditions in which the metal is present is less conducive to the corrosion process.
Reducing the presence of moisture and heat will help provide rust protection.
Plus, be sure to use compatible materials so that galvanic corrosion does not occur. Metals that are not compatible tend to have electrochemical properties that may interact and start the corrosion process.
In Australia, metal corrosion can be prevented by properly preparing and protecting the surface so that the process of corrosion does not begin.
Rust Bullet Australasia’s team can help you with any questions you may have on this process. We also have products in our shop that will slow this process down. Contact us via our website or call on 0415 168 902.
