Different Types of Corrosion in Metals

corrosion prevention

No matter what type of material a high-performing component is made of, it will get corroded. Luckily, there are corrosion-resistant coatings that can help increase its lifespan and reduce maintenance and replacement costs.

 

In order to choose the right coating, it is essential to know what type of corrosion makes the part of a component vulnerable. Remember that the corrosion type that develops will depend on what condition a part is exposed to and how it is being used.

 

Here are some of the common types of corrosion and how they develop.

 

Caustic agent

Caustic agents cause impure gas, liquids, or solids to wear a material down. One example of a caustic agent is hydrogen sulphide. While there are plenty of impure gases that do not damage metals in dry form, they can still form corrosive droplets if moisture is present.

 

Galvanic

The galvanic corrosion is a type of corrosion that occurs if two metals that possess various electrochemical charges are linked by a conductive path. This phenomenon happens when the metal ions move from the anodised metal to the cathodic metal. Also, this happens if there is an existing impure metal. Once it contains a combination of alloys that have different charges, the metal gets corroded.

 

General

If a metal is exposed to water, the surface undergoes oxidation. As a result, a thin layer of rust will appear. Like galvanic corrosion, general corrosion is also electrochemical. Oxidation can be prevented by using a protective coating to interfere with the reaction.

 

Localised

If a small part of a component is exposed to corrosion-causing stresses, localised corrosion is likely to occur. The small portion that is being affected by the corrosion gets corroded faster than the rest of the component.

 

Stress-corrosion cracking

In this type of corrosion, the damage to the component can reach a point where repair is no longer possible. Stress-corrosion cracking is caused by cold work, stress by thermal treatment, and welding. As these elements are combined with exposure to an environment, it will result in lasting damage on the metal.

 

One of the many methods of corrosion prevention is to make use of corrosion-resistant coatings. They come in variations depending on the metal they will be applied to. Coatings that are made from aluminium and zinc can be used in the prevention of galvanic corrosion in iron and steel alloys.

 

If you want to learn more about corrosion prevention and protective coatings, contact Unituffglobal.com today!