What is Corrosion? Corrosion Types and Prevention

Corrosion, which we encounter in many areas from daily life to industrial activities, is the process of metals losing their properties by interacting with environmental factors. This natural but undesirable process can lead to material losses and safety risks. 

As Ayba Metal, in this blog post, we examine what corrosion is, how it occurs and its types in detail. We will also answer the question of what are the corrosion protection measures.

What is Corrosion?

pipe with corrosion

Corrosion is the slow deterioration and degradation of metals and other materials by environmental influences, which has become a part of our daily lives. This process not only causes economic losses but also creates safety risks and environmental problems.

The deterioration and wear of metals and alloys over time as a result of interaction with environmental factors is called corrosion. This interaction usually occurs in the form of an electrochemical reaction and can lead to changes in the chemical structure of the metal, resulting in loss of strength, functional deterioration, and an aesthetically unpleasant appearance.

Corrosion is the process by which metals, in particular metals, gradually deteriorate as a result of chemical or electrochemical reactions by interacting with oxygen, water, and other chemicals. This process starts on the surface of the metal and can progress to the internal structure of the material over time. Corrosion changes the properties of the metal, reducing its durability, appearance, and functionality.

How Corrosion Occurs?

long pipe with corrosion

The occurrence of corrosion varies depending on the type of material and environmental conditions. The most common mechanism for metal corrosion is the initiation of an electrochemical reaction as a result of contact of the metal with a solution containing an electrolyte. 

This process is characterized by electron flow between two regions of different electrochemical potentials, called the anode and the cathode. The anode site undergoes oxidation (loss of electrons) and is converted into soluble metal ions, while the cathode site undergoes reduction (gain of electrons). The metal ions formed as a result of this electrochemical reaction react with oxygen, water, or other chemicals in the environment to form more stable compounds.

What are the Types of Corrosion?

yellow metal piece with corrosion

Types of corrosion can be seen in different types depending on different factors. The most common types of corrosion are as follows:

1. Homogeneous Corrosion 

In this type of corrosion, the entire surface of the metal corrodes evenly. It is one of the most common types of corrosion and is often referred to as atmospheric corrosion.

2. Galvanic Corrosion 

It is a type of corrosion caused by the contact of different metals with each other. The formation of an electrical potential difference between these metals causes the formation of an electrochemical cell and the degradation of the less noble metal.

3. Pitting Corrosion 

It is a type of corrosion that appears as localized deep pits on the surface of the metal. It often occurs as a result of damage to the passive layer in the presence of chloride ions.

4. Wear Corrosion

It is a type of corrosion caused by mechanical wear and the abrasive effect of fluids. It is frequently seen in metal structures exposed to abrasion such as pipelines, pumps, and turbines.

5. Stress Corrosion 

It is a type of corrosion that occurs in metal exposed to mechanical stress. It is more common, especially in cracks and welding seams.

6. Wear and Corrosion 

It is a type of corrosion in which wear and corrosion occur together. It is especially seen in moving parts and liquids with high flow rates.

What Can Be Done Against Corrosion?

pole with corrosion

Now that we have answered the question of what types of corrosion are, we can move on to the question of what methods can be applied to prevent or slow down corrosion. Among these, the most effective corrosion protection methods are as follows:

Protective Coatings: Metals can be protected against environmental factors by coating with protective layers such as paint, plastic, or special coatings. At this point, galvanized sheets stand out as one of the most ideal material choices as galvanized coating provides excellent protection against corrosion. 

You can make a more detailed examination by reading our content titled What is Galvanize? How is Galvanized Coating Made?

Anode Protection: By using sacrificial anodes, corrosion can be directed to another metal. These anodes extend the life of the metal to be protected by the corrosion it attracts on itself.

Corrosion Inhibitors: Electrochemical reactions can be slowed down by adding chemical inhibitors. These chemicals adsorb to the metal surface and form a layer that prevents corrosion.

Controlled Environment: Controlling the environmental conditions to which the metal is exposed, for example by reducing humidity or neutralizing the pH value, can help prevent corrosion.

inside of a pipe with corrosion

As a result, corrosion poses a major threat to engineering and industrial applications and, if not managed effectively, can lead to significant cost increases, equipment losses, and structural damage. This process affects a wide range of sectors, from infrastructure to transport, automotive to power generation. Therefore, understanding, controlling, and preventing corrosion is a critical branch of engineering and materials science.

Corrosion management is not only a branch of engineering and materials science but also critical to economic and environmental sustainability. Mitigating the effects of corrosion requires a multidisciplinary approach and continuous research. In this way, both costs can be reduced and safer and more durable structures can be built.