Corrosion

	Corrosion, often called rust:

Corrosion is enemy number 1 when it comes to your vehicle! Given our climate, the effects of humidity and calcium wage constant war on our vehicles. The following paragraphs are intended to provide you with a better understanding of the metal corrosion process.

Variations in the chemical composition of steel generate inconsistencies in the material (on a microscopic level). In addition, and as a result of physical stress (due to heat, cold, scratches, vibrations, etc.), areas of increased vulnerability will also develop in the metal. Areas of greater vulnerability are called “anodes” while the other areas are called “cathodes”.

There are three contributing factors in the development of corrosion: chemical, physical and electrochemical. The most common cause is electrochemical; we will further explain this process in the following section.

The most common form of corrosion may be represented as follows:

Fe + H₂O + ½O₂ = Fe(OH)₂

Iron + Water + Oxygen = Rust

This indicates that the initial reaction of iron with water and oxygen causes rust. If one of the three elements is missing, rust will not be able to form. Therefore, an effective anticorrosive product must eliminate any contact between iron and either water or oxygen. Because our vehicles are driven on land, as opposed to underwater, this would indicate that we must prevent the humidity in the air from coming into contact with the metal.

The process

Dissolved iron (Fe₂₊) is drawn toward the cathodic areas using the humidity on the surface of the steel. From there, it reacts with the oxygen in the air to form rust (Fe₂O₃*nH₂O(s)).

Humidity and the Air

In order for rust to form, both humidity and air must be present: humidity due to its role as a bridge in the process and air for its role in the formation of rust. Steel will not rust in dry air.

Salt

Salt accelerates the formation of rust. It dissolves in the humidity on the surface of metals and increases the conductivity of the water (accelerating and facilitating the transfer of iron to the cathodic areas), thereby accelerating the corrosion process. What’s more, the chloride ions in the salt accelerate both the iron dissolution process and the hole formation process.

Oil as a protective agent

Oil protects metal by preventing its contact with humidity and oxygen. If rust is already present, its progression will be slowed considerably. As most of us know, oil repels water, which tends to bead on its surface. The oil must be fluid enough to penetrate into any defects in the metal and infiltrate the smallest folds and nooks in order to eliminate humidity and cover the areas susceptible to corrosion. Keep in mind that only a thin layer of oil is required as these chemical processes take place on a microscopic level.