Should we treat aluminum bodies against rust?
Aluminum is an exceptional material because of its many advantages and its characteristics which protect it against corrosion. Unlike ferrous metals, it does not rust. Its oxidation allows it to generate a protective layer against rust.
There are therefore several debates concerning aluminum bodies and anti-rust treatments. What is the oxidation of aluminum? Should we treat aluminum bodies against rust?
What is galvanic corrosion?
Galvanic corrosion is an electrochemical reaction that results from the formation of a battery by contacting two different conductive metals.
Simply put, when two types of metal come into contact in an electrolytic environment, one of the two metals is likely to corrode faster than when they are separated. This phenomenon is called galvanic corrosion.
Galvanic corrosion can only take place if these three conditions are present:
- The dissolution potentials of the two metals in contact are different.
- The two metals are in direct contact or they have an electrical connection between them through another conductive body.
- Metals are found in an electrolytic medium such as seawater or road salt.
Galvanic corrosion is a common type of corrosion. It affects aluminum, but also other types of metal. As mentioned, galvanic corrosion only forms if the two materials have different dissolution potentials. This reaction occurs between a so-called reactive metal (the most likely to be corroded) and a so-called noble metal (the least likely to be corroded).
This list classifies the metals according to their dissolution potential, from the most likely to be affected by galvanic corrosion (reactive) to the most noble:
- Aluminum alloys
- Mild steel, cast iron
- Chrome (plated on steel)
- Yellow brass
- Lead tin solder (50:50% by weight)
- Pewter bronze
- Copper-nickel (70:30% by weight)
- Silver Nickel
- Stainless steel (alloy 316)
How does aluminum oxidize?
Oxidation of aluminum occurs when it comes into contact with another type of metal in a medium containing oxygen. When aluminum is the less noble of the two metals, it becomes the anode of the corrosion reaction.
As a result, an oxide layer is created on the aluminum, commonly referred to as aluminum oxide or alumina, as a protective barrier to protect the metal surface against corrosive atmospheres.
Pitting corrosion can also occur. In the presence of an electrolyte containing chloride ions, aluminum is susceptible to pitting corrosion. However, it is important to mention that this sensitivity is dependent on the nature of the alloy used. The autocatalytic pitting mechanism is shown schematically here:
Does an aluminum car need anti rust treatment?
Since aluminum does not contain iron or steel, it will not be affected by rust, but by a pitting corrosion oxidation process. Therefore, the application of an anti-rust treatment to protect the aluminum of the car is a necessity.
It is therefore advisable to have your car treated against rust for three main reasons. First, we must not forget that most of the components relating to the structure of the car are made of steel. Rust will devour the components of the car if the car has not been given an anti-rust treatment.
Second, aluminum can be damaged by oxidation or pitting corrosion.
Third, rustproofing must be part of your car’s auto maintenance if you want to protect your investment in the long run. Doing an anti-rust treatment contributes to the general good condition of the mechanics and the body of the car.
The best anti rust treatment on the market
Usually, some dealerships will offer the application of a rust proofing treatment with the purchase of a new vehicle. However, it is best to do business with an expert in the field.
Why treat your car at Antirouille Champlain? With more than 50 years of expertise, our technicians are specially trained to treat cars according to their make and model. Our team adapts to your specific needs and offers you the best guarantees.
Our anti-rust treatments are based on oil and grease with the addition of paraffin and calcium sulphonate. They guarantee full coverage of the most sensitive areas. They penetrate every crease in the sheets and frame, forming a barrier against moisture, salt, sand and dust to prevent rusting.