Can Aluminum Rust?
Rust and corrosion are often interchangeable, but they’re not the same. Corrosion refers to the wearing away of metal caused by a chemical reaction. Rust is a type of corrosion referring specifically to iron or steel oxidation caused by water or moisture interaction. So does aluminum corrode, or does aluminum rust in water?
Cars covered by snow on the street on a winter day aluminium doesn’t contain iron or steel so it doesn’t rust – but it is prone to corrosion when exposed to weathering and atmospheric oxygen. The process of aluminum corrosion is known as oxidation. The resulting aluminum oxide is a thin, hard layer that protects the metal from further corrosion.
Aluminum oxide appears as a powdery white or dull gray coating. As oxidation occurs, it hardens and creates a protective layer over the newly exposed areas of corroded aluminum. The aluminum corrosion process is halted by oxidation – the metal won’t continue to deteriorate unless the aluminum oxide is removed. Unlike rust, which has a flaky, reddish appearance, aluminum oxidation cannot be easily chipped off the metal surface.
Aluminum is a common metal that is used widely to produce a variety of products. These include automobiles, nuts, bolts, conductors, airplanes, etc. A growing number of automobile manufacturers are replacing iron and steel with aluminum for many reasons, such as:
- It is lighter
- Helps increase fuel efficiency
- Resists wear more effectively
- Has good strength
However, just like a coin has two sides, aluminum comes with its share of pros and cons. And one of the cons is that it is prone to corrosion. In the narrowest definition of rust, corrosion is interchangeably used with rust. Therefore, that technically means aluminum can rust.
Aluminum oxide appears as a powdery white or dull gray coating. As oxidation occurs, it hardens and creates a protective layer over the newly exposed areas of corroded aluminum.
Rust or corrosion happens because rock salt that is now commonly mixed with magnesium chloride and other salts for de-icing the roads during the winter season are added with bonding agents to keep the mixture from washing away. Due to the high salt concentration, the mixture created is more powerful and efficient at catalyzing corrosion. Thus, it results in faster corrosion of aluminum and steel.
An article published in FordProblems.com explained how Ford faced a class-action lawsuit when its aluminum hoods experienced corrosion. Ford is a leading auto manufacturer that has been at the forefront in embracing aluminum at a volume level. As aluminum was the company’s preferred choice, it later faced a lawsuit in the US District Court in New Jersey. It claimed that Ford used aluminum hoods and did not properly insulate them with old iron-based connecting and supporting parts—knowing that it would result in galvanic coupling and corrosion.
The post further explained that Ford concealed the problem from buyers and denied the claims. The automaker dismissed the claim and declared that it lacked merit.
Later, they sent dealers a Technical Service Bulletin that discussed blistering and bubbling under the paint on the aluminum body because of iron contamination. It further explained that testing showed that aluminum corrosion occurred because iron particles seeped in the aluminum body before it was painted. It’s crucial to understand that metal corrodes due to a chemical reaction between the oxygen present in the air, a metal, and a catalyst. Although iron corrodes faster, aluminum also corrodes, taking a little longer. Needless to say, the main culprit for corrosion in vehicles nowadays is rock salt on the roads.
However, rustproofing is the best way to protect your vehicle from corrosion or rust. Use NH Oil Undercoating to keep your vehicle rustproof. It pushes out moisture and provides a protective layer to the undercarriage, all much-needed to prevent oxidation and corrosion.
From keeping your vehicle rustproof to improving its visual appeal, NH Oil Undercoating is your best bet to prevent your vehicle from damage caused by corrosion or rust. For more information or to find a dealer for NH Oil Undercoating near you, contact us. We can help.
The Corrosion Resistance of Aluminum
Chemically, the film is a hydrated form of aluminum oxide. The corrosion resistance of aluminum depends upon this protective oxide film. Which is stable in aqueous media when the pH is between about 4.0 and 8.5. The oxide film is naturally self-renewing, and the surface film’s accidental abrasion or other mechanical damage is rapidly repaired. Therefore, the conditions that promote the corrosion of aluminum and its alloys must be those that continuously abrade the film mechanically or promote conditions that locally degrade the protective oxide film and minimize the availability of oxygen to rebuild it.
Aluminum Corrosion: Why it Happens and What to Do When It Does
- Apply a protective coating.
- Minimize or mitigate the effect of galvanic corrosion.
You should also consider the grade or series of aluminum you’re using. Some of these, notably 5052 and 3003, have better corrosion-resistance properties than others. More generally, 1xxx, 3xxx, 5xxx and 6xxx series alloys offer good corrosion resistance.
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