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 to iron or steel oxidation caused by water or moisture interaction. So, does aluminum corrode, or does aluminum rust in water?
The film present on aluminum consists of a hydrated form of aluminum oxide, serving to offer protection against corrosion. This protective oxide film exhibits stability in water within the pH range of 4.0 to 8.5. Moreover, the self-renewing nature of the oxide film enables rapid repair of any inadvertent abrasion or mechanical damage. Consequently, factors leading to the corrosion of aluminum and its alloys are those that perpetually subject the film to mechanical abrasion or locally degrade the protective oxide layer, thereby impeding the availability of oxygen for its regeneration.
Aluminum is a standard 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 has its share of pros and cons. 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 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 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. 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. Contact us for more information or to find a dealer for NH Oil Undercoating near you. We can help.
The Corrosion Resistance of Aluminum
The film on aluminum is a hydrated form of aluminum oxide, which provides corrosion resistance. This protective oxide film is stable in water when the pH is between 4.0 and 8.5. The oxide film is self-renewing and can rapidly repair any accidental abrasion or mechanical damage. Therefore, conditions that lead to the corrosion of aluminum and its alloys are those that continuously abrade the film mechanically or locally degrade the protective oxide film, preventing 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.
It would be best to consider the grade or series of aluminum you’re using. Some, notably 5052 and 3003, have better corrosion-resistance properties than others. More generally, 1xxx, 3xxx, 5xxx, and 6xxx series alloys offer good corrosion resistance.
How long does it take for aluminum to rust?
Corrosion refers to the gradual deterioration of materials caused by environmental elements such as moisture and chemicals. When it comes to aluminum, corrosion can occur over an extended period, ranging from weeks to months, and even years. This natural process can lead to the formation of large holes in aluminum products, compromising their structural integrity over time.
Find an NHOU® dealer near you.