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Corrosion of Different Metals

Postby Retna2000 » Wed Jan 07, 2015 10:37 pm

I am doing my science fair project. My hypothesis is that I think that aluminum is the most resistant to corrosion because it is protected by the aluminum oxide layer that is formed on the surface of the metal to prevent corrosion. In the middle, I was a little confused. My question to you is that if copper is the most resistant to corrosion or if aluminum is the most resistant to corrosion.
Thank you very much of this opportunity.


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Re: Corrosion of Different Metals

Postby bradleyshanrock-solberg » Tue Jan 20, 2015 7:56 pm

Well, the short answer is, they're different (as is galvanized steel).

Copper is not very reactive on its own, aluminum as you say forms a coat of aluminum oxide (a ceramic) which is also not very reactive (most ceramics and glass are highly resistant to any kind of chemical change). Galvanized steel also forms a protective coat, but it's vulnerable to some kinds of chemical interactions (especially if you mix copper and galvanized steel, you make the connection VERY vulnerable to corrosion).

The reasons for this involve chemistry you're not likely to see until 11th grade - the atomic structure of each material interacts with air and water, and impurities in the water that form acids or bases differently, both before and after they form protective layers (in the case of the two "not-copper" metals).

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