Blog 2 1/21/11

Continuing from blog 1, one metal that forms a tight layer is aluminum. One that does not is iron. The metals do this, because most metals except gold and platinum are not found in its pure form, and have to use lots of energy to extract from its ore. Therefore, the metal extracted from the ore is highly unstable. Essentially, the process of corrosion is reversing the process of extracting the metal from the ore, to a more stable oxide.