The Amazing Rusting Aluminum

The Amazing Rusting Aluminum: "By rusting, aluminum is forming a protective coating that's chemically identical to sapphire-transparent, impervious to air and many chemicals, and able to protect the surface from further rusting: As soon as a microscopically thin layer has formed, the rusting stops. ('Anodized' aluminum has been treated with acid and electricity to force it to grow an extra-thick layer of rust, because the more you have on the surface, the stronger and more scratch-resistant it is.)"