Corrosion is the deterioration of a metal caused by a chemical reaction. An example would be when your car battery's metal terminals start gunking up after a bit of the battery acid leaks on them....
Rusting is corrosion, but the term is usually only used when talking about steel.
Weathering is the breaking down of particles, but did you mean erosion?
Corrosion is a chemical oxidative process. Erosion is a physical wear process.
Ferrous rust's and non ferrous doesn't. :))