Corrosion implies damage that changes the material's properties, like strength or appearance. The sculpture's bronze has lost its luster due to corrosion.
Pro Tip 2/3
Time Factor
Corrosion is a gradual process; it doesn't happen overnight but over a longer period. Years of neglect led to the corrosion of the metal beams.
Pro Tip 3/3
Chemistry Involvement
Understand that corrosion involves chemical reactions, not just physical wear and tear. Saltwater speeds up the corrosion of steel.