Rusting of an article made up of iron is called

Rusting of an article made up of iron is called corrosion. It is a chemical change where iron and oxygen react together to make a new substance of completely different properties called iron oxide.

The chemical reaction is shown as:

4Fe + 3O₂ → 2Fe₂O₃

Note- Rust consists of hydrated iron(III) oxides Fe₂O₃→nH₂O, iron(III) oxide-hydroxide (FeO(OH), Fe(OH)₃