Rusting

• Rusting


  • when iron is exposed to oxygen and water for some time, a red brown substance, rust, slowly forms on the surface of the metal
  • rust is hydrated iron (III) oxide
  • rusting is the gradual oxidation of iron to form hydrated iron (III) oxide which requires oxygen and water
  • rusting takes place more quickly in salt solutions and acidic solutions
• Prevention of rusting


  • using a protective layer through painting, greasing or plastic coating which prevents oxygen and water form reaching the iron
  • using a sacrificial material through galvanising or attaching blocks of zinc or magnesium, since these metals are more reactive than iron, they have a greater tendency to lose electrons and be oxidised, thus they will corrode preferentially instead of iron