Rusting

• Corrosion is the reaction of metals with water and oxygen
• Rusting is the corrosion of iron/steel
• Sacrificial protection is when we mix or cover a metal with a metal that is more reactive than that metal. This causes the more reactive metal to react with the oxygen and water stopping the other metal corroding
• If we mix or cover iron with a metal that is more reactive (like aluminium) it will stop the iron from rusting. Instead the more reactive metal reacts with the water and oxygen. This is called sacrificial protection
• Very reactive metals like magnesium, calcium, sodium and potassium can't be used in sacrificial protection because they are too reactive
• For corrosion to work there needs to be water and oxygen present around the metal. So if you put water and a metal in a air sealed bottle corrosion would not happen as there is no oxygen
• Metals which are more reactive than iron (zinc, magnesium) prevent iron from rusting]
• Disadvantage of sacrificial protection is that it stops working when the more reactive metal is used up
• Rusting is the corrosion of iron
• Types of physical barriers are paint, oil, plastic, grease and less reactive metals
• Corrosion is the formation of a compound on the surface of a metal
• Sacrificial metals used are magnesium or zinc
• Sacrificial protection is attaching iron to a more reactive metal
• Physical barrier protection stops rusting as coating keeps out air and water
• Salt or acid speeds up rusting
• Disadvantage of using a physical barrier is that it stops working if the surface becomes scratched or broken
• Water and oxygen are needed for rusting
• Galvanising is coating iron in zinc
• When something rusts the mass increases because the iron nails react with the oxygen and the oxygen has a mass