corrosion & its prevention

• what is corrosion?

  destruction of materials by chemical reactions with substances in the environment
• what is necessary for iron to rust?

  air & water
• how can corrosion be prevented?

  • applying a coating that acts as a barrier
  • e.g. greasing, painting & electroplating
  • aluminium has an oxide coating that protects the metal from corrosion
  • some coatings contain a more reactive metal to provide sacrificial protection