Corrugated iron sheets are galvanised. Image credit alibaba.com

Corrugated iron sheets are galvanised. Image credit alibaba.com

ZIMSEC O Level Combined Science Notes: Galvinasing iron

  • Galvanising is one of the methods used to prevent iron from rusting
  • Iron and steel can be coated with zinc
  • Zinc is a fairly more reactive metal
  • This means it will corrode before the iron does
  • This is also known asĀ sacrificial plating
  • Even when the metal underneath (iron/steel) is exposed the zinc will corrode instead of thus protecting the iron
  • Zinc plating is also calledĀ galvanizing
  • It is usually used for small items such as nuts and bolts
  • It is also used on large items such as iron roofing sheets
  • Steel is used to make the galvanised roofing sheets
  • Steel sheets are cleaned first
  • They are then passed through molten zinc
  • An alloy of zinc and iron then forms on the surface of the steel sheets
  • The zinc in the galvanised iron sheets prevents the sheets from rusting
  • Zinc is more reactive than iron thus it will corrode first
  • Even if the iron is exposed to the atmosphere
  • This method is used to make corrugated roofing sheets which are widely used in Zimbabwe

To access more topics go to the Combined Science Notes page.