Rusting Flashcards
Under what conditions does iron rust
Water and oxygen
Give an example of a physical barrier.
Coating iron in paint, oil and grease, plastic coatings, tin plaiting, electroplating.
Give a disadvantage of the physical barrier
The coating would have to be maintained. If the coaching because scratched or broken then oxygen and water will get into the iron and it will rust.
Explain a physical barrier.
Stopping water and oxygen from getting to the metal
Why is rusting a problem?
Because it makes metals brittle
Explain sacrificial protection.
Attaching a more reactive metal to the iron like magnesium or zinc. The more reactive metal is sacrificed to save the iron and will react instead of it
Give an example of sacrificial protection.
Blocks of magnesium attached to railway lines.
Explain galvanising.
Dipping iron in molten zinc
Why is galvanising special
Cause it involves both a physical barrier and Sacrificial protection.
