Corrosion Flashcards
What is corrosion
When metals react with substances in the environment and are gradually destroyed
What is the word for iron corroding
Rust
What does Iron need in order to rust
Oxygen water which are present in the air
What is the stuff we call rust
Compound hydrated iron oxide
Rust equation
Iron + oxygen + water —-> hydrated iron (III) oxide
Where does corrosion only happen
On the surface of material that is exposed to the air
Why would an Iron object eventually corrode away
Rust flakes after leaving more iron available to rust again
Why is an aluminium completely destroyed by corrosion
Aluminium oxide that forms when aluminium corrodes doesn’t flake away it forms a protective layer that sticks firmly to the aluminium and stops any further reaction
What is needed for an iron nail to rust
Air and water
What can be used as a coat on iron to protect it from corrosion
Painting and coaching with plastic ideal for big and small structures alike can we decorative too
Electroplating this uses electrolysis to reduce metal irons onto an iron electrode it can be used to coat the iron with a layer of a different material that won’t corrode away
How can oil and greasing be used to prevent an iron corrosion 
Used when moving parts are involved like on a bike chains
What is the sacrificial method of protecting iron
Placing a more reactive metals such as income magnesium with the iron water and oxygen react with the sacrificial metal instead
How can an object be protected by both techniques
An object can be galvanised by spraying it with a coating of zinc zinc Leah is fiercely protective but if scratched the sink around the side of the scratch works as a sacrificial metal
