Alloys And Corrosion Flashcards
How are alloys made
By adding another element to a metal disrupting the structure of the metals and making it harder than pure metals
Properties and uses of low carbon steel
Easily shaped
Car bodies
Properties and used of high carbon steel
Very hard
Inflexible
Blades for cutting tools
Properties and uses of stainless steel
Corrosion resistant
Cutlery and contains for corrosive substances
What are types do alloys
Alloys of iron is steel Bronze Brass Gold alloys Aluminium alloys
Bronze uses
Make medals
Decorative ornaments
Statues
Brass properties and uses
More malleable than bronze
Used where low friction is required like water taps and door fittings
What metals harden gold
Zinc copper and silver
What is corrosion
Where metals react with substance in their environment and are gradually destroyed
Does iron corrode easily
Yes
It rusts
When in contact with oxygen and water which is present in air
What is Rust and what’s it’s equation
Hydrated iron lll oxide
Iron + oxygen + water > hydrated iron lll oxide
What happens to the Rust On iron
It soon flakes off and leaves more iron available to rust so eventually all iron corrodes away
What happens to aluminium when it corrodes
The aluminium oxide that forms when it corrodes doesn’t flake away
It actually form a protective layer that sticks firmly to the aluminium and stops any further reaction taking place
How can you show that water and oxygen both need to be present for iron to rust
Put an nail in a tube
Boil water and use oil to stop air getting in
Or
Put the nail in an empty tube and put calcium chloride in to absorb any water form the air
How do you prevent rusting
Painting/ coating with plastic
Electroplating (electrolysis used)
Oiling/ greasing (for moving parts)
