alloys

• alloy

  it is a mixture of a metal with another element
• pure metal arrangement

  in a pure metal the atoms are all the same size and are arranged in regular layers

  This means that they layers can slide over each other

  this is why pure metal are soft and malleable

  
• what do alloys do?

  they contain different atom of different sizes which distorts the regular arrangement.

  this makes it more difficult for the layers to slide over each other, which then make the alloy harder and stronger

  
• gold

  very soft metal

  pure gold ring would get scratched and bent of shape easily

  often alloyed with silver and copper - harder so it wears better

  cheaper

  change its colour
• what is carat

  how much gold there is in an alloy
• 24k


  pure gold (100%)
• 22k


  22/24 x 100 = 91.7%
• copper

  very soft

  excellent electrical conductor - electrical wires
• bronze

  bronze is an alloy of copper with various amount of tin

  harder than pure copper

  resistant to corrosion

  sonorous if hit
• what is bronze used for?

  statues, medals, bells
• brass

  alloy of copper and varying amounts of zinc

  harder than pure copper

  still malleable

  sonorous

  resists corrosion

  nice colour
• what is brass used for?

  door knobs

  ornaments

  musical instruments
• aluminium alloys

  low density

  used for aircrafts