Using Materials

• What is corrosion?

  • is the destruction of materials by chemical reactions with substances in the environment.
• Example of corrosion 


  • Rusting
• Conditions needed for rusting

  • Air and water are necessary for iron to rust
• How can different coatings prevent corrosion?

  Greasing, painting or electroplating

  • coating the metals with a protective layer that will stop reactions between the metal and the environment.
• What is special about aluminium?

  • Has an oxide layer that is inert
  • does not react further so protects the metal from further corrosion
• Explain sacrificial protection 


  • Some coatings are reactive and contain a more reactive metal to provide sacrificial protection.
• An example of sacrificial protection : 


  • Zinc is used to galvanise iron
• Why use a more reactive metal like zinc for sacrificial protection?

  • Zinc is more reactive than iron therefore will lose its electrons more easily than iron and is oxidised more easily.
• What happens if it is lower in reactivity than iron?

  • Not suitable for sacrificial protection
  • s iron would be oxidised, causing it to rust
• Alloys


  • Formulation
  • Alloys are mixtures of metals and other elements
• Bronze : An alloy of? 


  • Copper and tin
• Brass : An alloy of?

  • Copper and Zinc
• Uses of Gold 


  • Jewellery e.g rings, necklaces
  • Decorations e.g gilded furniture
• Gold : An alloy of?

  • Silver
  • Copper
  • Zinc
• How is the proportion of gold measured?

  • Carats
• 24 carat being : 


  • 100% pure gold
• 18 carat being :

  • 75% gold
• Steel : An alloy of?

  • Iron that contains specific amounts of carbon and other metals
• Properties of high carbon steel

  • Strong
  • Brittle
• Properties of low carbon steel :

  • Softer
  • More easily shaped
• Stainless steels : An alloy of?

  • Nickel
  • Chromium
• Properties of stainless steels

  • Hard and resistant to corrosion
• Uses of steel


  • In construction to produce tools
  • Manufacture of ships and cars
• Properties of aluminium alloys

  • Low density
• Uses of aluminium alloys : 


  • Manufacture of aircraft
• Uses and properties of bronze

  • is harder than pure copper
  • used in sculpture and construction
• Uses and properties of brass

  • Brass is more malleable than copper.
  • Decoration e.g plaques
  • manufacture of musical instruments.
• Material that most of our glass is made out of?

  • Soda-lime glass, made by heating a mixture of sand, sodium carbonate and limestone.
• Types of glass that melt at higher temperatures than soda-lime glass :

  • Borosilicate glass, made from sand and boron trioxide
• What are clay ceramics?

  • Shaping wet clay and then heating in a furnace
  • Pottery, Bricks
• What monomers of ethene produce?

  • Low density (LD) poly (ethene)
  • High density (HD) poly (ethene)
• Thermosoftening polymers


  • Melt when heated
• Thermosetting polymers


  • Do not melt when heated
• The properties of the polymer will depend on both :

  • monomers they are made from
  • the conditions under which they are made.
• How are low density poly(ethene) produced?

  • Moderate temperature and high pressure
  • Flexible and is used commonly in plastic bags and bottles
• How is high density poly(ethene) produced?

  • Low temperature and low pressure
  • Employs a catalyst in its production
  • Yields a more rigid polymer
  • Water tanks and drain pipes
• Structure of thermosetting polymers

  • They contain monomers that connect polymer chains which makes the polymer solid more rigid.
  • These connections are known as cross linked.
• Structure of thermosoftening polymers

  • Contain no cross links.
  • These polymers are less rigid.
  • melt upon heating 
• What are composites?


  • are made of two material
• What are reinforcements?


  • a matrix or binder surrounding and binding together fibres or fragments of the other material