materials + corrosion

• Ceramics come in many different forms
• What is heated to make soda-lime glass?

  limestone

  sand

  sodium carbonate
• Borosilicate glass has a higher melting point than soda-lime glass
• What is heated to make borosilicate glass?

  sand

  boron trioxide
• Composites are usually made of two different materials.
• Composites are made of one material embedded in another.
• Fibreglass has low density but it is very strong.
• What is fibreglass used for?

  skis

  boats

  surfboards
• Carbon fibre is very strong and light.
• What is carbon fibre used for?

  aerospace

  sports cars
• Concrete is made from aggregate embedded in cement
• aggregate is a mixture of sand and gravel
• Wood is a natural composite of cellulose fibres
• How it is made and what it is made from can influence the properties of polymers
• Low density poly(ethene) is made from ethene at moderate temperature under high pressure.
• What is LD poly(ethene) used for?

  bags and bottles
• High density poly(ethene) is made from ethene at low temperatures and pressures with a catalyst.
• What is HD poly(ethene) used for?

  water tanks and drainpipes
• Thermosoftening polymers can be melted and remoulded
• Thermosetting polymers don't soften when heated, they stay hard, soft and rigid.
• Ceramics and polymers are insulators of heat.
• Ceramics and metals are stiff.
• Polymers do not conduct electricity well.
• Metals conduct electricity well.
• Name 3 ways of coating iron to stop rusting.

  painting/coating with plastic

  electroplating

  oiling/greasing
• You can prevent rust by using another, more reactive metal with the iron so it reacts with that instead of the iron. This is called the sacrificial method.