(4.10.3)(Using materials)

What is corrosion?

Corrosion is the destruction of materials by chemical reactions with substances in the environment.

What is one example of corrosion?

Rusting.

What are the ways corrosion can be prevented?

It can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating.

OR

By sacrificial protection

Why is aluminium protected from corrosion?

It has an oxide coating to protect itself.

What is an example of sacrificial protection?

Zinc used to galvanise (coat) iron.

What is bronze an alloy of?

Tin and copper.

What is brass an alloy of?

Copper and zinc.

What is gold normally used for jewellery an alloy of?

Silver, copper and zinc.

How is gold in jewellery measured?

Using carats.

24 carat being 100% gold and 18 carat being 75%

(6 carat is 25%)

What are the 3 types of steels?

Stainless steels, low carbon steel and high carbon steel.

What is stainless steel?

Steels containing chromium and nickel.

These are hard and are resistant to corrosion.

(Used in grills, cookers etc)

What is the advantage and disadvantage of high carbon steel?

High carbon steel is strong but brittle.

(Used in cutting tools)

What is the advantage and disadvantage of low carbon steel?

Low carbon steel is softer and more easily shaped.

(Used in pipes)

What density are aluminium alloys?

Aluminium alloys are low density.

What is the glass we mostly use made out of and what is its name?

Soda-lime glass which is made by heating a mixture of sand, sodium carbonate and limestone.

What is another type of glass other than soda-lime?

Borosilicate glass which is made from sand and boron trioxide also it melts at higher temperatures than soda-lime glass.

How are clay ceramics made?

Shaping wet clay and heating it in a furnace.

What do the properties of polymers depend on?

The conditions in which they are made and the monomers used.

What is thermosoftening polymers and what is their structure?

They are made of individual tangled polymer chains which are easily separated and are melted by heat.

What is thermosetting polymers and what is their structure?

They are made of polymer chains which cross link so that they do not melt when heated.

Most composites are made of two materials, what are they called?

A matrix or binder,

surrounding and binding together fibres or fragments of the other material and this is called reinforcing.

Give some examples of composites.

Carbon fibre, fibreglass and concrete.