1
Q
What are alloys and why are they useful?
A
- mixture of two or more metals
- mixture of metal and a non-metal
- often have properties that are different from the metals they are made of
- new properties may make the alloy more useful than the pure metal
2
Q
Name some alloys and there properties?
A
- steel:
- iron and carbon
- harder and stronger than iron (if carbon not higher than 1%), steel corrodes less quickly
- uses: bridges, ships and cutlery
- brass:
- copper and zinc
- mixture of copper and zincs properties, harder than either of them
- uses:instruments and doorknobs
- bronze:
- copper and tin
- harder and stronger than tin, more resistant to corrosion than tin or copper
- uses:springs, bells
- solder:
- lead and tin
- indefinite boiling point unlike pure materials, gradually solidifies as cools
- uses:solder things together
- amalgam:
- alloy containing mercury
- tooth fillings
3
Q
What is nitinol what are its properties?
A
- nickle and titanium
- smart alloy as it has shape memory
- remembering its original shape and goes back to it even when bent
- uses: nitinol glasses frames
4
Q
Why do iron and steel corrode easier than aluminium for cars?
A
- aluminium doesn’t corrode when wet
- what happens it, aluminium reacts very quickly with oxygen to form aluminium oxide
- this acts as a protective layer, sticking firmly to the aluminium below and stops any further reaction taking place
- oxide not crumbly and flaky like rust, so no falling off
5
Q
What is the disadvantage of aluminium over steel for cars?
A
-expensive
6
Q
What are the advantages of aluminium over steel?
A
- low density so cars will be lighter, giving aluminium cars better fuel economy which saves fuel resources
- corrodes less, so longer lifetime
7
Q
Why is recycling cars important?
A
-saving natural resources, save money and reduce landfill
8
Q
What materials do you need to build a car and why?
A
- steel: strong and can be hammered into sheets and welded together (good for bodywork)
- aluminium: strong and low density (parts of engine)
- glass: transparent (windows and windscreens)
- plastic: light and hard-wearing (internal covering for doors) electric insulators (covering electric wires)
- fibres (natural and synthetic): hard-wearing (cover seats and floors
9
Q
What parts are cars are recycled?
A
- a lot of metal from cars is recycled
- most other materials, e.g. plastics and rubber, go to landfill
- laws placed in Europe to recycle 85% of materials used in a car (95% by 2015)
