Alloys
Chemistry: AQA GCSE Higher, topic 10.3.3
Metal Alloys
An alloy is a metal that is mixed with other elements. By adding these other elements, we can change a metal's properties. Most metals that we use in day-to-day life are alloys.
Bronze
- Bronze is an alloy of copper and tin.
- Adding tin increases the hardness of the material.
- Uses include making coins, electrical hardware and statues.
Brass
- Brass is an alloy of copper and zinc.
- Adding zinc makes the material more malleable (easy to bend).
- Uses include hinges, locks, plumbing and plug sockets.
Gold
- The softness of pure gold means that jewellers will often add metals such as silver, copper and zinc to produce a more resilient substance.
- Carats provide a measure for the purity of a gold alloy:
- 24 carats = 100% gold
- So, 12 carats = 50% gold
Steel
- Steels are alloys of iron that contain carbon as well as other metals.
- High carbon steels are strong but brittle. Uses include making cutting tools and blades.
- Low carbon steels are soft but malleable. Uses include making car bodies.
- Stainless steels (steels containing chromium and nickel) are strong and resistant to corrosion. Uses include cooking utensils and cutlery.
Aluminium
- A key feature of aluminium alloys is their low density, which makes them suitable for use in manufacturing planes.
- Other uses include armour plating for military vehicles.
Test yourself on Alloys
Metals added to pure gold to make it more resilient
A workshop wants to make a blade that stays sharp and holds its shape. Which metal should it use?
Why are aluminium alloys used to build the bodies of planes?
Elements found in all steels
Metals added to iron to make stainless steel