Alloys
Science: KS3, topic 2.8.2
Alloys
An alloy is a mixture of different metals.
Use of alloys
- Alloys are useful because they tend to be harder than pure metals
Pure metals
- Pure metals have atoms that are arranged in layers.
- These layers can slide over each other.
- This makes them soft and also malleable.
Alloys are strong
- Alloys have metal atoms of different sizes, that are mixed up with each other.
- This means the atoms are not arranged in layers and it becomes distorted.
- It is harder for them to slide over each other.
- This makes them stronger.
Steel
- Steel is an alloy.
- It is made by adding carbon to iron.
- This makes steel harder than pure iron.
Common alloys include:
- Brass – Copper and Zinc – Used for making coins
- Bronze – Copper and Tin – Making bells
- Rose Gold – Gold and Copper – Jewellery
The elements that make up an alloy
- Alloys often have physical and chemical properties from those elements that made them up.
- They may become denser and they may have higher melting points.
Test yourself on Alloys
What materials are alloys a mixture of?
Bronze is an alloy made from copper and tin, which have atoms of different sizes mixed together. Why is bronze harder than pure copper?