Alloys (Edexcel IGCSE Chemistry)

• An alloy is a mixture of two or more metals or metal with a non-metal such as carbon
  • Steel is made from iron and carbon
• Alloys often have properties that can be very different from the metals they contain
  • They can be stronger and harder
  • They are resistant to corrosion or extreme temperatures
• These enhanced properties can make alloys more useful than pure metals

Why are alloys harder than pure metals?

• Alloys are harder than pure metals because: 
  • Alloys contain atoms of different sizes
  • This distorts the regular arrangements of atoms
  • So it is more difficult for the layers of atoms to slide over each other
• Brass is a common example of an alloy which contains 70% copper and 30% zinc

Alloy structure

The regular arrangement of a metal lattice structure is distorted in alloys