Alloys

• an alloy is a mixture of two or more metals or a metal with a non-metal such as carbon. They often have properties that can be very different from the metals they contain e.g. have more strength, hardness or resistance to corrosion or extreme temperatures. These enhanced properties can make alloys more useful than pure metals

  • remember they are mixtures of substances and are not chemically combined, they are not compounds
• • Brass is an alloy of copper and zinc and is much stronger than either metal. It is used in musical instruments, ornaments and door knobs
  • stainless steel is a mixture of iron and other elements e.g chromium, nickel and carbon. It is used in cutlery because of its hardness and resistance to corrosion. Alloys of iron with tungsten are extremely hard and resistant to high temperature
  • Aluminium is mixed with copper, manganese and silicon for aircraft body production as the alloy is stronger but still has a low density
• • since they contain atoms of different sizes that distort the normally regular arrangements of atoms in metals makes it more difficult for the layers to slide over each other and so are usually much harder than pure metal