Magnetic and non-magnetic materials
The following materials can be magnetized and attracted by a magnet:
iron steel cobalt nickel
Not all materials can be magnetized, the following are examples of the many materials that
cannot:
Lead aluminium brass
copper tin wood
plastic glass
The magnetic properties of iron and steel
Steel is used for making permanent magnets because although it is quite difficult to
magnetise it, it is also difficult to demagnetise. Iron is used for making electromagnets that
are switched on and off. It is easy to magnetise and demagnetise.
Other magnetic materials
Many new kinds of magnetic materials have been made since the discovery of lodestone.
One of these is ferrite - a ceramic material made from magnetic powder (a mixture of iron
oxide and barium oxide). Ferrites are used in radio aerials and you will probably have used
one type - magnadur - in your school. These ceramic magnets are magnetsied when the
material is soft and then fired to produced strong but rather brittle magnetic materials.
Other materials used are Alnico (a mixture of iron, nickel, cobalt and aluminium giving a
permanent magnet) and Mumetal (nickel, iron and copper) giving a material that can be
magnetised and demagnetised easily.
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