Magnetization is the process by which a material that does not have magnetic characteristics becomes a magnet. Materials such as iron and metal alloys composed of aluminum, nickel, copper and cobalt they have low resistance to magnetization and are often used in the composition of permanent magnets. The magnetized material remains with the characteristics of a magnet for a certain period of time.
Magnets
Magnets are materials capable of producing disturbances in space called magnetic field. These disturbances can guide the electrons that make up some materials, causing them to be attracted by the magnet.
Triferro tetroxide ore (Fe3O4) is a natural magnet that was first found in a region of Asia called Magnesia, so this ore came to be called magnetite.
Magnetization Processes
There are three ways to magnetize a material:
- Friction magnet
Occurs when a material is rubbed in a single direction with a permanent magnet. After friction, the free electrons that make up the material will all be oriented in the same direction and, momentarily, the material will behave like a magnet.
- Magnetic induction magnetization
When a material is left for a while near a permanent magnet, it momentarily becomes a magnet.
- Electric current magnet
Moving electric charge produces magnetic field, so if a certain material is rolled up by a conducting wire, if there is electric current, the generated magnetic field will magnetize the material. This is the process for manufacturing a electromagnet.
Nail magnetized by electric current.
building a compass
an easy way to build a compass is to magnetize a needle by friction, stick it in a piece of polystyrene and place the set in a basin of water. The magnetic field generated by the magnetized needle will orient itself according to the Earth's magnetic field and then the compass will be ready!
Temperature and magnetization
The call Curie point is the maximum temperature at which a material remains magnetized. Above the temperature referring to the Curie point, the magnetic effects of the material are extinguished. Each material has a characteristic temperature value at which the effects of magnetization are nullified. For iron and nickel, for example, these values are, respectively, 770 °C and 354 °C.
By Joab Silas
Graduated in Physics
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/fisica/o-que-imantacao.htm
