Magnets generate a force-field that either pulls or repels certain objects, such as iron. Almost all businesses use magnets at one time or the other. But very few business owners know about the different types of magnets. Read on to know more about various kinds of magnets and their commercial uses.
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Types of Magnets
It might come as a surprise to some, but not all magnets are composed of the same elements. Hence, they can be classified according to their composition as well as a source of magnetism. They can be broadly classified into the following based on their magnetism:
- Permanent magnets
- Temporary magnets
- Electromagnets
Permanent Magnets
As the name suggests, permanent magnets are those magnets that don’t lose their magnetism once they are magnetised. There are four types of permanent magnets such as neodymium iron boron (NdFeB), samarium cobalt (SmCo), alnico, and ceramic or ferrite magnets. Let’s take a quick look at these.
Neodymium Iron Boron (NdFeB)
This is a magnet made of a rare earth magnetic material and comes with a high coercive force. As such, this magnet has a higher energy product range of up to 50 MGOe. This makes them suitable for use in small compact sizes. However, they are brittle and possess low corrosion resistance.
Samarium Cobalt (SmCo)
These are extraordinarily strong and difficult to demagnetize. They are oxidation-resistant and temperature resistant and can resist temperatures up to 300 degrees Celsius. But they are quite expensive and have low-mechanical strength.
Alnico
Alnico magnets are made of aluminium, nickel, and cobalt – hence the name. Although they offer great temperature resistance, they are easy to demagnetise.
Ceramic or Ferrite
These magnets comprise of sintered iron oxide and barium or strontium carbonate. Ceramic or ferrite permanent magnets are generally inexpensive and easy to produce through sintering or pressing. However, they are brittle and hence require grinding using a diamond wheel. One of the most used magnets they are strong and difficult to demagnetize.
Temporary Magnets
Temporary magnets are materials that perform like permanent magnets in the presence of a magnetic field but lose the magnetism when not in a magnetic field. They also vary in composition because any material that behaves like a magnet in the presence of a magnetic field can be a temporary magnet. Some of the common items such as paper clips, metal nails, and other items made of soft iron are the best example of temporary magnets.
Electromagnets
Electromagnets are made of a coil of wire wrapped around a metal core, mostly iron. These materials if not exposed to an electric current do not create any magnetic field. However, when you pass an electrical current through the wire, it creates a magnetic field until the current is turned off. The intensity of the magnetic field of an electromagnet can be adjusted by changing the amount of current passing through the wire. Furthermore, it is possible to reverse the polarity of the magnet by reversing the flow of electrical current.
Industrial Application of Magnets
Magnets are widely used by various industries for a wide range of applications such as sorting and separating impure metals during manufacturing or recycling. Devices such as speakers, televisions, telephones, radios, and videotapes use magnets in various forms.