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Rare Earth Magnets-2

by Stanford Magnets

Rare Earth Magnets are used in many devices that we use daily but there are few who know what exactly Rare Earth Magnets are. So here is an article that discusses the origin, types and uses of Rare Earth Magnets.
Rare earth Magnets are strong magnets, which are small in size but massive in strength. They are permanent magnets that consist of alloys of rare earth elements. They are names after these elements, which are found in the Rare Earth or Lanthanides part of the periodic table. Lanthanides are elements, which have an f-shell that is not fully filled. Electrons in such cases are strongly confined and restricted which makes them retain their magnetic properties and attributes them the potential to create a paramagnetic surrounding around them.

These magnets as stated earlier are stronger (almost fifteen times stronger) than any other ferrite or alnico magnets. These rare earth magnets are so strong that they can lift four hundred times their own weight. They are used in expensive electronic gadgets such as cell phones, computer hard drives and the like; and since they are expensive, to save them from chipping and breaking, these rare earth magnets are coated with nickel. This nickel coating also protects them from rust, makes them shiny and stain resistant as well.

Types of Rare Earth Magnets

Rare Earth Magnets broadly fall into two categories which are as follows:

Neodymium (Nd-Fe-B) magnets- Neodymium magnets consist of neodymium, iron, boron and some of the transition metals. These magnets are the strongest and are also quite affordable amongst all the rare earth magnets. These are the types that are used in the hard drives of computer and speakers as they have the strongest magnetic field. These magnets are expensive as the cost of raw materials required is quite high and also because of the licensing of the patents. These magnets are also not very resistant to oxidation and temperature, thus they have to be coated with nickel or gold. Neodymium magnets are also corrosive but the main advantage is they give high-energy output compared to their size. These magnets can be used in microphones and computer printers and speakers.

Samarium- Cobalt (Sm Co) magnets-Samarium cobalt magnets consist of samarium, cobalt and iron. These magnets are not as commonly found the Neodymium magnet since the latter is easy to produce compared to the former and also gives a better magnetic field in terms of strength though Samarium Cobalt magnets are resistant to demagnetization and also stable under high temperature unlike Neodymium magnets. These magnets are also resistant to oxidation but shaped magnets are prone to breaking and chipping when they are exposed to thermal shocks. These magnets can be used in satellite systems and traveling wave tubes.

Rare Earth Magnets are very strong, thus they have to be handled carefully. It has to be remembered that small children should not be allowed to play with such magnets. These magnets should be not be put in to the mouth or consumed. Since these rare earth magnets are very strong their magnetic fields are also large and powerful, therefore people who have pacemakers should not come in close proximity of these magnets. They should also be kept away from credit cards, computers, cell phones and any other electronic equipment that can be influenced by the strong magnetic field of these rare earth magnets.

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