Types of Rare Earth Magnets

Magnets have been in existence for a very long time and magnet strength has increased as innovations and further research continues. A stronger magnetic material was developed in the 1900s and it has continued to be used in various industrial applications.

This material is composed of a combination of rare earth elements. Magnets derived from these materials are therefore known as rare earth magnets. They are the strongest magnets currently available, with their strength being significantly higher than all regular magnets. They may produce a magnetic field of about 1.4 teslas while other magnets produce about 0.5 to 1 tesla.

Rare earth metals are not really rare because their abundance may be similar to metals like lead or tin. These metals are naturally ferromagnetic. This means that they can be magnetized permanently but their natural magnetism is only visible below certain temperatures. When mixed with metals that possess magnetism at higher temperatures such as nickel, iron and cobalt they form quality compounds that make for good magnets.

Weak points

Their biggest weakness is that they are very brittle. They break very easily and can easily get corroded or chipped. They are therefore usually covered in a less brittle material like plastic to avoid constant damage from breakage or chipping.

Advantage

The atoms found in rare earth elements have been found to have a very high magnetic anisotropy. This refers to the ability of the particles to get easily magnetized in one direction but they resist magnetization in another direction.

Rare earth magnets are of two types, namely samarium-cobalt magnets and neodymium magnets. Of the two types, neodymium magnets are more common.

Samarium-cobalt (SmCo) magnets

These are the first type of rare earth magnets that were invented but they are not commonly used. This is due to the fact that they have a weaker magnetic strength and are more expensive. They are however used for applications that require a high magnetic field strength under high temperatures because their Curie temperature (the temperature at which it loses its magnetism) is higher.

Neodymium magnets

These are made of neodymium, iron and boron and may sometimes be referred to as NIB. They are the most affordable and strongest of rare earth magnets. Their application is mainly in devices that require strong permanent magnets for instance jewelry clasps, cordless tools and computer hard drives. They have to be coated to prevent corrosion.

 Ferrite magnets

These are made of compounds that are combinations of iron (III) oxide and ceramic materials. They are brittle, hard and normally non-conductive. There are hard and soft ferrite magnets.

AlNiCo

AlNiCo is actually an acronym that stands for aluminum, nickel and cobalt since these magnets are alloys of these three materials. You will sometimes find titanium and copper in them. They are highly resistant to losing magnetism, are ferromagnetic and are therefore used in the production of permanent magnets. They were actually the strongest magnets before rare earth magnets were developed in the 1970s. Their strength is only exceeded by rare earth magnets where more powerful magnets are required for industrial use.

For more information about various magnets, please visit http://www.usrareearthmagnet.com/