About Neodymium Magnets

The tetragonal Nd₂Fe₁₄B crystal structure has exceptionally high uniaxial magnetocrystalline anisotropy (HA~7 teslas – magnetic field strength H in A/m versus magnetic moment in A.m²). This gives the compound the potential to have high coercivity (i.e., resistance to being demagnetized). The compound also has a high saturation magnetization (J_s ~1.6 T or 16 kG) and typically 1.3 teslas. Therefore, as the maximum energy density is proportional to J_s², this magnetic phase has the potential for storing large amounts of magnetic energy (BH_max ~ 512 kJ/m³ or 64 MG·Oe). This property is considerably higher in NdFeB alloys than in samarium cobalt (SmCo) magnets, which were the first type of rare-earth magnet to be commercialized. In practice, the magnetic properties of neodymium magnets depend on the alloy composition, microstructure, and manufacturing technique employed.
 

Magnet Terminology

The terminology of magnetics is not widely understood. You can find definitions of most terms on our Glossary of Magnet Terminology Page.

Rare Earth

Neodymium magnets are a member of the Rare Earth magnet family and are the most powerful permanent magnets in the world. They are also referred to as NdFeB magnets, or NIB, because they are composed mainly of Neodymium (Nd), Iron (Fe) and Boron (B). They are a relatively new invention and have only recently become affordable for everyday use.

Grades of Neodymium

N35, N38, N42, N38SH…what does it all mean? Neodymium magnets are all graded by the material they are made of. As a very general rule, the higher the grade (the number following the ‘N’), the stronger the magnet. The highest grade of neodymium magnet currently available is N52. Any letter following the grade refers to the temperature rating of the magnet. If there are no letters following the grade, then the magnet is standard temperature neodymium. The temperature ratings are standard (no designation) – M – H – SH – UH – EH. You find the temperature rating of each grade on our Specifications of Neodymium Magnets Page.

Specifications of Neodymium Magnets

If you need detailed information about the physical and thermal properties of neodymium magnetic materials, you can find it on ourSpecifications of Neodymium Magnets Page.

Platings/Coatings

Neodymium magnets are a composition of mostly Neodymium, Iron and Boron. If left exposed to the elements, the iron in the magnet will rust. To protect the magnet from corrosion and to strengthen the brittle magnet material, it is usually preferable for the magnet to be coated. There are a variety of options for coatings, but nickel is the most common and usually preferred. Our nickel plated magnets are actually triple plated with layers of nickel, copper, and nickel again. This triple coating makes our magnets much more durable than the more common single nickel plated magnets. Some other options for coating are zinc, tin, copper, epoxy, silver and gold. Our gold plated magnets are actually quadruple plated with nickel, copper, nickel and a top coating of gold.

Machining

Neodymium material is brittle and prone to chipping and cracking, so it does not machine well by conventional methods. Machining the magnets will generate heat, which if not carefully controlled, can demagnetize the magnet or even ignite the material which is toxic when burned. It is recommended that magnets not be machined.

Demagnetization

Rare Earth magnets have a high resistance to demagnetization, unlike most other types of magnets. They will not lose their magnetization around other magnets or if dropped. They will however, begin to lose strength if they are heated above their maximum operating temperature, which is 176°F (80°C) for standard N grades. They will completely lose their magnetization if heated above their Curie temperature, which is 590°F (310°C) for standard N grades. Some of our magnets are of high temperature material, which can withstand higher temperatures without losing strength.

Strength

If you’ve never handled neodymium magnets before, you will be amazed at their strength. Neodymium magnets are over 10x stronger than the strongest ceramic magnets. If you are currently using ceramic magnets in your project, you could probably use a much smaller neodymium magnet and have greater holding force. You can get an idea of the relative strength of each of our magnets on our Magnet Summary Page. The surface field of each of our stock magnets is also listed on that same page. We also offer an online magnet calculator to help you estimate the pull force and field strength of magnets at any distance from the magnet.