Best in magnetic performance and energy. The NdFeB magnet is currently the strongest one available.
General Information: Neodymium Iron Boron (NdFeB) magnets, of the Rare Earth class, have been commercially available since the mid -1980's. Their popularity has grown rapidly due to their high Maximum Energy Product and their wide range of available shapes, sizes, and grades.
Today, a Remanence of over 1,4 Tesla is possible. Energy products of up to 50MGOe are currently available. The majority of NdFeB magnets are anisotropic and can only be magnetized in the orientation direction. In general, magnetizing fields of approximately 30KOe are required to saturate NdFeB magnets.
An important disadvantage of the NdFeB magnet is its sensitivity to corrosion. Therefore, to prevent undesired oxidation, the finnished magnets are coated with a zinc-, nickel-, tin-, al-, au- or epoxy layer. The NdFeB magnets are produced in big blocks which are pressed in a mold and then sintered. A smaller block, a disc, a ring, a bar or a rotor will be cut out of the big block by computer controlled electrowire or by diamond blade, drilled with special drills, and finally ground.
The longer the more, NdFeB magnets will replace, where ever possible, the SmCo magnet, due to its lower price.
Temperature Effects: The magnetic properties of NdFeB deteriorate significantly when exposed to temperatures exceeding 130°C, depending on the grade of material and the permeance coefficient. As a rule, NdFeB magnets with a higher permeance coefficient can sustain higher temperatures without loss of magnetic properties. Operational temperatures or up to 200°C are possible.
Applications: Motors, generators, charged particle beam guidance, headphones, holding systems, instrumentation, loudspeakers, magnetic bearings, magnetic couplings, magnetic resonance, magnetic separations, microphones, particle accelerators, relays, switches, as well as many other applications.
Data Sheets: Sintered Neodymium Iron Boron (see also: weight loss graph)