Permanent Magnets - NdFeB

As high-energy magnets, permanent magnets made from "rare" earths are referred to. These materials are characterized by their high energy product of over 300 kJ per cubic meter. The following materials are of practical significance: - Samarium-Cobalt (SmCo) - Neodymium-Iron-Boron (NdFeB) The production of Sm-Co and NdFeB magnets involves melting the alloy. After that, the material blocks are broken and ground into a fine powder, pressed in a magnetic field, and then sintered. The shape magnets are cut from the raw blocks using a diamond saw under water. For large quantities, the powder is pressed into molds and then sintered. Comparison: A barium ferrite magnet must be 25 times larger than a samarium-cobalt magnet to achieve the same effect (e.g., 100mT induction at a distance of 1 mm from the pole surface). The energy product of NdFeB is even about 50% higher!