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NdFeB magnets are again manufactured using a powder metallurgy route. After sintering the material is ground or sliced to size before coating & magnetisation. Sintered NIB magnets offer the highest energy per unit volume of any permanent magnet material, it can lift up to 1000 times its own weight. It is manufactured in numerous energy and temperature grades, current energy levels start at 33 MGO, with up to 50 MGO having been developed in the laboratory. The intrinsic (jHc) coercive force determines the maximum operating temperature, however, it should be noted that even the SH (high coercivity) 150°C degree materials still have a poor temperature coefficient which means that an open circuit magnet can lose about 0.10% of Remanence per °C. These losses are called Reversible Losses and the Remanence will recover as the temperature falls. A vast section of standard disc & blocks sizes are available from stock. Non standard sizes can be manufactured using diamond slicing or grinding techniques at short notice. Apart from temperature difficulties NIB also suffers from corrosion because of its high Iron content and although the magnets are normally supplied coated particular care must be taken to avoid Hydrogen or salt water environments. Although Neodymium offers 30-40% higher energy levels than SmCo alloys and is considerably lower in cost and less brittle, SmCo magnets should still be considered your first choice if either high temperatures & or hostile environments are to be encountered within your application.
Applications for Neodymium magnets are diverse & wide ranging, magicians to Aerospace Engineers have found its outstanding performance invaluable. Its power to weight ratio has made applications previously thought to be impossible achievable thus changing design concepts for the modern Engineer. Warning: Because of the brittle nature and high attractive forces generated by NdFeB magnets great care is needed during handling. Please study the Safety Instructions.
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