NdFeB magnet

Sintered neodymium-iron-boron (NdFeB) magnets, also referred to as "neo" magnets, have been commercially available since November 1984. They offer the highest energy product of any material today and are available in a very wide range of shapes, sizes and grades. Earliest use of neo magnets was primarily for voice coil motors (VCM's) in hard disk drives and this market still accounts for about 55% of total sales dollars. Other applications include high performance motors, brushless DC motors, magnetic separation, magnetic resonance imaging, sensors and loudspeakers.
MAXIMUM USE TEMPERATURE AND CORROSION

The first materials produced achieved about half the theoretical maximum energy product of 64 MGOe (509 kJ/m3). Refinements over the past few years have allowed commercial supply of magnets close to 50 MGOe (398 kJ/m3). High temperature (>180?C) compositions have been developed with intrinsic coercivity greater than 25,000 oersteds (1990 kA/m). Higher temperature materials, however, tend to have lower maximum energy products.