Isotropic polymer bonded SmFeN magnets Sm-Fe-N magnet powders are produced in a similar way to Nd-Fe-B, except that nitrogen is introduced by heat treatment of rapidly quenched Sm-Fe flakes in a nitrogen atmosphere. These flakes are then mixed with a polymer binder and pressed or injected to make isotropic bonded magnets. Magnetic performance of (BH)max=112 [...]
Typical Compression Bonded Magnetic Properties Many suppliers publish specifications for a nominal 10 MGOe magnets with a minimum limit of 9 MGOe. Similar for a nominal 11 MGOe magnet; minimum limit is 10 MGOe. Have to design to lower limit of BHmax Typical Compression Bonded Magnetic Properties BHmax Improvement in Compression Bonded Magnets The BHmax of a compression bonded isotropic NdFeB magnet is influenced by the following two factors: 1. Volume fraction of magnetic phase in the magnet – typically measured by the density of the magnet. • We are investigating increasing the pressing pressure which requires special press construction, lubricants and tooling materials – current production pressing pressures are 7tonnes/cm2 for 5.9 g/cm3 and 10MGOe; estimated that > 20 tonnes/cm2 required for 6.3 g/cm3 and > 11 MGOe. • Optimize the particle encapsulation chemistry and process. • Tailored multimodal PSD’s for maximum packing density. • Particle shape control. 2. Magnetic powder Br/BHmax • Increase isotropic Br of powders while maintaining sufficient Hci to have “linear” B‐H demagnetization characteristic at the application temperature. Arc Permanent Magnet Neodymium Nickel N35UH Neodymium Generator Arc Magnet Nickel N33H Arc Neodymium Magnet Nickel N30H Segment Neodymium Magnet Nickel N52