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
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.