Re-Fe-B powder coating for improvements in corrosion resistance, flux aging loss and mechanical strength of bonded magnets

Nd₁₂Fe₇₇Co₅B₆ and Nd₁₂Fe₈₀Nb₂B₆ powders are coated with an epoxy-based binder system. Each component of the binder is mixed under high shear in the presence of an organic solvent with the powders. The coated powders are then compacted into magnets and cured. Long term magnetic flux measurements are conducted, some samples are also placed in a humidity chamber and their weight gain is measured. Tests on axial crushing strength and ejection pressure are also performed on the magnets. Three point bending strength is determined by fracturing rectangular bars using a load cell to measure the maximum force applied to break each specimen.