Enhancing Magnetic Properties of Bulk Anisotropic Nd–Fe–B/$alpha$-Fe Composite Magnets by Applying Powder Coating Technologies

Bulk anisotropic composite Nd
₁₄
Fe
_79.5
Ga
_0.5
B
₆
/alpha-Fe magnets with (BH)
_max
=45-55 MGOe were synthesized by compacting Nd-Fe-Ga-B powders coated with thin alpha-Fe layers followed by hot compaction at 600degC to 700degC and hot deformation (die upsetting) at 850degC to 950degC with a height reduction of 71%. The coating techniques used include DC and RF sputtering, pulsed laser deposition, chemical coating, and electrolytic coating. Composite magnets prepared using these techniques demonstrate enhanced intrinsic coercivity and significantly improved squareness of intrinsic demagnetization curves