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

摘要

Bulk anisotropic composite Nd$_14$Fe$_79.5$Ga$_0.5$B$_6$/$alpha$-Fe magnets with$(hbox BH)_max= 45$–$55$MGOe were synthesized by compacting Nd–Fe–Ga–B powders coated with thin$alpha$-Fe layers followed by hot compaction at 600$^circ$C to 700$^circ$C and hot deformation (die upsetting) at 850$^circ$C to 950$^circ$C 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.