Rapidly solidified Nd₇Fe₆₇B₂₂Mo ₃Zr₁ nanocomposite permanent magnets

Nd₇Fe₆₇B₂₂Mo₃Zr₁ magnets in rods have been prepared by annealing the amorphous precursors produced through injection casting. Phase formation, microstructure and magnetic properties of Nd₇Fe₆₇B₂₂Mo₃Zr ₁ magnets have been investigated and discussed in the as-cast and annealed states. Cast Nd₇Fe₆₇B₂₂Mo ₃Zr₁ rods have the soft magnetic characteristics, which changed into magnetically hard by annealing. Magnetic properties in Nd ₇Fe₆₇B₂₂Mo₃Zr₁ magnets are influenced by the intrinsic properties of magnetically soft α-Fe (Fe₃B) and hard Nd₂Fe₁₄B phases. The Zr and Mo elements in the Nd₇Fe₆₇B₂₂Mo₃Zr ₁ alloy promote the formation of amorphous phase and reduce the grain size of magnetic phases. Optimal annealed Nd₇Fe₆₇B ₂₂Mo₃Zr₁ rods of 2 mm in diameter and 52 mm in length presented maximum magnetic properties such as: remanence (B_r) of 0.53 T, coercivity (_iH_c) of 1110 kA/m and maximum energy product (BH)_max of 49.5 kJ/m³.