# Fe70−xNd7B21Zr2Nbx (x = 0–3.0) Permanent Magnets Produced by Crystallizing Amorphous Precursors

## TL;DR

This paper explores how adding niobium to a specific alloy improves the magnetic properties of permanent magnets made from amorphous materials.

## Contribution

The novel contribution is the demonstration that niobium enhances magnetic performance through improved microstructure and exchange coupling.

## Key findings

- Adding niobium increases the soft magnetic phase volume and strengthens exchange coupling.
- The optimized alloy achieved a magnetic energy product of 37.59 kJ/m³.
- Uniform microstructure of α-Fe and Nd2Fe14B phases contributes to good magnetic properties.

## Abstract

The phase evolution, magnetic properties and microstructure of rod-shaped permanent magnets prepared by annealing the amorphous precursor Fe70−xNd7B21Zr2Nbx (x = 0–3.0) were systematically studied. X-ray diffraction analysis, magnetometer, microstructure and δM-plots studies show that the good magnetic properties of the magnet are attributed to the uniform microstructure composed of exchange-coupled α-Fe and Nd2Fe14B phases. Nb addition to Fe67.5Nd7B21Zr2Nb2.5 alloy led to an increase in the volume fraction of the soft magnetic phase, reinforced exchange coupling and improved magnetic properties. The magnetic properties of the optimized annealed Fe67.5Nd7B21Zr2Nb2.5 rod are: coercivity (Hci) = 513.92 kA/m, remanence (Br) = 0.58 T, squareness (Hk/Hci) = 0.24 and magnetic energy product ((BH)max) = 37.59 kJ/m3.