Microstructural characteristics of Nd2Fe14B/α-Fe nanocomposite ribbons bearing Nb element

The effects of Nb on the microstructure and magnetic properties of （Nd0.9Dy0.1）9.5Fe79_xCo5NbxB6.5 （x = 0, 1） nanocomposite magnets were investigated. A fine and uniform microstructure was achieved for the ribbons annealed at 710℃ for 4 min, enhancing the interaction coupling between grains and improving the magnetic properties. The results of three-dimensional atom probe （3DAP） indicated that Fe-Nb-B inter- granular phase existed at the grain boundaries, suppressing the grain growth during the crystallization process. The coercivity was improved from 224 to 643 kA/m for the modification of the microstructure.