Short-time annealing enhancing the magnetic properties and microstructure uniformity of melt-spun (Nd,Pr)-Fe-B ribbons

Melt spinning is an effective method for preparing nanocrystalline permanent magnet materials. During the rapid-quenching process, uneven undercooling can easily lead to uneven distribution between the ribbons. Due to the difference in cooling speed between the roller surface and the free surface, the microstructure in one ribbon is also uneven. In this work, to solve the problem of poor uniformity of the melt-spun (Nd,Pr)-Fe-B ribbons obtained by direct rapid-quenching, appropriate short-time annealing had been implemented. The microstructure and magnetic properties of the melt-spun (Nd,Pr)-Fe-B ribbons before and after annealing showed a significant improvement in the uniformity. The improvement of uniformity could be beneficial for the application of melt-spun powders in bonded magnets and hot-deformed magnets, enhancing the magnetic properties of related products.