Mechanical properties and the composition of Nd-rich phase in sintered Nd-Fe-B magnets prepared by spark plasma sintering

摘要

To study the relationship between the mechanical properties of sintered NdFeB magnets and composition of the Nd-rich phase, sintered NdFeB magnets with different mechanical properties and composition of Nd-rich phases were prepared by spark plasma sintering technology (SPS). Several correlations including the bending strength of the magnet to sintering temperature (sigma(bb)-t), the rare earth content in the Nd-rich phase to the sintering temperature (n(RE)-t) and the iron content in the Nd-rich phase to the sintering temperature (n(Fe)-t) were investigated. Several empirical formulas for these relationships ware obtained by fitting these experimental curves. It is found that there is almost no change in the sum of Re and Fe content, revealing that the diffusion direction of RE and Fe atoms in the boundary phase between the main phases during sintering is opposite, and the relationship of sigma(bb) to n(RE) are approximately linear. Based on these, the mechanism of improving the mechanical properties of sintered NdFeB materials via changing the composition of Nd-rich phase was discussed.