Sintered Nd–Fe–B magnets with improved impact stability

The impact stability of sintered Nd–Fe–B magnets with nominal compositions of NdxFe94−xB6 (x=14.6,16.4,18.2,20,22x=14.6,16.4,18.2,20,22) has been investigated by a falling-weight impact test. In comparison, the impact stability of several kinds of permanent materials also was measured. It shows that the impact stability of sintered Nd–Fe–B magnets increases with increasing Nd content. Compared with the commercial Nd–Fe–B sintered magnets, the experimental magnets with 22 at% Nd have a 137% significant improvement on average impact stability. Tumbling test further verified the improved impact resistance of the high Nd magnets. The increased Nd-rich phase, which may contribute to the improvement of impact stability by its plastically deforming, was observed in the microfractograghs.