The evaluation of high-temperature oxidation for the original and recycled Nd-Fe-B sintered magnets

The high-temperature oxidation resistance is a critical evaluation index for the practical applications of Nd-Fe-B sintered magnets. In this paper, the high temperature (> 523 K) oxidation behavior of the recycled Nd-Fe-B sintered magnets was investigated and compared with the original magnets. The results show that both magnets exhibit similar high-temperature oxidation characteristics. The recycled magnets oxidized after 300 h at 673 K possesses remanence (B-r) of 1.189 T, coercivity (H-ci) of 1688 kA/m, and maximum energy product [(BH)(max)] of 268 kJ/m(3). Compared with the recycled magnet before oxidizing, the oxidized recycled magnets retain 96.0% of B-r, 85.2% of H-ci, and 92.2% of (BH)(max), respectively. The recycled magnets negatively influence the high-temperature oxidation resistance compared with the original magnets, demonstrating the recycled magnets' applicability. (C) 2021 Published by Elsevier B.V.

Automated summary

The high-temperature oxidation resistance is a critical evaluation index for the practical applications of Nd-Fe-B sintered magnets. In this study, the high-temperature oxidation behavior of recycled Nd-Fe-B sintered magnets was investigated and compared with the original magnets. The results show that recycled magnets negatively influence the high-temperature oxidation resistance compared with the original magnets.