Al‐Fe‐Nd‐B magnets: Where does the Al go? (abstract)

One successful additive to Fe‐Nd‐B magnets has been Al, which enhances the _iH_c significantly, even for a 2 at. % (0.8 wt. %) addition. However, in these magnets it is not clear whether Al partitions into the Re₂Fe₁₄B phase, the grain boundary phase, or to the interphase interfaces. The main problem, in this case, is the detection of such small quantities in the microstructure. To overcome this ‘‘detectability’’ problem, magnets with 3.9 wt. % of Al have been prepared by the standard sintering route. These magnets exhibit higher _iH_c compared to the 0.8 wt. % magnet. The results of magnetic, structural, microstructural and microanalytical examination will be reported in this paper. It is hoped that this will clarify unambiguously the question of Al partitioning.