Effects of Nd and B contents on the thermal stability of nanocomposite (Nd,Zr)2Fe14B/α-Fe magnets

The effects of Nd and B contents on the microstructure and thermal stability of nanocomposite (Nd,Zr)2Fe14B/α-Fe magnets have been investigated. It is shown that for NdxFe93−xZr1B6 (x = 9–11) alloys, the volume fraction of Nd2Fe14B increases with increasing Nd content, and the sample with x = 10 exhibits the optimal microstructure and thermal stability. Though the room-temperature iHc of Nd11Fe82Zr1B6 sample is the highest, it decreases more rapidly than that of Nd10Fe83Zr1B6 as temperature increases, indicating the deterioration of the temperature coefficient β. For Nd10Fe89−yZr1By (y = 5–8) alloys, the remanence and the temperature coefficient α deteriorate with increasing B content. The coercivity and the temperature coefficient β first improve with increasing B content, reaching the optimal values at y = 7, then deteriorate with further increasing B. Coarse grains and the Fe3B phase are observed in the Nd10Fe81Zr1B8 alloy.