Effects of Nb and C additions on the crystallization behavior, microstructure and magnetic properties of B-rich nanocrystalline Nd-Fe-B ribbons

摘要

The effects of Nb and C additions on the crystallization behavior, microstructure and magnetic properties of B-rich Nd_(9.4)Fe_(79.6-x)Nb_xB_(11-y)C_y (x = 0,2, and 4;y = 0, 0.5, and 1.5) alloy ribbons have been investigated. The results show that Nb and C additions change the crystallization behavior of Nd_(9.4)Fe_(79.5)B_(11), avoid the formation of metastable Nd_2Fe_(23)B_3 phase, leading to the simultaneously precipitation of alpha-Fe and Nd_2Fe_(14)B phases. The results also show that Nb and C additions suppress the formation and growth of the soft a-Fe phases, leading to the presence of a large amount of Nd_2Fe_(14)B phases. Nb and C additions also refine the structure, and thus increase the exchange coupling interaction between the soft and hard phases. Excellent magnetic properties of B_r = 0.85T,~ iH_C = 1106kA/m, and (BH)_(max) = 117kJ/m~3 have been achieved in Nd_(9.4)Fe_(75.6)Nb_4B_(10.5)C_(0.5) alloy ribbons.