Effect of Nb addition on magnetic properties and the microstructure of Fe_3B/Nd_2Fe_(14)B nanocomposite permanent magnets

摘要

The microalloying effect of Niobium on the microstructure and magnetic properties of Fe_3B/Nd_2Fe_(14)B nanocomposite permanent magnet has been investigated. As a result, Niobium addition stabilizes the amorphous phase and hinders the kinetics of the crystallization of the Fe_3B particles. Niobium added in combination with Cu reduces grain size of Fe_3B particles more remarkably than that without Niobium; Niobium addition enhances magnetic properties of the alloy, but the amount must be suitable. Optimum magnetic properties with B_r=1.15T, _jH_c=467kA/m and (BH)_(max)=132.7kJ/m~3 were obtained by annealing a melt-spun Nd_(5.5)Fe_(70.0)Co_5Cu_(0.5)Nb_(0.5)B_(18.5) amorphous ribbon at 670°C for 40min.