Phase Diagram of Crystallization of Amorphous Nd-Fe-B Alloys

Abstract

Crystallization processes for a wide range of amorphous Fe_1−x(Nd_1−yB_y)_x alloys (0.1≤x≤0.6, 0≤y≤1) have been investigated by calorimetry, X-ray diffraction, Mössbauer spectroscopy and magnetization. The phase regions of formation of various kinds of phases included metastable ones have been determined in detail. The metastable Nd₂Fe₂₃B₃ phase is formed at boron-rich region (0.18≤x≤0.27, 0.61≤y≤0.78) at a temperature range from 900 to 1000 K. Instead, the metastable NdFe₁₂B₆ phase only appears together with Nd₂Fe₂₃B₃ and is not formed in the alloy of the stoichiometric composition of the compound (Fe_0.63Nd_0.05B_0.32).