Phase precipitation behavior of rapidly quenched ternary La–Fe–B alloy and the effects of Nd substitution

To understand the structure and phase precipitation behavior of the ternary La–Fe–B alloy, the effects of wheel speed and heat treatment on the melt spun La₂Fe₁₄B alloy were investigated. The results show that the hard magnetic La₂Fe₁₄B (2:14:1) phase is difficult to obtain in the ternary alloy. The α -Fe and La phases mainly precipitated as spun ribbons prepared at relatively low wheel speeds, and a more amorphous phase formed at higher wheel speeds. With the annealing temperature increasing from 400 °C to 500 °C and 800 °C, the α -Fe and La phases also gradually precipitated from the amorphous matrix. A liquid La-rich phase and α -Fe phase could coexist in the alloy at high temperature. However, the substitution of Nd for La can greatly enhance the formation of a hard 2:14:1 phase. The effects of Nd substitution on the structure and phase precipitation during annealing for the (La_1−x Nd_x )₂Fe₁₄B ( x   =  0.1. 0.2, 0.3 and 0.4) alloys have been also investigated. The present results are important for exploring high-performance low-cost La-based Nd–Fe–B magnets. (paper)