Magnetic properties of (misch metal, Nd)-Fe-B melt-spun magnets

Abstract

The effect of replacing Nd with misch metal (MM) on magnetic properties and thermal stability has been investigated on melt-spun (Nd1-xMMx)13.5Fe79.5B7 ribbons by varying x from 0 to 1. All of the alloys studied crystallize in the tetragonal 2:14:1 structure with single hard magnetic phase. Curie temperature (Tc), coercivity (Hcj), remanence magnetization (Br) and maximum energy product ((BH)max) all decrease with MM content. The melt-spun MM13.5Fe79.5B ribbons with high ratio of La and Ce exhibit high magnetic properties of Hcj = 8.2 kOe and (BH)max= 10.3 MGOe at room temperature. MM substitution also significantly strengthens the temperature stability of coercivity. The coercivities of the samples with x = 0.2 and even 0.4 exhibit large values close to that of Nd13.5Fe79.5B7 ribbons above 400 K.