Tailoring the magnetic properties and microstructure of NdFeB ribbon alloys by Hf addition

Abstract

In this paper, the effects of Hf addition on phase composition, Curie temperature, exchange coupling effect, coercivity mechanism, room temperature magnetic properties, high temperature magnetic properties and thermal stability of NdFeB alloys with different Nd content (27–31 wt%) are systematically studied. Hf addition showed different effects on the magnetic properties of NdFeB alloys at different Nd contents and different test temperatures. At 300 K, the intrinsic coercivity is increased with low Nd content (27 wt%), while the remanence and the maximum magnetic energy product are significantly improved with higher Nd content (29 wt%, 31 wt%). At 398 K, the intrinsic coercivity, the remanence, the maximum magnetic energy product and the temperature stability improved in NdFeB alloys with high Nd content (29 wt%, 31 wt%).