Phase Formation and Magnetic Properties of La- and Ce-Substituted (Nd1-2xRExPrx)2.28Fe13.58B1.14 Melt-Spun Ribbons

The effects of La and Ce substitution on phase formation and magnetic properties of (Nd1-2xRExPrx)(2.28)Fe13.58B1.14 (rare earth [RE] = La and Ce; x = 0.05 and 0.10, hereafter defined as La5Pr5, La10Pr10, Ce5Pr5, and Ce10Pr10) ribbons prepared via melt-spinning technology are studied experimentally. According to the phase structure analysis of as-cast alloys and melt-spun ribbons, the as-cast alloys are composed of the 2:14:1-type main phase with the tetragonal Nd2Fe14B structure and alpha-Fe minor phase, whereas the melt-spun ribbons are a single 2:14:1-type main phase, except for La5Pr5 ribbon with an additional alpha-Fe minor phase. Based on magnetic measurements, the magnetic properties of La5Pr5, La10Pr10, Ce5Pr5, and Ce10Pr10 melt-spun ribbons are determined. The remanence (B-r), the coercivity (H-cj), and the maximum magnetic energy product ((BH)(max)) of La5Pr5 and La10Pr10 increase greatly, whereas B-r and (BH)(max) of Ce5Pr5 and Ce10Pr10 decrease and H-cj of these two ribbons increases. Meanwhile, the Curie temperatures (T-c) of all the ribbons reduce with increasing La-Pr and Ce-Pr substitutions. In particular, La10Pr10 ribbon and Ce5Pr5 ribbon as Nd-Fe-B ribbons with La-Pr and Ce-Pr substitutions exhibit better magnetic properties.