Structure and magnetic properties of chilli-cast and melt-spun Nd-x(Fe3Al)(100-x) and Nd-33(FeyAl)(67) alloys

The magnetic properties of chill-cast Nd-Fe-Al rods have been studied as a function of Nd and Al concentrations. High coercivities were obtained ia Nd -60(Fe3Al)(40), Nd-50(Fe3Al)(50) and Nd-33(Fe10Al)(67) alloys. The study on the melt-spun ribbons of these alloys has shown that coercivity is depende nt on the quenching rate, and high coercivity could only be obtained in all oys prepared after a relatively low quenching rate. Several crystalline Nd- Fe-Al phases have been investigated in this work. A metastable tetragonal p hase existed as nearly the single phase in Nd-33(FeyAl)(67) with y = 2-4. T he tetragonal phase is antiferromagnetic with a Neel temperature of 260 K. Metamagnetism and magnetoresistivity have been observed. The study on the a nnealed Nd-33(FeAl)(67) alloy has shown that a hexagonal phase and an unkno wn were formed and these two Fe-containing phases, among which one is an an tiferromagnetic with a Neel temperature of 280 K and the another is ferroma gnetic below 130-140 K.