Hard magnetic bulk amorphous alloys

An amorphous phase in Ln-Fe-Al (Ln=Nd and Pr) systems is formed in dde composition ranges of 0 to 90 at% Fe and 0 to 93 at% Al by melt spinning, Ferromagnetic Ln(90-x)Fe(x)Al(10) bulk amorphous alloys with high coercive force (H-i(c)) at room temperature are obtained by copper mold Easting. The maximum diameter of the cylindrical amorphous samples is 12 mm far the Nd-30%Fe-Al alloy and 3 mn far the Pr-30%Fe-Al alloys and decreases with deviating Fe content. The extremely high T-x/T-m and small Delta T-m(=T-m-T-x), which are evaluated by the crystallization (T-x) temperature (T-x) and melting temperature (T-m), are the reason for the achievement of large glass-forming ability in these systems, The bulk amorphous Ln(60)Fe(30)Al(10) alloys are ferromagnetic with the Curie temperature of 515 to 600 K which are higher than those for Nd-Fe and Pr-Fe binary amorphous ribbons. The remanence and H-i(c) are 0.089 to 0.122 T and 277 to 321 kA/m, respectively, and the crystallization to Ln+Al(2)Ln+delta causes a ferromagnetic- to -paramagnetic transition. Thus, the hard magnetic properties are achieved only in the amorphous state.