High magnetic coercivity due to a new phase in cast eutectic FeNd alloys

• Published in: Materials letters 1988-11, Vol.7 (5), p.215-218
• Main Authors: Schneider, G., Martinek, G., Stadelmaier, H.H., Petzow, G.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Domain effects, magnetization curves, and hysteresis; Exact sciences and technology; Magnetic properties and materials; Materials science; Metals, semimetals and alloys; Other topics in magnetic properties and materials; Physics; Specific materials
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/0167-577X(88)90014-6

Arc melted Fe + 80 at.% Nd and similar alloys develop intrinsic coercivities as high as 400 kA/m (5.0 kOe) in the as-cast condition. This property is attributed to a fine-grained eutectic microstructure in which the magnetically hard phase containing 20 at.% Nd, is stabilized by oxygen and has a Curie temperature of 235°C. The high coercivity in these alloys confirms an old (1935) report that Nd containing 7% Fe (presumably by mass) has a coercive field of 4300 Oe and also explains the high coercivity of melt-spun ribbons of boron-free Fe-Nd, which can now be correlated with bulk Fe-Nd alloys by X-ray diffraction and Curie temperature. The eutectic also extends into Fe-Nd-B alloys, and replaces the regular eutectic containing Fe 14Nd 2B.