Magnetic properties enhancement of Nd2Fe14B/α-Fe nanocomposites by Ta substitution

Nanostructured Nd9.5Fe84−xB6.5Tax (x=0, 0.5, 1, 1.5, and 2) ribbons composed of Nd2Fe14B and α-Fe phases with a high coercivity and maximum energy product are fabricated by direct melt spinning. The effects of Ta addition on the structures and magnetic properties of melt-spun Nd9.5Fe84−xB6.5Tax (x=0, 0.5, 1, 1.5, and 2) ribbons have been investigated. Compared with addition-free ribbons, small addition of Ta is found to reduce the grain sizes of the samples and improve their magnetic properties due to a strong exchange coupling between the Nd2Fe14B hard phase and α-Fe soft phase. A coercive field of 750 kA/m and a maximum energy product of 158 kJ/m3 in melt-spun Nd9.5Fe82.5B6.5Ta1.5 ribbons are obtained at room temperature.