Synthesis and characterization of Nd4+xFe72Co5Ga2B17−x nanocomposite ribbons

Abstract

A series of alloys with compositions of Nd4 + xFe72Co5Ga2B17−x, where x = 0–10, were prepared by rapid solidification. Annealing the as-spun alloys above primary crystallization (Tx1) formed nanocomposite ribbons. While x-ray diffraction measurements showed the annealed alloys to be nanocrystalline, the phases present in each alloy were found to vary with Nd content. The alloys with x = 0, 7.5, and 10 contained a majority fraction of the Nd2Fe14B phase, along with Fe3B, α-Fe, and/or Nd2Fe23B3 phases. These alloys showed room temperature coercivities and remanent magnetizations of 199, 446, and 1034 kA/m and 120, 82, and 70 A m2/kg, respectively. The x = 5 and 7.5 samples were primarily made up of Nd2Fe23B3, and therefore, showed little coercivity. At elevated temperatures, the presence of Co and Ga were found to increase the coercivity of the Nd2Fe14B phase.