Microstructure of Nd55−xCoxFe30Al10B5 hard magnetic alloy investigated by electron microscopy techniques

Microstructure of Nd55−xCoxFe30Al10B5 (x=0, 5, 10, 15 and 20) alloy fabricated by copper mold suction-casting method was investigated by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) combined with energy dispersive X-ray (EDX), selected area electron diffraction (SAED) and electron backscatter diffraction (EBSD) techniques. The results show that the alloy consists of both the amorphous and crystalline phases with their fraction depending on Co-concentration. The tetragonal-Nd2(Fe,Co)14B, double hexagonal close packed-Nd, face centered cubic-Nd and orthorhombic-Nd3Co crystallites were detected in the alloy. The size and structure of the Nd2(Fe,Co)14B crystallites depend on the Co-concentration resulting in the change of coercivity and Curie temperature of the alloy.