Structure and intrinsic magnetic properties of MMb>2b>Feb>14b>B (MM=La, Ce, Pr, Nd) alloys
文摘
MMb>33b>Feb>66b>B (MM=La, Ce, Pr, Nd) alloys (mass ratio) were prepared by induction melting and heat-treated at 1353 K for 24 h to produce homogeneous MMb>2b>Feb>14b>B phase. The phase structure and element distribution of the alloys were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The alloys were applied ball milling to obtain powders with good size distribution and then magnetic aligned in a static magnetic field of 2 T for 4 h, in order to achieve the intrinsic magnetic properties by vibrating sample magnetometer (VSM). XRD results showed that the alloys were composed of the single 2:14:1 main phase and RE-rich phase, which was similar to Ndb>2b>Feb>14b>B structure. Magnetic measurements showed that the saturation magnetization (Mb>sb>) and anisotropy field (Hb>Ab>) of the MMb>33b>Feb>66b>B alloy were 11.3 kGs and 48.4 kOe, respectively, demonstrating its good potential as permanent magnets. The Curie temperature of the MMb>33b>Feb>66b>B alloy was determined as 502.9 K by magnetization-temperature curves. Microstructure observation showed that Nd and Pr were mainly in the 2:14:1 ferromagnetic phase, while La and Ce prefered to aggregate in the RE-rich grain boundary phase, which is beneficial to fabricating (Pr, Nd, MM)b>2b>Feb>14b>B magnets with good magnetic properties.