材料期刊网

Magnetic properties, phase evolution and microstructures of Pr_9.44Fe_90.56-xB_x (x=7.16 and 4.76) nanocomposite magnets have been investigated. Both as-spun ribbons exhibit two-step demagnetization curves, indicating the feature of partial crystallization. By using differential scanning calorimeter (DSC) measurements, remained amorphous phase of ribbon with x=7.16 shows a higher crystallization temperature. At optimum annealing temperature of 650 ℃ for 10 min, better magnetic properties, M_r=1.01 T, _jH_c=796 kA/m and (BH)_max=136 kJ/m³ were obtained in the sample with x=4.76. Transmission electron microscopy (TEM) observation confirms that the sample with x=4.76 possesses much finer grain size, which causing a better exchange coupling between soft and hard magnetic grains.