Magnetic properties of Pr-Dy-Fe-Co-B sintered materials with a high cobalt content

Materials (Pr_1?x Dy _x )_12–17(Fe_1?y Co _y )_balB_5–15 (x = 0.44–0.51 at %, y = 0.15–0.87 at %) have been studied. It is shown that the abrupt decrease in the coercive force of the (Pr_1?x Dy _x )_12–17(Fe_1?y Co _y )_balB_5-15 sintered materials with x = 0.44–0.51 and y > 0.25 is determined by the amount of boron-containing phases. In this case, an increase in the boron content in the (Pr_0.72Dy_0.28)_14.5(Fe_0.50Co_0.50)_balB _z material with an unchanged dysprosium content leads to an increase in the coercive force by 4.5 times. It is assumed that the escape of boron from the near-surface areas of R ₂ F ₁₄B-phase grains leads to the formation of regions characterized by a low anisotropy constant, which serve as nuclei for the formation of reverse-magnetization domains.