Increase in the Boron Content in Pr–Dy–Fe–Co–B Materials by Solid-Phase Alloying

Resumo

Abstract—Changes in the magnetic properties of the sintered (Pr_0.76Dy_0.24)_12.9(Fe_0.53Co_0.47)_81.5B_5.6 material, which are caused by solid-phase alloying with the (Pr_0.63Dy_0.37)(Fe_0.31Co_0.69)₂B₂ alloy are studied. The dependences of the phase composition and the coercive force of the sintered material on the amount of the added alloy is obtained. As the boron content in the sintered material increases, the content of the main magnetic (Pr, Dy)₂(Fe, Co)₁₄B phase decreases from 89.2 to 51.4 vol % and the content of the (Pr, Dy)(Fe, Co)₃ phase increases from 7.1 to 43.9 vol %. It was found that, in the course of 190-h storage of sintered magnets in air, their coercive force and density are first unchanged and subsequently decrease; the coercive force decreases to zero.