Effect of Tungsten Addition on Phase Constitution and Magnetic Properties of the Bulk $Fe_{65}Pr_{9}B_{26-x}W_x$ Alloys

The effect of tungsten addition on phase constitution and magnetic properties of the bulk $Fe_{65}Pr_9B_{26-x}W_{x}$ (where x=2, 4, 6, 8) alloys was studied. The base alloys were prepared by arc-melting of the high purity elements under Ar atmosphere. Samples were produced by suction of an arc-molten alloy to a water-cooled copper mould (the suction-casting method). In order to develop nanocrystalline structure, the samples were subjected to annealing. Heat treatment resulted in an evolution of the phase constitution that caused changes in magnetic properties of the alloys. X-ray diffractometry was used to determine the phase composition of annealed samples. The analysis showed presence of hard magnetic $Pr_2Fe_{14}B$, paramagnetic $Pr_{1+x}Fe_4B_4$ and soft ferromagnetic α-Fe phases of annealed samples. The room temperature magnetic properties were determined from hysteresis loops measured by VSM magnetometer in the external magnetic field up to 2 T. The highest hard magnetic parameters were measured for the rod sample of $Fe_{65}Pr_9B_{20}W_6$ annealed at 1003 K for 5 min.