Effect of Annealing Temperature on the Magnetic Properties of Pr-Fe-Co-Zr-Nb-B Alloys Ribbons

The properties of rapidly solidified ribbons of Pr9Fe50+xCo13Zr1Nb4B23-x (where x = 2, 5, 8) alloys annealed at temperatures ranging from 923 K to 1033 K were investigated. The heat treatment of the fully amorphous as-cast ribbons led to the simultaneous crystallization of the hard magnetic Pr-2 (Fe,Co)(14)B, the soft magnetic alpha-Fe and the paramagnetic Pr1+xFe4B4 phases. However, the crystallization of the alpha-Fe phase took place as the second crystallization event at higher temperatures for the x = 8 alloy. The Rietveld analysis of the X-ray diffraction patterns was used to calculate the crystallite sizes of constituent phases. Additionally, using PONKCS method the weight fractions of crystalline and amorphous components were quantified. For all alloy compositions the temperature dependencies of magnetic parameters were determined from the hysteresis loops.