Optimization of the magnetic properties of nanocrystalline Pr5Fe77−xCrxB18 alloys

Abstract Ribbons of Pr 5 Fe 77− x Cr x B 18 ( x =0, 1, 2, 2.5, 3, 4, 5) alloys were produced by melt spinning and then annealed to develop enhanced-remanence nanocrystalline magnetic material. Four different types of annealing were used in order to optimize the magnetic properties of these alloys. A conventional annealing, where the ribbons were encapsulated in quartz tubes with argon gas, was the method that led us to the best Pr 2 Fe 14 B/Fe 3 B nanocomposite with Cr. The annealed samples were studied by magnetic measurements, X-ray diffraction and scanning electron microscopy. The best magnetic properties are found for Pr 5 Fe 74 Cr 3 B 18 . The value for the coercive field for this composition is at least 50% higher than for the material without Cr and 40% higher than for the Nd 2 Fe 14 B/Fe 3 B nanocomposite with Cr. X-ray diffraction data and Curie temperature measurements showed that the main phases present in these samples are Pr 2 Fe 14 B, Fe 3 B and α-Fe.