Effect of sintering conditions on the magnetic and microstructural properties of Nd-Fe-B sintered magnets doped with DyF3 powders

Abstract

The microstructural and magnetic property changes of DyF3-doped (Nd-26.06, Dy-6.51)-Fe-bal-B-0.97-M-2.39 (wt. %) (M = Cu, Al, Co, and Nb) sintered magnets as functions of the sintering conditions were studied. The sintering conditions for the optimum core-shell microstructure were determined. When the magnets were sintered at 1050 degrees C for 4 h, a coercivity of 35.1 kOe was obtained without sacrificing the remanence. When the magnets were doped with DyF3, the formation of the RE-rich phase (Nd-Dy-O) was effectively suppressed and, hence, saving the Dy. In addition, the formation of a cubic-NdOF triple-junction phase (TJP) improves the interface uniformity and enhances the coercivity. (C) 2012 American Institute of Physics. [doi:10.1063/1.3672246]