Tailoring The Microstructure And Magnetic Properties Of (Nd,Pr)(2)Fe14b/Alpha-Fe Nanocomposite Magnets Via Ta Addition

The effect of Ta addition on the microstructure and magnetic properties of (Nd0.4Pr0.6)(9)Fe85-xTaxB6 nanocomposite magnets prepared by melt spinning was studied. Microstructure studies reveal that Ta addition is effective in refining the microstructure of nanocomposite magnets. The temperature coefficient of coercivity (p) is improved from -0.350%degrees C for x = 0 to -0.329%degrees C for x = 2 in the temperature range 27 degrees C-175 degrees C. With the increase in x from 0 to 2, the coercivity of the alloys is improved remarkably from 6.1 kOe to 10.4 kOe at the expense of remanence. As a result, the optimal magnetic properties with H-ci = 7.5 kOe and (BH)(max) = 23.4 MGOe have been achieved at x = 1. Minor hysteresis loops were analyzed to determine the coercivity of (Nd0.4Pr0.6)(9)Fe85-xTaxB6 nanocomposite magnets by inhomogeneous domain wall pinning mechanism. The significant enhancement of magnetic properties mainly results from grain refinement achieved by introducing Ta.