Magnetic properties enhancement of nanocomposite Nd9.5Fe81.5B9 melt-spun ribbons by La and Cr substitutions

The phase transformation and magnetic properties of nanocomposite (Nd0.95La0.05)(9.5)(Fe1-xCrx)(81.5)B-9, where x = 0, 0.033, 0.067, and 0.1, melt-spun ribbons have been studied. For Cr-free ribbons (i.e, x=0,) a slight substitution of La for Nd decreases the crystallization temperature of the over-quenched ribbons. Moreover, the (Nd,La)(3)Fe62B14 and (Nd, La)(2)Fe23B3 phases were found to coexist with (Nd, La)(2)Fe14B/Fe3B/alpha-Fe phases in the crystallized (Nd0.95La0.05)(9.5)Fe81.5B9 ribbons. The crystallization temperatures of (Nd0.95La0.05)(9.5)Fe1-xCrx)(81.5)B-9 were found to increase with Cr concentration. The intrinsic coercivity of (Nd0.95La0.05)(9.5)(Fe1-nCrx)(81.5)B-9 increased from 6.2 kOe for x=0 to 10.7 kOe for x=0.1: Transmission electron microscopy-energy dispersion analytical x-ray analyses indicated that the increase in intrinsic coercivity may be associated with the increase in Cr concentration around grain boundaries. A sample with B-r = 8.3 kG, H-i(0) = 9.1 kOe, and (BH)(max) = 12.5 MGOe was obtained on (Nd0.95La0.05)(9.5)(Fe0.967Cr0.033)(81.5)B-9 after appropriate thermal treatment. (C) 1997 American Institute of Physics.