Technical magnetic properties of melt-spun (Nd1-xPrx)2Fe14B at low temperature

The spin-reorientation temperatures T-s and technical magnetic properties (coercivity H-ei and energy product (BH)(max)) of isotropic and aligned compacts of the pseudoternary melt-spun compound (Nd1-xPrx)Fe14B (0 less than or equal to x less than or equal to 0.52) have been studied as a function of temperature for 10 K less than or equal to T less than or equal to 150 K. Results measured on thermomechanically processed ('die-upset') samples are included for comparative purposes. Lattice parameters were measured with transmission synchrotron X-ray diffraction to verify the nominal compositions, and grain size determined by peak-broadening confirmed that these materials are nanoscaled. The spin-reorientation temperatures decrease with increasing x and are Found to be significantly lower than their bulk-literature counterparts. Both the coercivity and the energy product of the isotropic compacts decrease with increasing temperature; no anomaly in either property is found at T-s. The relative decrease in a technical magnetic property from its value at 10 K becomes smaller with increased Pr-content. The substitution of only a few atomic percent of Pr for Nd causes the coercivity to decrease sharply from its Pr-free value; the coercivity gradually recovers as increasing amounts of Pr art substituted into the lattice. (C) 1997 Elsevier Science B.V. All rights reserved.