TRANSFORMATION OF THE CRYSTALLINE AND ELECTRON STRUCTURES OF THE NdFeB ALLOYS MODIFIED WITH TITANIUM

D.DEREWNICKA; LEDE E.; M. PAGNOLA; M.SPYRA; F. D. SACCONE; L. G. PAMPILLO; M. LEONOWICZ

Nagasaki

Workshop; The 22nd International Workshop on Rare-Earth Permanent Magnets and their Applications; 2012

Abstract: Rapid quenched ribbons of the NdyFe(86-x-y)B14Tix (x = 0, 4; y = 7, 8) alloys were annealed at 953K for 20 minutes. The best properties(JHc =648kA/m, Jr=972mT, (BH)max=143kJ/m3) were obtained for the alloy composition Nd8Fe74B14Ti4. The magnetically hard phase Nd2Fe14B dominates in the ternary alloy (x=0). It transforms into the Nd2Fe12.6BTi1.4 phase with the addition of Ti to the alloy. Titanium replaces the iron atoms in the elementary cell of the Nd2Fe14B in a continuous manner, which results in a variable content of this element in individual grains. The presence of α-Fe, Nd2Fe23B3, Fe2B and Nd1.1Fe4B4 was identified. These phases are also enriched in Ti. The proportion of the phases varies depending on the percentage of the elements in the investigated alloys. X-Ray absorption spectrum for Nd and Fe showed that in samples without Ti there is a charge transfer from Nd to Fe while Nd concentration increases from 7 to 8 at.%. It was found that Ti addition promotes modifications of the electronic structures of Nd and Fe sub-bands.