Title :
Effect of Ti-C and Cr Additions on Magnetic Properties of Nanocrystalline (Pr,Nd)-Fe-B Alloys
Author :
De Franco, Vin?cius C. ; Murakami, Regina K. ; Rechenberg, Herc?lio R. ; Yonamine, Taeko ; Missell, Frank P. ; Villas-Boas, Valqu?ria
Author_Institution :
Centro de Cienc. Exatas e Tecnol., Univ. de Caxias do Sul, Caxias do Sul
Abstract :
The addition of both Ti-C and Cr as grain refiners in Nd-Fe-B nanocomposites substantially increases the coercive field Hc. This motived our investigation of the effect of Ti-C and Cr on Pr-Fe-B nanocomposites. Melt-spun ribbons of composition (Pr9.5 Fe84.5 B6 )0.97 - x Crx (TiC)0.03(x = 0; 0.25; 0.5; 0.75; 1) and (Nd 9.5Fe 84.5B 6) 0.97-x Crx(TiC) 0.03( x = 0.5 and 1) were produced for study. For a Pr nanocomposite with 1% Cr, Hc = 12.5 kOe. However, the energy product was limited to 13.6 MGOe by the remanence value. Rietveld analysis of X-ray spectra showed the ribbons to consist of predominantly hard ( ~ 70 wt%) R 2Fe 14B, the soft phase being ( ~ 30 wt%) alpha-Fe. Mossbauer measurements at 300 K are consistent with a reduced hyperfine field for the hard magnetic phase due to the Cr addition. Analysis of transmission electron microscopy images showed the Pr nanocomposite with 1% Cr to have an increased average grain size.
Keywords :
Mossbauer effect; X-ray diffraction; X-ray spectra; chromium; coercive force; iron alloys; nanocomposites; titanium alloys; transmission electron microscopy; Cr; Mossbauer measurements; Nd-Fe-B; Pr-Fe-B; Rietveld analysis; Ti-C; X-ray spectra; coercive field; grain refiners; hard magnetic phase; melt-spun ribbons; nanocomposites; nanocrystalline magnetic propery; temperature 300 K; transmission electron microscopy; (Pr,Nd)-Fe-B; Cr additions; MÖssbauer spectroscopy; X-ray diffraction (XRD); magnetic properties; nanocomposites;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2008.2002243
