(Pr,Nd)-Fe-B nanocrystalline magnetic materials with TiC additions

摘要

The effect of titanium carbide (TiC) addition and Pr substitution in nanocrystalline Nd-Fe-B based magnetic materials has been investigated. Rapidly solidified (Pr,Nd)-Fe-B alloys were prepared by melt spinning. The compositions studied were (Pr_xNd_(1-x)_(9.5)Fe_(84.5)B_6 (x=0, 0.1, 0.25, 0.5, 0.75, and 1) with the addition of 3 at. percent TiC. Varying the wheel speed from 15 to 30 m/s, the best magnetic properties were found for samples prepared at 20 m/s. All samples were nanocrystalline in the as-cast state. The average coercive field ranged from 10.0 to 12.6 kOe and energy product from 7.8 to 9.0 MGOe. The improvement in the coercive field compared to similar Nd based alloys was about 30 percent. Rietveld analysis of x-ray data for the Pr_(9.5)Fe_(84.5)B_6 sample revealed that this material consists of approximately 70 wt. percent of 2:14:1 phase and 30 wt. percent of alpha-Fe. This result was confirmed by Mossbauer data analysis and is in agreement with compositions expected from the ternary phase diagram.