K. Pawlik

Nanocrystalline (Pr,Dy)-(Fe,Co)-Zr-Ti-B magnets produced directly by rapid solidification

Hard magnetic thick ribbon samples of a series of Pr9-xDyxFe60Co13Zr1+yTi3-yB14 alloys (where x=0;1 and y=0;1) (having average thicknesses tr of~ 140 µm) were produced directly by the melt-spinning technique under an Ar atmosphere. The phase constitution of the samples in the as-cast state was determined by X-ray diffractomety and Mossbauer spectroscopy. Hysteresis loops measurements at room temperature indicated very good hard magnetic properties for the alloys, which the coercivity attaining a maximum values of 1.58 MA/m. This is comparable with the coercivities of commercial NdFeB magnets based on melt spun ribbon and with those for nanocrystalline Nd-Fe-B magnets produces by other processes such as mechanical alloying or HDDR.

Rotational hysteresis and magnetization reversal mechanisms in Sm–Fe–N permanent magnets

Abstract The mechanism of magnetization reversal processes in Sm–Fe–N permanent magnets has been investigated on the basis of the analysis of the rotational hysteresis energy, W r , calculated from the magnetic torque curves. Moreover, the anisotropy constants K 1 and K 2 have been determined from the Fourier analysis of the torque curves. The results are compared with the theoretical predictions.