Production and Characterization of Nanostructured Powders of Nd 2 Fe 14 B and Fe 90 Al 10 by Mechanical Alloying.

The objective of this work is to evaluate the applicability of exchange coupling between nanoparticles of Nd 2 Fe 14 B (hard magnetic material) and Fe 90 Al 10 (soft magnetic material), as permanent magnets produced by surfactant-assisted mechanical alloying. The obtained powders were then mixed with 85% of the Nd 2 Fe 14 B system and 15% of the Fe 90 Al 10 system and subsequently sintered at 300 °C, 400 °C and 500 °C for one hour. The results obtained by Mössbauer spectrometry (MS) show a ferromagnetic behavior with six magnetic sites represented by sextets (16k1, 16k2, 8j1, 8j2, 4c and 4e), characteristic of the Nd 2 Fe 14 B system. X-ray diffraction (XRD) results show a tetragonal and BCC structure for the Nd 2 Fe 14 B and FeAl systems, respectively. The results obtained by vibrating sample magnetometry (VSM), for mixtures of the Nd 2 Fe 14 B and Fe 90 Al 10 sy stems sintered at 300 °C, 400 °C and 500 °C, allow for the conclusion that the coercive field (Hc) decreases drastically with temperature and the percentage of soft phase at values of Hc = 132 Oe compared to the coercive field values reported for Nd 2 Fe 14 B Hc = 6883 Oe, respectively. Images obtained by transmission electron microscopy (TEM), for the Fe 90 Al 10 system, show a tendency for the nanoparticles to agglomerate.