Crystallization Process of α-Fe/Nd2Fe14B Type Nanocomposite Magnet Alloys
The crystallization process of α-Fe/Nd2Fe14B type nanocomposite magnet alloys has been studied with the x-ray diffraction method and Mössbauer spectroscopy. Melt-spun alloy ribbons with the compositions of Nd8Fe81Co4Nb0.5B6.5 and Nd9Fe79Co4Nb1.5B6.5 were annealed at 600, 650, 700 and 750 °C for the former, and at 700 °C for the latter, respectively. In the case of Nd8Fe81Co4Nb0.5B6.5, the α-Fe and Nd2Fe14B phases appear in the very early stage of the crystallization process, that is at 650 °C. On the other hand, the alloy of Nd9Fe79Co4Nb1.5B6.5 annealed at 700 °C has fewer α-Fe and more Fe3B phases compared with the case of Nd8Fe81Co4Nb0.5B6.5. Discussions taking notice of the atomic ratio of Fe in the above alloys lead us to the conclusion that α-Fe and Nd2Fe14B are crystallized at comparatively low annealing temperature when the Fe ratio is high in the alloys, while fewer α-Fe and more Fe3B phases appear when the Fe ratio is low.
Keywordsnanocomposite magnet Mössbauer spectroscopy crystallization process intermediate metastable phase
Unable to display preview. Download preview PDF.