Highly oriented NdFeB nanocrystalline magnets from partially recombined compacts with ultrafine grain size by reactive deformation under low pressure

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• 作者：Yunping YU ((余云萍)) ; Jun LI ((李 军)) ; ^{abthonyli@163.com" class="auth_mail" title="E-mail the corresponding author} ; Ying LIU ((刘 颖)) ; Renquan WANG ((王仁全)) ; Qing ZHENG ((郑 青)) ; Lixian LIAN ((连利仙))
• 关键词：Nd2Fe14B ; nanocrystalline ; HDDR ; deformation ; anisotropy ; rare earths
• 刊名：Journal of Rare Earths
• 出版年：2015
• 出版时间：1 December 2015
• 年：2015
• 卷：33
• 期：12
• 页码：1298-1302
• 全文大小：2377 K

文摘

The partially recombined compacts with ultrafine grain size were taken advantage of preparing anisotropic nanocrystalline magnets with full density and homogenous microstructure and texture by reactive deformation under low pressure. Because of the ultrafine grain size of the precursors, the partially recombined phases could quickly achieve recombination. The results suggested that the newly recombined Nd₂Fe₁₄B grains with fine grain size could undergo deformation immediately during the desorption-recombination reaction, and then an obvious anisotropy and uniform alignment would be obtained. The magnetic properties, (BH)_max=214 kJ/m³, B_r= 1.26 T, H_cj=463 kA/m, were obtained after being treated for 5 min at 820 °C in high vacuum under low pressure less than 26 MPa. Microstructures of the magnets were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) respectively. Magnetic measurements were carried out using a vibrating sample magnetometer (VSM) with the maximum field of 2.88 T. Accurate phase contents were measured by a Mossbauer spectrometer.