Ma Hao Xuan, Kim Chang Woo, Kim Dong Soo, Jeong Ji Hun, Kim In Ho, Kang Young Soo
Korea Center for Artificial Photosynthesis and Department of Chemistry, Sogang University, Seoul 121-742, Korea.
Nanoscale. 2015 May 7;7(17):8016-22. doi: 10.1039/c5nr01195g.
The Nd2Fe14B alloy has been successfully synthesized by nitrate-citrate auto-combustion followed by the reduction and diffusion process with low energy consumption. H3BO3, Fe(NO3)3·9H2O, and Nd(NO3)3·6H2O were used as precursors and citric acid was used as the chelating ligand of metal ions. Ammonia water was used to adjust pH to 7. CaH2 was used as a reducing agent for the reduction and diffusion process. NdFeO3 and Fe2O3 were produced during auto-combustion of gel. The combustion process of the gel was investigated by TGA/DTA curve measurements. The phase compositions were studied by XRD measurements. The differences of the overall morphology and magnetic properties were measured by SEM, TEM and vibrating sample magnetometry (VSM) at 300 K. The comparison of the magnetic properties of the reduced samples between the pellet type and the random powder type was done with VSM and it showed better magnetic properties of the pellet type Nd2Fe14B. Making a compact pellet type sample for reduction is more efficient for solid reduction and phase transition for higher coercivity.
通过硝酸盐 - 柠檬酸盐自燃烧法，随后进行低能耗的还原和扩散过程，成功合成了Nd2Fe14B合金。使用H3BO3、Fe(NO3)3·9H2O和Nd(NO3)3·6H2O作为前驱体，并使用柠檬酸作为金属离子的螯合配体。用氨水将pH值调节至7。CaH2用作还原和扩散过程的还原剂。在凝胶自燃烧过程中生成了NdFeO3和Fe2O3。通过TGA/DTA曲线测量研究了凝胶的燃烧过程。通过XRD测量研究了相组成。在300 K下，通过SEM、TEM和振动样品磁强计（VSM）测量了整体形貌和磁性的差异。用VSM对压块型和无规粉末型还原样品的磁性进行了比较，结果表明压块型Nd2Fe14B具有更好的磁性。制备紧凑的压块型样品进行还原，对于提高矫顽力的固体还原和相变更有效。
