title: Preparation of Nd-Fe-B by nitrate-citrate auto-combustion followed by the reduction-diffusion process.
abstract: 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.
authors: Korea Center for Artificial Photosynthesis and Department of Chemistry, Sogang University, Seoul 121-742, Korea. yskang@sogang.ac.kr.
authors: Hao Xuan
authors: HX
authors: Ma
authors: Chang Woo
authors: CW
authors: Kim
authors: Dong Soo
authors: DS
authors: Kim
authors: Ji Hun
authors: JH
authors: Jeong
authors: In Ho
authors: IH
authors: Kim
authors: Young Soo
authors: YS
authors: Kang