Journal of Materials Chemistry A
·
2013
·Vol. 1
·期 12
·3983-3991
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IF 0
Lina Chong,Jianxin Zou,Xiaoqin Zeng,Wenjiang Ding
In this work, a reversible hydrogen storage composite, 3NaBH4/NdF3, has been prepared using a mechanical milling method. The de-/rehydrogenation properties as well as the mechanisms of reversible hydrogen sorption in the composite were carefully investigated. Based on the pressure–temperature–composition measurements, the de-/rehydrogenation enthalpies of the 3NaBH4/NdF3 composite are determined to be 86.4 kJ mol−1 H2 and −13.2 kJ mol−1 H2, respectively. The onset dehydriding temperature of the composite is determined to be 413 °C in 0.1 MPa Ar atmosphere and can be as low as 80 °C under vacuum conditions. Analyses revealed that NdB6, Nd2H5 and NaF were formed after the decomposition of the composite, which can be hydrogenated to produce NaBH4 and NaNdF4. The formation of NaNdF4 instead of NdF3 in the hydrogenated products is believed to be responsible for the reduced hydrogen storage capacity, while the intermediate formation of B, Nd and NdB4 during dehydrogenation accounts for the asymmetric hydriding/dehydriding behaviors in the 3NaBH4/NdF3 composite.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
MATERIALS TRANSACTIONS
·
2017
·Vol. 58
·期 3
·395-399
·
IF 0.713
Xiaolong Liu,Chao Huang,Bing Li
In this paper, the cyclic voltammetry was applied to investigate the electrochemical reduction processes of Nd(III) ions in NdF3-LiF melts with or without excessive metal Nd. Equilibrium experiments were carried out in NdF3-LiF melts with excessive spheric metal Nd to investigate the relationship between the NdF3:LiF mass ratio and NdF2 concentration. Electrolysis experiments were performed in NdF3-LiF-Nd2O3 melts with different NdF3:LiF mass ratios to explore the relationship between the NdF2 concentration and the current efficiency.The results indicated that Nd(III) ions in the melts were reduced in two steps, i.e., Nd(III)→Nd(II) and Nd(II)→Nd(0). NdF2 could be formed by the comproportionation reaction between Nd(III) and Nd(0) and could stably exist in NdF3-LiF melts containing metal Nd(0). NdF2 mass concentration in the melts decreased from 45.5% to 36.4% with the increase of NdF3-LiF mass ratio from 7:3 to 9:1 in NdF3-LiF melts containing excessive spheric metal Nd, which resulted in a higher current efficiency during the electrolysis. And the highest current efficiency of about 50% for Nd extraction has been obtained by electrolysis in NdF3-LiF (9:1 mass ratio) melts with Nd2O3 (2%, mass concentration) at 1423 K.
研究领域:
冶金学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF FLUORINE CHEMISTRY
·
2015
·
IF 1.948
Songxia Yu,Ruijun Cao,Jun Li,Lingjie Meng
NdF 3 nanoflakes and hexagonal NaNdF 4 nanorods were successfully prepared in a facile manner by the one-pot microwave-assisted hydrothermal reaction of Nd(NO 3 ) 3 ·6H 2 O and NaF within 3 h at pH = 1 and pH = 3–10, respectively. Ethylenediaminetetraacetic acid disodium salt (C 10 H 14 N 2 O 8 Na 2 ·2H 2 O, EDTA–2Na) was used as the morphology-controlling agent. The size, morphology, and crystallinity of the resulting nanocrystals can be easily tuned by adjusting the reaction temperature and time. The as-prepared NdF 3 nanoflakes and NaNdF 4 hexagonal prisms were characterized by X-ray diffraction and scanning electron microscope. All nanocrystals exhibited a typical hexagonal phase, and their crystallization improved with increasing reaction temperature and reaction time. A strong emission spectrum was observed at approximately 850–900, 1060, and 1330 nm for both NdF 3 nanoflakes and NaNdF 4 nanorods under a laser excitation of 354 nm, indicating that Nd 3+ exhibits high luminescence in these two nanocrystals.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2023
·Vol. 54
·期 4
·1675-1686
·
IF 3
Fu Yingzheng,Zhang Zhimin,Lu Xuchen,Yan Yan,Pan Binfeng
To increase the reaction driving force and prepare Mg–Nd master alloys, the synergistic interaction between NdCl 3 and NdF 3 was used in the magnesiothermic reduction process in NdCl 3 –NdF 3 -containing molten salt. Thermomechanical analysis was used to investigate the possibility of the synergistic interaction in molten salt. Then the verification of synergistic interaction was conducted by analyzing the composition of the molten salt and the alloys obtained in the magnesiothermic reduction process. After that, the factors affecting synergistic interaction were investigated. At last, the mechanism of the synergistic interaction between NdCl 3 and NdF 3 in molten salt was proposed and discussed. The coupling reaction formed in the magnesiothermic reduction process and the existence of three reaction mechanisms increased the reaction driving force. Mg–RE master alloys with the content of Nd being 25 to 30 wt pct were prepared under the optimum conditions and the conversion rate of NdF 3 was greater than 70.94 pct. The content of Nd and the content of various impurities in the alloys obtained both met the requirements of the commercial Mg–Nd master alloys.
研究领域:
材料科学
·
冶金学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Changchao Su,Yuheng Sun,Hongqun Tang,Youbin Wang,Fuxu Tao,Zhengbin Xu,Chunhua Wei,Zezuo Jiang,Shiqiang Wei
Rare-earth metal neodymium is an important raw material for NdFeB permanent magnets, and its demand has significantly increased in recent years. Molten salt electrolysis is the main method for the production of metal neodymium, so the study of the electrodeposition process of neodymium ions in molten salt at the cathode is of great significance for the production of metal neodymium. In this paper, the electrochemical deposition process of neodymium ions on a tungsten working electrode was studied in a LiF-NdF 3 -Nd 2 O 3 molten salt system using electrochemical methods such as cyclic voltammetry and open circuit potential. Additionally, the influence of LiF content in the molten salt on the electrodeposition process was analyzed. The experimental results indicate that the reduction of neodymium ions in the LiF-NdF 3 -Nd 2 O 3 molten salt system consists of two stepwise quasi-reversible redox reactions: Nd(III) → Nd(II) and Nd(II) → Nd(0). The corresponding reduction peak potentials are −0.78 V and −1.19 V, respectively. The Nd(III) → Nd(II) reaction is solely diffusion-controlled, while the Nd(II) → Nd(0) reaction is governed by both surface control and diffusion control in the electrochemical process. The increase in LiF content in the molten salt leads to a shift of the cathodic overpotential in the positive direction. When the LiF content is high, the reduction of neodymium ions on the electrode becomes unstable, making it unfavorable for the deposition of metal neodymium on the tungsten electrode.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）