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为了改善AB2型Laves相贮氢合金的电化学性能,对AB2型Ti基及Ti-Zr基贮氢合金进行快淬处理。用XRD和SEM分析了铸态及快淬态合金的相结构,并观察了合金的微观组织形貌。研究了快淬工艺参数对AB2型Laves相贮氢合金的电化学性能及微观结构的影响。研究的结果表明快淬对AB2型Laves相贮氢合金电化学性能的影响与合金的成分密切相关。对Ti基合金,随淬速的增加,合金的容量显著提高,在一定淬速下出现极大值。快淬对合金的活化性能基本没有影响,合金的循环稳定性有所改善但不显著;对Ti-Zr基合金,随淬速增加,合金的循环稳定性得到大幅度提高,而合金的容量及活化性能明显降低。快淬使AB2型贮氢合金电化学性能发生变化的根本原因是合金的微观结构发生了变化。 相似文献
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用铸造及快淬工艺制备了稀土基AB5型Mm(NiMnSiAl)4.3 Co0.6-xFex(x=0、0.1、0.2、0.3、0.4、0.5、0.6)贮氢电极合金,测试了合金在铸态及快淬态下的微观结构与电化学性能.研究了Fe替代Co对铸态及快淬态贮氢合金微观结构及电化学性能的影响.研究结果表明,Fe替代Co对铸态及快淬态合金的相结构没有明显影响,但对合金的电化学性能产生显著影响.对铸态及快淬态合金,随Fe替代量的增加,合金的容量下降,但合金的循环寿命得到不同程度的改善.Fe替代Co对快淬态合金循环寿命的改善更加显著,导致这一结果的主要原因是Fe替代Co使快淬态合金的微观组织显著细化. 相似文献
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采用真空电弧炉(在氩气保护下)制备Zr1-xTixMn0.4Cr0.4Ni1.2贮氢合金,通过XRD、SEM和恒流充放电研究了合金的相结构、形貌和电化学性能。结果表明:Ti为C14型Laves相的稳定性元素,随着Ti含量的增加,C14型Laves相增多,C15型Laves相减少。当x=0.1时,合金综合性能最好,表现出良好的活化性能、循环稳定性能和高倍率放电特性,在放电电流300mA/g的条件下,充放电循环50次,合金保持稳定的放电容量。当X〉0.1时,合金放电容量下降。Ti的加入使合金氢化物稳定性降低,加入少量Ti,有利于合金的放电容量的提高和高倍率放电性能的提高。 相似文献
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快淬低钴AB5型贮氢合金的研究及产业化前景 总被引:2,自引:0,他引:2
快淬技术就是使金属或合金熔体经过快速凝固,获得具有特殊微观结构的非平衡组织。钢铁研究总院将真空快淬工艺应用到AB5型贮氢合金的制备中,获得具有微晶、纳米晶、非晶混合结构的组织。具有这类结构的AB5型合金不仅解决了低钴AB5型贮氢合金循环寿命低的问题,而且合金保持了高的电化学容量、优良的初始活化性能以及高的倍率放电能力。该项技术已经通过中试试验,合金的电化学性能、制备工艺技术及设备等均达到了实用化及产业化要求,具有广阔的应用前景。 相似文献
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系统研究了单辊快淬快速凝固处理对低Co贮氢合金MlNi4.0Co0.2Mn0.40Al0.30Cu0.10的相结构和电化学性能的影响.XRD分析表明,铸态和快凝合金均为单相CaCu5型结构,但快凝合金的成分和结构均匀性得到明显改善,并具有较低的吸氢体积膨胀率(△V/V).电化学测试表明,快速凝固处理后合金的活化性能不变,循环稳定性得到显著改善,但其放电容量和高倍率放电性能有所降低.研究发现,快速凝固低Co合金循环稳定性能的改善主要归结于快凝合金具有较低的吸氢体积膨胀率和较好的成分均匀性,而快凝合金电极的电催化活性以及氢在合金中的扩散速率较铸态合金有所减小是导致其高倍率放电性能降低的主要原因. 相似文献
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Koultoukis ED Makridis SS Röntzsch L Pavlidou E Ioannidou A Kikkinides ES Stubos AK 《Journal of nanoscience and nanotechnology》2012,12(6):4688-4696
In this work, TiFe-based alloys have been developed according to the stoichiometry Ti1-xAx Fe1-yBy (A [triple bond] Zr; B [triple bond] Mn, V). The hydrogen solubility properties have been investigated to develop dynamic hydrides of Ti-based alloys for hydrogen storage applications. The hydrogenation behavior of these alloys has been studied, and their hydrogen storage capacities and kinetics have been evaluated. Several activation modes, including activation at high temperatures under hydrogen pressure, have been attempted for the as-milled powders. In order to clarify the structural/microstructural characteristics, and chemical composition before and after hydrogenation, X-Ray Diffraction (XRD), EDAX-Mapping Analysis and Scanning Electron Microscopy (SEM), have been carried out for the samples. Modeling of the isotherms has been performed by using MATLAB programming. The maximum gravimetric density of 4.3 wt%, has been obtained on the sample with the BCC main phase. The calculated enthalpy of reaction (deltaH) is found to be about 4 kJ/mol. 相似文献
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采用固相烧结合成Sn0.4Co0.4Zn0.2合金,再以H2SO4进行酸腐蚀,探索了H2SO4浓度对合金结构和电化学性能的影响。实验结果表明,Sn0.4Co0.4-Zn0.2合金由CoSn、Co3Sn2、CoSn2相和单质Zn组成,H2SO4使合金中部分Zn腐蚀溶解,在颗粒内部形成孔隙,并且使颗粒内部失去粘结而粉化,颗粒细化变小。酸腐蚀改善了Sn0.4Co0.4Zn0.2合金的电化学性能,当H2SO4浓度为0.02mol/L时,合金的首次放电容量为295mAh/g,经过100次循环后的放电容量为234mAh/g,保持了首次放电容量的79.3%,表现出良好的电化学活性。 相似文献
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Martin Søndergaard Mogens Christensen Kasper A. Borup Hao Yin Bo B. Iversen 《Journal of Materials Science》2013,48(5):2002-2008
Compounds of Mg2Si1?x Sn x are environmentally friendly, inexpensive and high-efficiency thermoelectric materials for energy conversion in the temperature range 300–550 °C. In this study, the thermal stability is investigated of fine powders and sintered pellets of the compounds Mg2Si0.4Sn0.6 and Mg2Si0.6Sn0.4 by heating the samples from room temperature to ~400 °C in air, while measuring powder X-ray diffraction patterns. The diffractograms of the pellets show no significant changes upon heating for several hours, while the powder samples show increasing emergence of a Mg2Sn-rich, Mg2Si1?x Sn x phase, and other impurities upon heating for only several minutes. This is attributed to the larger amount of surface area in the powder samples. The appearance of the Mg2Sn-rich phase is most pronounced for the Sn-rich composition. In addition, the thermal expansion coefficients were extracted from the powder diffraction patterns. All materials have been synthesized by induction-melting followed by ball milling and spark plasma sintering. The thermal conductivity, Seebeck coefficient, electrical resistivity and Hall carrier concentrations have been measured from room temperature to 400 °C on the pellets. 相似文献
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V. P. Pashchenko A. N. Ul'yanov A. A. Shemyakov S. I. Khartsev N. I. Mezin Yu. V. Medvedev G. V. Gusakov V. A. Turchenko 《Inorganic Materials》2002,38(3):302-307
The effect of Ba content on the phase composition, lattice parameter, 55Mn NMR spectrum, resistance, and magnetoresistance of La0.6Sr0.4 – x
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MnO3 perovskites was studied. The lattice parameter of the single-phase ceramic samples was found to increase with increasing x. The tolerance factor increases and the ionic field strength decreases asx increases from 0 to 0.4. The 55Mn NMR results obtained at 77 K indicate a high-frequency electron exchange between Mn3+ and Mn4+ in the ferromagnetic phase. The peak-magnetoresistance temperature tends to decrease with increasing x. The magnetoresistance of the ceramics is correlated with the bond covalence. It is inferred that the ceramics contain inhomogeneities differing in nature and length scale (macroscopic, mesoscopic, and microscopic), which influence their magnetoresistance. 相似文献
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