Y.J. Zhang
,
X.H. Li
,
S. Wang
,
K.Y. He
金属学报(英文版)
At different annealing temperatures, the saturation magnetostrictions and the correlation between the permeability μi and the temperature T(μi-T curves) of the Co66Fe4Mo2Si16B12 alloy were investigated using a small-angle magnetization tester and core tester. The experimental results showed that the μi-T curves had different shapes at different ranges of annealing temperature; the permeability μi of the alloy improved with increasing the annealing temperatures below 460℃; when the alloy was annealed above 480℃, the poor magnetic properties were considered to be caused by larger saturation magnetostriction.
关键词:
Co66Fe4Mo2Si16B12 alloy
,
null
,
null
Journal of Materials Research
The effect of Li(3)N additive on the Li-Mg-N-H system was examined with respect to the reversible dehydrogenation performance. Screening Study with varying Li(3)N additions (5, 10, 20, and 30 mol%) demonstrates that all are effective for improving the hydrogen desorption capacity. Optimally, incorporation of 10 mol% Li(3)N improves the practical capacity from 3.9 wt% to approximately 4.7 wt% hydrogen at 200 degrees C, which drives the dehydrogenation reaction toward completion. Moreover, the capacity enhancement persists well over 10 de-/rehydrogenation cycles. Systematic x-ray diffraction examinations indicate that Li(3)N additive transforms into LiNH(2) and LiH phases and remains during hydrogen cycling. Combined structure/property investigations suggest that the LiNH(2) "seeding" should be responsible for the capacity enhancement, which reduces the kinetic barrier associated with the nucleation of intermediate LiNH(2). In addition, the concurrent incorporation of LiH is effective for mitigating the ammonia release.
关键词:
complex hydrides;improvement;mixtures;imides;amide;h-2
陈瑞福
,
王文继
无机材料学报
Li1+2x+yAlxNdyTi2-x-ySixP3-xO12 锂快离子导体（以下简称Al-Nd-Lisicon）可以用精选的天然高岭石Al4[Si4O10]（OH）8为起始原料，经与Li2CO3、TiO2、NH4H2PO4进行高温（800～1000℃）固相反应约20h而制得.一个空间群属于R3c的固溶体导电相可在y=0．5，x≤0.3和y=1.0，x≤0．4的组成范围内发现.该相具有较好的电导性和较低的活化能．起始组成y=1．0,x=0．3的合成物具有最高的电导率，在400℃时；其电导率达到3．08×10-2S／cm，离子导电激活能为35．2kJ／mol.
关键词:
矿物快离子导体
,
null
,
null
Journal of Physical Chemistry C
The Li-Mg-N-H system was prepared by reacting magnesium amide [Mg(NH(2))(2)] with lithium nitride (Li(3)N) and investigated with regard to the hydrogen storage properties. Our study shows that the present method is superior to the conventional route in enhancing the reversible dehydrogenation properties. Through optimizing the Li(3)N:Mg(NH(2))(2) ratio in the starting materials, the reversible capacity of U-Mg-N-H system increases to 4.9 wt %, 18% higher than that typically obtained from the Mg(NH(2))(2) + 2LiH mixture at 200 degrees C. Furthermore, increasing the Li(3)N:Mg(NH(2))(2) ratio is effective for mitigating the ammonia release from thus-prepared samples. Combined property/structure investigations indicate that the obtained enhancements should be ascribed to the effects of LiNH(2) and LiH that were in situ generated from the excess Li(3)N. LiNH(2) may promote the dehydrogenation reaction via seeding the reaction intermediate. The concurrently generated LiH acts as an effective ammonia trapping agent. These findings highlight the potential of "intermediate seeding" as a strategy to enhance the reversible hydrogen storage properties of metal-N-H systems.
关键词:
complex hydrides;ultrafast reaction;amide;improvement;desorption;linh2;destabilization;mechanism;mixtures;imides
裴增文
,
刘晓鹏
,
黄倬
,
李志念
,
王树茂
,
蒋利军
稀有金属
doi:10.3969/j.issn.0258-7076.2010.04.013
采用等容法研究了机械球磨工艺制备的Li-Mg-N-H材料储氧性能,结果发现,在室温下采用氦气对样品室体积进行标定时,由于Li-Mg-N-H材料对氦气有一定量的物理吸附,造成准确Li-Mg-N-H材料样品体积标定误差,进而造成Li-Mg-N-H储氢材料在503 K下放氢容量随压力的降低而增加异常变化.为准确标定样品体积,通过对Li-Mg-N-H材料室温氮气吸附容量测定,并采用迭代计算方法获得准确的储氢材料样品体积,进而测定Li-Mg-N-H储氢材料503 K下放氢PCT曲线,其表现为放氢容量随压力降低而减小的正常变化规律.Li-Mg-N-H储氢材料503 K,9.6 MPa氢压下的最大储氢容量为4.81%(质量分数),放氢过程表现为单一放氢平台特性.
关键词:
轻质储氢材料
,
Li-Mg-N-H
,
储氢性能
,
等容测试方法
许天才
,
彭晓东
,
张玺
,
陈元芳
,
姜军伟
,
陈洁
功能材料
doi:10.3969/j.issn.1001-9731.2014.07.013
利用光学显微镜(OM)、扫描电子显微镜(SEM)、X 射线衍射仪(XRD)分析了 Li 元素对 Mg-x Li-3Al 合金组织的影响,并用电子万能试验机测试合金的拉伸性能.结果表明,Li 含量的变化可以明显改变合金的相组成.当 m (Li)＜5．7％(质量分数)时合金由单一α-Mg 相组成；Li 含量在5．7％~10．3％(质量分数)之间时,合金为α-Mg＋β-Li 双相；m (Li)＞10．3％(质量分数)时合金为单一β-Li 相.合金的塑性随 Li 含量的升高而增加,铸态 LA113合金的延伸率高达37．36％,但挤压态下合金强度随 Li 含量升高而降低,挤压态 LA53合金具有最佳抗拉强度,达到263．28 MPa.当 Li 含量升高,合金中的第二相粒子会出现 Al12 Mg17转变为 LiMgAl2.
关键词:
镁锂合金
,
铸态
,
挤压态
,
微观组织
,
拉伸性能
Journal of Alloys and Compounds
Motivated by the ion migration mechanism proposed by David et al. [J. Am. Chem. Soc. 129 (2007) 1594-1601], we mechanically mill the Li3N/Co powder mixture to obtain defective Li3N-type structure with enhanced Li+ mobility. Compared with Li3N the hydrogen storage property of such defective phase is markedly improved, presumably due to the ion-migration-enhancing effect from the incorporation of Co and Fe (from milling utensils). During subsequent cycling, however, this effect cannot persist due to the precipitation of Co-Fe alloy upon hydrogenation. The close correlation between Co-Fe incorporation/precipitation and property variation of Li3N hydrogen storage material provides a preliminary evidence to support the ion migration mechanism. (C) 2007 Elsevier B.V. All rights reserved.
关键词:
Hydrogen absorbing materials;Nitride materials;hydrogen-storage;lithium amide;mechanism;nitride;batteries;mixtures;hydride;imides;linh2;anode
Energy & Environmental Science
The Li-Mg-B-H system that is prepared from 2LiH + MgB(2) or 2LiBH(4) + MgH(2) possesses high hydrogen capacity and relatively favorable thermodynamics, but it is greatly restricted in practical hydrogen storage applications by problematic H-exchange kinetics. In the present study, TiF(3) was mechanically milled with a 2LiH + MgB(2) mixture and examined with respect to its effect on reversible dehydrogenation of the Li-Mg-B-H system. Experimental study showed that TiF(3) is highly effective for promoting the two-step dehydrogenation reaction in the Li-Mg-B-H system. Compared to the neat 2LiH + MgB(2) sample, the 2LiH + MgB(2) + 0.01TiF(3) sample exhibits significantly reduced dehydrogenation temperature and markedly enhanced dehydriding rate at both steps. Furthermore, the catalytic enhancement arising upon adding TiF(3) additive was observed to persist well in the hydrogenation/dehydrogenation cycles. Based on the results of phase analysis and a series of designed experiments, the mechanism underlying the observed property improvement is discussed.
关键词:
complex hydrides;libh4;tif3;kinetics;naalh4
米菁
,
郝雷
,
刘晓鹏
,
杜淼
,
蒋利军
,
王树茂
金属功能材料
doi:10.13228/j.boyuan.issn1005-8192.2015053
基于对Li-Mg N-H体系放氢动力学机理的研究发现,其放氢过程的速率控制步骤是Li+、H+或H-的扩散.在实验中,原位析出的Li3Bi相增加了Li-Mg-N-H体系放氢过程中Li+离子的扩散速率,进而使得该体系在200℃下放氢量(质量分数)从4.37％增加到4.55％,达到90％放氢量的放氢时间从298 min缩短到11 min.
关键词:
储氢材料
,
Li-Mg-N-H Li3Bi
,
放氢
袁志山
,
陆政
,
谢优华
,
戴圣龙
,
刘常升
稀有金属材料与工程
采用拉伸试验、扫描电镜和透射电镜等测试手段,研究了固溶淬火后预变形程度对新型高强Al-Cu-Li-X铝锂合金2A97组织和性能的影响.结果表明:随预变形量增加,135℃时效48 h合金强度明显提高,塑性缓慢下降,变形量为4.7%合金的抗拉强度为584 MPa,延伸率为12.6%,淬火后的预变形量控制在4%～6%得到比较理想的强塑性匹配.预变形促进基体T1相析出,并使其显著细化和均匀分布.
关键词:
机械热处理
,
铝锂合金
,
预变形
,
2A97
,
Al-Cu-Li-X
