Al对MLNi3.85—xMn0.4Co0.75Alx合金贮氢特性的影响

采用富Ｌａ混合稀土金属（ＭＬ）对ＭＬＮｉｃ３．８５－ｘＭｎ０．４Ｃｏ０．７５Ａｌｘ（ｘ＝０．１～０．５）五元贮氢合金吸放氢性能进行了测试，并计算出其热力学参数，结果发现Ａｌ含量增加，贮氢量下降，添加Ａｌ分解压降低，有利贮氢。     

Al对MLNi_（3．85－x）Mn_（0．4）Co_（0．75）Al_x合金贮

采用富Ｌａ混合稀土金属（ＭＬ）对ＭＬＮｉ（３．８５－ｘ）Ｍｎ（０．４）Ｃｏ（０．７５）Ａｌｘ（ｘ＝０．１～０．５）五元贮氢合金吸放氢性能进行了测试，并计算出其热力学参数。结果发现Ａｌ含量增加，贮氢量下降，添加Ａｌ分解压降低，有利贮氢。     

LaNi_（5－x）Al_x贮氢合金的研究

用Ａｌ置换ＬａＮｉ５贮氢合金中部分Ｎｉ，得到一系列ＬａＮｉ（５－ｘ）Ａｌｘ（ｘ＝０．１，０．３，０．５）贮氢合金．通过对合金的热力学性能的测试可知：随着Ａｌ的加入及其含量的增加，贮氢合金的平台氢压降低，吸氢量有所减少，而吸氢速度有所增加．通过对合金及吸氢后氢化物品体结构的Ｘ射线衍射分析，发现Ａｌ的加入并未使晶体结构类型发生变化，只是晶格常数略有增加；同时还证明了ＬａＮｉ（５－ｘ）Ａｌｘ合金吸氢后其晶体结构也未发生变化，但晶格常数增加较大．     

镧镍铜锰吸氢合金的制备与表面性质

用共沉淀还原扩散法制备了新的镧系吸氢合金ＬａＮｉ４Ｃｎ０．５Ｍｎ０．５，借助ＸＰＳ技术研究合金的表面偏析等性质，确定了合金表面的化学组成，讨论了合金在空气中暴露程度对表面性质的影响以及表面性质对合金吸氢性能的影响，并结合吸氢测试研究了合金的活化，提出了ＬａＮｉ４Ｃｕ０．５Ｍｎ０．５的活化机制。     

贮氢合金热力学测试装置及测试方法的研究

通过对贮氢合金热力学主要研究内容的分析，研究了贮氢合金热力学的ｐ－Ｃ－Ｔ曲线的测定和计算方法，并通过对ＬａＮｉ＿５合金的性能测试，证明了该合金具有良好的活化性能和吸氢性能，在３０℃常温下吸氢平衡压仅为０．２８ＭＰａ，吸氢量（Ｈ／Ｍ）可达１，吸放氢反应热焓达３１．９ＫＪ／ｍｏｌ。     

LaNi5-xMx高温氢化时的歧化行为研究

借助Ｘ射线衍射、差热分析及电化学方法,研究了吸氢合金ＬａＮｉ５－ ｘＭｘ 在高温氢化反应时的歧化行为及其反应产物的电化学性能．结果表明,ＬａＮｉ５－ ｘＭｘ 在２．５ＭＰａ 氢压和大于５５０ ℃保温一定时间后可发生明显歧化反应,并析出纳米相Ｎｉ．歧化反应的程度与加热温度、时间、第三组元Ｍ 及合金的生成焓关系密切．电化学交换电流密度测定表明,经歧化反应得到的含纳米相Ｎｉ的复相组织与原始合金组织相比具有较高的吸放氢电催化活性     

SmNi5—xCux吸氢性能研究

研究了用Ｃｕ逐步取代ＳｍＮｉ５中的Ｎｉ原子所得的系列ＳｍＮｉ５－ｘＣｕｘ物质的吸氢性能。经测定ＳｍＮｉ５和ＳｍＣｕ５饱和吸氢量很小，分别为０．４Ｈ／ｍｏｌ和０．２５Ｈ／ｍｏｌ，但当Ｃｕ取代ＳｍＮｉ５中部分Ｎｉ时，饱和吸氢量明显增加，其中ＳｍＮｉ４Ｃｕ的饱和吸氢量最大，在０℃时可达３．５Ｈ／ｍｏｌ。ｘ－射线衍射分析结果表明ＳｍＮｉ５－ｘＣｕｘ均属六方晶系，ＣａＣｕ５型结构。     

Zr-Hf-Co合金储氢性能研究

研究了Hf部分替代Zr对Zr-Hf-Co合金储放氢性能的影响,结果表明:Zr-Hf-Co合金保持原始Zr-Co合金单一的立方相结构,且Hf含量变化对合金晶胞体积影响不大;随Hf替代量增加,Zr-Hf-Co合金的放氢平台压升高,100 kPa平衡放氢压力对应的放氢温度显著降低,由Zr-Co合金的673 K降低到Zr0.7Hf0.3Co合金的618 K;热力学计算结果得到Zr-Hf-Co合金的放氢反应焓变ΔH随Hf替代量增加而降低,表明Zr-Hf-Co合金氢化物的稳定性降低,有利于合金在较低温度下放氢;合金的最大吸氢量随Hf替代量增加而略有降低,但吸氢动力学性能变化不明显.     

LaNi_(2.5)Co_(0.5)储氢合金在充放电循环过程中的电化学性能研究

以感应熔炼法制备的LaNi_(2.5)Co_(0.5)合金为研究对象,对该合金及其氢化物的相结构进行了分析,并对合金电极的放电容量保持率、高倍率放电性能、氢扩散系数及极化电流密度等电化学性能进行了研究.结果表明:吸氢后的合金会产生明显的非晶化现象,造成合金吸放氢能力和氢化物稳定性下降.随着循环次数的增加,合金的放电容量和高倍率放电性能均表现出先快速下降到逐渐缓慢降低的趋势,而合金的氢扩散系数和极化电流密度却呈现出不同的变化趋势.高倍率放电性能的下降主要与合金表面反应活性相关,说明表面劣化现象是造成合金电化学性能衰退的主要因素.     

FexMn1-x合金电子结构及其磁性的理论研究

采用第一性的线性缀加平面波（ＬＡＰＷ）的理论计算方法，对ＦｅｘＭｎ１－ｘ合金体系的电子结构与磁性进行了理论研究，并与实验进行了比较，结果表明，ｂｃｃ Ｆｃ０．７５Ｍｎ０．２５剑金为铁磁性，而ｆｃｃ结构的Ｆｅ０．５Ｍｎ０．５和Ｆｅ０．２５Ｍｎ０．７５合金为反铁磁性，而且在铁磁性区域，理论计算磁矩的大小与实验值符合得很好。     

The formation and stability of Si1-x C x alloys in Si implanted with carbon ions

Si_1-xC_x alloys of carbon (C) concentration between 0.6%—1.0% were grown in Si by ion implantation and high temperature annealing. The formation of Si_1-xC_x alloys under different ion doses and their stability during annealing were studied. If the implanted dose was less than that for amorphizing Si crystals, the implanted C atoms would like to combine with defects produced during implantation and it was difficult to form Si_1-xC_x alloys after being annealed at 850℃. With the increment of implanted C ion doses, the lattice damage increased and it was easier to form Si_1-xC_x alloys. But the lattice strain would become saturate and only part of implanted carbon atoms would occupy the substitutional positions to form Si_1-xC_x alloys as the implanted carbon dose increased to a certain degree. Once Si_1-xC_x alloys were formed, they were stable at 950℃, but part of their strain would release as the annealing temperature increased to 1 000℃. Stability of the alloys became worse with the increment of carbon concentration in the alloys.     

Zr对Al-Ni-Y-(Zr,Cu)合金系非晶形成能力及热稳定性的影响

通过Zr部分取代Al80Ni10YsCu5中的Y,获得了Al80Ni10Y5-xZrxCus（x=0、1、2、3、4）铝基非晶合金．用XRD和DSC等测试手段1分析了单辊旋淬法制备的该合金非晶条带,研究了Zr对合金体系非晶形成能力和热稳定性的影响．结果表明,x=2或x=3的合金的衍射峰较为宽化;当x从0增加到2时,合金的晶化温度增加,此后,随x的进一步增加,合金的晶化温度先降低后又有所回升．Al80Ni10Y3Zr2Cu5合金既具有相对较好的非晶形成能力,又具有较高的热稳定性．     

Formation and properties of high Fe-content Fe-(B-Si)-Zr bulk amorphous alloys

The present work is devoted to the development of Fe-(B-Si)-Zr amorphous alloys with high glass-forming ability and good magnetic properties. Using the cluster-plus-glue-atom model proposed for ideal amorphous structures, [FeFe₁₁B₃Si](Fe_1?xZr_x) was determined as the cluster formula of Fe-(B-Si)-Zr alloys. The glass formation and thermal stability of the serial alloys, namely, [FeFe₁₁B₃Si](Fe_1?xZr_x) (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.75, and 1.0), were studied by the combination of copper mold casting, X-ray diffraction, and differential thermal analysis techniques. The maxima of glass-forming ability and thermal stability were found to occur at the compositions of [FeFe₁₁B₃Si](Fe_0.6Zr_0.4) and [FeFe₁₁B₃Si](Fe_0.5Zr_0.5). The alloys can be cast into amorphous rods with 1.5 mm diameter, and upon reheating, the amorphous alloys exhibit a large undercooled liquid span of 37 K. The saturation magnetization of the [FeFe₁₁B₃Si](Fe_0.5Zr_0.5) amorphous alloy was measured to be 1.4 T.     

Effect of stoichiometry and Cu-substitution on the phase structure and hydrogen storage properties of Ml-Mg-Ni-based alloys

To improve the electrochemical properties of rare-earth-Mg-Ni-based hydrogen storage alloys, the effects of stoichiometry and Cu-substitution on the phase structure and thermodynamic properties of the alloys were studied. Nonsubstituted Ml_0.80Mg_0.20(Ni_2.90Co_0.50-Mn_0.30Al_0.30)_x (x=0.68, 0.70, 0.72, 0.74, 0.76) alloys and Cu-substituted Ml_0.80Mg_0.20(Ni_2.90Co_0.50-y Cu_y Mn_0.30Al_0.30)_0.70 (y=0, 0.10, 0.30, 0.50) alloys were prepared by induction melting. Phase structure analysis shows that the nonsubstituted alloys consist of a LaNi₅ phase, a LaNi₃ phase, and a minor La₂Ni₇ phase; in addition, in the case of Cu-substitution, the Nd₂Ni₇ phase appears and the LaNi₃ phase vanishes. Thermodynamic tests show that the enthalpy change in the dehydriding process decreases, indicating that hydride stability decreases with increasing stoichiometry and increasing Cu content. The maximum discharge capacity, kinetic properties, and cycling stability of the alloy electrodes all increase and then decrease with increasing stoichiometry or increasing Cu content. Furthermore, Cu substitution for Co ameliorates the discharge capacity, kinetics, and cycling stability of the alloy electrodes.     

Hydrogen storage performance of LaNi3.95Al0.75Co0.3 alloy with different preparation methods

Rare-earth AB₅-type La–Ni–Al hydrogen storage alloys are widely studied due to their extensive application potentials in hydrogen isotope storage, hydrogen isotope isolation and hydrogen compressors, etc. Good hydriding/dehydriding kinetics, easily activation, high reversibility are important factors for their practical application. However, their overall hydrogen storage performance, especially plateau pressure and hydrogen absorption/desorption durability need to be further optimized. In this study, the microstructures and the hydrogen storage properties of as-cast, annealed, and melt-spun LaNi_3.95Al_0.75Co_0.3 alloys were investigated. The experimental results of XRD and SEM showed that all alloys contained a pure CaCu₅ type hexagonal structure LaNi₄Al phase. The cell volume increased in an order of annealed ?> ?melt-spun ?> ?as-cast, resulting in a lower hydrogen absorption/desorption plateau pressure and a more stable hydride phase. The hydrogen storage capacity of three alloys was almost the same. The slope factor of the annealed and melt-spun alloys is smaller than the as-cast alloy, indicating that heat-treatment process can make the alloys more uniform. For the cycle stability of the alloys, the hydrogen absorption rate of the annealed alloy and melt-spun alloy was much faster than that of the as-cast alloy after 500 cycles. The melt-spun alloy showed high pulverization resistance during hydrogen absorption/desorption, and exhibited an excellent cycling retention of 99% after 500 cycles, suggesting that melt-spinning process can enhance the cycle stability and improve the cycle life of the alloy.     

MgxZn1－xSe合金的电子结构、光学性质和稳定性的第一性原理研究

基于密度泛函理论的第一性原理计算,研究了闪锌矿MgxZn1－xSe合金的稳定性、电子结构和光学性质.研究结果表明,闪锌矿ZnSe和MgxZn1－xSe合金都为直接带隙半导体,MgxZn1－xSe合金的带隙宽度Eg和形成能Eb分别可以由Eg＝1.30＋1.34x和Eb＝－1.48＋0.60x－0.27x2进行估计.同时,MgxZn1－xSe合金的价带顶主要取决于Se 4p 和 Zn 3p态电子的相互作用,而其导带底则主要由Zn 4s、Zn 3p 以及Se 4s态电子共同决定.此外,随着镁掺杂系数x的逐渐增大,MgxZn1－xSe合金的静态介电常数逐渐减小,而其吸收谱则出现明显的蓝移现象.研究结果为MgxZn1－xSe合金在光电探测器方面的应用提供了重要的理论指导.     

TiAl-Nb合金相平衡转变及显微组织结构研究

采用定性定量衍射检测和金相检测法分析了Ti-Al和Ti-Al-Nb合金中的物相组成和显微组织结构特征,研究Nb元素的添加对Ti-Al-Nb合金物相组成、晶粒尺寸和分布等特征的作用和影响。结果表明,Nb元素能够促进合金结构中β相和α₂相的稳定性,抑制α相的生成和γ相的析出,扩展了α₂+γ两相区并使得γ相区右移。另外,Nb元素的添加在特定的成分范围内细化了合金的晶粒。     

Dy对Nd_(60)Fe_(30)Al_(10)磁性能的影响

通过X射线衍射仪、差热扫描量热仪和振动样品磁强计研究Dy对Nd-Fe-Al非晶合金的热稳定性及磁性能的影响.结果表明,加入Dy可提高非晶合金的热稳定性,(Nd1-xDyx)60Fe30Al10(x=0,0.1,0.2)非晶合金的剩磁随Dy质量分数的增加呈单调下降趋势,矫顽力随Dy质量分数的增加而增加.Nd-Fe-Al非晶合金的矫顽力来源于稀土元素较大的磁晶各向异性场.     

Dy对Nd60Fe30Al10磁性能的影响

通过X射线衍射仪、 差热扫描量热仪和振动样品磁强计研究Dy对Nd-Fe-Al非晶合金的热稳定性及磁性能的影响. 结果表明, 加入Dy可提高非晶合金的热稳定性, (Nd_1-xDy_x)₆₀Fe₃₀Al₁₀（x=0,0.1,0.2）非晶合金的剩磁随Dy质量分数的增加呈单调下降趋势, 矫顽力随Dy质量分数的增加而增加. Nd\|Fe\|Al非晶合金的矫顽力来源于稀土元素较大的磁晶各向异性场.      

AB3型储氢合金复合电极材料制备及电化学性能

以La_2Mg_(17)作为中间合金采用熔炼法成功制备了AB_3型合金La_(0．7)Mg_(0．3)Ni_(2．875)Co_(0．525)Mn_(0．1),与球磨法制得的NiB进行不同比例的复合．对合金复合前后的电化学容量、循环寿命、高倍率放电以及电化学交流阻抗(EIS)进行了测试,结果表明储氢材料经NiB复合后,合金电极循环稳定性明显提高,但是其最高放电容量有所降低；高倍率放电能力增强,抗腐蚀性能增强．