用富镧混合稀土合金(MlNi_(4.5)Al_(0.5))分离氢中氪、氙的研究

在文献〔1〕的基础上,本文简要叙述了 M1Ni_(4.5)Al_(0.5)合金在不同温度下分离氢中氪、氙的情况,当温度为353K 时,分离浓度随放氢量的变化以及 M1Ni_(4.5)Al_(0.5)合金与 TiFe_(0.86)Mn_(0.1)合金分离性能的比较。     

混合稀土金属—镍中加入锰或铝的伪二元合金贮氢特性

本文报导了在混合稀土金属(Mm)及富镧稀土金属(Ml)为吸氢元素的AB_6型贮氢金属中加入Mn、Al元素部分置Ni,组成MmNi_(5-X)M_X(M:Mn、Al;X:0.25、0.5、0.75、1.0)和MlNi_(3-X)M_X(M:Mn、Al;X:0.25、0.5、0.75、1.0)二类伪二元金属化合物的贮氢特性。绘出了二类合金的一系列等温线和动力学曲线。在所试验的范围内(X≤1),合金仍保持六方晶体结构的单相组织。以Mn或Al部分取代Ni极大地改善了MmNi_5的活化特性,并使平台压丸大幅度降低。又以Mn部分置换Ni时吸氢能力降低很小,是个良好的取代元素。作者认为MmNi_(4.5)Mn_(0.5)和MlNi_(4.75)Al_(0.25)MlNi_(4.5)Mn_(0.5)合金的贮氢性能近于LaNi_5而成本低廉,是种很有实用价值的贮氢材料。     

TiFe0.86Mn0.1贮氢合金的抗辐射性能

从60年代科学家们发现某些金属具有吸、放氢的奇异特性以来,对贮氢功能材料的理论及应用研究都有长足进展,应用领域随着理论研究的不断深入而扩大。目前,贮氢功能材料已不仅仅应用于氢气的贮存及纯化,而是更多地着眼于热泵、压缩机、燃料电池、镍氢电池、氮气纯化、氩气纯化、催化剂、氢同位素分离的应用研究上。文献较系统地研究了TiFe_(0.86)Mn_(0.1)合金及M1~*Ni_(4.5)A1(0.5)合金分离氢中Kr、     

表层涂碳MlNi_(3.93)Co_(0.46)Mn_(0.27)Al_(0.34)/Co_3O_4CeO_2复合贮氢合金电极制备及电化学性能

通过分层涂浆制备表层涂碳的MlNi_(3.93)Co_(0.46)Mn_(0.27)Al_(0.34)/Co_3O_4CeO_2电极,并建立表层涂碳的MlNi_(3.93)Co_(0.46)Mn_(0.27)Al_(0.34)/Co_3O_4CeO_2电极反应机理模型。物理表征结果表明,活性碳(AC)具有高比表面积,为二维结构,贮氢合金呈块状固体,为单相的CaCu5型六方结构;电化学测试结果表明,活性碳形成双电层的同时也作为导电剂在MlNi_(3.93)Co_(0.46)Mn_(0.27)Al_(0.34)/Co_3O_4CeO_2电极表面形成导电网络,可改善贮氢合金电极的电化学性能,在0.2C充放电下,放电比容量292.6mAh·g-1,以1500mAh·g-1倍率放电时,高倍率放电性能(HRD值)为82.5%,循环100次后容量保持率95.91%,在50%DOD下,氢扩散系数及交换电流密度依次为4.7×10-11cm2·s-1,315.6mA·g-1,相比于未涂炭的MlNi_(3.93)Co_(0.46)Mn_(0.27)Al_(0.34)/Co_3O_4CeO_2电极,分别提高了2.4mAh·g-1、20.94%、5.53%、38.2%、34.5%。     

微量元素Al对La_(0.75)Ce_(0.25)Fe_(11.51)Mn_(0.24)Si_(1.25)H_y合金磁热效应与制冷能力的影响

采用高频悬浮熔炼炉制备了La_(0.75)Ce_(0.25)Fe_(11.51)Mn_(0.24)Si_(1.25)Al_(0.3)和La_(0.75)Ce_(0.25)Fe_(11.51)Mn_(0.24)Si_(1.25)合金样品。样品在0.05 MPa压力、598 K氢气中吸氢至饱和。经X射线衍射及SEM分析La_(0.75)Ce_(0.25)Fe_(11.51)Mn_(0.24)Si_(1.25)Al_(0.3)H_y样品为NaZn_(13)型结构。研究结果表明,在1.5 T磁场下,La_(0.75)Ce_(0.25)Fe_(11.51)Mn_(0.24)Si_(1.25)Al_(0.3)H_y合金样品的等温磁熵变ΔS_M为9.06 J/(kg·K),直接测量的样品绝热温变为2.53 K,均比不含Al元素的La_(0.75)Ce_(0.25)Fe_(11.51)Mn_(0.24)Si_(1.3)H_y略低;但磁熵变ΔS_M和绝热温变ΔT_(ad)的半峰宽δT均大幅提高;同时,合金制冷能力提高。     

Influence of CO on PCT Properties of LaNi_5, LaNi_(4.7)Al_(0.3) and MlNi_(4.5)Al_(0.5) Alloys

Influence of CO on PCT Properties of LaNi_5, LaNi_(4.7)Al_(0.3) and MlNi_(4.5)Al_(0.5) Alloys     

新技术与成果

球形储氢合金及其制造方法本发明属储氢合金电极材料的制备。球形储氢合金粉:MmNi_(3.8)Co_(0.5)Mn_(0.4)Al_(0.2)Li_(0.1)(Mm为富镧混合稀土合金)、LaNi_(4.2)Sn_(0.1)Al_(0.5)、TiNi、Ti_2Ni、TiNi_(0.9)Al_(0.1)、Ti_3Ni_(1.75)     

Mn,Al元素替代对A_2B_7型La-Y-Ni储氢合金的影响

采用高频感应熔炼法制备了A_2B_7型LaY_2Ni_(10.5-x)(MnAl)_x, LaY_2Ni_(10.5-0.8x)Mn_(0.5x)Al_(0.3x), LaY_2Ni_(10.5-0.6x)Mn_(0.5x)Al_(0.1x)(x=2.0, 1.5, 1.0)储氢合金,在Ar气氛和925℃下对铸态合金进行退火处理,通过X射线衍射(XRD)和电化学测试等分析方法系统研究了Mn, Al部分替代Ni元素对合金相结构和电化学性能的影响。研究结果表明:合金由Ce_2Ni_7相、 Gd_2Co_7相、 LaNi_5相、 PuNi_3相和Ce_5Co_(19)相组成,随着Mn, Al替代量的降低,合金中的Gd_2Co_7相含量减少至消失, Ce_2Ni_7相含量增加,各相晶胞体积减小。电化学P-C-T曲线显示不同吸氢态造成的双平台现象,随着Mn, Al替代量的降低,合金吸放氢坪台压升高,平台区域变宽。电化学性能测试表明,随着Mn, Al替代量的减少,合金的最大放电容量,倍率性能和循环性能明显提高。合金高倍率性能的提升主要与合金中Gd_2Co_7相含量降低和Ce_2Ni_7相的增加有关。     

LaNi_(4.5)Mn_(0.5)合金中分量的快速分析方法

稀土系储氢合金的成分分析,国外多用ICP-AES法。本文结合我国实际,继LaNi_5、LaNi_(4.5)Cu、LaNi_(4.5)Sn(0.5)之后,提出了LaNi_(4.5)Mn_(0.5)合金中分量的分析方法,方法终点锐敏、快速而简便、结果可靠。 镧、镍、锰离子皆可与EDTA生成配合物,其稳定常数分别为15.50,18.60,13.90。此外,镧与氟离子生产溶度积很小的沉淀,锰与三乙醇胺生成稳定的配合物。因此,在pH5～6的试液中加入过量的EDTA,用偶氮胂Ⅲ作指示剂,用Pb~(2+)溶液滴定过量     

Ti-Fe-Mn-V四元合金贮氢性能的研究

本文研究了 TiFe_(～0.15)Mn_YV_X 四元合金的贮氢量,放氢 P-C-T 曲线,并研究了这些性能与组成变化的关系,以及晶胞参数和体系中3d 层电子密度对合金贮氢性能的影响。     

还原扩散法直接制备AB5型多元贮氢合金

采用CaH2作为还原剂,稀土氧化物以及其它金属氧化物为原料,直接通过还原扩散反应成功制得了多元贮氢合金La0.4Ce0.1Nd0.2Pr0.3Ni3.55Co0.75Mn0.4Al0.3。     

CO对MlNi_(4.5)Al_(0.5)合金吸氢动力学特性的影响

研究了氢中含有不同浓度CO杂质对MlNi4 .5Al0 .5的动力学曲线及循环性能的影响。MlNi4 .5Al0 .5被CO毒化后动力学性能退化 ,同一CO浓度下随着循环次数的增加 ,动力学性能退化加剧 ,随着CO浓度增加 ,合金的循环性能降低 ,动力学曲线衰退严重。探讨了被CO毒化合金动力学曲线衰退的原因。     

含Fe低CoAB5型贮氢合金的性能与结构

得到综合电性能良好的低CoAB5型贮氢合金成分。本文对所设计的一系列含Fe低CoAB5型贮氢合金MmNi3．55Co0.75-xMn0.4Al0.3Fex（x=0，0.1，0.2，0.3，0.4，0.5）进行了相关性能与结构测试，同时分析了对低CoMmB5合金结构参数与电性能之间的关系进行详细分析与表征。     

制氧机闲置的氪、氙回收设备的恢复利用

将三套全提取空气分离设备的氪氙系统进行组合,实现互联、互替,从而解决了其中一套氪氙系统设备因缺陷而不能生产的问题。     

Amplification and entailed resolution degradation in high-pressure gas ionography

This work deals with the introduction of a gas electronic gain factor in high-pressure ionography (or "electron radiography"). The purpose is to check the possibility of a further reduction of radiation dose per radiograph. It is shown tha xenon or krypton can be mixed with special molecular gases in order to achieve charge-carrier multiplication at comparatively weak electrostatic fields and in an easily controllable manner. Some radiographs are reproduced which have been obtained in the amplifying working modes of the system. Relevant image characteristics and their limits are discussed. The obtainable resolution is limited by electron diffusion and by quantum noise (lowering of the effective quantum-detection efficiency).     

粉末冶金NiFe_(19)Al_(25)合金的组织与性能研究

用粉末冶金技术制备Ni-Fe-Al合金,将Ni、Fe、Al的元素粉与预合金粉等量混合后在500MPa下压制成形,于1280℃的温度烧结后进行热处理,对合金烧结态和淬火态进行密度、力学性能检测及X射线衍射分析、断口形貌及微观组织观察。结果表明:NiFe19Al25合金烧结态为(β+γ)双相组织,合金的密度达6.54g/cm3(相对密度为94.0%),抗拉强度达到771MPa,形变量为5.3%;合金淬火态处于(β′+γ)双相区,具有马氏体结构的NiFe19Al25合金在应力作用下呈现出线性超弹性,抗拉强度达到761MPa,形变量高达8.1%,最高形变恢复量超过4%。     

Magnetocaloric effect and magnetic properties of La_（0.9）Ce_（0.1）（Fe_（0.99）Mn_（0.01））_（11.6）Si_（1.4）H_（1.6） compound

Magnetocaloric effect and magnetic properties of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 and its hydride La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 were investigated. The Curie temperature of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was increased by hydrogen absorption. XRD patterns showed that the structure of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 remained NaZn13-type. The Curie temperature (TC) of the sample was increased from 174 K to 331 K. The homogeneity of the hydrogen absorption for La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 was proven very well by the random measurement of DSC. The magnetic entropy △SM of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 had peak at 326 K. The peak value of-△SM-was 12.3 and 7.8 J/(kg.K) under magnetic field change of 0-2 T and 0-1 T,respectively,which was comparable with Gd5Si2Ge2. The negative slope and inflection point of the Arrott curve indicated that the first-order magnetic transition of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was reserved after hydrogen absorption.     

Enhancing mechanical properties and air permeability of corundum porous materials by in situ formation of LaAl_(11)O_(18) in bonding phase

Corundum porous materials of particle-packing type with different contents of in situ formed LaAl_(11)O_(18)were prepared using tabular corundum,reactive alumina and La_2O_3 powder as raw materials.The effects of the introduction of LaAl_(11)O_(18) on the microstructure.phase composition and properties of the porous materials were investigated.The specimens were characterized by scanning electron microscopy.X-ray diffraction and mercury porosimetry.Results show that platelet-like LaAl_(11)O_(18) is formed in situ by the reactions of La_2O_3 and Al_2O_3.With a certain amount of La_2O_3 added.the cold crushing strength,cold modulus of rupture and hot modulus of rupture(1400 x 0.5 h) of the specimens are increased,and the air permeability is improved simultaneously.However.upon further increasing the amount of La_2O_3 added,the mechanical properties and air permeability of the porous materials then decrease gradually owing to the increased numbers of pores and cracks in the bonding phase.The enhanced mechanical properties of the specimens with La_2O_3 added are attributed to the strengthening effects of plate-like LaAl_(11)O_(18) in the bonding phase and to the activated sintering of both Al_2O_3 powder and corundum coarse aggregate for the diffusion of La~(3+)in Al_2O_3 lattice.In addition,the improved air permeability of the specimens should be related to the decreased content of pores in the bonding phase and the reduced number of interfacial cracks.     

LaNi4.7Al0.3储氢合金氧化前后吸放氢性能研究

研究了LaNi4.7Al0.3贮氢合金被微量氧气毒化前后贮氢性能的变化，测定了合金的贮氢量，吸氢动力学曲线.并采用扫描俄歇电子能谱(AES)原位研究了LaNi4.7Al0.3储氢合金中毒前后化学成分变化，结果表明：氧含量较低时，不会影响合金的初始吸氢速率，但会降低合金的贮氢容量；随着O2的剂量的逐渐增大，合金的吸氢速率变慢，合金的储氢容量大大降低。原位分析氧毒化LaNi4.7Al0.3贮氧合金表明，O2在清洁LaNi4.7Al0.3表面吸附离解后，优先与表面镧原子结合生成La的氧化物，再与部分表面镍原子结合生成Ni的氧化物氧化过程中La向表面富集，同时有金属态的Ni析出.