球磨对Mg22Y2Ni10Cu2+50％Ni复合材料电化学性能的影响

将通过真空冶炼获得的Mg22Y2Ni10Cu2合金与其自身质量分数50％的Ni粉混合后,分别进行了10,20,30和40 h的球磨.之后,研究了球磨时间对复合材料的结构和电化学储氢性能的影响.结果表明:经过10 h球磨后,材料Mg2 Ni,Mg,YMgNi4相,以及添加的单质Ni构成;随着球磨时间的延长,XRD的衍射峰明显减弱,复合材料的晶粒明显细化,甚至形成了纳米晶以及非晶组织.电化学性能测试结果表明:随着球磨时间的延长,材料的放电比容量逐渐增加,球磨40 h时材料最大放电比容量达到了423.2 mAh/g,同时球磨能够明显改善合金的动力学性能,球磨40 h的合金具有较好的高倍率放电性能、较小的电极电荷转移阻力和较大的极限电流密度.但球磨过程弱化了合金的循环稳定性.     

富镁Mg70(Ni3RE)30非晶合金的玻璃形成能力研究

玻璃形成能力(GFA)是判断合金非晶态结构形成的重要指标.利用甩带快冷技术制备了Mg70(Ni3RE)30(RE=La、Ce、Pr、Nd、Y)非晶合金条带(宽5mm,厚0.2mm),通过差示扫描量热技术(DSC)表征了合金条带的非晶结构转变及其热稳定性.从原子尺度,对合金的原子尺寸参数(δ)、电负性差(Δx)以及原子结构参数(λ)进行了计算和分析.实验数据和理论分析结果表明:RE=Pr时,相应合金的玻璃形成能力最大,RE=Y的最小,其大小次序为:Mg70(Ni3Pr)30> Mg70(Ni3la)30> Mg70(Ni3Ce)30> Mg70(Ni3Nd)30>Mg70(Ni3Y)30,影响Mg70(Ni3RE)30非晶合金玻璃形成能力的主要因素是电负性差,原子尺寸参数和原子结构参数的作用次之.     

机械合金化制备Fe40Ni40Si5C15非晶合金

采用机械合金化方法制备了Fe-Ni-Si-C系的非晶态合金粉末,在球磨过程中对合金粉末进行取样,用XRD和DTA对不同球磨时间的Fe40Ni40Si5C15混合粉末进行了分析,发现合金粉末在球磨40 h开始部分非晶化,随球磨时间的增大晶粒尺寸减小。研究结果表明:在Fe-Ni-Si合金中加入C,可促进其形成非晶。通过机械合金化法,通过控制合理的球磨时间,在球磨70 h成功获得了Fe40Ni40Si5C15非晶粉末。     

机械合金化制备Mg-Cu非晶合金粉末的机理研究

采用XRD和TEM研究了MgCu2和Mg58Cu42混合粉末在机械合金化过程中的结构变化。结果表明:Mg、Cu粉末在机械合金化过程中是互溶的,机械合金化可以大大提高它们之间的固溶度;球磨过程中,Mg原子逐步溶入Cu基体中,形成Mg在Cu中的过饱和固溶体;固溶体的变形能量积聚到很大时,发生固溶体晶体结构的失稳,最后形成非晶态合金。在相同的球料比的条件下,提高球磨转速,可以大大促进非晶化的形成过程,缩短非晶形成的时间。     

微量Ni对MgNi合金组织与性能的影响

在铸态情况下,研究了添加微量Ni对MgNi合金的微观组织、力学性能、硬度及断裂方式的影响.结果表明,纯Mg的组织主要为α相,MgNi系列合金MgNi0.28,MgNi0.99,MgNi1.54合金除了α固溶体外,还存在γ相和Ni相.纯Mg的晶粒粗大,加入Ni后,晶粒得到细化,大小趋向均匀.当添加少量Ni时,合金的抗拉强度显著增加;但当Ni含量超过0.28%时,抗拉强度增加不明显.随Ni含量的增加,MgNi合金的延伸率、硬度先增大后减小;MgNi合金的断裂方式由解理断裂向沿晶断裂方向发展.     

机械激活和固相反应合成Mg2Ni合金

通过机械合金化机械激活和固相反应制备了Mg2Ni合金，用XRD和EDS对合金进行了分析，实验研究表明：混合粉经机械研磨激活和适当增加固相烧结反应的温度，这样可有效增加固态扩散反应能力，有利于固相反应进行，使形成Mg2Ni的量明显提高，实验结果发现，成分配比、烧结反应温度及时间均影响最终Mg2Ni的纯度，其中反应温度是影响固相反应Mg2Ni形成的重要因素，当Mg增量取0.5%，烧结温度为700℃，保温时间6h时可得到组织单一和纯度较高的Mg2Ni合金相。     

富镁Mg_（70）（Ni_3RE）_（30）非晶合金的玻璃形成能力研究

玻璃形成能力（GFA）是判断合金非晶态结构形成的重要指标。利用甩带快冷技术制备了Mg70（Ni3RE）30（RE=La、Ce、Pr、Nd、Y）非晶合金条带（宽5 mm,厚0.2 mm）,通过差示扫描量热技术（DSC）表征了合金条带的非晶结构转变及其热稳定性。从原子尺度,对合金的原子尺寸参数（δ）、电负性差（Δx）以及原子结构参数（λ）进行了计算和分析。实验数据和理论分析结果表明：RE=Pr时,相应合金的玻璃形成能力最大,RE=Y的最小,其大小次序为：Mg70（Ni3Pr）30〉Mg70（Ni3la）30〉Mg70（Ni3Ce）30〉Mg70（Ni3Nd）30〉Mg70（Ni3Y）30,影响Mg70（Ni3RE）30非晶合金玻璃形成能力的主要因素是电负性差,原子尺寸参数和原子结构参数的作用次之。     

机械合金化法制备Ti-Zr-Ni-Cu储氢合金

使用行星式球磨机,用机械合金化法制备了Ti60Zr15Ni15Cu10储氢合金.采用X射线衍射仪XRD、示差扫描量热计DSC分析了球磨粉末的物相、晶粒尺寸的变化;采用扫描电子显微镜SEM、能谱EDS分析了机械合金化过程中粉末的形貌和成分;并对球磨粉末进行了P-C-T曲线测量.研究结果表明,粉末晶粒尺寸随球磨时间增加不断减小.球磨120 h粉末含有大量非晶相.粉末颗粒中有明显的冷焊合层状结构.随球磨时间增加,层状结构的层厚不断减小,颗粒中的元素分布趋于均匀,合金化过程中的冷焊合和断裂作用逐渐趋于平衡.合金的最大吸氢量物质的量为1.63%,纳米结构粉末的吸氢量高于非晶结构粉末.     

Mg70(A0.25Ni0.75)30合金结构及储氢性能

为研究稀土元素Ce、Y对非晶储氢合金催化及其性能的影响,采用快淬法制备Mg70(A0.25Ni0.75)30(A=Ce,Y)合金,使用Sievert’s气体吸附技术和差示热扫描技术研究其储氢性能和热力学稳定性。XRD衍射分析显示,快淬制备的合金为非晶合金,但在573K、2MPa的氢压下,氢化后的Mg70(Y0.25Ni0.75)30会产生MgH2、Mg2NiH4和2相,Mg70(Ce0.25Ni0.75)30会产生Mg2NiH4、CeNi5和MgH2相。不同温度的动力学测试结果表明,快淬法制备的Mg70-(Ce0.25Ni0.75)30和Mg70(Y0.25Ni0.75)30合金分别获得的最大吸氢量为质量分数4.42%和3.09%,Mg70(Ce0.25Ni0.75)30和Mg70(Y0.25Ni0.75)30合金前100s吸氢量分别达到各自最大吸氢量的97%和87%。通过对DSC曲线的分析发现,Mg70(A0.25Ni0.75)30的脱氢活化能较低,分别为111.025±2.790kJ/mol(A=Ce)、84.843±2.057kJ/mol(A=Y)和152.207±6.764kJ/mol(A=Y)。实验结果表明,Y元素对Mg70(A0.25Ni0.75)30合金催化及储氢性能的改善要优于Ce元素。     

Mg2Ni氢化物电子结构的研究

利用电荷自洽离散变分Xα对Mg2Ni氢化物的电子结构进行研究，结果表明，在Mg2Ni氢化物中，H与Nj原子之间强烈的成键作用是导致Mg2Ni合金释放氢的温度比较高的原因．在A2B型贮氢合金中，因为氢原子更倾向于进入吸热型元素周围的品格位置，所以吸热型元素在储氢合金中起到了增强对氢原子吸附力的作用．吸氢后，A2B型合金出现了A-B键受到减弱的现象，使得贮氢合金的性能降低了．     

球磨法制备Si-C-N/Ni纳米粉

以Si-C-N纳米粉和Ni微粉为原料,利用高能球磨法制备Ni包覆Si-C-N纳米粉.Si-C-N纳米粉由原始的灰色转为包覆后的深黑色,Ni除包覆在Si-C-N纳米粉体表面,部分还在复合粉体之间形成了粉体之间的镶嵌和塑性连接.实验结果表明:球磨时间是影响包覆粉体粒度的重要条件,在10h内,球磨时间长,粉体粒径小,最小粒径约为100nm.球磨时,液相载体正己醇的加入改善了复合粉体分散性,并且纳米粉体保持了一定的非晶性质.     

An Investigation on Hydrogen Storage Kinetics of the Nanocrystalline and Amorphous LaMg_(12)-type Alloys Synthesized by Mechanical Milling

Nanocrystalline and amorphous LaMg_(12)-type LaMg_(11)Ni + x wt% Ni(x = 100, 200) alloys were synthesized by mechanical milling. Effects of Ni content and milling time on the gaseous and electrochemical hydrogen storage kinetics of as-milled alloys were investigated systematically. The electrochemical hydrogen storage properties of the as-milled alloys were tested by an automatic galvanostatic system. And the gaseous hydrogen storage properties were investigated by Sievert apparatus and a differential scanning calorimeter(DSC) connected with a H_2 detector. Hydrogen desorption activation energy of alloy hydrides was estimated by using Arrhenius and Kissinger methods. It is found that the increase of Ni content significantly improves the gaseous and electrochemical hydrogen storage kinetic performances of as-milled alloys. Furthermore, as ball milling time changes, the maximum of both high rate discharge ability(HRD) and the gaseous hydriding rate of as-milled alloys can be obtained. But the hydrogen desorption kinetics of alloys always increases with the extending of milling time. Moreover, the improved gaseous hydrogen storage kinetics of alloys are ascribed to a decrease in the hydrogen desorption activation energy caused by increasing Ni content and milling time.     

An Investigation on Hydrogen Storage Kinetics of the Nanocrystalline and Amorphous LaMg<Subscript>12</Subscript>-type Alloys Synthesized by Mechanical Milling

Nanocrystalline and amorphous LaMg₁₂-type LaMg₁₁Ni + x wt% Ni (x = 100, 200) alloys were synthesized by mechanical milling. Effects of Ni content and milling time on the gaseous and electrochemical hydrogen storage kinetics of as-milled alloys were investigated systematically. The electrochemical hydrogen storage properties of the as-milled alloys were tested by an automatic galvanostatic system. And the gaseous hydrogen storage properties were investigated by Sievert apparatus and a differential scanning calorimeter (DSC) connected with a H₂ detector. Hydrogen desorption activation energy of alloy hydrides was estimated by using Arrhenius and Kissinger methods. It is found that the increase of Ni content significantly improves the gaseous and electrochemical hydrogen storage kinetic performances of as-milled alloys. Furthermore, as ball milling time changes, the maximum of both high rate discharge ability (HRD) and the gaseous hydriding rate of as-milled alloys can be obtained. But the hydrogen desorption kinetics of alloys always increases with the extending of milling time. Moreover, the improved gaseous hydrogen storage kinetics of alloys are ascribed to a decrease in the hydrogen desorption activation energy caused by increasing Ni content and milling time.     

La0.67Mg0.33Ni2.5Cu0.5贮氢合金磁热处理工艺的正交设计

利用L9（34）正交表安排实验,考察磁热处理的温度、时间及磁感应强度对La0.67Mg0.33N i2.5Cu0.5合金的吸放氢反应热力学和动力学的影响,结合极差分析和方差分析研究了各因素对考核指标的显著性影响,并得到合金磁热处理的优化工艺：热处理温度850℃,处理时间1 h和磁感应强度4 T.在此条件下处理后的合金,吸放氢的质量分数分别为1.33%和1.14%,焓变为-59.69 kJ/mol,吸热峰顶所对应的温度为86.3℃,吸放氢特征时间（tξ=0.875）分别为11.2和108.7 s.结果表明,该合金与其它工艺下的样品相比,吸氢量最大,放氢后物相结构最稳定,吸热峰顶所对应的温度最低,吸放氢速度最快.     

Electrochemical Hydrogen Storage Performance of the Nanocrystalline and Amorphous Pr-Mg-Ni-based Alloys Synthesized by Mechanical Milling

The PrMg12-type composite alloy of PrMg₁₁Ni + x wt% Ni (x=100,200) with an amorphous and nanocrystalline microstructure were synthesized through the mechanical milling.Effects of milling duration and Ni content on the microstructures and electrochemical hydrogen storage performances of the ball-milled alloys were methodically studied.The ball-milled alloys obtain the optimum discharge capacities at the first cycle.Increasing Ni content dramatically enhances the electrochemical property of alloys.Milling time varying may obviously impact the electrochemical performance of these alloys.The discharge capacities show a significant upward trend with milling duration prolonging,but milling for a longer time more than 40 h induces a slight decrease in the discharge capacity of the x=200 alloy.As milling duration increases,the cycle stability clearly lowers,while it first declines and then augments under the same condition for the x=200 alloy.The high-rate discharge abilities of the ball-milled alloys show the optimum values with milling time varying.     

高能球磨Fe70Ni30纳米晶的XRD和HRTEM研究

用XRD（X射线衍射）和HRTEM（高分辨透射电镜）研究了高能球磨Fe70Ni30二元金属合金的微结构随球磨时间（t）的变化情况。结果表明：以羰基铁和羰基镍为原料，通过高能球磨得到了bcc结构FeNi纳米晶合金。球磨10h时，羰基铁和羰基镍开始形成合金，但大部分R、Ni原子仍分别以bcc结构和fcc结构存在。球磨100h时，样品以bcc结构的FeNi合金为主，球磨200h后，样品中fcc结构Ni特征峰几乎消失，FeNi纳米晶达到最小粒径的平衡值。～8nm。高能球磨过程中，晶界区域的层错缺陷是合金化和纳米晶形成的重要因素．     

STUDY ON MAXIMUM HYDROGEN CAPACITY FOR Zr-Ni AMORPHOUS ALLOY

To design the amorphous hydrogen storage alloy efficiently, the maximum hydrogen capacities for Zr-Ni amorphous alloy were calculated. Based on the Rhomb Unit Structure Model (RUSM) for amorphous alloy and the experimental result that hydrogen atoms exist in 3Zr1Ni and 4Zr tetrahedron interstices in Zr-Ni amorphous alloy, the numbers of 3Zr-1Ni and 4Zr tetrahedron interstices in a RUSM were calculated which correspond to the hydrogen capacity. The two extremum Zr distribution states were calculated, such as highly heterogeneous Zr distribution and homogeneous Zr distribution. The calculated curves of hydrogen capacity with different Zr contents at two states indicate that the hydrogen capacity increases with increasing Zr content and reaches its raximum when Zr is 75%. The theoretical maximum hydrogen capacity for Zr-Ni amorphous alloy is 2.0 (H/M). Meanwhile, the hydrogen capacity of heterogeneous Zr distribution alloy is higher than that of homogenous one at the same Zr content. The exrperimental resu     

Influence of substituting Ni with Co on hydriding and dehydriding kinetics of melt spun nanocrystalline and amorphous Mg2Ni-type alloys

In order to improve the hydriding and dehydriding kinetics of the Mg₂Ni-type alloys, Ni in the alloy is substituted by element Co. The nanocrystalline and amorphous Mg₂Ni-type Mg₂Ni_1−x Co _x (x=0, 0.1, 0.2, 0.3, 0.4) alloys were synthesized by melt-spinning technique. The structures of the as-cast and spun alloys were studied with an X-ray diffractometer (XRD) and a high resolution transmission electronic microscope (HRTEM). An investigation on the thermal stability of the as-spun alloys was carried out with a differential scanning calorimeter (DSC). The hydrogen absorption and desorption kinetics of the alloys were measured with an automatically controlled Sieverts apparatus. The results demonstrate that the substitution of Co for Ni does not alter the major phase of Mg₂Ni but results in the formation of secondary phase MgCo₂. No amorphous phase is detected in the as-spun Co-free alloy, but a certain amount of amorphous phase is clearly found in the as-spun Co-containing alloys. The substitution of Co for Ni exerts a slight influence on the hydriding kinetics of the as-spun alloy. However, it dramatically enhances the dehydriding kinetics of the as-cast and spun alloys. As Co content (x) increases from 0 to 0.4, the hydrogen desorption capacity increases from 0.19% to 1.39% (mass fraction) in 20 min for the as-cast alloy, and from 0.89% to 2.18% (mass fraction) for the as-spun alloy (30 m/s).     

Preparation and properties of 4.25Cu-0.75Ni/NiFe_2O_4 cermet

1INTRODUCTION NiFe2O4cermets,whichareexpectedtobe usedastheinertanodesforaluminumelectrolysis, havelowcorrosionandoxidation,goodelectricalconductivityandhighthermalshockresistance[15]. Nickelferritespinelformsacorrosion resistant networkthatcontainstheelectricallyconductivecopper basedmetallicphase.Especially,Gregget al[6]foundacermetofNiFe2O4 18%NiO 17%Cu (massfraction),whichshowedfavorablecorrosion andconductivitypropertiesasinertanodesinsmalllaboratorycells.However,itwasalsoshowedth…     

La_(1.8)Ca_(0.2)Mg_(14)Ni_3合金在甲苯溶液中球磨改性后的储氢性能

采用在甲苯介质中球磨以改善La1.8Ca0.2Mg14Ni3的储氢性能。随着球磨时间的增加,合金的吸放氢性能得到显著地提高,在20 h达到最高。其在513 K,4.0 MPa氢压下初次活化时,吸氢质量分数达到了3.95%,在3次活化后,300 K时的吸氢质量分数达到3.85%,在613 K,一个大气压的放氢质量分数在900 s内达到了4.92%。通过XRD和SEM分析,球磨后合金颗粒粒径明显减小且有非晶化趋势。在球磨过程中形成了电子络合体(electrondonor-acceptor,EDA)体系。合金颗粒粒径、非晶化程度和EDA共同作用使球磨20 h的合金表现出最优异的吸放氢性能。