化学镀铜对A_2B_7型贮氢合金电极电化学性能的影响

以A2B7型贮氢合金La0.75Mg0.25Ni3.44Al0.06为对象,系统研究了合金覆铜后进行不同温度退火处理的电极电化学性能。结果表明,表面包覆Cu及退火处理后的贮氢合金电极的活化性能及循环稳定性有所提高。线性极化扫描和电化学阻抗图谱分析结果表明,包覆Cu及退火处理后提高了合金电极的交换电流密度I0,降低了电化学阻抗,说明包覆处理改善了合金表面的电催化活性,加快了合金表面电荷的迁移速率,从而提高了高倍率放电能力。     

无Co稀土系储氢合金La(NiM)5+x的组织结构及MH电极性能研究

制备和研究了过化学计量比无钴合金La(NiM)5+x(M= Cu, Mn, Al,x=0.3～1.0)在常规熔铸、高温退火+淬火及快速凝固不同制备条件下的组织结构和电化学性能.X射线衍射分析表明,熔铸合金组织均由CaCu5型主相和少量第二相组成;当M为Cu和Mn元素时,退火+淬火处理及快速凝固合金在x=0.3～1.0范围内为单相组织,而含Al合金则很难获得单相组织.电化学实验表明,退火+淬火处理后的合金MH电极具有易活化、电化学容量较高、电极循环稳定性得到不同程度改善,其中以含Cu和Mn元素的单相组织合金循环稳定性最好.快速凝固合金均大大提高了合金的电化学稳定性,但其活化性能和电极容量明显下降.     

锂离子电池用Si-Fe复合电极材料的制备及其性能

以Fe粉与Si粉为混合粉原料,研究经机械球磨、退火热处理后混合粉的形貌、结构与恒电流充放电性能,同时对比研究Si-Fe合金粉的性能.研究结果表明:混合粉原料经过高能机械球磨,生成了Si-Fe合金相,而Si-Fe合金的生成改善了Si作为锂离子电池负极材料的循环性能;与工业级Si-Fe合金负极材料相比,合金化程度影响了合金材料的电化学性能,合金化程度越高,合金材料电化学性能越好;而退火热处理也可以在一定程度上改善合金材料的脱嵌锂性能.     

锂离子电池负极材料纳米Ni3Sn2的溶剂热合成与电化学性能

采用溶剂热法合成锂离子电池负极材料纳米Ni3Sn2合金粉末并研究了该合金粉末作为新型锂离子二次电池负极材料的电化学性能。合成的合金粉末经过了XRD和FESEM的表征,采用Li/LiPF6(EC DMC)/Ni3Sn2模拟电池测定合成的合金粉末的电化学性能。研究表明,该合金粉末的首次可逆容量为136mAh.g-1,退火后的合金粉末表现出更好的循环稳定性。     

退火温度对Nb掺杂SrTiO_3薄膜光电化学性能的影响(英文)

研究了Nb掺杂SrTiO3薄膜的光电化学性能及其对储氢合金薄膜的光充电性能。采用射频磁控溅射将SrTiO3薄膜沉积在镍片基体上,在300～600℃退火处理后,采用直流磁控溅射将LaNi3.9Al1.3储氢合金薄膜沉积在镍片基体的背面构成SrTiO/Ni/储氢合金电极。随着Nb掺杂SrTiO薄膜热处理温度的升高,阳极光电流和光充电性能先增大后减小。     

添加Zn对5083铝合金组织和腐蚀性能的影响

通过铸锭冶金法制备5083铝合金、加0.7％Zn(质量分数)5083铝合金、β(Al3Mg2)相和τ(Mg32(Al,Zn)49)相,对添加Zn和未添加Zn的5083合金进行冷轧180℃,2h退火处理后,利用剥落腐蚀测试、极化曲线测定和透射电镜研究少量Zn对冷轧退火后5083铝合金组织和腐蚀性能的影响,并通过电化学测试研究β相、τ相与α(Al)的电化学特征.研究结果表明:退火后不含Zn的合金中杆状的β相在晶界连续分布,合金的剥落腐蚀等级为EA,腐蚀电位为-0.651V.而加入0.7％Zn的合金在相同状态下,τ相部分取代了β相,且其主要呈球状,在晶界、晶内不连续分布,合金的剥落腐蚀等级为PB,腐蚀电位为-0.54 V.加少量Zn明显提高5083合金的耐蚀性.测得β相的腐蚀电位(-1.085V)比α(Al)的腐蚀电位(-0.812 V)低,而τ相的腐蚀电位(-0.813V)与α(Al)的腐蚀电位基本相同,τ相的形成缩小第二相与铝基体的电位差,优化合金的耐腐蚀性能.     

退火温度对Nb掺杂SrTiO3薄膜光电化学性能的影响

研究了Nb掺杂SrTiO3薄膜的光电化学性能及其对储氢合金薄膜的光充电性能。采用射频磁控溅射将SrTiO3薄膜沉积在镍片基体上，在300-600℃退火处理后，采用直流磁控溅射将LaNi3.9Al1．3储氢合金薄膜沉积在镍片基体的背面构成SrTiO3／Ni／储氢合金电极。随着Nb掺杂SrTiO3薄膜热处理温度的升高，阳极光电流和光充电性能先增大后减小。     

Al替代部分Ni对储氢合金La0.63Gd0.2Mg0.17Ni3.0Co0.3微观组织和电化学性能的影响

采用感应熔炼及退火处理制备的稀土-镁-镍系AB3.3型La0.63 Gd0.2 Mg0.17 Ni3.0-x Co0.3 A1x(x=0、0.1、0.2、0.3、0.4)储氢合金,系统研究了Al元素部分替代Ni后对合金的相结构和相组成及电化学性能的影响规律.X射线衍射(XRD)和显微电子探针(EPMA)方法分析结果表明...     

熔体过热对Bi-Sb20合金熔体结构转变和退火稳定性的影响

熔体过热处理可以使熔体微结构发生转变,进而改变凝固后的组织和性能.以Bi基二元合金Bi-Sb20为研究对象,对合金Bi-Sb20分别进行700℃、900℃恒温熔体过热处理,通过测量熔体的电阻率随时间的变化曲线来研究熔体结构的转变.实验中发现Bi-Sb20合金熔体的结构转变存在一个临界温度,超过临界温度熔体合金的组织结构会发生变化,金相实验显示Bi-Sb20合金在经过900℃熔体过热处理后晶粒显著细化.但是对比700℃熔体过热处理、凝固后250℃退火处理和900℃熔体过热处理、凝固后250℃退火处理,实验结果表明900℃熔体过热处理后再进行合金退火后反而晶粒变大,且组织结构不稳定.因此经过熔体过热处理晶粒已经细化的合金不需再进行退火处理.该研究为有效开发利用过热处理工艺改变Bi-Sb20合金的结构和性能提供一定的实验依据.     

喷丸及退火处理对1Cr18Ni9Ti合金抗高温氧化性能的影响

研究了经过喷丸处理及400℃退火处理的1Cr18Ni9Ti合金试样在900℃空气中的循环氧化性能。经SEM,EDS分析及氧化动力学研究发现:喷丸处理虽然促进了铬的选择性氧化,但却使合金表面的压应力增大,所形成的氧化膜的抗剥落性能也不好;退火处理不仅使喷丸试样表面的应力得以消除,并且起到了低温预氧化的作用。经过退火处理的合金表面形成了附着性良好的选择性氧化铬膜,其氧化增重与氧化膜剥落量下降,起到了很好的保护作用,提高了合金的抗高温氧化性能。     

Hydrogen storage and low-temperature electrochemical performances of A2B7 type La-Mg-Ni-Co-Al-Mo alloys

The effect of Mo-addition on hydrogen storage and low-temperature electrochemical performances of La-Mg-Ni-Co-Al alloys is investigated. The alloys were synthetized via vacuum induction melting followed by annealing treatment at 1123 K for 8 h. The major phases in the annealed alloys are consisted of (La, Mg)2Ni7, (La, Mg)5Ni19 and LaNi5 phases. Mo-addition facilitates phase transformation of LaNi5 into (La, Mg)2Ni7 and (La, Mg)5Ni19 phases. Hydrogen absorption/desorption PCI curves indicates that the hydrogen storage capacity of the alloy increases remarkably with the addition of Mo. Furthermore, the La0.75Mg0.25Ni3.05Co0.2Al0.05Mo0.2 alloy shows excellent hydriding/dehydriding kinetics with a higher capacity, requiring only 100 s to reach its saturated hydrogen capacity of 1.58 wt% at low temperature of 303 K, and releasing 1.57 wt% hydrogen within 400 s at 338 K. Electrochemical experiments manifest that the Mo-added alloy electrode has perfect activation properties and the maximum discharge capacity. The low-temperature dischargeability shows that the La0.75Mg0.25Ni3.05Co0.2Al0.05Mo0.2 alloy exhibits the excellent low-temperature discharge performance, and the maximum discharge capacity is improved from 231.0 to 334.6 mAh/g at 253 K. The HRD property of the alloy electrode is enhanced, suggesting that Mo enhances the kinetic ability at low-temperature.     

烧结温度对La-Mg-Ni系储氢合金的相结构与电化学性能的影响

采用粉末烧结法制备La0.7Mg0.3Ni2.8Co0.5合金,并系统研究1173和1273 K下Ar保护分别烧结12 h所制备合金的微观结构与电化学性能。结果表明:合金均由(La,Mg)Ni3和LaNi52种主相所构成,1173 K条件下却含有少量MgNi2相,而1273 K条件下所制备的合金相结构中不含MgNi2相,这说明高温条件较有利于合金的合成。高温条件下所制备的合金具有较高的放电容量,且循环稳定性和高倍率放电性能均有明显的提高,电化学动力学也随制备温度的增高而改善。     

喷射成形制备La62Al15.7(Cu,Ni)22.3块体非晶合金

采用喷射沉积成形方法制备了La62Al15.7(Cu,Ni)22.3块体非晶合金. 结果表明,沉积态La62Al15.7(Cu,Ni)22.3非晶合金比以往报道的采用甩带法制备的同成分非晶合金具有更大的约化玻璃转变温度和更宽的过冷液相区. 非晶的晶化实验表明,晶化初期多种晶相同时结晶析出. 483K退火时,在非晶基体中析出Al和AlNi. 503K退火时进一步析出La和未知相. La62Al15.7(Cu,Ni)22.3非晶合金在573K退火没有新相产生,合金晶化态组织由Al、AlNi、La和未知相组成.     

Dependence of mechanical behavior on grain size of metastable Ti–Nb–O titanium alloy

Cold-rolled metastable β-type Ti–38Nb-0.2O alloy was subjected to annealing treatment to obtain different precipitates and grain sizes. The influence of annealing on microstructure and mechanical properties was investigated. The alloy annealed at 673 ?K or 773 ?K exhibited a single-stage yielding with high strength and low uniform elongation, due to the residual work hardening and the precipitation of ω or α phases. The alloy annealed at above 873 ?K exhibited an obvious double yielding behavior resulting from the stress-induced martensitic transformation. The grain growth kinetics of single β phase alloy is sensitive to temperature, and it is suggested that the existence of oxygen decreases the grain growth exponent and increases the required activation energy for grain growth. The critical stress for slip decreased monotonously with the increase of grain size, following the classic Hall-Petch relationship. However, the critical stress for martensitic transformation decreased to a minimum and then increased again, as the grain size increased. The results are worth for design of the heat-treatment parameters of the Ti–38Nb-0.2O alloy for engineering applications.     

合金元素Cr对LaNi5基Ni/MH电极性能的影响

测定了LaNi5基储氢合金的相成分,晶体结构和电化学性能.电化学测试是以合金粉制成负极,以烧结Ni(OH)2为正极,以6mol/L KOH溶液为电解液,制成开口式MH-Ni二次电池,在室温下测定的.结果显示,Cr部分替代LaNi4.7Si0.3合金中的Si形成的LaNi4.7Si0.3-xCrx合金均为CaCu5结构,未改变原合金的晶体结构.其中LaNi4.7Si0.22Cr0.08合金具有较高的放电容量,较好的放电平台和较快的活化速度.小电流放电性能比大电流放电好.     

Mn—Al—Fe系合金磁特性

基于室温磁制冷材料应具备的条件，讨论了Ｍｎ－Ａｌ－Ｆｅ系合金Ｋ相的磁性与成分间的关系。发现合金样品在退火前磁性与Ｆｅ含量变化主线性关系，退火后呈非线性关系．还从磁性方面讨论了该系合金作为室温磁制冷材料的可行性．     

Effect of heat treatment on hydrogen storage properties and thermal stability of V68Ti20Cr12 alloy

Effect of heat treatment on the crystal structure, microstructure, hydrogen storage properties and thermal stability of V68Ti20Cr12 alloy prepared by arc-melting was studied in this work. It was found that both the as-cast and annealed (973 K/72 h) V68Ti20Cr12 alloys consisted of a single body-centered cubic (bcc) phase. After heat treatment, the hydrogen absorption/desorption kinetic characteristics of the as-cast alloy was improved greatly due to the homogeneous composition and perfect structure. The mechanism of hydrogen absorption/desorption process in the as-cast and annealed alloys was further investigated according to the Johnson-Mehl-Avrami (JMA) equation. The hydrogen absorption process of the as-cast and annealed alloys would be controlled by the one-dimensional diffusion process, while the hydrogen desorption process in the as-cast and annealed alloys was dominated by the geometrical contraction model. The pressure-composition-temperature (PCT) measurements show that the plateau pressure of the annealed alloy becomes comparatively flat. Furthermore, the activation energies of the dehydrogenation in the as-cast and annealed alloys were calculated using the Kissinger method, indicating that heat treatment is a very beneficial way to improve hydrogen absorption/desorption kinetics of the alloy.     

Ni50.3Mn27.3Ga22.4磁性形状记忆合金薄膜的磁场增强马氏体相变应变研究

采用磁控溅射方法制备Ni50.3Mn27.3Ga22.4磁性形状记忆合金薄膜。研究薄膜的晶体结构、磁化行为以及磁场对马氏体相变应变的影响。试验结果表明,经823 K退火1 h的Ni50.3Mn27.3Ga22.4薄膜,室温下处于奥氏体态,呈较强的(110)织构特性,且室温饱和磁化强度约为40 emμ/g。试验还发现,当沿膜面方向施加0到0.8 T磁场时,Ni50.3Mn27.3Ga22.4薄膜的马氏体相变应变量随磁场强度的增大而增大,呈现出磁场增强马氏体相变应变效应。     

Microstructure and mechanical properties of the SiC/Zr4 joints brazed with TiZrNiCu filler for nuclear application

Si C ceramic has been successfully joined to Zr4 alloy using Ti Zr Ni Cu filler within the temperature range1173 K–1263 K and 15 min holding time. The morphology of the Si C/Zr4 joints was investigated by SEM, and the phases in the joints were characterized by XRD and TEM. The results indicated that part of the Zr4 substrate dissolved into the molten filler during the brazing process, contributed to the increasing Zr content and the formation of Zr[Ti] solid solution in the joints. In addition, β-Ti phase was discovered in the brazing seam. This might be attributed to the existence of β-Ti stable elements, Cu and Ni. The interface characterization showed that Si C reacted with filler alloy during the brazing process, formed a(Zr, Ti)C reaction layer on Si C surface and Zr2 Si compound near Si C substrate. Finally, the mechanical properties of the joints, evaluated by a shear strength test, reached a maximum of 95 MPa at the brazing temperature of 1203 K.     

Ni50.3Mn27.3Ga22.4磁性形状记忆合金薄膜的磁性能研究

采用磁控溅射方法制备Ni50.3Mn27.3Ga22.4磁性形状记忆合金薄膜。系统研究薄膜的马氏体相变行为、磁场增强相变应变特性以及温度对磁感生应变的影响。试验结果表明,经823 K退火1 h的Ni50.3Mn27.3Ga22.4薄膜室温下处于奥氏体态,马氏体相变开始温度为271.5 K。当沿膜面方向施加0—0.8 T磁场时,Ni50.3Mn27.3Ga22.4薄膜的马氏体相变应变量随磁场强度的增大而增大,呈现出磁场增强马氏体相变应变效应。试验还发现,饱和磁感生应变显著依赖于测试温度。当测试温度低于拟马氏体相变结束温度时,饱和磁感生应变随温度的升高先缓慢增大,在马氏体相变开始温度附近磁感生应变值发生跳跃式增加,然后随测试温度的进一步升高而降低。