Effects of Ga and Sn on the electrochemical behavior of Mg–6Al–1Zn as anode materials

The microstructure and electrochemical behavior of Mg–6Al–1Zn, Mg–6Al–1Zn–1Ga, Mg–6Al–1Zn–1Sn, and Mg–6Al–1Zn–0.5Sn–0.5Ga as anode materials in a 3.5 wt% NaCl solution are compared systematically. The results show that Sn alloying refines the second-phases of Mg–6Zn–1Al by promoting tiny granular Mg₁₇Al₁₂ phases containing Sn, and inspires their disperse distribution. However, the Ga results in the formation of semicontinuous reticular Ga containing Mg₁₇Al₁₂ phases. The comparison of discharge tests indicates that Mg–6Al–1Zn–1Sn has the highest discharge activity, and Mg–6Al–1Zn–1Ga displays the largest hydrogen evolution corrosion resistance in 3.5 wt% NaCl solution at 298 K. The synergy of Ga and Sn can shorten discharge activation time and promote low discharge potential. In addition, the utilization efficiencies of the alloys decrease as follows: Mg–6Al–1Zn–1Ga > Mg–6Al–1Zn–0.5Sn–0.5Ga > Mg–6Al–1Zn–1Sn > Mg–6Zn–1Al. This study illustrates that the Mg–6Al–1Zn–0.5Sn–0.5Ga alloy has acceptable utilization efficiency and desirable electrochemical activity, which implies that doping Ga and Sn obtains a balance between discharge activity and utilization efficiencies.     

In对Al-Mg-Ga-Sn-(In)铝合金阳极组织及电化学性能的影响

在Al基体中添加Mg、Ga、Sn、In合金元素,通过正交试验设计了9组铝-空气电池阳极材料。采用动电位极化试验、析氢试验和恒电流放电试验对铝合金阳极的电化学性能进行优化,通过扫描电镜和能谱测试仪观察了合金的显微组织及成分。结果表明,没有添加In元素的1号合金(Al-0.5Mg-0.05Sn-0.05Ga)、5号合金(Al-Mg-0.1Sn-0.2Ga)和9号合金(Al-2Mg-0.2Sn-0.1Ga)铝阳极具有较差的放电性能和较高的自腐蚀速率,而添加0.05wt% In元素的7号铝阳极(Al-2Mg-0.05Sn-0.2Ga-0.05In)具有最好的放电电压(平均电位-1.968 V)和抗腐蚀性能 (自腐蚀速率0.193 mL·cm^-2·min^-1)。对比去腐蚀产物后的合金表面形貌,发现5号合金的腐蚀表面布满较深的腐蚀坑,这增加了铝合金的自腐蚀,而7号合金的表面具有较浅的腐蚀坑,这减缓了电解液中离子传递和自腐蚀速率。 因此,7号铝合金适合用作铝-空气电池阳极材料。     

Li掺杂Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li(1/7-x))O3高熵陶瓷的制备及介电性能研究

近年来,在高熵合金基础上发展起来的高熵陶瓷逐渐引起了研究者的广泛关注,其出现为开发高性能的无机非金属材料提供了新的设计思路。本文采用固相法制备了BaMO3基钙钛矿型高熵陶瓷Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li(1/7-x))O3 (x = 0, 2.3%, 5.3%, 8.3%, 11.3%),并研究了Li含量对高熵陶瓷物相结构、微观形貌及介电性能的影响。结果表明,Li含量对陶瓷结构的影响不大,陶瓷均保持立方钙钛矿结构,且无杂相产生;陶瓷的晶粒尺寸相对较均匀。当x = 0时,即B位七元等摩尔比Ba(Ti1/7Sn1/7Zr1/7Hf1/7Nb1/7Ga1/7Li1/7)O3高熵陶瓷,其介电常数达到了最大值2920 (@100 Hz),相较于已报道的不掺Li的六元高熵钙钛矿陶瓷Ba(Ti1/6Sn1/6Zr1/6Hf1/6Nb1/6Ga1/6)O3提升了近50倍。     

Evaluation of nanometer-sized zirconium oxide incorporated Al—Mg—Ga—Sn alloy as anode for alkaline aluminum batteries

Zirconium oxide nanoparticles with 0.4 wt.% and 0.8 wt.% are incorporated into the Al—0.65Mg—0.05Ga— 0.15Sn (wt.%) alloy anode (base alloy) in order to improve the performance of the resulting anodes. Electrochemical characterization of the reinforced alloys was done by potentiodynamic polarization, electrochemical impedance spectroscopy and galvanostatic discharge and corrosion behavior was evaluated using self-corrosion rate and hydrogen evolution in 4 mol/L KOH solution. The surface morphology of the alloys was also studied using field emission scanning electron microscope (FESEM). The obtained results indicate that the base alloy shows high corrosion rate in 4 mol/L KOH solution by releasing 0.47 mL/(min·cm²) hydrogen gas, whereas the alloy containing 0.8 wt.% ZrO₂ provides the lowest hydrogen evolution rate by releasing 0.32 mL/(min·cm²) hydrogen gas. Furthermore, by increasing zirconium oxide nanoparticles, the corrosion current density of the aluminum anodes is decreased and their corrosion resistance increases significantly compared to the base alloy in alkaline solution. In addition, nanometer-sized zirconium oxide incorporated anodes exhibit the improved galvanic discharge efficiencies, so that 0.8 wt.% nano-zirconium oxide incorporated base alloy displays the highest power density and anodic utilization compared with the others in 4 mol/L KOH solution.     

制备工艺参数与合金元素对铝(合金)—水(0℃)反应产氢性能的影响

通过机械合金化技术制备了含镓和铟的铝合金,研究该合金与纯水之间的水解反应来考察氢产率的变化。X射线衍射、扫描电镜与能谱分析结果表明镓和铟元素分别主要以溶解与沉积相的形式存在于合金之中。溶解的镓和铟通过增强水解反应活性来提高铝合金的产氢率。此外,由球磨时间决定的沉积相的数量及分布也会直接影响合金的产氢率,具有均匀分布及合适数量沉积相的铝合金能与0℃水反应产生1132.8ml/g的氢气。     

纯铝在NaCl溶液中活化溶解时电化学行为研究

通过动电位扫描、交流阻抗和恒电位集气的方法研究了纯铝在含Zn2+、In3+、Sn2+、Ga3+活化离子的0.5mol/LNaCl溶液中电化学行为,研究表明这些离子促进了铝电极在中性NaCl溶液中的活化,同时抑制了铝的负差数效应,其中Zn2+和In3+对铝的活化和抑制负差数效应呈现为协同作用,比照Al-Zn-In牺牲阳极研究了Zn2+和In3+协同作用机理,并进一步探讨了铝电极负差数效应机制.     

AgCuZn-X(Ga, Sn, In, Ni)钎料显微组织及钎焊接头研究

研究了不同合金元素Ga,Sn,In和Ni添加对Cd银基钎料及其钎焊接头的显微组织影响,同时对AgCuZn-X(Ga,Sn,In,Ni)钎料的对接和搭接实验做了对比实验分析。结果表明,添加Ga,Sn,In和Ni4种元素的银钎料具有"特有的镓结构",具有较低的固相线和液相线,其钎缝力学性能优异,由SEM观察钎缝显微组织可知,低银含镓钎料具有与高银高镓钎料相近的织网状致密组织,添加适当的元素可以显著提高低银钎料的性能。     

Preparation of low cobalt high rate discharge hydrogen storage alloy MlNi_(3.85)Co_(0.45) Mn_(0.4)Al_(0.3)X_(0.1)(X=Mg,Si,Sn)

1　INTRODUCTIONInrecentyears,Ni/MHbatterythatisanewgenerationbatterywithhighenergydensitywasrapidlydevelopedafterwardsNi/Cdbattery .WiththeincreasinglymatureofNi/MHbatteryproductiontechnique,itbeginstojointhefieldofhighpowerandgreatcapacitycell,andbecomesgraduallythemostpromisinggreendynamiccellthatwasappliedtoelectromotivemotor .Thehydrogenstoragealloy ,asthekeymaterialofNi/MHdynamiccell,mustbecharacterizedbyitshighspecialcapacity ,highvolt ageplatform ,goodcatalyzeactivity ,longcycl…     

Influence of thermo hydrogen treatment on microstructure and mechanical properties of Ti-5Al-2.5Sn ELI alloy

Thermo hydrogen treatment(THT) of titanium is a process in which hydrogen is used as a temporary alloying element in titanium alloys. It is an attractive approach for controlling the microstructure and thereby improving the final mechanical properties. In the present study, the microstructure of the original(non-hydrogenated) sample has only α phase and the grains is coarse with an average size of ~ 650 μm. While the grain size of thermo hydrogen treated Ti-5Al-2.5Sn ELI alloy became finer and the mechanical properties were improved significantly. When the hydrogen content of the hydrogenated Ti-5Al-2.5Sn ELI alloy is 0.321 wt.%, β phase and δ titanium hydride appear. Also the average grain size decreases to 450 μm. When the hydrogen content is 0.515 wt.%, the grain size decreases to 220 μm. The mechanical properties were tested after dehydrogenation, and the mechanical properties improved significantly compared to the unhydrogenated specimens. The tensile strength of the Ti-5Al-2.5Sn ELI alloy improved by 17.7% when the hydrogen content increased to 0.920 wt.%, at the same time the percentage reduction of area(Z) increased by 33% and the impact toughness increased by 37%.     

ON THE THERMAL STABILITY OF Ti ALLOYS I. The Electron Concentration Rule for Formation of Ti_3X-Phase

根据Hume Rothery规律和相稳定性与电子结构的关系,对合金元素的原子特性进行考查,发现Ti与Al,Ga,In,Sn,Zr的原子半径和负电性相近。这是合金化的有利因素。因此推断,电子浓度是控制α-Ti_3X相界的主要因素。 对Ti-Al-Ga,Ti-Al-Sn,Ti-Al-Zr,Ti-Al O四个三元合金系的实验表明:Ti_3X相的形成是遵守电子浓度规律的,且合金元素的价电子数是由它们的电子结构决定的。对过渡族元素Ti,Zr价电子数为N_(Ti)=N_(Zr)=2;对非过渡族元素Al,Ga,Sn,O价电子数分别为N_(Al)=N_(Ga)=3(s~2p~1),N_(Sn)=4(s~2p~2),N_o=6(s~2p~4)。Ti_3X相形成的特征电子浓度可表示为(?)_c=∑Nifi=2.12。     

Ga含量对Al-Mg-Ga-Sn合金组织和降解性的影响

采用电炉熔炼制备了不同Ga含量的Al-Mg-Ga-Sn合金。通过光学显微镜(OM) 、扫描电镜(SEM)和X射线衍射仪(XRD)对其显微组织的形貌和成分进行了表征;在30℃、40℃、70℃、90℃的纯水中进行降解速率的测定;采用电化学工作站测试了室温电化学性能。结果表明：Al-Mg-Ga-Sn合金在Mg+Sn为定值10wt.%的情况下,Ga含量分别为0 wt.%、4 wt.%、8 wt.%、12 wt.%、16 wt.%时,合金组织均有铝基体相和Mg<sub>2</sub>Sn相,且随着Ga含量的增加合金组织中出现了Ga<sub>5</sub>Mg<sub>2</sub>相。Al-Mg-Ga-Sn合金的降解性特点是主要由铝基体相中点蚀开启,由Mg<sub>2</sub>Sn和Ga<sub>5</sub>Mg<sub>2</sub>化合物相的晶间腐蚀加速;不同Ga含量合金的起始降解温度由固溶于铝基体中的低熔点元素(Ga+Sn)的含量决定;相同Ga含量的合金随温度升高降解速率加快,降解反应动力学遵从阿伦尼乌斯公式。室温电化学分析表明：Al-Mg-Ga-Sn合金随Ga含量增加,腐蚀电位不同程度地负移,腐蚀电流逐渐增大。     

Minor Ga addition to effectively inhibit PdSn4 growth between Sn solder and Pd substrate

PdSn₄ is the major reaction phase in the Sn-based or Sn–Ag–Cu solder joints with Pd substrate and it exhibits an extremely high growth rate. Ga is considered as a candidate alloying element in the Sn–Ag–Cu solders. This paper investigates the effects of Ga addition on the interfacial reactions between Pd and Sn–Ga (0.1wt.%–1wt.%Ga) solders by solid-state aging at 160, 180, and 200 °C and liquid-state aging at 250 °C. The most important finding is that minor Ga addition can effectively inhibit the fast PdSn₄ growth. In the solid-state reaction, with only 0.1wt.%Ga addition, the PdSn₄ growth was suppressed by ∼50%, compared with the pure Sn/Pd reaction. When the Ga content increased to 0.5wt.%, the PdSn₄ growth was further reduced by over 90%. In addition, a thin PdGa phase layer was formed at the interface between PdSn₄ and Pd, which was the main cause for the inhibition of PdSn₄ growth. The growth kinetics was systematically explored. The PdSn₄ growth had a higher activation energy for the higher Ga addition (>0.5wt.%). Furthermore, a similar reduction in the PdSn₄ growth was observed in the liquid-state reaction, but it was not as strong as in the solid-state reactions. The PdGa phase was not formed in the liquid-state reaction and the growth inhibition could be attributed to the Ga doping in the PdSn₄ lattice to retard the Sn diffusion.     

Effect of Ca addition on the as-cast microstructure and creep properties of Mg-5Zn-5Sn magnesium alloy

The effect of Ca addition on the as-cast microstructure and creep properties of Mg-5Zn-5Sn magnesium alloy was investigated. The results indicate that adding 1.0 wt.% Ca to Mg-5Zn-5Sn alloy can effectively refine the as-cast microstructure of the alloy, and the CaMgSn phase with high thermal stability is formed in the alloy. In addition, adding 1.0 wt.% Ca to Mg-5Zn-5Sn alloy can also improve the creep properties of the alloy. After adding 1.0 wt.% Ca to Mg-5Zn-5Sn alloy, the second creep rate of the alloy at 150°C and 50 MPa for 100 h decreases from 4.67 × 10⁻⁸ to 1.43 × 10⁻⁸ s⁻¹. The strengthening mechanism is mainly attributed to the microstructural refinement and the formation of CaMgSn phase.     

铸态Mg-xSn-1Mn合金的显微组织和阻尼性能

采用光学显微镜(OM)、维氏硬度计、热动态分析仪、X射线衍射(XRD)、多功能内耗仪等,研究了Sn含量对Mg-xSn-1Mn合金显微组织、阻尼性能和力学性能的影响。结果表明:当Sn含量从2%增加到8%时,Mg-xSn-1Mn合金的枝晶间隙呈现细化的趋势,硬度从43.84 HV0.1增加至54.00 HV0.1,呈单调增加的趋势。应变无关阻尼随着Sn含量的增加呈现先增后减的趋势,在Sn含量为4%时达到最大,应变相关阻尼则随着Sn含量的增加呈现逐渐减小的趋势。在低温阶段,相同Sn含量的合金的阻尼随着频率的增大呈现增加的趋势;但在高温下,阻尼值在低频时的上升速率比高频时快,并随着温度的升高,低频阻尼和高频阻尼趋向于相等。当Sn含量不同时,随着温度的升高,Sn含量较高的合金的阻尼值上升速率变快。     

Effect of microstructure on discharge performance of Al–0.8Sn–0.05Ga–0.9Mg–1.0Zn (wt%) alloy as anode for seawater-activated battery

The electrochemical performance and discharge behavior of Al–0.8Sn–0.05Ga–0.9Mg–1.0Zn (wt%) alloys in as-cast, homogenized, and annealed states were investigated through electrochemical means, corrosion rate test, and discharge test in a 3.5 wt% NaCl solution. Results suggest that the discharge performance of this alloy is enhanced by rolling and subsequent annealing treatment. This is attributed to the fact that the microstructure of the alloy is greatly improved through rolling and subsequent annealing treatment. The 400°C-annealed alloy exhibits the most excellent discharge activity than alloys in other states, which is due to more regions being activated by a finer and more uniform Sn-rich phase. Furthermore, the anode efficiency of the 400°C-annealed alloy is higher than that of as-cast and homogeneous alloys due to the more uniform distribution of Sn in the aluminum matrix.     

Effects of Ga,Sn Addition and Microstructure on Oxidation Behavior of Near-α Ti Alloy

We investigated the effects of adding Ga or Sn, with almost the same Al equivalent, on the oxidation behaviors of near-α Ti alloy with the bimodal structure and lamellar structure. The replacement of Sn with Ga decreased the alloy weight gain during oxidation, suppressed oxide growth, and improved adherence between the oxide and substrate. A lamellar alloy structure showed a lower weight gain during oxidation compared to the bimodal structure. Unlike conventional near-α alloys, recrystallization occurred near the oxide/substrate interface in Ga-modified alloy, which may contribute to the release of stress, improvement of the adherence between the oxide and substrate, and prevention of oxide-scale spallation from the Ga-modified alloy. A possible mechanism for the recrystallization in the Ga-modified alloy was also discussed.     

Sn-Ag-Cu-Ce无铅钎料合金体系的热力学计算及预测

利用周模型对Sn—Ag—Cu—Ce无铅钎料合金体系进行了热力学计算预测。热力学计算结果表明，Ag、Cu含量(质量分数)分别为0．5％-4．5％时，当Ce的含量(质量分数)超过0．05％时，体系达到化学平衡状态；当Ce的含量(质量分数)达到0．6％左右时，Sn、Ag、Cu分别都出现了“等活度系数”现象。这一研究结果可为无铅钎料合金的成分设计提供理论指导。     

The site occupancies of alloying elements in TiAl and Ti3Al alloys

The site occupancies of V, Cr, Mn, Fe, Ni, Zr, Nb, Mo, Ta, Ga and Sn (1–5 at.%) in TiAl alloys with different compositions, and in Ti₃Al with the compositions of Ti–26 at.%Al–(1–2 at.%)X, were measured by the atom location channelling enhanced microanalysis (ALCHEMI) method. For TiAl alloys, the results show that Zr, Nb and Ta atoms invariably occupy Ti sites, while Fe, Ni, Ga and Sn atoms occupy Al sites, the alloy composition having no significant influence on their site preference. By contrast, the site preference of V, Cr, and Mn changes considerably with alloy composition (the Ti/Al ratio in particular), the probability of these elements substituting for Ti decreasing in the above order. For quaternary Ti–Al–V–Cr alloys, the site occupancies of V and Cr do not show much mutual influence. In general, with increasing atomic number, elements in the same period show increasing tendency to substitute for Al, as is the tendency to substitute for Ti for elements in the same group of the periodic table. For Ti₃Al alloys, Ga and Sn atoms occupy Al sites, while V, Cr, Mn, Zr, Nb, Mo and Ta atoms occupy Ti sites, the site preference of V, Cr, Mn and Mo in TiAl alloys being different from that in Ti₃Al. The experimental results are interpreted in terms of a Bragg–Williams-type model and bond-order data obtained from electronic structure calculation. Qualitative agreement between the model and measurements is reached.     

Ab initio and thermodynamic modelling of alloying effects on activity of sacrificial aluminium anodes

This work summarizes the experimental literature to date on Al-alloy sacrificial anodes and shows that the presence of Sn as an alloying element in solid solution form consistently debases the alloy corrosion potential. This study then assesses the lattice expander theory, which states that lattice-expanding dopants can be used to increase Sn solubility in Al and thereby reduce passivation. The thermodynamic effects on Sn solubility of lattice expanders (Ga, Mg, Zr, In and Bi) are predicted with ab-initio methods. Our results support lattice expander theory although we demonstrate that Sn solubility can decrease by alloying with even large dopants if they form compounds with Sn.     

LaNixSny金属氢化物电极的制备及性能

从电化学角度研究了含锡贮氢合金的贮氢性能，并对金属氢化物电极制作技术进行了探索。结果表明，用这种贮氢合金制成的电极容量达到３４０ｍＡｈ／ｇ以上，而且容易活化。采用颗粒细小的镍粉较粒径较大的铜粉好，导电剂用量１０％；采用混合粘结剂ＣＭＣ和ＰＴＦＥ，ＣＭＣ用量为０．４％，ＰＴＦＥ用量为１０％。