铜金合金中金的精确分析方法——王水溶解—活性炭富集—氢醌容量法

通过不同含量的铜金合金的取样试验,确定具有代表性铜合金的取样量。将取样用王水分解定容后,经试验,分取适量铜合金溶液加活性炭分离富集,过滤并洗净活性炭,灰化灼烧。金颗粒用王水溶解,用盐酸赶硝酸并蒸发至无酸味后,在pH 2～3磷酸二氢钾—磷酸缓冲溶液里,用氢醌标准溶液滴定金,方法快速、准确,精密度在1.5%～3.5%,金的加入回收为98.0%～100.5%。

铜锌合金的研究现状及其进展

介绍了铜锌二元系记忆合金存在的马氏体稳定化现象和力学性能较差等缺点带来的实际生产应用阻碍,以及解决这些问题的研究进展;铜锌合金仿金电镀,以酒石酸系列、焦磷酸盐系列和HEDP系列为主的3种无氰环保的铜锌合金仿金电镀代替污染严重的氰化物镀铜锌合金的研究进展;铜锌合金滤料在水处理行业的研究现状及其进展。

Cu_3Au合金熔体的中程有序结构

采用紧束缚(Tight-binding,简称TB)原子间相互作用势,利用分子动力学模拟(MolecularDynamics,简称MD)的方法研究了Cu3Au合金熔体的微观结构,发现Cu3Au合金体系在高于熔点以上的400K～500K的温度范围内,结构因子上存在预峰,且在此范围内,随着温度的升高,预峰的强度逐渐降低。当温度超过1764K时,预峰开始消失。通过Lorentzian近似和Scherrer公式,可得预峰所对应的原子团簇尺寸位于1.35nm～1.85nm之间,属于中程有序结构范畴。Bhatia-Thornton(BT)偏结构因子表明,预峰的起源应归咎于体系中存在的化学序与拓扑序。BT形式的双体分布函数也证实,体系中存在着较强的化学序,且团簇中原子间的配位倾向于同类原子的配位。

Cu_3Au与Au_3Cu中点缺陷的分子动力学研究兼论L1_2型合金点缺陷的性质

讨论了Ｌ１２型合金中点缺陷的各种可能构型，然后运用分子动力学的方法，采用由Ａｃｋｌａｎｄ等提出的ＣｕＡｕ体系的多体势函数，计算了具有Ｌ１２结构的Ｃｕ３Ａｕ与Ａｕ３Ｃｕ中点缺陷的构型、形成能及缺陷体积。

Influence of solidification mode on pore structure of directionally solidified porous Cu-Mn alloy

By the directional solidification of metal-gas eutectic method（GASAR）,porous Cu-Mn alloy with oriented pores was fabricated successfully.The variation of pore structure was studied by experiments.The results show that the pore structure is primarily dependent on the solidification mode（planar,columnar cellular,columnar dendritic,equiaxed dendritic）,which is controlled by the solidification process.By numerical simulation,it is noted that along with solidification,the solidification mode of the alloy transforms from cellular to columnar dendritic and finally to equiaxed dendritic.Through increasing melt temperature and mold preheating,the range of equiaxed dendrite could be decreased,which helps to extend the region of oriented pore structure.

(CuAu_3)_n和(Cu_3Au)_n(n=1～15)团簇基态能量和结构的Monte Carlo模拟研究

本文采用Monte Carlo方法和Gupta势函数对(CuAu_3)_n和(Cu_3Au)_n团簇的基态能量和结构进行了模拟研究,通过计算平均结合能、结合能的一阶差分和二阶差分,分析了团簇的稳定性.结果表明:(Cu_3Au)_n和(CuAu_3)_n团簇都为立体结构,都是以二十面体为基础形成的;(Cu_3Au)_n和(CuAu_3)_n团簇结构中金原子都有位于团簇表面的倾向;这两类团簇结构的区别在于:在(Cu_3Au)_n团簇中,铜一金原子混合程度高;而(CuAu_3)_n团簇中,形成金原子位于表层,铜原子位于中心的层状结构;且当n=3、5、7、9时,(Cu_3Au)_n和(CuAu_3)_n团簇在各自的序列中相对稳定性较邻近团簇高,特别是n=7的团簇,相对稳定性最高.

The effect of the support on the surface composition of PtCu alloy nanocatalysts: In situ XPS and HS-LEIS studies

Supported PtCu alloys have been broadly applied in heterogeneous catalysis and electrocatalysis owing to their excellent catalytic performance and high CO tolerance. It is important to analyze the outermost surface composition of the supported alloy nanoparticles to understand the nature of the catalytically active sites. In this paper, homogeneous face-centered cubic PtCu nanoparticles with a narrow particle size distribution were successfully fabricated and dispersed on a high-surface-area Ti〇2 powder support. The samples were oxidized and reduced in situ and then introduced into the ultrahigh vacuum chamber to measure the topmost surface composition by high-sensitivity low-energy ion scattering spectroscopy, and to determine the oxidation states of the elements by X-ray photoelectron spectroscopy. The surface composition and morphology, elemental distribu-tion, and oxidation states of the components were found to be significantly affected by the support and treatment conditions. The PtCu is de-alloyed upon oxidation with CuO wetting on the TiO2 sur-face and re-alloyed upon reduction. Phase diagrams of the surface composition and the bulk com-position were plotted and compared for the supported and unsupported materials.

High temperature mechanical behavior of alumina dispersion strengthened copper alloy with high content of alumina

The microstructure and its effects on the high temperature mechanical behavior of Cu-2.7%Al_2O_3 （volume fraction） dispersion strengthened copper （ADSC） alloy were investigated. The results indicate that fine alumina particles are uniformly distributed in the copper matrix, while a few coarse ones are distributed on the grain boundaries. Tensile tests results show that Hall-Petch mechanism is the main contribution to the yield strength of ADSC alloy at room temperature. Its high temperature strength is attributed to the strong pinning effects of alumina particles on the grain and sub-grain boundaries with dislocations. The ultimate tensile strength can reach 237 MPa and the corresponding yield strength reaches 226 MPa at 700℃. Tensile fracture morphology indicates that the ADSC alloy shows brittleness at elevated temperatures. Creep tests results demonstrate that the steady state creep rates at 400 ℃ are lower than those at 700 ℃. The stress exponents at 400 ℃ and 700℃ are 7 and 5, respectively, and the creep strain rates of the ADSC alloy are controlled by dislocation core diffusion and lattice diffusion.

Enhanced thermal stability and mechanical properties of high-temperature resistant Al-Cu alloy with Zr and Mn micro-alloying

The high temperature(HT)thermal stability and mechanical properties of Al-5%Cu(AC)and Al-5%Cu-0.2%Mn-0.2 Zr%(ACMZ)alloys from 573 to 673 K were systematically studied.The results displayed that micro-alloying additions of Zr and Mn elements have presented a significant role in stabilizing the main strengthening metastableθ′precipitates at a temperature as high as 573 K.Simultaneously,the HT tensile test demonstrated that ACMZ alloy retained their strength of(88.6±8.8)MPa,which was much higher than that of AC alloy((32.5±0.8)MPa)after the thermal exposure at 573 K for 200 h.Finally,the underlying mechanisms of strength and ductility enhancement mechanism of the ACMZ alloy at HT were discussed in detail.

Efficient electrocatalytic reduction of carbon dioxide to ethylene on copper–antimony bimetallic alloy catalyst

The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate.

Microstructure evolution and mechanical properties of Al-6.5Cu-0.6Mn-0.5Fe alloys with different Si additions

The effect of Si content on the microstructures and mechanical properties of the heat-treated Al-6.5 Cu-0.6 Mn-0.5 Fe alloy was investigated using image analysis,scanning electron microscopy(SEM),transmission electron microscopy(TEM),and tensile testing.The results show that the mechanical properties of Al-6.5 Cu-0.6 Mn-0.5 Fe alloys decrease slightly when the Si content is below 1.0%.This can be attributed to the comprehensive effect of microstructure evolution,including the increase of nano-sized α-Fe,the coarsened grain size,and an increase in Al2 Cu content at the grain boundary.When the Si content is 1.5%,the mechanical properties of the Al-6.5 Cu-0.6 Mn-0.5 Fe alloys decrease significantly,and this can be attributed to the agglomerated second intermetallics,which is resulted from the formation of excess Si particles.

Modeling of whole process of ageing precipitation and strengthening in Al-Cu-Mg-Ag alloys with high Cu-to-Mg mass ratio

A physically based numerical model to predict the microstructure evolution and yield strength of high Cu-to-Mg mass ratio Al-Cu-Mg-Ag alloys during the whole ageing process was developed.A thermodynamically-based precipitation model,employing the classical nucleation and growth theories,was adapted to deal with the precipitation kinetics (evolution of radius and volume fraction of precipitates for Ω phase) of aged Al-Cu-Mg-Ag alloys.The model gives an estimation of the precipitation kinetics (evolution of radius and density of precipitates for both θ' and Ω phases) of the alloy.The strengthening model based on Orowan mechanism was deduced.The microstructural development and strength predictions of the model are generally in good agreement with the experimental data.

High damping capacities of Mg-Cu based alloys

The dynamic mechanical analyzer(DMA)was applied to investigate the damping properties of Mg-Cu based alloys.The results show that the as-cast hypoeutectic Mg-Cu binary alloys exhibit ultra-high damping capacities,while the eutectic Mg-Cu alloy exhibits low damping capacity.The strain amplitude dependent damping performance reveals that the dislocation damping mainly dominates in Mg-Cu alloys.Furthermore,the influence of eutectic phase on damping mechanisms of Mg-Cu binary alloys was discussed in detail and the effect of Si addition on the damping of Mg-1%Cu based alloy was also reported.Two damping peaks are observed on the temperature dependent spectrum of Mg-Cu based alloys.One is located at room temperature,which is dislocation related peak;and the other is located at moderate temperature,which is caused by the grain boundary sliding.

Thermal performance of sputtered Cu films containing insoluble Zr and Cr for advanced barrierless Cu metallization

Pure Cu films and Cu alloy films containing insoluble substances(Zr and Cr)were deposited on Si(100)substrates,in the presence of interfacial native suboxide(SiOx),by magnetron sputtering.Samples were vacuum annealed between 300℃and 500 ℃to investigate effects of Zr and Cr additions on the thermal performance of Cu films.After annealing,copper silicides were found in the Cu(Zr)films,while no detectable silicides were observed in Cu and Cu(Cr)films.Upon annealing,Zr accelerated the diffusion and reaction between the film and the substrate,and lowered the thermal stability of Cu(Zr)alloy films on Si substrates,which was ascribed to the‘purifying effect’of Zr on the Si substrates.Whereas,Cr prohibited the agglomeration of Cu films at 500℃and decreased the surface roughness.As a result,the diffusion of Cu in Si substrates for Cu(Cr)films was effectively inhibited.In contrast to the high resistivity of Cu(Zr)films,the final resistivity of about 2.76μΩ·cm was achieved for the Cu(Cr)film.These results indicate that Cu(Cr)films have higher thermal stability than Cu(Zr)films on Si substrates and are preferable in the advanced barrierless Cu metallization.

Dissolution kinetics of copper from multi-metal copper alloy roasted in oxygen

A kinetic study on the sulfuric acid leaching of multi-metal oxide, which is the product of multi-metal copper alloy with iron trioxide roasted in oxygen, was carried out. The effects of leaching time, stirring speed, sulfuric acid concentration, reaction temperature, and particle size of the multi-metal oxide on the kinetics and mechanism of copper extraction were studied. It was found that the reaction kinetic model about the copper extraction from multi-metal oxide follows the mixed kinetic shrinking core mode： 1/31n（1-X）＋（1-X）-l/3-1=680.5C（H2SO4）0.4297dp0.75115exp（-Ea/RT）t.

Corrosion performance and tribological behavior of diamond-like carbon based coating applied on Ni−Al−bronze alloy

The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.

Effects of rapid solidification process and 0.1%Pr/Nd addition on characteristics of Sn-9Zn solder alloy and interfacial properties of Cu/solder/Cu joints

Rapidly solidified Sn-9Zn-0.1Pr(/Nd) alloy foils were prepared by melt-spinning method. Through comparison, the effects of rapid solidification process and 0.1%Pr/Nd(mass fraction) addition on the microstructure, thermodynamic characteristic of Sn-9Zn solder alloy were analyzed. The tensile-shear tests were used to evaluate the mechanical properties of solder/Cu joints. The results show that the rapid solidification process can greatly refine the microstructure of Sn-9Zn-0.1Pr(/Nd) alloys. After rapid solidification, the effects of Pr/Nd addition on microstructure are depressed. The pasty range of the rapidly solidified Sn-Zn-RE solders is also reduced significantly. The mechanical properties of solder/Cu joints are obviously improved using the rapidly solidified Sn-9Zn-0.1Pr(/Nd) solder alloy, which results in the formation of uniform interface. The promotion effect of Nd addition in Sn-9Zn alloy on the interfacial reaction of solder/Cu joint is more remarkable than that of Pr.

Vacuum Brazing of TiAl Based Alloy with 40Cr Steel

The vacuum brazing of TiAl based alloy with 40Cr steel was investigated using Ag-Cu-Ti filler metal. The experimental results show that the Ag, Cu, Ti atoms in the filler metal and the base metal inter-diffuse toward each other during brazing and react at the interface to form an inter-metallic AlCu 2Ti compound which joins two parts to produce a brazing joint with higher strength.

Interaction Kinetics between Sn-Pb Solder Droplet and Au/Ni/Cu Pad

The interracial phenomena of the Sn-Pb solder droplet on and needle-like AuSn4 are formed at the interface after Au/Ni/Cu pad are investigated. A continuous AuSn2 the liquid state reaction （soldering）. The interracial reaction between the solder and Au layer continues during solid state aging with AuSn4 breaking off from the interface and felling into the solder. The kinetics of Au layer dissolution and diffusion into the solder during soldering and aging is analyzed to elucidate intermetallic formation mechanism at the solder/Au pad interface. The concentration of Au near the solder/pad interface is identified to increase and reach the solubility limit during the period of liquid state reaction. During solid state reaction, the thickening of Au-Sn compound is mainly controlled by element diffusion.

Cu_3Au薄膜中的[001]方向反相畴界

采用Ｍｏｎｔｅ Ｃａｒｌｏ 方法对Ｃｕ３Ａｕ 合金薄膜系统的有序—无序转变过程进行了计算机模拟。计算结果表明反相畴界的薄膜系统中的性质与在体材料中的不同。［００１］方向反相畴界的类型取决于薄膜系统的层数的奇偶性。当薄膜系统的原子层数为偶数时，薄膜中只出现非保守性的反相畴界，而当薄膜系统的原子层数为奇数时，薄膜中只出现保守性的反相畴界或不出现反相畴界。与体材料相同，在非保守性的反相畴界处发现了浸润现象。