Multilayer aluminum composites prepared by rolling of pure and anodized aluminum foils

Experimental results on processing,structural and mechanical characterization of a multilayer composite based on commercially pure aluminum foils were presented.A multilayer composite was produced by hot-rolling of anodized and non-anodized aluminum foils alternately sandwiched.In addition,the same process was applied for bonding of non-anodized foils.In both cases,obtained multilayer composites were compact and sound.In order to study composites microstructural evolution and mechanical properties,optical and scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),X-ray diffraction(XRD)analysis,hardness,tensile and three-point flexural tests were performed.Microstructural characterization confirmed that the rod-like particles distributed in parallel rows in the composite aluminum matrix with anodized foils correspond to Al2O3.Maximum and minimum peaks of oxygen and aluminum,respectively,suggest that after the final hot-rolling of composite with non-anodized foils,a small amount of coarser particles were formed at boundaries between foils.Hardness,strength,modulus of elasticity and flexural strength of both multilayer composites were much higher than those of pure aluminum,whereas ductility was significantly less.The composite with anodized foils exhibited the highest strength and modulus of elasticity,but lower ductility compared to composite processed from non-anodized foils.Fracture failure corresponded to the change of ductility.

Microstructure and abrasive wear behaviour of anodizing composite films containing Si C nanoparticles on Ti6Al4V alloy

Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film(3.73×10-8 A/cm2). The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.

Rare Earth Application in Sealing Anodized Al-Based Metal Matrix Composites

A new method for corrosion protection of Al-based metal matrix composites (MMC) was developed using two-step process, which involves anodizing in H2SO4 solution and sealing in rare earth solution. Corrosion resistance of the treated surface was evaluated with polarization curves. The results showed that the effect of the protection using rare earth sealing is equivalent to that using chromate sealing for Al6061/SiCp. The rare earth metal salt can be an alternative to the toxic chromate for sealing anodized Al MMC.

Corrosion Behavior and Protection Efficiency of 2024Al and SiC_p/2024Al Metal Matrix Composite

The corrosion resistance of 2024 Al and SiC particle reinforced 2024 Al metal matrix composite (SiCp?024AI MMC) in 3.5% NaCl solution was investigated with electrochemical method and immersion test, and the corrosion protection of sulfuric acid anodized coatings on both materials was evaluated by electrochemical impedance spectroscopy. The results showed that the SiCp?024AI MMC is more susceptible to corrosion than its matrix alloy in 3.5% NaCI. For 2024AI, the anodized coating provides excellent corrosion resistance to 3.5% NaCI. The anodized coating on the SiCp?024AI provides satisfactory corrosion protection, but it is not as effective as that for 2024AI because the structure of the anodized layer is affected by the SiC particulates.

Corrosion and discharge performance of Mg-9%Al-2.5%Pb alloy as anode for seawater activated battery

To obtain a new kind of Mg?Al?Pb alloy anode material with low content of Pb, the corrosion and discharge behavior of Mg?9%Al?2.5%Pb (hereafter in mass fraction) alloy were investigated by immersion tests and electrochemical techniques, and compared with those of Mg?6%Al?5%Pb alloy. The results indicate that Mg?9%Al?2.5%Pb alloy exhibits a lower self-corrosion rate and higher utilization efficiency in contrast with Mg?6%Al?5%Pb alloy because of the higher content of Al. As the result of the decrease of Pb content, the discharge activity of Mg?9%Al?2.5%Pb alloy is relatively weaker but still meets the requirement of anode. These results reveal that Mg?9%Al?2.5%Pb alloy with a low content of Pb can serve as a good candidate for the anode material used in seawater activated battery.

JOINING MECHANISMS OF β"-Al_2O_3 CERAMIC AND PYREX GLASS TO Al MATRIX COMPOSITE

The bonding of β″-Al2O3 and pyrex glass to A1 matrix composites by anodic bonding process is achieved. The microstructure of the bonded interface and the joining mechanisms are analyzed with scanning electron microscope （SEM）, energy dispersive X-ray fluorescence spectrometer （EDX）. It is observed that the bonding region across the interface consists of the metal layer, oxide transitional layer and the ceramic layer, with the transitional layer composed of surface region and sub-surface region. The bonding process can mainly be categorized into anodic bonding process and solid state diffusing process. The pile-up of the ions and its drift in the interface area are the main reasons for anode oxidation and joining of the interface. The temperature, voltage and the drift ions in the ceramic or glass during the bonding process are the essential conditions to solid state diffusing and oxide bonding at the interface. The voltages, temperature, pressure as well as the surface state are the main factors that influence the anodic bonding.

Formation and capacitance properties of Ti-Al composite oxide film on aluminum

Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.

Layered Metal Composites: Newest Generation of Radiation-Protective Materials

The expediency of development of one of the newest highly effective radiation-protective materials—layered composites of “light metal/heavy metal” type is substantiated. The characteristics of the internal architecture of composites of Al/Pb type made by consecutive application of vacuum and normal atmospheric rolling are adduced. The differences between the radioisotope and accelerating techniques of experimental testing of radiation-protective properties of materials are described. The results of the testing of composites and the influence of their structure on radiation-protective properties of the investigated materials are characterized. It is shown that the radiation-protective efficiency of composites certain structures may be 30% - 40% higher than the aluminum. This gives the opportunity to reduce the weight of radiation-protective structure at preservation of effectiveness of protection at aluminum level, or to increase the effectiveness of protection at constant weight of this structure.

Al/Pb-Ag-Co阳极中的Co在锌电沉积过程中的催化机理

为了研究Al/Pb-Ag-Co阳极中Co在锌电沉积过程中的催化过程及机理,将铝板置于甲基磺酸镀液中电沉积Pb-Ag和Pb-Ag-Co层制成Al/Pb-Ag和Al/Pb-Ag-Co阳极,分析镀层中Co在锌电沉积过程中的催化过程与机理。结果表明:Al/Pb-Ag-Co阳极比Al/Pb-Ag阳极有更好的电催化活性;极化24 h后,Al/Pb-Ag-Co阳极表面的四边形晶体PbSO4是不定向生长的;Al/Pb-Ag-Co阳极中Co在锌电沉积过程中的催化过程可能是Co→Co2+→Co3+。

电沉积Al/Pb-Ag阳极在电积锌过程中的耐腐蚀性

采用电沉积的方法在甲基磺酸镀液中制备了一种新型的锌电积Al/Pb-0.23%Ag阳极。腐蚀实验和电化学分析显示,Al/Pb-0.23%Ag阳极与传统Pb-0.25%Ag阳极相比,具有较低的腐蚀速率,较高的腐蚀电位和较低的腐蚀电流密度,较高的电催化活性;金相显微镜、扫描电子显微镜和X射线衍射分析显示,Al/Pb-0.23%Ag阳极的晶粒细小、致密,极化48 h后有PbSO4、α-PbO2和β-PbO2生成。

铝离子对锌电积用Al/Pb-0.2%Ag合金阳极电化学性能的影响

采用循环伏安、塔菲尔曲线、阳极极化、交流阻抗测试研究在含不同铝离子(Al^(3+))浓度的锌电解液中极化24 h后的Al/Pb-0.2%Ag(质量分数)阳极的腐蚀行为和析氧行为,并通过扫描电镜和X射线衍射仪分别观察阳极的表面形貌和阳极氧化膜的物相组成。结果表明:随着Al^(3+)浓度的增大,阳极的析氧电位、自腐蚀电流密度以及电极的电荷传质电阻呈现出逐渐增大的趋势;表观交换电流密度呈现出逐渐减小的趋势;α-PbO_2(111)衍射峰强度呈现出逐渐减弱的趋势,Pb(101)衍射峰强度呈现出逐渐增强的趋势;阳极表面氧化层被腐蚀的程度逐渐加深。Al^(3+)的存在降低了阳极的耐腐蚀性能和导电性能。

液固包覆法制备Al-Pb层状复合材料及其界面研究

利用键参数函数理论分析了第三组元Bi或Sn作为Al-Pb非混溶体系实现冶金结合一体化的可行性,并采用液-固包覆成型的方法制得了Al-Bi-Pb及Al-Sn-Pb层状复合材料,通过SEM、EDS等检测手段分析研究试样的显微组织,并讨论了界面的扩散现象。结果表明:第三组元Bi或Sn的引入将Al、Pb的混合焓ΔHmin降低到零以下,在扩散动力学作用驱使下使各元素间在界面处发生了迁移和互扩散,形成了成分调控区,表现为一条状的均质固溶体带,实现了Al与Pb之间的冶金结合。

Bi对Pb-Al层状复合电极材料制备与性能的影响

采用热物理温度场浸镀成Al-Bi双金属层状板材,并利用液固包覆技术制备Pb-Bi-Al层状复合电极材料,借助线性扫描伏安法(LSV)、SEM、抗弯曲性能试验等测试手段对样品的结构与性能进行表征。结果表明,第三组元过渡金属Bi的引入,实现了Pb与Al之间的冶金结合,所制得的Pb-Bi-Al层状复合电极材料与同体积的传统Pb合金电极相比,机械强度提高33.7%,质量减轻11.0%,电极极化电位降低21.8%,且在极化区具有趋近于0的致钝电流。因此,Al-Bi-Pb层状复合电极材料是一种质量轻、导电好、强度高、耐腐蚀的电极材料,有着重要的开发应用前景。

一种Al-Pb-钢背轴瓦材料连铸复合新方法及其生产装置

提出了Al Pb 钢背轴瓦材料的连铸复合方法,设计研制了实现该方法的水平连铸复合装置。实验结果表明,采用该种方法及装置所获得的冷却速度、轴瓦材料的Pb相分布和粘结强度完全可以满足实际生产的要求。

磁控溅射共沉积Al-Pb复合薄膜微观结构及电性能

采用磁控溅射共沉积法制备Al-Pb复合薄膜,运用TEM、SEM、EDX和电阻-温度仪对薄膜微观结构和电性能进行研究。结果表明,Al-Pb薄膜具有温度敏感性,电阻温度系数(TCR)可达8.4×10-3℃-1。薄膜微观结构含富Al基体相和富Pb第二相,呈两相组织。随着厚度的增大,第二相粒子及基体相晶粒粒度增大,界面密度降低,界面电子散射效应减弱,电阻率下降,TCR值增大。与Al膜和移去Al基体形成的Pb膜的电性能对比研究显示,Al-Pb薄膜存在并联导电机制,电阻率受两相电阻率和体积分数的影响。

喷射成形及轧制钢/Al-Pb合金复合板材的界面结合强度

对喷射成形钢/Al-Pb复合板的界面结合进行了研究,结果表明喷射成形的钢/Al-Pb复合板经变形量达50%左右的轧制和320℃×5h退火处理后可获得良好的界面结合,其剪切强度可达72MPa。分析显示双金属界面结合强度的提高是扩散层形成的结果。

Al-Pb新型复合电极材料的制备及其性能研究

寻求一种好的电极材料一直是蓄电池工业和湿法冶金工业竞相发展的重要课题。实验以Bi作为Al、Pb之间的结合介质,制备出Al-Bi-Pb的复合电极材料。该Al-Bi-Pb复合电极材料与传统Pb合金电极材料相比,具有抗弯强度提高,极化电位降低,电阻小等特点。

喷射成形钢/AlPb轴瓦合金复合板材的组织及耐磨性

对喷射成形制备的钢/Al Pb合金复合板材的微观组织,轧制和退火处理后的组织及耐磨性进行了研究。喷射成形钢/Al Pb合金复合材料中的Al Pb合金层经变形量为50%的轧制和320℃×5h的退火处理后,形成致密的组织,Pb相粒子尺寸仅为1～2μm,材料的耐磨性得到提高。

机械合金化制备Al-Pb纳米相复合结构的热力学分析

参考Miedema半经验公式,建立Al-Pb系机械合金化过程的热力学模型,并对所制备的Al-10%Pb粉末进行热力学计算和对比分析。实验表明利用机械合金化方法可以获得在Al基体上均匀弥散分布着纳米相Pb的复合结构;热力学计算结果表明,Al-Pb系粉末机械合金化过程不具备形成非晶相、固溶体和中间化合物的热力学驱动力。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)分析Al-10%Pb合金在高能球磨过程中的组织结构,表明,所建立的热力学模型是正确的。

增强型Al-Pb层状复合电极材料制备与性能研究

以Pb-Al层状复合电极材料与传统Pb合金电极为研究对象,通过在Al与Pb合金之间引入过渡金属Sn制备出Al-Sn-Pb层状复合电极材料,与Pb合金电极对比研究了物理性能及电化学行为.测试电阻分布、重量、电极极化曲线、耐蚀性、槽电压等分析表明:与传统Pb合金电极相比,其电阻减少24%,重量减轻37.6%,电极极化电位降低2.3%,腐蚀损耗降低90.8%,槽电压降低200mV。因此ASP层状复合电极材料是一种重量轻、导电好、耐腐蚀的电极材料,有着重要的开发应用前景。