High speed fabrication of aluminum nanostructures with 10 nm spatial resolution by electrochemical replication

A high fidelity electrochemical replication technique for the rapid fabrication of Al nanostructures with 10?nm lateral resolution has been successfully demonstrated. Aluminum is electrodeposited onto a lithographically patterned Si master using a non-aqueous organic hydride bath of aluminum chloride and lithium aluminum hydride at room temperature. Chemical pretreatment of the Si surface allows a clean detachment of the replicated Al foil from the master, permitting its repetitive use for mass replication. This high throughput technique opens up new possibilities in the fabrication of Al-related nanostructures, including the growth of long range ordered anodic alumina nanochannel arrays.     

Nucleation and initial growth processes of diamond thin films for stripper foils

Carbon ion beam stripper foils were fabricated from diamond films synthesized on silicon via chemical vapor deposition. Fine-grained polycrystal diamond foils with decent surface flatness were obtained using a nucleation enhancement pretreatment process. Freestanding diamond foils were formed by etching a portion of the silicon substrate on which the diamond films well-adhered. In preliminary lifetime evaluations, the 1–3 μm-thick diamond foils lasted between 20 and 420 min for 3.2 MeV Ne⁺ion-beam charge stripping.     

Effect of Trace Sn on Pitting Behaviors of High Voltage Anode Aluminum Foil

The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn content were determined by using a secondary ion mass spectrometer. It was found that the micro-alloyed Sn is enriched at the external surface. The mechanism of pitting behavior of trace Sn on aluminum surface is similar with that of lead. Enrichment of Sn in the surface layer provides large numbers of sites for initiation of pitting corrosion, while pitting sites appeared relatively inhomogenously in the foils without Sn. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils, in which the volume fraction of cube texture is not reduced.     

Effect of hydrogen plasma pretreatment on the growth of silicon nanowires and their employment as the anode material of lithium secondary batteries

Silicon nanowires were grown from a silane and argon gas mixture directly on a stainless steel substrate by radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) and used without any further treatment as the anode in the fabrication of lithium ion batteries. It was found that suitable pretreatment of the stainless steel substrate was required for the satisfactory growth of the silicon nanowires. In this study, the substrates were polished, etched in HF solution, coated with an aluminum catalyst layer with a thickness of c.a. 10 nm and then treated with a hydrogen plasma before the growth of the silicon nanowires. SEM (Scanning Electron Microscopy) and AFM (Atomic Force Microscopy) analyses showed that the grain size and surface roughness were increased after the hydrogen plasma pretreatment. The electrochemical performance of the silicon nanowires anode was also improved when the aluminum coated stainless steel substrate was exposed to the plasma for 20 min or longer; the initial coulombic efficiency was increased from 69.7% to 82% at a current density of 30 mA cm(-2).     

Replication of DNA microarrays prepared by in situ oligonucleotide polymerization and mechanical transfer

In this paper, we describe a method for replication of DNA microarrays. The approach involves in situ, enzymatic synthesis of a DNA complement array using a prefabricated master array, followed by mechanical transfer of the complement array to a second substrate. The new findings reported here include the following. DNA spots as small as approximately 100 microm can be faithfully replicated, replica arrays consisting of several different oligonucleotide sequences can be prepared, and such arrays are active toward hybridization of their complements. Up to 10 replicas can be prepared from a single master with no detectable progressive degradation of their activity. DNA master arrays consisting of long DNA templates (80-mer) can be replicated, as can large-scale master arrays consisting of approximately 2300 spots.     

Grain refinement in rapidly solidified W-Si alloys

Grain refinement in rapidly solidified W-Si alloys has been investigated with respect to silicon content and solidification rate. Solid-solution W-Si alloys with varying silicon content were prepared into small buttons by arc melting, from which rapidly quenched foils of various thickness were made by the hammer and anvil technique. The grain size of the foils was studied with respect to thickness and silicon content. The results show that the grain size is inversely proportional to the thickness of a foil and also is an exponential function of silicon content on an empirical basis. The combined effect of cooling rate and silicon content on the grain size can be expressed by an exponential function.     

药用PVC硬片／铝箔热合强度不合格影响因素研究

本文研究了药用聚氯乙烯（PVC）硬片／铝箔的热合强度不合格影响的因素,通过材料鉴别和热合强度比较,得出PVC硬片热溶出物对其热合强度影响较小;铝箔内层粘合胶种类不同对其热合强度有影响,需指定铝箔与PVC硬片一一对应关系才能降低检验的风险性;铝箔内层粘舍胶涂布均匀性是影响其热合强度主要因素,同一样品不同部位热合强度差异比较明显;最后样品热合强度值会随着放置时间的增加而增加,于12h后达到平衡。     

Effect of Al-5Ti-1B on the microstructure of near-eutectic Al-13.0%Si alloys modified with Sr

The addition of Sr in Al-Si alloys as a modifier causes a transition of the morphology of eutectic silicon from coarse plate-like or acicular to fine fibrous. However, it may also lead to the formation of long columnar dendritic -Al phase. Al-5Ti-1B master alloy is often used as a grain refiner to achieve the fine equaixed grains in aluminum and aluminum alloys. The aim of the present study is to highlight the effect of Al-5Ti-1B master alloy additions on the microstructure of near-eutectic Al-Si alloys modified with Sr. When the addition of Al-5Ti-1B master alloy was below 0.82 mass%, the dendritic -Al phase changed from long columnar to equiaxed, and there were no noticeable changes of the morphology and size of eutectic silicon, while the size of eutectic cells decreased slightly. However, when the addition was above 0.82 mass%, the deleterious influence of Al-5Ti-1B master alloy on the modification effect of Sr emerged and with further increases in addition level a fully unmodified microstructure was finally produced. The results indicate that the effective Sr in the melt decreases with increased addition of Al-5Ti-1B. The poisoning event of Al-5Ti-1B master alloy on the modification of Sr is supposed to be related with the interaction between Sr and Ti.     

Benign joining of ultrafine grained aerospace aluminum alloys using nanotechnology

Ultrafine grained aluminum alloys have restricted applicability due to their limited thermal stability. Metalized 7475 alloys can be soldered and brazed at room temperature using nanotechnology. Reactive foils are used to release heat for milliseconds directly at the interface between two components leading to a metallurgical joint without significantly heating the bulk alloy, thus preserving its mechanical properties.     

微变形对强立方织构铝箔腐蚀发孔的影响

利用蚀坑法对强立方织构铝箔腐蚀发孔的机理进行了研究,通过对退火铝箔施加拉伸微变形,使箔内位错密度急剧增加,蚀孔数目以及面积比均得到提高.实际生产中该方法可用于提高高纯铝箔腐蚀的发孔率.     

中间退火对高纯铝箔立方织构的影响

采用晶体取向分布函数（ODF）研究和分析了中间退火对高纯铝箔立方织构的影响。研究结果表明：中间退火对高纯铝箔冷轧形变织构影响不大,但对成品退火箔材中立方织构和R织构含量产生重要影响,在300C/2h中间退火条件下,成品箔材中再结晶立方织构物取向密度最大,R织构含量较小。     

表面自组装法制备高比容Al2O3/TiO2复合膜

通过提高工作介质氧化膜的介电常数来增加电容器的比容量, 是解决铝电解电容器小型化、轻量化常用的方法之一。本研究采用表面自组装法, 在铝箔表面引入磺酸基团使铝箔表面的荷电性质发生改变, 铝箔与二氧化钛前驱体胶粒间的静电斥力转变为静电引力, 从而增加了二氧化钛在铝箔表面的沉积量。经过热处理与阳极氧化后, 在铝箔表面形成了高介电常数Al₂O₃/TiO₂复合膜。相对未涂覆TiO₂的阳极铝箔, 采用表面自组装法制备的复合膜表面的钛含量增加了30倍, 其比容量在400 V耐压下提高了44.26%。本方法制备的大比容量阳极氧化铝箔在铝电解电容器行业有巨大的应用潜力。     

Fabrication of poly(methyl methacrylate) microfluidic chips by atmospheric molding

A greatly simplified method for fabricating poly(methyl methacrylate) (PMMA) separation microchips is introduced. The new protocol relies on UV-initiated polymerization of the monomer solution in an open mold under ambient pressure. Silicon microstructures are transferred to the polymer substrate by molding a methyl methacrylate solution in a sandwich (silicon master/Teflon spacer/glass plate) mold. The chips are subsequently assembled by thermal sealing of the channel and cover plates. The new fabrication method obviates the need for specialized replication equipment and reduces the complexity of prototyping and manufacturing. Variables of the fabrication process were assessed and optimized. The new method compares favorably with common fabrication techniques, yielding high-quality devices with well-defined channel and injection-cross structures, and highly smoothed surfaces. Nearly 100 PMMA chips were replicated using a single silicon master, with high chip-to-chip reproducibility (relative standard deviations of 1.5 and 4.7% for the widths and depths of the replicated channels, respectively). The relatively high EOF value of the new chips (2.12 x 10(-4) cm(2) x V(-1) x s(-1)) indicates that the UV polymerization process increases the surface charge and hence enhances the fluidic transport. The attractive performance of the new CE microchips has been demonstrated in connection with end-column amperometric and contactless-conductivity detection schemes. While the new approach is demonstrated in connection with PMMA microchips, it could be applied to other materials that undergo light-initiated polymerization. The new approach brings significant simplification of the process of fabricating PMMA devices and should lead to a widespread low-cost production of high-quality separation microchips.     

Application of Ti: W barrier metallization for integrated circuits

Aluminum metallization is the most widely used for contacts and interconnections in integrated circuits. However, the solid state diffusion of aluminum in silicon during contact sintering or high temperature packaging can result in junction shorting or leakage in shallow (<1 μm) emitter-base junction devices. The interposition of a barrier metal between the aluminum and the silicon is one solution to this problem. A sputter-deposited pseudo-alloy of Ti:W (10:90 wt.%) with PtSi contacts is suitable for this application. Resistivity ratio measurements on SiO₂/ ti:W/Al film test samples have shown that the resistivity of aluminum increases owing to diffusion of titanium or tungsten into the aluminum. However, the kinetic data show that no more than a 10% increase in the resistivity of the aluminum can be expected in the useful life of a device. High current stress data show that Ti:W/Al interconnections are comparable with those of aluminum films. Auger depth profiling of si/Ti:W/Al samples annealed at 450, 500 and 550°C in N₂ shows no aluminum at the Si-(Ti:W) interface. Application of the PtSi/Ti:W/Al metallization system for large-scale integrated circuits is described.     

铝电解电容器用电子铝箔的性能分析与比较

利用原子吸收光谱仪(AAS)、电子扫描电镜(SEM)、电子背散射技术(EBSD)、电化学工作站等方法对不同厂家生产的铝电解电容器用电子铝箔各方面的性能进行比较和分析。结果表明,国产铝箔在微量元素设计和杂质控制,立方织构控制方面已达到国外同类产品的先进技术水平,但表面加工质量,氧化层均一性和微量元素的分布控制方面与国外存在差距。     

Effect of boron on microstructure and mechanical properties of eutectic aluminum‐silicon alloy modified with phosphorus

In order to understand the effect of boron on the microstructure and mechanical properties of eutectic aluminum‐silicon alloy modified with phosphorus, complex modification of eutectic aluminum‐silicon alloy by aluminum‐3phosphorus and aluminum‐3boron was conducted. The results show that the area fraction of primary α‐aluminum in eutectic aluminum‐silicon alloy modified with aluminum‐3phosphorus increased first and then decreased with increasing amounts of aluminum‐3boron. The area fraction and the size of primary silicon decreased rapidly first and then stabilized. The morphology of eutectic silicon transformed from needle‐like into fine short rods or granules after complex modification with aluminum‐3phosphorus and aluminum‐3boron. The ultimate tensile strength of the alloy modified with 0.4 wt.% aluminum‐3phosphorus and 0.2 wt.% aluminum‐3boron increased by 18 %, compared with that of the eutectic aluminum‐silicon alloy modified with aluminum‐3phosphorus, while the elongation decreased by 5 %. It was concluded that the comprehensive mechanical properties of eutectic aluminum‐silicon alloy were improved.     

Production and performance of the inFOCmicroS 20-40-keV graded multilayer mirror

The International Focusing Optics Collaboration for microCrab Sensitivity (InFOCmicroS) balloonborne hard x-ray telescope incorporates graded Pt/C multilayers replicated onto segmented Al foils to obtain the significant effective area at energies previously inaccessible to x-ray optics. Reflectivity measurements of individual foils demonstrate our capability to produce a mass quantity of multilayered foils with a rms roughness of 0.5 nm. The effective area of the completed mirror is 78 and 22 cm2 at 20 and 40 keV, respectively. The measured half-power diameter is 2.0 +/- 0.6 are min (90% confidence). The successful completion of this mirror demonstrates its applicability to future x-ray telescopes such as Constellation-X.     

转换阵列式碳纳米管薄膜至铝箔上的工艺

描述了一种将阵列式碳纳米管(CNTs)膜从石英基底转移至新基底(铝箔)上的工艺。用SEM检测了转移至铝箔上后各层膜的形貌并测试了铝箔CNTs膜的电阻。结果表明转基底工艺可以显著提高CNTs薄膜的利用率。去除90%不干胶后铝基CNTs薄膜的电阻可以达到0.3Ω以下。     

Roll-to-roll anodization and etching of aluminum foils for high-throughput surface nanotexturing

A high-throughput process for nanotexturing of hard and soft surfaces based on the roll-to-roll anodization and etching of low-cost aluminum foils is presented. The process enables the precise control of surface topography, feature size, and shape over large areas thereby presenting a highly versatile platform for fabricating substrates with user-defined, functional performance. Specifically, the optical and surface wetting properties of the foil substrates were systematically characterized and tuned through the modulation of the surface texture. In addition, textured aluminum foils with pore and bowl surface features were used as zeptoliter reaction vessels for the well-controlled synthesis of inorganic, organic, and plasmonic nanomaterials, demonstrating yet another powerful potential use of the presented approach.     

Growth of tensile and fatigue cracks in metal foils

The extension of cracks in thin foils of copper, brass, and tantalum has been investigated for both monotonic and cyclic loading using optical microscopy and scanning electron microscopy. Crack growth in both tension and fatigue is found to occur primarily by a void coalescence mechanism, as previously reported for aluminum foils. The particular morphology of void formation exhibited by a given material is determined by its purity level and stacking fault energy, the latter being important as it affects the slip character—varying from planar to wavy—of the metal.Fatigue crack growth without void formation has also been observed in brass and tantalum. The resulting fracture surfaces are flat; a different growth mechanism, attributed to plane strain conditions at the crack tip rather than plane stress, accounts for this mode of propagation.