低轮廓电解铜箔表面微细粗化工艺研究

目的 针对低轮廓电解铜箔剥离强度不足的问题,进行铜箔表面微细粗化处理研究,通过在铜箔表面生成可控形态的针状结构粗化层,以期在不影响低轮廓铜箔表面整体轮廓的条件下,提高铜箔的抗剥离性能。方法 采用电化学微细粗化法,以NaOH和K2S2O8的混合溶液为粗化电解液,研究电流密度、NaOH浓度及K2S2O8浓度等主要工艺参数对铜箔表面针状结构形貌、粗糙度及铜箔剥离强度的影响。结果 经过微细粗化处理后,低轮廓电解铜箔表面形成了针状多面体结构,在粗化电流密度为1.5 A/dm²、粗化液中NaOH质量浓度为100 g/L、K2S2O8质量浓度为20 g/L的条件下,粗化层形成的针状多面体结构致密且均匀,铜箔的剥离强度提升至0.48 N/mm。结论 通过电化学微细粗化法,在低轮廓电解铜箔表面成功制备了针状结构的粗化层,通过优化微细粗化工艺参数,实现了铜箔表面针状结构粗化层的可控制备,在保证铜箔低表面粗糙度的同时,有效提高了铜箔的剥离强度。     

A general in situ hydrothermal rolling-up formation of one-dimensional, single-crystalline lead telluride nanostructures

In this study we demonstrate that one-dimensional (1D) nanostructured lead telluride (PbTe) can be synthesized in a hydrothermal reaction between lead foil and tellurium powder. The resulting materials were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The formation of the 1D structure can be explained by an in situ hydrothermal rolling-up mechanism whereby PbTe is formed hydrothermally and deposited on the lead substrate. The lead underneath the PbTe layer is then selectively etched by a cetyltrimethylammonium bromide solution, thus allowing the PbTe to roll up into 1D structures. This method can be extended to prepare other 1D tellurides, including CdTe, Cu(2)Te, and Ag(2)Te.     

考虑压缩空气边界的爆炸箔起爆器飞片运动模型

为了研究爆炸箔起爆器中的飞片运动规律,对爆炸桥箔蒸气驱动飞片的过程机理进行了研究。在假设爆炸箔电爆炸后形成的蒸气均匀膨胀以及飞片进行一维刚体运动的基础上,考虑桥箔蒸气内部的压力梯度,引入了压缩空气边界条件,进行飞片运动速度的计算,得到特定发火电路中以桥箔长度、桥箔厚度、飞片厚度以及发火电压为自变量的飞片运动速度模型。根据实测飞片速度的PDV(光子多普勒测速仪)测试结果,引入能量利用率对飞片运动速度曲线进行修正,并且拟合得到了能量利用率关于上述4种自变量的经验公式。结果表明：电爆炸推动飞片运动过程中,能量利用率与桥箔厚度和飞片厚度正相关,而与桥箔长度和发火电压负相关;初期,桥箔蒸气内部具有明显的压力梯度,最大压力可达10 GPa数量级;压缩空气段长度随着时间由0逐渐增大;在桥箔长度与加速膛厚度之比为0.4¹.2、桥箔厚度与加速膛厚度之比为0.002⁰.010、飞片厚度与加速膛厚度之比为0.025⁰.160的范围内,减小桥箔长度、桥箔厚度以及飞片厚度对提高加速膛出口飞片速度、降低爆炸箔起爆器的发火能量具有积极的作用。     

Generating high-power hard X-ray pulses in a rod-pinch diode with radial foil

A new method of low-impedance rod-pinch diode formation has been proposed and used. With this approach, the rod-pinch diode is preliminarily shorted by a thin radial foil. A low-impedance diode is formed when the foil, accelerated by current of a high-current generator, is detached from the anode rod. It is established that a series of sequential current closures via plasma of the foil and rod in this configuration can be used to obtain a train of short hard X-ray pulses.     

Experimental study of the pressure field of an electric explosion of plane ring foil

Results of an experimental study of the pressure field of a shock acoustic wave in a closed chamber with condensed matter are presented; this wave results from the electric explosion of a plane ring foil, on which discharge current passes in the radial direction. The presence of a pronounced pressure maximum with regard to the electrode-system axis can be interpreted as the effect of nonlinear interaction of elements of the shock acoustic waves excited on diametrically opposite sides of the exploding ring foil.     

Targets emitting transition radiation for performing X-ray lithography by the tabletop synchrotron MIRRORCLE-20SX

The tabletop storage ring synchrotron (SRS) MIRRORCLE-20SX is a powerful source of soft X-rays emitted from transition radiation (TR) targets. SRS can be used as a source for performing X-ray lithography (XRL) when it emits TR power P_XRL50–100 mW of photons having energy in the range 490–1860 eV. One-foil targets in SRS can emit a high TR power, and the electron beam geometry of MIRRORCLE-20SX requires using TR strip targets with a width 3 mm. P_XRL emitted by one-foil strip TR targets is estimated for several foil materials, and varying foil thickness d. These results show that a target containing one C foil with d260 nm can be used for performing XRL. Target made of one collodion foil with d290 nm, and target of one Al foil with d200 nm emit less, but could also be used for XRL. We manufactured such targets by depositing layers of these materials on slide glass, using Teepol as a releasing agent, and subsequently floating them on a water surface. The C layer is prepared by a horizontal resistance thermal evaporation, and supported by a 270–300 nm thick collodion layer, formed onto the Teepol film. The Al layer is thermally evaporated.     

Photosensitive Film Formation on Copper

When copper foil was dipped into aqueous solutions of copper (In halides a photosensitive layer formed on the copper which, if the foil is subsequently exposed to light the film blackens. Measurement of the threshold wavelength for the reaction and the variations with the different halide ions was investigated.     

Investigation of the aluminium-aluminium oxide reversible transformation as observed by hot stage electron microscopy

Thin foils of high purity aluminium and an Al-Al₂O₃ SAP type of alloy were oxidised in a specially designed hot stage specimen chamber in an electron microscope. Below 450° C, amorphous aluminium oxide formed on the foil surface and was first detectable at foil edges, holes, and pits. Islands of aluminium then nucleated in this amorphous oxide. The aluminium islands displayed either a lateral growth with eventual coalescence with other islands, or a reoxidation process which caused the islands to disappear. The aluminium island formation was determined to be related to the presence of the electron beam. A mechanism based upon electron charging due to the electron beam was proposed to explain the nucleation, growth, coalescence, disappearance, and geometry of the aluminium islands.     

Modification of a gas jet transport system for the supression of heavy-mass fission product homologues

The uranium target of a gas jet transport system for fission products has been modified by the addition of an aluminum cover foil. The new modification allows fission fragments of low mass to enter a continuous chemistry system while heavier fragments are stopped in the aluminum. The elimination of the heavier homologues allows development of simpler and faster chemical separation procedures. In addition, since the lighter fragments are slowed down by the cover foil a smaller target chamber can be used. This leads to a reduction in system holdup time.     

Calibration of X-Ray Film Used in the Detection of Soft X-Rays from the CTR Device Sceptre

To assist in the interpretation of X-ray pinhole photographs in thermonuclear research with the toroidal pinch device Sceptre, with a view to applying such photographs to the study of the energy spectrum of the electron flux incident upon the torus walls (constructed from aluminium and copper), experiments have been performed to determine the photographic effect of the X-rays produced from a known flux of electrons of given energy. A demountable X-ray tube was made in which the target was alternately copper or aluminium foil, indirectly heated, and in which a beam of electrons of known energy was focused on the foil. X-rays from the target fell upon llford Industrial G type X-ray flim, after passing through one or more metal foils. By maintaining a known beam current for different times, a range of exposures was given to different parts of the same film specimen and density-log exposure curves were compiled. Results of such experiments are presented for target elements of aluminium and copper and various thicknesses of absorbing foil, for electron energies in the range 1.8-8.4 KeV. A method is suggested by which data accumulated in this way may be used in analysis of electron energy spectra.     

The investigation on electrochemical denatured layer of 304 stainless steel

Electrochemical grinding (ECG) is one of nontraditional manufacturing methods that are widely used on various chromium alloys like 304 stainless steel and GCr15, etc. It has been considered that a thin passive film is formed on alloys during the electrochemical process and much research has been done on it. However, it is found that a kind of denatured layer (which is much thicker than passive film) is formed on 304 stainless steel surface during the process while the characteristics and influence factors of the denatured layer have been rarely focused. In this paper, an experimental study as well as a computational method were implemented to investigate characteristics of denatured layer on 304 stainless steel and influential mechanisms of electrochemical parameters on thickness of denatured layer. We found that the hardness of denatured layer was decreased by 70%, and third-order equations for predicting layer thickness under different electrochemical parameters were proposed. The obviously reduced hardness and controllable thickness of the denatured layer are expected to be of great significance in machining of chromium alloy.     

Fully coupled linear modelling of incompressible free‐surface flow,compressible air and flexible structures

Incompressible free‐surface flow is a common assumption for the modelling of water waves. Connected with the aim to develop very large floating platforms, air chamber supported floating structures have attracted considerable research interest in the past. Such structures are carried by air entrapped in chambers formed by stiff, vertical walls. In order to model these types of structures, the interactions between surface gravity waves and compressible air must be taken into account. If the payload requirements for air chamber supported structures are low enough, the air chambers may be formed by flexible membrane cylinders. In such systems, pressure variations can lead to considerable changes in chamber volume. Therefore, the flexibility of the bounding structures must be taken into account. We present a modelling strategy to tackle the fully coupled problem of compressible gas in a flexible chamber and incompressible free‐surface flow in an unbounded domain. The governing equations and boundary conditions are described and solved by the finite element method. A perfectly matched layer is used to obtain a solution for an unbounded domain. Finally, the numerical implementation is validated by various test cases. Copyright © 2015 John Wiley & Sons, Ltd.     

Film-induced Tensile Stress during CorrosionProcess for α-Ti

The α-Ti foil with protective layer in one side bended to corrosion surface gradually during corrosion process in 0.1 mol/L H2SO4, while the passive film was formed, i.e., a tensile stress was developed in the surface layer of the sample. The extra tensile Stress grew gradually, whose maximum value is =313 MPa (average of 5 samples), which is near or reaches the yield stress. The extra tensile stress would be added to the load Stress during SCC to facilitate the emission and motion of dislocation, so that SCC cracks could nucleate in lower Stress(or lower KI).     

Deposition of titanium/titanium oxide clusters produced by magnetron sputtering

Titanium clusters of nanometer sizes are produced by magnetron sputtering with subsequent aggregation in an argon gas flow. The produced Ti clusters are directed and deposited on a silicon substrate. Deposited films are analyzed by X-ray photoelectron spectroscopy in order to obtain the chemical composition and by atomic force microscopy and X-ray reflection methods to obtain information about the film structure. Experiments were carried out at different temperatures of the walls of the magnetron chamber. The size and the flux of clusters from the magnetron chamber are obtained by the analysis of the substrate surface with deposited clusters. It is found that the cluster parameters strongly depend on the temperature of the magnetron chamber walls. Molecules of titanium oxides may be nuclei of condensation and accelerate the nucleation process. A theoretical analysis based on experimental results is presented. It allows us to describe various stages of cluster evolution from their formation up to the deposition on the substrate and provides estimations for parameters of the processes involving clusters.     

活性钎焊法连接碳化硅陶瓷的连接强度和微观结构

采用三元Ag-Cu-Ti活性焊料连接常压烧结碳化硅陶瓷,研究了反应温度、保温时间等钎焊工艺对碳化硅陶瓷连接强度的影响,分析了连接界面的微观结构和反应产物. 实验结果表明,在实验范围内,钎焊温度和保温时间对碳化硅陶瓷的连接强度均有峰值,四点弯曲强度最高达到342MPa,随着钎焊温度的升高,界面反应层厚度增加,连接强度提高,但过高的钎焊温度引起焊料的挥发而使连接强度下降. 焊料中的活性元素Ti与碳化硅发生反应在连接界面形成均匀致密的反应层,反应层厚度约1μm,XRD和EDX能谱分析结果表明反应产物是TiC和Ti₅Si₃.     

Development of a new thoron progeny detector based on SSNTD and the collection by an electric field

The importance of (220)Rn (thoron) progeny for human exposure has been widely recognised in the past decades. Since no stable equilibrium factor was found between indoor thoron and its progeny, and the concentration of thoron progeny varies with time, it is necessary to develop detectors for long-term measurement that directly sample and detect thoron progeny. However, power supply of this kind of detectors has always been a problem. In this study, a set of device that is suitable for long-term measurement is introduced. A high-voltage electric field was formed for the collection of charged aerosols attached by (222)Rn (radon) and thoron progenies on solid-state nuclear track detector. Impact from radon progeny could be eliminated with a shield of Al foil of appropriate thickness. Tests were made both in an experimental house and in a thoron chamber in Helmholtz Zentrum München to determine the parameters and to verify the universality under different conditions.     

In-situ synchrotron X-ray scattering study of thin film growth by atomic layer deposition

We report an atomic layer deposition chamber for in-situ synchrotron X-ray scattering study of thin film growth. The chamber was designed for combined synchrotron X-ray reflectivity and two-dimensional grazing-incidence X-ray diffraction measurement to do a in-situ monitoring of ALD growth. We demonstrate ruthenium thermal ALD growth for the performance of the chamber. 10, 20, 30, 50, 70, 100, 150 and 250-cycled states are measured by X-ray scattering methods during ALD growth process. Growth rate is calculated from thickness values and the surface roughness of each state is estimated by X-ray reflectivity analysis. The crystal structure of initial growth state is observed by Grazing-incidence X-ray diffraction. These results indicate that in-situ X-ray scattering method is a promising analysis technique to investigate the initial physical morphology of ALD films.     

Pulsed high energy density plasma processing silicon surface

Pulsed high energy density plasma (PHEDP) is a new material modification technique, which has the features of: high energy density (1–10 J/cm²), high plasma density (10¹⁴–10¹⁶ cm⁻³), high electron temperature (10–100 eV), high directed plasma velocity (10–100 km/s) and short pulse duration (10–100 μs). PHEDP interacting with material will result in rapid melting and re-solidification of surface layer with a quenching rate up to 10⁸ K/s; thus the material surface properties are modified. At the same time, PHEDP contains condensable ions or/and atoms, so a thin film layer can be formed on the modified surface and the deposited layer can be mixed with the substrate (or previous deposited layer) during following pulses. Therefore, this technique actually combines film deposition and mixing into one step. In this paper, we have reported the research results on the metallization of Si by PHEDP. The Ti---Si reactions under PHEDP are also discussed.     

Diffusion bonding stainless steel to alumina using aluminium interlayers

A study has been conducted to identify the effects of fabrication temperatures pressures, times and other variables on the strengths of diffusion-bonded joints between alumina and BS321 stainless steel produced using aluminium foil interlayers. The strengths of the alumina-aluminium and steel-aluminium interfaces were found to be influenced differently by some fabrication parameters, thus increasing the fabrication temperature promoted alumina-aluminium bonding but also accelerated the growth of ultimately weakening intermetallic layers at steel-aluminium interfaces. It was concluded that the optimum conditions for bonding BS321 stainless steel to alumina could be achieved by using a 0.5 mm aluminium foil, applying a 50 MPa pressure for 30 min in an evacuated chamber at 625° C. In discussing the results of this study, attention is paid to the problems or advantages of using foils and metal components other than aluminium or BS321 steel and particular note is taken of thermal expansion mismatch effects.     

Effect of radiation-induced charge accumulation on build-up cap on the signal current from an ionisation chamber

The signal current from a thimble ionisation chamber with a build-up cap made of an insulator decreases by about 0.41 % after being irradiated for 17 h at an air kerma rate of 41 Gy h(-1) by a collimated (60)Co gamma-ray beam in air. In contrast, the signal current remains constant when the thimble ionisation chamber is irradiated in a water phantom. During irradiation, positive charge is considered to accumulate near the outer surface of the build-up cap where electron equilibrium is not achieved. Secondary electrons travelling in the build-up cap and the chamber wall toward the ionisation volume are decelerated by the electric field generated by the positive charge. Consequently, the signal current decreases with increasing charge accumulation because some secondary electrons are prevented from entering the ionisation volume. In the water phantom, electron equilibrium is established in and around the ionisation chamber and charge does not accumulate. To confirm this hypothesis, the signal current was measured for an ionisation chamber in air with a build-up cap wrapped with Al foil and covered with PMMA tubes. Electron equilibrium was established over the build-up cap because the tubes were thicker than the secondary electron range. The signal current decreased with increasing positive voltage applied to the Al foil. It was estimated from the results that positive charges equivalent to a voltage of over 6 kV applied to the Al foil accumulated during irradiation. The signal current was also measured for an ionisation chamber with a metal build-up cap and for an ionisation chamber with a wall and build-up cap made of conductive plastic.