Showing papers on "Electroplating published in 2012"

Fabrication of Al/Ni/Cu composite by accumulative roll bonding and electroplating processes and investigation of its microstructure and mechanical properties

Abstract: Al–Ni–Cu composite was produced using accumulative roll bonding (ARB) and electroplating processes. Nickel was electroplated on copper substrate for a certain time and voltage. In this study, the microstructural evolution and mechanical properties of the Al–Ni–Cu composite during various ARB cycles were studied by optical and scanning electron microscopes, microhardness, tensile and bending tests. It was observed that at first, nickel layers and then copper layers, were necked, fractured and distributed in aluminum matrix as accumulative roll bonding cycles were increased. Finally, after 11 cycles of ARB process, a completely uniform composite was produced with a homogeneous distribution of copper and nickel particles in aluminum matrix. The results showed that by increasing the number of ARB cycles, the bending strength of produced composite was increased. Also, it was found that when the number of cycles was increased, not only elongation was increased but also the tensile strength of the composite was improved. Microhardness for different elements in different cycles was also evaluated. Finally, fracture surfaces of samples were studied, using scanning electron microscopy (SEM), to reveal the failure mechanism.

Preparation and Characterization of Nickel-Coated Carbon Fibers by Electroplating

Abstract: Electroplating technique was applied to coat carbon fibers with nickel. Before plating, the initial fibers were pretreated to improve the wettability in bath. The electroplating parameters were optimized to obtain high-quality nickel-coated carbon fibers, and the effects on plating were studied. The coated carbon fibers were characterized by SEM, XRD, and XPS. The coatings are uniform, smooth, bright, and adherent to carbon fibers not only along length but also along the diameter of the filaments, and mainly composed of pure nickel. Metal-carbon-oxygen bonds are present at the interface between nickel coatings and fibers, which provides the interfacial binding force. The results of performance tests showed that the nickel-coated fibers possess a good bonding strength not less than 78.5 kPa, and exhibit excellent oxidation resistance at high temperature. Compared with the initial fibers, the wettability with aluminum is also improved obviously.

Drop-on-Demand Laser Sintering With Silver Nanoparticles for Electronics Packaging

Abstract: This paper proposes a “dry” laser-sintering method and discusses characteristics of a laser-sintered silver thin film on a polyimide or a copper substrate. This novel technology consists of the following processes: first, ink-jet printing of metal nanoparticles with dispersants and solvents for minute patterning; second, short preheating to remove organic substances in the ink; and finally, millisecond-order laser-beam irradiation under atmospheric conditions with the flow of argon gas for metallization. Regarding the wiring, visible lasers with high absorption on the ink develop rapid metallization and activate solvent evaporation, resulting in a rough surface with large pores. Interface adhesion is increased by the anchoring effect in the course of laser irradiation. In contrast, near-infrared lasers with low absorption heat the ink from the polyimide interface, yielding a dense, low-specific-resistance structure. Regarding pad formation on the copper leadframe without any surface pre-treatments, interdiffusion takes place at the Ag/Cu interface and increases adhesivity. The structural quality of the laser-sintered silver pad is almost the same as that of an electroplated one, so that no difference in good wire-bondability is obtained when the near-infrared continuous-wave laser is irradiated for a short time of a millisecond order per lead.

High-Efficiency MEMS Electrochemical Actuators and Electrochemical Impedance Spectroscopy Characterization

Abstract: We present high-efficiency Nafion-coated electrochemical actuators having biocompatible construction suitable for biomedical applications such as drug delivery. High flow rates of up to 141.95 ± 0.46 μL/min were achieved (at 13 mA). Nafion coating increased efficiency across all current values tested and prevented current-induced damage to electrodes. The effects of coating thickness, electroplating, actuator orientation, and changes in temperature on actuator performance were studied. Electrochemical impedance spectroscopy is introduced as a tool for characterizing electrodes, quality of electrochemical cleaning, determining surface area activity, and also for understanding the impact of electrolyte coatings, electroplating, and substrate changes on actuator performance. Parylene and polyetheretherketone (PEEK) were investigated as flexible substrate substitutes for soda lime glass. The higher surface roughness of the PEEK substrate compared to glass led to actuators with improved flow rates.

Electrodeposition and characterization of Ni–Zn–P and Ni–Zn–P/nano-SiC coatings

Abstract: Alloy coatings and metal based composites have been given special attention for their unique properties. In the present study, a novel electroplating bath was introduced. Ni–Zn, Ni–Zn–P nickel rich alloy coatings and Ni–Zn–P/nano-SiC nickel rich composite coating were successfully deposited on low carbon steel substrates. The optimum bath composition was found by comparing the amount of coating cracks checked by a scanning electron microscope (SEM). The presence of nearly homogeneous SiC nanoparticles in the coating was confirmed by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX) and MAP analysis. The effect of operating conditions on the mechanical properties of nanocomposite coatings was investigated. The wear resistance of the coatings was examined by pin on disk wear tests. The nanocomposite coatings had a lower weight loss compared to the Ni–Zn–P coatings in the wear test.

Rechargeable dual electroplating cell

Abstract: A dual electroplating cell comprising: (a) an electrolyte component containing therein ions of a first metal; (b) a porous cathode current collector having surface areas to capture and store metal ions directly thereon, wherein the cathode current collector has a specific surface area greater than 100 m 2 /g that is in direct contact with said electrolyte; (c) a porous anode current collector having surface areas to capture and store metal ions thereon, wherein the anode current collector has a specific surface area greater than 100 m 2 /g that is in direct contact with the electrolyte; (d) a porous separator disposed between the anode and the cathode; and (e) an ion source of the first metal disposed in the anode current collector or the cathode current collector and in electronic contact therewith to obtain an open circuit voltage (OCV) from 0.3 volts to 3.5 volts when the cell is made.

Toward a Better Understanding of the Effect of Cu Electroplating Process Parameters on Cu 3 Sn Voiding

Abstract: “Kirkendall voiding” in the interfacial Cu3Sn intermetallic compound is often observed in solder joints made between Sn-containing alloys and Cu interconnect pads, during extended thermal aging or electromigration testing. It is commonly believed that voids arise from the Kirkendall effect, i.e., the imbalance of diffusion fluxes of Cu and Sn atoms in Cu3Sn. However, recent studies have demonstrated that the propensity for voiding is greatly affected by the amount of organic impurities incorporated during Cu electroplating. The level of impurities was shown to depend on various electroplating parameters, such as current density, bath temperature, bath age, etc. In this study, a general picture is proposed to provide a better understanding of the effect of electroplating process parameters on Cu3Sn voiding. The picture correlates the level of impurity incorporation to (1) the applied electroplating overpotential, and (2) the crystallographic orientation of the Cu deposit. As a first-order approximation, the picture is supported by a variety of electroplating experiments, secondary-ion mass spectroscopy (SIMS), and x-ray diffraction (XRD) analysis.

Electroplating apparatus for tailored uniformity profile

Abstract: Methods of electroplating metal on a substrate while controlling azimuthal uniformity, include, in one aspect, providing the substrate to the electroplating apparatus configured for rotating the substrate during electroplating, and electroplating the metal on the substrate while rotating the substrate relative to a shield such that a selected portion of the substrate at a selected azimuthal position dwells in a shielded area for a different amount of time than a second portion of the substrate having the same average arc length and the same average radial position and residing at a different angular (azimuthal) position. For example, a semiconductor wafer substrate can be rotated during electroplating slower or faster, when the selected portion of the substrate passes through the shielded area.

Comparative study of protective nickel–tungsten deposit behavior obtained by continuous and pulsed currents from citrate–ammonia media

Abstract: A comparative study of protective Ni–W deposit behavior obtained by continuous (cc) and pulsed (pc) currents from citrate–ammonia media on copper surface was presented. Effects of electroplating process on microstructures, in terms of crystallization, proportion and grain size were investigated using SEM/EDS and XRD. The results show that Ni–W morphology obtained by (cc) and (pc) was quite different; it changed from rigorous and irregular to smooth and granulate. Corrosion mechanisms and stability in 10 h of immersion into 3% NaCl of various treated-coatings were discussed in the consideration of electrical conductivity, microhardness, porosity and inhibition efficiency.

A new architecture for solar cells involving a metal bridge deposited between active TiO2 particles

Abstract: The efficiency of titanium dioxide (TiO2)-based film solar cells fabricated by combined spray and electroplating methods was improved by forming metal bridges in the pores between TiO2 nanoparticles. The interfaces between TiO2 nanoparticles and metal bridges formed Schottky contacts, which minimized recombination of electron-hole pairs and increased electron transfer. A maximum efficiency of 4.38% was achieved for cells plated at 50 mA and 55 °C. This efficiency is higher than that reported for solar cells with a similar structure [Saehana et al., AIP Conf. Proc. 1284, 154 (2010); 1415, 163 (2011); IJBAS/IJENS 11, 15 (2011)]. We also identified that both current and temperature influence the morphology of the metal bridges and efficiency of the solar cell.

Treatment method for electroplating sludge

Abstract: The invention discloses a treatment method for electroplating sludge, comprising the following steps of: a) mechanically dewatering the electroplating sludge; b) drying the mechanically-dewatered electroplating sludge, to obtain a dried material; and c) mixing the dried material, a slag forming agent, a reducing agent and a solvent to obtain the mixed material, and smelting the mixed material under the temperature of 1200-1350 DEG C, so that metal melt and slag can be obtained The treatment method for the electroplating sludge according to embodiments of the invention adopts mechanical dewatering, so that the sludge drying energy consumption can be reduced, and the problems that the current electroplating sludge treatment is high in energy consumption and bad in economic benefit can be solved; the metal is enriched by a smelting technology, so that the treatment method is high in metal recovery rate; and the waste slag can be sold to the cement industry, the zero discharge of wastewater can be realized, and the waste gas is processed by adopting an active carbon absorbing process, a cloth bag dedusting process and an alkaline water washing process, so that the requirement of the industrial policy can be met, and the cleaning recovery of the electroplating sludge can be realized

Surface treatment process of copper foil for high-Tg halogen-free plate

Abstract: The invention relates to a surface treatment process of a copper foil for a high-Tg halogen-free plate, belonging to the technical field of a production process of a high-precision electrolytic copper foil. In the surface treatment process provided by the invention, a structure shape of a coarsening layer is changed by using a special mixed additive in a coarsening step so as to improve anti-stripping strength; an ultra-fine nanoscale electroplated nickel-zinc alloy is used as a barrier layer to assure the corrosion resistance of the copper foil. Internal properties and pressure plate back color of the copper foil which is treated by the process provided by the invention are similar with those of the copper foil which is imported abroad; the anti-stripping strength on the high-Tg (Tg170) and the halogen-free plate is more than 1.5 N/mm; and the copper foil has characteristic of environmental friendliness and does not contain harmful matters, such as arsenic, antimony, mercury, cadmium, hexavalent chromium and the like.

Electrodeposition methods of gallium and gallium alloy films and related photovoltaic structures

Abstract: Photovoltaic devices and methods for preparing a p-type semiconductor layer for the photovoltaic devices generally include electroplating a layer of gallium or a gallium alloy onto a conductive layer by contacting the conductive layer with a plating bath free of complexing agents including a gallium salt, methane sulfonic acid or sodium sulfate and an organic additive comprising at least one nitrogen atom and/or at least one sulfur atom, and a solvent; adjusting a pH of the solution to be less than 2.6 or greater than 12.6. The photovoltaic device includes an impurity in the p-type semiconductor layer selected from the group consisting of arsenic, antimony, bismuth, and mixtures thereof. Various photovoltaic precursor layers for forming CIS, CGS and CIGS p-type semiconductor structures can be formed by electroplating the gallium or gallium alloys in this manner. Also disclosed are processes for forming a thermal interface of gallium or a gallium alloy with the electroplating process.

Aluminum alloy surface treatment method

Abstract: The invention provides an aluminum alloy surface treatment method which comprises the steps of sequentially carrying out pretreatment, chemical plating and electroplating on an aluminum alloy matrix, wherein the pretreatment comprises the steps of sequentially carrying out anode oxidation, laser etching, erosion and acid etching on the aluminum alloy matrix. By using the method for forming electroplating texture on the surface of an aluminum alloy, the obtained product has natural texture, is not subject to skip plating, bubbling and discoloration phenomena and has a good decorative effect. Besides, the method has the advantage of simple operation, realizes the unshaded treatment and the convenient maintenance by using the technology of anode oxidation plus electroplating, and facilitatesthe mass production.

Study on the internal stress of nickel coating electrodeposited in an electrolyte mixed with supercritical carbon dioxide

Abstract: This study focuses on the internal stress in the nickel deposit during electroplating through the additive-free Watts bath electrolyte mixed with and without supercritical carbon dioxide (Sc-CO 2 ). The results showed that the Ni films plated in Sc-CO 2 had brighter, smoother surface and higher hardness than plated in conventional electrolyte without Sc-CO 2 . However, there existed more nano-sized pinholes via TEM and AFM measurements in the Sc-CO 2 specimens. It was found that during electroplating the Sc-CO 2 occluded into the coating through the nano-sized pinholes/voids influenced the internal stress of the deposit. On the other hand, the periodic plating characteristics of the Sc-CO 2 electroplating led to higher relative peak magnitude of Ni {111} over {200} in crystalline orientation revealed in X-ray diffraction patterns. As a result, the internal stress in the nickel film plated through the Sc-CO 2 method was significantly higher than that in the conventional one. Moreover, the more CO 2 volume fraction used in Sc-CO 2 electroplating resulted in even higher internal stress of nickel film.

Method for plating zinc-nickel alloy in alkaline electroplate liquid

Abstract: The invention discloses a method for electroplating alkaline Zn-Ni alloy, comprising the steps of: preparing alkali wash and acid wash, preparing electroplating Zn-Ni alloy plating solution, mechanical grinding, degreasing with organic solvent or water-based detergent, alkali washing, acid washing and electroplating The invention provides a stable electroplating solution formula and complete electroplating process The coating electroplated by the method is proved to have good flat surface, uniform coating distribution and alloy distribution, the coating is single gamma-phase, the nickel hasa content of 10% to 15%; the coating has superior corrosion resistance, red rust appears on the non-passivated Zn-Ni coating after 1500 hours in a neutral salt spray test; compared with general alkali electroplating solution, the coating has high current efficiency, reaching up to 80% to 90%