Showing papers on "Electroplating published in 2019"

Upcycling of Electroplating Sludge into Ultrafine Sn@C Nanorods with Highly Stable Lithium Storage Performance

Abstract: Sn-based anode materials have become potential substitutes for commercial graphite anode due to their high specific capacity and good safety. In this paper, ultrafine Sn nanoparticles embedded in nitrogen and phosphorus codoped porous carbon nanorods (Sn@C) are obtained by carbonizing bacteria that adsorb the Sn electroplating sludge extracting solution. The as-prepared Sn@C rod-shaped composite exhibits superior electrochemical Li-storage performances, such as a reversible capacity of approximate 560 mAh/g at 1 A/g and an ultralong cycle life exceeding 1500 cycles, with approximately no capacity decay. The ultrastable structure of the Sn@C was revealed using in situ transmission electron microscope at the nanoscale and indicated that the Sn@C composite could restrict the volume expansion of Sn nanoparticles during the lithiation/delithiation cycles. This work provides a new insight into addressing the electroplating sludge and designing novel lithium ion battery anodes.

Single-Atom Electroplating on Two Dimensional Materials

Abstract: Catalyst doped with a single-atom noble metal displays distinctive catalytic behavior from the bulk counterparts, with tunable electronic structures and spatial versatilities, which excels in today’s heterogeneous catalysis. To deposit noble metals in a single atomic level requires a restricted chemical environment and precise thermodynamic control. Electroplating methods are commercially used to deposit uniform and conformal metal thin films on different hardware surfaces. Yet the atomic level electroplating has never been achieved. Herein we demonstrate a voltage gauged electrochemical deposition method to synthesize single-atom Pt, Au, and Pd on MoS2 and other two-dimensional (2D) materials. The surface atomic doping level for Pt, Au, and Pd can reach 1.1, 7.0, and 14%, respectively, and the doping sites are precisely positioned at Mo- and S-vacancies. The monodispersed noble atoms show enhanced hydrogen evolution activity and saturated CO tolerance, as explained by density functional theory calculatio...

Nano-scale twinned Cu with ultrahigh strength prepared by direct current electrodeposition

Abstract: An equiaxed grained nanotwinned Cu was firstly prepared by direct current electroplating using composite gelatin and poly-2-sulfur-2-propane sodium sulfonate additive, whose microstructure was similar to that prepared by pulse electroplating. This equiaxed grained nanotwinned Cu exhibited an ultrahigh tensile strength of 764 MPa, about 40% higher than that of columnar grained nanotwinned Cu. It suggested that the ultrahigh strength of Cu can be achieved through a microstructure of fine equiaxed grained nanotwin rather than large columnar grained nanotwin. It was thought that the grain growth along preferred orientation could be prevented through the dynamic competitive adsorption of poly-2-sulfur-2-propane sodium sulfonate and gelatin, which well explained the microstructural modification from columnar grain into equiaxed grain after SPS addition. The preparation of nt-Cu with ultrahigh strength by direct current electroplating has a potential application in production of ultrathin Cu foil used in lithium ion battery.

Additive Manufacturing of Sub-Micron to Sub-mm Metal Structures with Hollow AFM Cantilevers.

Abstract: We describe our force-controlled 3D printing method for layer-by-layer additive micromanufacturing (µAM) of metal microstructures. Hollow atomic force microscopy cantilevers are utilized to locally dispense metal ions in a standard 3-electrode electrochemical cell, enabling a confined electroplating reaction. The deflection feedback signal enables the live monitoring of the voxel growth and the consequent automation of the printing protocol in a layer-by-layer fashion for the fabrication of arbitrary-shaped geometries. In a second step, we investigated the effect of the free parameters (aperture diameter, applied pressure, and applied plating potential) on the voxel size, which enabled us to tune the voxel dimensions on-the-fly, as well as to produce objects spanning at least two orders of magnitude in each direction. As a concrete example, we printed two different replicas of Michelangelo's David. Copper was used as metal, but the process can in principle be extended to all metals that are macroscopically electroplated in a standard way.

Characterization of Pulse and Direct Current Methods for Electrodeposition of Ni-Co Composite Coatings Reinforced with Nano and Micro ZnO Particles

Abstract: Ni-Co composite coatings reinforced with ZnO particles are prepared by either pulsed current (PC) or direct current (DC) electrodeposition methods. X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and EDX mapping are employed to investigate phase structure, surface morphology, elemental composition, and elemental distribution of coating, respectively. The effects of electrodeposition parameters such as stirring rate, average current density, and ZnO particles concentration on the microhardness of electrodeposited composite coating reinforced with nano and micro ZnO particles are investigated. Optimal values are determined for all of the above-mentioned parameters, which result in the maximum hardness of the coating. Any deviation from the optimal parameters leads to a reduction of the coating’s microhardness. The SEM, atomic force microscopy (AFM), wear test, and electrochemical examinations revealed that changing the electrodeposition method from DC to PC and varying the size of ZnO particles from micro to nano affect the surface morphology from rough to smooth and reduce the surface friction coefficient, both of which enhanced the wear resistance of the coating and improved its corrosion resistance. The SEM results from worn surfaces illustrated that the size of reinforcing ZnO particles and the electroplating method change the wear mechanisms and worn surface morphology.

Low-Cost Manufacturing of Metal-Ceramic Composites through Electrodeposition of Metal into Ceramic Scaffold.

Abstract: Infiltration of a molten metal phase into a ceramic scaffold to manufacture metal-ceramic composites often involves high temperature, high pressure, and expensive processes. Low-cost processes for fabrication of metal-ceramic composites can substantially increase their applications in various industries. In this article, electroplating (electrodeposition) as a low-cost, room-temperature process is demonstrated for infiltration of metal (copper) into a lamellar ceramic (alumina) scaffold. Estimation shows that this is a low energy consumption process. Characterization of mechanical properties showed that metal infiltration enhanced the flexural modulus and strength by more than 50% and 140%, respectively, compared to the pure lamellar ceramic. More importantly, metal infiltration remarkably enhanced the crack initiation and crack growth resistance by more than 230% and 510% compared to the lamellar ceramic. The electrodeposition process for development of metal-ceramic composites can be extended to other metals and alloys that can be electrochemically deposited, as a low-cost and versatile process.

Electroplating of Pt–Ni–Cu nanoparticles on glassy carbon electrode for glucose electro-oxidation process

Abstract: Platinum and nickel–copper nanoparticles were electrodeposited on glassy carbon electrode (GCE) by using cyclic voltammetry (CV)-based electroplating technique. Morphology and chemical composition ...

Electrodeposition of Ni–TiO2 Composite Coatings Using Electrolyte Based on a Deep Eutectic Solvent

Abstract: Deep eutectic solvents are nowadays considered to be very promising analogues of room temperature ionic liquids. They can make a significant contribution to the development of novel efficient, economic and environmentally friendly processes, particularly, in surface engineering and electroplating. The electrodeposition of Ni–TiO2 composite coatings from an electrolyte based on a deep eutectic solvent, ethaline, was studied in this work. Titania particles were introduced into the plating bath in the form of Degussa P 25 nanopowder. The content of titania in electrodeposited composite coatings was shown to depend on the stirring rate, current density and TiO2 concentration in the electrolyte and can reach ca. 2.35 wt %. The microstructure and the surface morphology of the obtained composite layers were characterized. The formation of nanocrystalline nickel matrix was detected. The introduction of TiO2 particles into nickel-based coatings resulted in an increase in the microhardness of deposits. The data obtained via the electrochemical impedance spectra technique revealed an improvement in the corrosion resistance of coatings due to titania particles incorporation into deposits. The Ni–TiO2 composite coatings manifested a photocatalytic activity towards the reaction of photochemical degradation of methylene blue organic dye in water solution.

Pulsed-light surface annealing for low contact resistance interfaces between metal electrodes and bismuth telluride thermoelectric materials

Abstract: Traditional deposition methods of electroplating, sputtering and evaporation can produce weak and inconsistent interfaces between the electrode contact and Bi2Te3-based nanostructured thermoelectric (TE) materials. The electrode contact layers with low bonding strength are mainly due to the severe damage to the top layer of the TE material during surface preparation. We report a novel and cost-effective method for the surface preparation of thermoelectric materials (Bi2Te3) using pulsed light annealing prior to nickel electroplating. Short duration high-energy light absorption at the surface of the TE material causes reflow and annealing of surface structures, which enhance the electrical and thermal flow across the interface through more consistent and stronger bonding between the electrode metal and TE material. An electrical contact resistance reduction on the order of 5 μΩ cm2 and a pull strength of around 8 MPa were reproducibly measured for both p-type (Bi0.5Sb1.5Te3) and n-type (Bi2Te2.7Se3) compositions compared to electroplated nickel samples that did not receive pulsed light annealing treatment. This novel technique for surface preparation prior to metallization is applicable to a range of TE materials, and will lead to a significant improvement in the performance of TE modules and devices.

Transparent Bendable Secondary Zinc-Air Batteries by Controlled Void Ionic Separators.

Abstract: First ever transparent bendable secondary zinc-air batteries were fabricated. Transparent stainless-steel mesh was utilized as the current collector for the electrodes due to its reliable mechanical stability and electrical conductivity. After which separate methods were used to apply the active redox species. For the preparation of the anode, zinc was loaded by an electroplating process to the mesh. For the cathode, catalyst ink solution was spray coated with an airbrush for desired dimensions. An alkaline gel electrolyte layer was used for the electrolyte. Microscale domain control of the materials becomes a crucial factor for fabricating transparent batteries. As for the presented cell, anionic exchange polymer layer has been uniquely incorporated on to the cathode mesh as the separator which becomes a key procedure in the fabrication process for obtaining the desired optical properties of the battery. The ionic resin is applied in a fashion where controlled voids exist between the openings of the grid which facilitates light passage while guaranteeing electrical insulation between the electrodes. Further analysis correlates the electrode dimensions to the transparency of the system. Recorded average light transmittance is 48.8% in the visible light region and exhibited a maximum power density of 9.77 mW/cm2. The produced battery shows both transparent and flexible properties while maintaining a stable discharge/charge operation.

Effect of Plating Materials on the Corrosion Properties of Steel Alloy 4130

Abstract: The performance of weathering decay of uncoated and Ni, Cu and Cd coated steel alloy 4130 in 3.5 wt. % NaCl solution was anticipated. The Ni-coated sample showed greater corrosion inhibition effect than both Cu-coated and Cd-coated depending on the obtained results of open circuit potential, polarization curves, cyclic voltammetry, and impedance spectroscopy. The surface of uncovered and covered electrodes are described by subjecting to scanning electron microscopy prior and afterward engagement in a salt solution. The best corrosion resistance and surface morphology achieved in Ni-coated steel alloy. The inhibition efficiencies of tested samples were 90.7, 89.1 and 56.9 for the Ni-coated, Cu-coated, and Cd-coated respectively.