Papers by Keyword: Jet Electrodeposition

Abstract: Jet electrodeposition process is a very promising method in fabricating metal matrix composites reinforced with ceramic particles. In use of this method, insoluble particles suspended in an electrolytic bath are impinged onto and embedded in a growing metal layer. This paper is focused on the investigations of the copper matrix nanocomposite coatings with hard Al2O3 nanoparticles, electrochemically deposited from jet-circulated baths on 304 stainless steel substrate. The Cu-Al2O3 composite coating was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The effects of electrolyte jet velocity, current density, addition amount of Al2O3 in the electrolyte were analyzed on the microstructure change, surface morphology change as well as codeposited content of Al2O3 particles in the composite coating. It was found that increasing content of Al2O3 particles in electrolyte may improve composite coating surface morphology and increase the practical current density by exerting impingement effect on the cathode deposit surface, till excessive Al2O3 e.g.20g/L particles was added. Besides, appropriate amount of nanoparticles in the electrolyte also could offer grain refinement by providing nanocrystalline sized between 30~60 nm with current density in the range of 100~500 A/dm2.

Abstract: Jet electrodeposition is one of electrochemical machining methods, which is able to increase cathodic current density, therefore having high deposition rate, good locality and nanocrystalline structure. These advantages enable jet electro-deposition to integrate with rapid prototyping technology in an effort to achieve selective electro-deposition on the cathode surface. This paper combine both methods to prepare nanocrystalline copper parts. The equipment system is developed, which is mainly composed of computer control system, machine body, electrolyte circulation system, nozzle and its hoisting mechanism and other parts. Deposition rate, locality, deposit thickness distribution and forming accuracy are analyzed. A group of nanocrystalline copper parts having good shape and size precision have been prepared. Influencing factors on forming accuracy are analyzed.

Abstract: The bulk porous nickel was fabricated by layer scanning jet electrodeposition, a novel porous metal preparation technique. The dendritic crystalline layer or normal layer of the bulk porous nickel can be obtained by controlling of the growth conditions. The effects of deposition conditions, such as jet velocity, deposition current density, jet scanning mode, scanning rate, electrolyte solution, etc., on the morphology and growth process of the dendritic structures were studied in detail. It is revealed that the deposition rate and the uniformity of the pore distribution for the bulk porous Ni increase with the decrease of jet velocity. The depositing current density has an upper and lower limit. The dendritic structures are sensitive to the scanning rate, scanning mode, electrolyte solution. As a result, the optimized bulk porous nickels with controllable dendritic crystalline layered structure, pore size and porosity were fabricated by accurately controlling the growth conditions above.

Abstract: The principles of jet electrodeposition orientated by rapid prototyping were introduced , The nanocrystalline nickel parts with simple shape were fabricated using jet electrodeposition oriented by rapid prototyping. The microstructure and phase transformation of nanocrystalline nickel were observed under the scanning microscope and X-ray diffraction instrument . The results show that the successful fabrication of metallic parts demonstrates the potential of the jet electrodeposition process for prototyping technology . The jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The nickel parts prepared by jet electrodeposition own a fine-grained structure( average grain size 25.6nm) with a smooth surface and high dimensional accuracy under the optimum processing parameters..The dimensional accuracy as well as the surface quality of metallic parts and tools manufactured using jet electrodeposition techniques still lag far behind those of conventionally machined parts.

Abstract: Jet electrodeposition orientated by rapid fabrication were introduced , The nanocrystalline nickel parts were fabricated using jet electrodeposition . The microstructure and phase transformation of nanocrystalline nickel were observed under the scanning microscope and X-ray diffraction instrument . The results show that the jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The nickel parts prepared by jet electrodeposition own a fine-grained structure with a smooth surface and high dimensional accuracy under the optimum processing parameters.

Abstract: The influences of jet flow rate and temperature on cathodic polarization of nickel deposits have been studied in this paper. The results indicate that increasing jet flow rate and temperature of the electrolyte make the equilibrium electrode potential decrease. When jet flow rate increases from 1.0 L/min to 6.0 L/min, the grain size of nickel deposits decreases from 22.6 nm to 18.9 nm. X-ray diffraction patterns show that increasing jet flow rate results in (111) preferred growth orientation for nickel deposits.

Abstract: The system components and the theory of jet electrodeposition orientated by rapid prototyping (RP) are introduced.The nanocrystalline copper parts with simple shape were fabricated by RP technology. The microstructure evolution of the nanocrystalline Copper layer was examined by means of the Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The results show that the jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The copper deposited layers have nanocrystalline microstructure with average size of 55.6nm. The grain size decreases to 41.4 nm in crystal plane (311).

Abstract: A jet electrodeposition device was carried out to prepare Cu-Al₂O₃ nanocomposite coatings. The influence of the concentration of Al₂O₃ in the electrolyte and parameters on the content of the Al₂O₃ in the deposite were investigated. The coatings ingredient and microstructure was measured by the scanning electron microscope, the microhardness tests were conducted on an microhardness tester. The results show that the copper deposited layers have nanocrystalline microstructure with grain size of about 50nm . The amount of Al₂O₃ in composites first increased and then decreased with an increase in the concentration of Al₂O₃, current density, temperature and jet velocity. The composite with optimum atomic percent of Al₂O₃ (14.4 at%) can be obtained at the concentration of 30 g/l , cathodic current densities 300 A/dm², temperature 30°С , and jet velocity 8 m/s . The addition of Al2O3 in copper increases the microhardness of the electrodeposited coatings.

Abstract: A jet electrodeposition device was carried out to prepare Cu-Al₂O₃ nanocomposite coatings. The influence of the concentration of Al₂O₃ in the electrolyte and the parameters on the content of the Al₂O₃ in the deposit was investigated. The coatings ingredient and microstructure was measured by the scanning electron microscope, the microhardness tests were conducted on an microhardness tester. The results show that the copper deposited layers have nanocrystalline microstructure with grain size of about 50nm . The amount of Al₂O₃ in composites first increased and then decreased with an increase in the concentration of Al₂O₃, current density, temperature and jet velocity. The composite with optimum atomic percent of Al₂O₃ (14.4 at%) can be obtained at the concentration of 30 g/l , cathodic current densities 300 A/dm2, temperature 30°C, and jet velocity 8 m/s . The addition of Al₂O₃ in copper increases the microhardness of the electrodeposited coatings.

Abstract: The principles of jet electrodeposition orientated by rapid prototyping were introduced. The nanocrystalline nickel parts with simple shape were fabricated using jet electrodeposition. The microstructure and phase transformation of nanocrystalline nickel were observed under the scanning microscope and X-ray diffraction instrument. The results show that the jet electrodeposition can greatly enhance the limited current density, fine crystalline particles and improve deposition quality. The nickel parts prepared by jet electrodeposition own a fine-grained structure (average grain size 25.6nm) with a smooth surface and high dimensional accuracy under the optimum processing parameters.