Papers by Author: Yi Qiang He

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 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.