Papers by Keyword: Electroforming

Abstract: This paper has introduced moulding method of electroforming combining with arc spraying. Compared with electroforming moulding, it has shortened moulding production cycle and reduced cost of production. Compared with arc spraying moulding, it has improved mould’s surface quality and hardness.

Abstract: The micro gear molds for powder injection molding were fabricated by electroforming process of Ni-Fe alloys. The residual stress at interface between electrodeposit and substrate was important for micro electroforming. Addition of 6 g/L saccharin lowered residual stress from 466.3 MPa up to 32.8 MPa and increase of Fe content resulted in increase of residual stress. Electrodeposition by pulse current decreased residual stress in deposit although Fe content was increased. These results reveal clearly that decrease of residual stress due to pulse current is larger than increase of residual stress due to higher Fe content. The micro electroformed gear molds with 550 μm and 2,525 μm in outer diameter and 400 μm in height were fabricated by micro electroforming and 316L feedstock was injection-molded into micro molds. As a result, it is suggested strongly that micro electroforming is very useful process to manufacture micro mold with high dimensional accuracy for micro PIM.

Abstract: Spherical abrasives were employed to polish the growing deposited layer during nickel electroforming process. On a translational flat cathode, nickel deposits with distinct polishing mark were obtained. It was found that the abrasive polishing can help to improve the microstructure and increase the mechanical properties of the nickel deposits. Compared with the deposits prepared with traditional method, the microstructure became more homogeneous and the microhardness increased nearly two times. The increase of current density led to coarse structure and lower microhardness.

Abstract: To improve the mechanical properties of the EDM electrode material, the electroforming process for fabricating copper-nanozirconia (ZrO₂) particles composite aided by ultrasonic has been presented. In this research, some vital process parameters such as concentration of ZrO₂, rotational speed and ultrasonic frequency have been evaluated. Two inspection criteria, content of ZrO₂ and micro hardness of deposited layer were employed to evaluate the fabrication quality of copper-nanozirconia (ZrO₂) composite material. The experimental results indicate that nanocomposites grains electroformed aided by ultrasonic are refined. Their organizations are more uniform and dense, the surface is flatter and the microhardness of nanocomposites is significantly improved.

Abstract: Ni-ZrO₂-CeO₂ nanocomposites were prepared by double-pulse current in an ultrasonic field. The effect of average current density, duty ratio and frequency of double-pulse current on nanoparticles content of Ni-ZrO₂-CeO₂ nanocomposites was studied. Meanwhile, surface morphology and microhardness of nanocomposites were analyzed. The results show that, with the positive average current density, positive duty ratio and positive frequency increased, the nanoparticles contents increased at first and then decreased. On the contrary, it reduced while reverse average current density, reverse duty ratio and reverse frequency were increasing. Compared with Ni-ZrO₂-CeO₂ prepared by direct current and monopulse current, grain of Ni-ZrO₂-CeO₂ nanocomposite prepared by double-pulse current is finer, the microhardness is also higher.

Abstract: t is possible to get electroforming deposit with numerous special functions by adoption of traditional electroforming technique, but in which there are defects such as uneven electroforming deposit and unstable performance, etc. In order to enhance the quality and speed of electroforming deposit, this article has proposed the particle flow erosion precision electroforming technology, particle flows such as huge amount of micro glass bead is used in the process of electro-deposit for erosion of electroforming deposit surface, so that micro glass beads continuously abrade and impact cathode surface. As indicated in electroforming test of metallic nickel, in comparison with traditional electroforming technology, particle flow erosion precision electroforming technology can effectively change the microscopic structure of electroforming deposit, refine grain and realize evener distribution of grains, so as to reduce the diffracted intensity of all crystal faces and enhance mechanical property of electroforming deposit.

Abstract: Nickel layers with tensile or pressure residual stress were prepared by electroforming technique from two kinds of electrolyte. Subsequent heat treatment was adopted to get the stress released. The coefficients of thermal expansion (CTEs) were measured with a thermal dilatometer and the relationship between residual stress and the measured CTEs was revealed both from experimental results and theoretical analysis.

Abstract: The basic principle and technological methods of electroforming are briefly described. With the progress in materials, processes and equipment, electroforming has got a considerable development. It is increasingly combined with other technologies, such as assembling electrotype, fabrication of MEMS, LIGA, etc. The shortcomings of electroforming technologies at present stage are also pointed out. As an inter-disciplinary subject area, electroforming will be widely developed and applied.

Abstract: In this paper, the effect of CeO2 nanoparticles content in the bath on the weight percent of CeO2 particles, morphology, texture, and high temperature oxidation resistance of the nanocomposite coatings was examined. With a rise in the loadings of CeO2 particles in the bath from 10 gl-1 to 40 gl-1, the CeO2 particles weight percent in the nanocomposite coatings gradually increases. Further increased the loadings of particles in the bath to 50 gl-1, the weight percent reversely reduces. The maximum of CeO2 nano particles weight percent in the nanocomposite coatings is 4.98 wt% obtained at current density of 3 Adm-2 from the bath containing 40 gl-1 CeO2 particles. The high temperature oxidation resistance of Ni-CeO2 nanocomposite coatings significantly rise compared with that of bare nickel coatings, and enhanced with a rise in the loadings of CeO2 nano particles from 10 gl-1 to 30 gl-1. The wear resistance of deposits is also consist with the nanoparticles content in the bath。

Abstract: In order to improve the corrosion resistance of sintered NdFeB magnet, experiments are done by the new process which involves ultrasonic electroforming Ni–P alloys. The influence of ultrasonic on electroforming Ni–P alloy on NdFeB was studied by using microscope, adhesion test and NaCl solution immersion test.The results showed that the Ni–P alloy deposit on NdFeB is rough and has poor adhesion without ultrasonic agitation; However, the Ni–P alloy deposit on NdFeB with ultrasonic agitation has the following advantages: uniform and smooth deposit grains, strong adhesion and good corrosion resistance.