Papers by Keyword: Pulse Plating

Abstract: The effects of positive and reverse working time, electroplating time, current density, duty cycle on the weight-gain rate were investigated. The optimized technical parameters were as follows: room temperature, 300 ms of positive working time, 30 ms of reverse working time, 40% of duty cycle, 8.20 ×10-5 A/mm2 of current density, 6 min of electroplating time. The quality of copper coating was checked with SEM. The adhesion between the coating and carbon fibers was tested by the method of psychro-thermal cycles. Additionally, comparison to pulse plating and direct current plating was made. The obtained results showed that a flat, detailed and well-crystalloid copper coating on the carbon fiber surface was obtained with the present conditions. The adhesion between the coating and carbon fibers was 450kPa.

Abstract: A Ni-SiC nano-composite plating coating was prepared by using composite plating technology adding nano-SiC in the bath.Then the surface morphology was examined by scanning electron microscope (SEM), the transmission electron microscope (TEM) was used to study the grain size,the porosity, corrode-resistant, combines intensity and wearability of the composite plating coating were also tested and contrasted the result with the pure nickel coating. The results shows the surface of Ni-SiC composite coating are more uniform and compact for the adding of nano-Sic refined the grain, the wear resistance,microhardness and corrosion resistance of the composite coating are also significantly improved.

Abstract: Pulse electrodeposition was used to produce nanocrystalline (nc) copper from copper sulfate electrolyte with saccharin as additive. The grain size of nanocrystalline coatings was determined using x-ray diffraction and atomic force microscopy (AFM) which was about 30 nm. Microcrystalline copper deposits were also produced by direct current electrodeposition processes and compared with pulse plated ones. Corrosion behavior of the coatings was investigated using polarization and Impedance measurements in different solutions. The oxidation test was carried out at 650°C in an electrical furnace. It was demonstrated that the nanocrystalline film was markedly superior to regularly grained films made by direct current (DC) plating; nanocrystalline deposits show higher corrosion resistance and much higher oxidation resistance.

Abstract: The aim of this study was to investigate the effects of direct current (DC) and pulse current (PC) parameters on the properties of cobalt (Co) coatings electrodeposited from a chloride acidic bath. The effects of peak current density, frequency and duty cycle on the surface morphology, crystal size, thickness, current efficiency, and preferred orientation of the deposits were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental thickness of the deposit was lower for pulse plating compared to that of DC plating. The current efficiency was comparatively higher for pulse plating. Less porosity and fine grains were formed by pulse plating. From XRD analysis, the calculated grain sizes of nano and micro Co coatings were around 65nm and 430nm, respectively. The results showed that, with an increase in duty cycle, grain sizes would increase, too. As pulse frequency was increased to 50Hz, grain sizes would also decrease. However, at higher frequencies, grain sizes would increase again.

Abstract: A new method for preparation of coatings with codeposition plating on the ordinary A3 steel and heat treatment later. Research the coatings on electrochemical corrosion behavior variation in Q-sun. Results show that corrosion potential shuffle, corrosion current density reduced nearly two number magnitudes value, polarization resistance increased, the cathode polarization effect enhanced obviously in polarization curves, and self-corrosion current reduced, impedance increased twenty times in alternating current impedance atlas than A3 steel substrate without coatings. It was indicated that the coating improve effectively the corrosion resistance of plain carbon steel.

Abstract: The current research focuses on developing nano-crystalline nickel coating for engineering applications through pulse plating technique. Based on the literature survey, the current density, duty cycle and frequency were identified as important grain refining parameters. Coating was done over a mild steel sample after mechanical polishing, vapour degreasing and anodizing. Experiments were conducted using the three determining parameters and their influence on the properties of the coating was evaluated. Coatings were then characterized for the surface morphology and hardness. The XRD analysis for the surface morphology resulted in the grain size of 19 nm and the hardness measured from the microhardness tester was 677 HV which is higher than the hardness reported in the available literatures. The influence of the pulse plating parameters on the grain size and hardness of the coating has been listed out for the benefit of the scientific community.

Abstract: In this study, a Ni-P alloy electroforming nanostructure material with low surface roughness and low internal stress was developed by using a pulse current. Square-wave cathodic current modulation was employed to electrodeposit ultrafine-grained Ni-P films from an additivefree Sulfamate nickel bath. The effect of various factors, such as peak current density, duty cycle and pulse frequency on the roughness and internal stress were investigated. Pulse current significantly influences the microstructure of Ni-P alloys. The internal stress and roughness of Ni-P alloys increased as peak current density increased, but the internal stress of Ni-P alloys decreased as duty cycle decreased.

Abstract: Nickel tungsten (Ni-W) alloy coating was electroplated to increase its mechanical properties. Tungsten cannot be electroplated by itself, however, it is codeposited with other iron group metals especially with nickel. The morphologies of nickel tungsten coating were varied with current density. To eliminate the formation of cracks, pulse plating was employed. Crackless nickel tungsten alloy were obtained in pulse reverse electroplating. Hardness of nickel tungsten coating has twice higher compared to the normal electroplated nickel.

Abstract: The dishing phenomena of soft materials in chemical mechanical polishing (CMP) process were problematic in delineating inlaid metal patterns. The inlaid copper structures were fabricated on Si wafer where SiO2 was thermally grown. Seed layer was deposited by thermal evaporate method followed by copper electrodeposition. Copper was electrodeposited with IBM paddle type electroplating machine to obtain uniform thickness of coating. The dishing amounts were measured at various current density and current type. The dishing amounts with pattern density and line width were also measured. The losses of copper were not sensitively dependent on current density however those were dependent on current type. The dishing amount of copper was decreased at high pattern density especially over 50% and increased with line width. Surface topology and grain size of coating were investigated with surface profilometer and FESEM.

Abstract: Copper via filling is an important factor in 3D stacking interconnection of SiP (system in package). As the packaging density is getting higher, the size of via is getting smaller. When DC electroplating is applied, a defect-free hole cannot be obtained in a small size hole. To prevent the defects in holes, pulse and pulse reverse current was applied in copper via filling. The size of 50, 70, 100
in diameter and 100
in height. The holes were prepared by DRIE method. TaN and Ta was sputtered for copper diffusion barrier. Via specimen were filled by DC, pulse and pulse-reverse current electroplating methods. The effects of additives and current types on copper deposits were investigated. Vertical and horizontal cross section of the via were observed by SEM to find the defects in via. When pulse-reverse electroplating method was used, defect free via were uccessfully obtained.