Papers by Keyword: Electroplating

Abstract: Electrochemical deppsition methods (electroless plating and electroplating) were used to deposit a thick nickel on surface of quartz optical fibers. A thin Ni--P film was firstly to be deposited on the fiber by electroless plating. Then a thick Ni coating with thickness of about 1.7 mm was deposited on the Ni-P film,as a substrate, by electroplating. The effects of the concentrations of NiSO₄·6H₂O, NaH₂PO₂·H₂O , C₃H₆O₂ , H₃BO₃ , pH value and temperature on the quality of Ni-P coatings were investigated and their optimal values were determined by orthogonal test method..The effects of concentrations of NiSO₄·6H₂O and C₁₂H₂₅―OSO₃Na and current density on Ni deposition were studied and the optimum technical conditions were discussed. Under the optimal conditions, the thin Ni-P film possessed good smoothness and strong adhesive force and the Ni-coating had good quality with fine Ni crystals and uniform surface.

Abstract: In order to obtain a electroplated CBN cylindrical grinding wheel with ordered abrasive pattern, based on the phyllotaxis theory of biology, the cylindrical grinding wheel with phyllotactic pattern and its mask were designed, this wheel was fabricated with lithography mask electroplating technology, and also some problems on processes were investigated by experiments. The research results that the ordered abrasive pattern on cylindrical grinding wheel can be realized with the help of the phyllotaxis theory and lithography mask electroplating technology, which can give some references for making this kind of the engineered grinding wheel.

Abstract: The main aim of this paper is to study copper ions electroplating, evaluating the cathodic current efficacy, from cyanide ion free alkaline baths, stabilized by different complexant agents for the Cu²⁺ ions. The cathodic current efficacy was assessed through quartz microbalance measurements, employing different current modulations. Results revealed that the pulsed current application has great influence on the cathodic current efficacy during electroplating in the baths under study.

Abstract: In this study, the mechanical properties of a weaving machine component made of cast stainless steel are improved by the duplex coatings of electroplated hard-chrome and sputtered metal nitride layers. The effects of the first and second coat layers of three metallic nitrides, including TiN, TiN-Ni and NiN, were comparatively studied. The structural characteristics of the coating materials were studied by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Vicker hardness was then measured by nanoindenter. It was found that the duplex coating surfaces gives better surface quality than those of single-layer coated ones. In addition, the hardness of single-layer coating either with hard-chrome or metal nitride was only 2-3 times higher than uncoated ones whereas duplex coating with both layers synergistically increases the hardness by a factor of 7-8. Moreover, duplex coating with TiN exhibits relatively high hardness compared with other metal nitrides.

Abstract: A development of a novel electro thermal micro-gripper for handling of Head Gimbal Assembly (HGA) is an ultimate goal of this study. The scope of this study covers a design, fabrication and performance evaluation of the electro thermal micro-gripper. ANSYS software was used to examine the magnitude of tip displacement, exerting force and induced stress to investigate the mechanism’s viability for handling of HGA. Electroplating of nickel was employed to construct the micro-gripper’s mechanisms with three different sizes, and their displacement and exerting force were then examined. From the experiments, each mechanism deflected between 100 to 220 μm while the exerting force was over 200 mN at 25 ^oC above room temperature. Therefore, the results suggested that the new electro thermal micro-grippers are viable for the HGA handling application.

Abstract: In this paper, the NiCu alloy coatings were electroplated on the 304 stainless steel coupon. The XRD was used to identify the phase structure of the as-prepared products. The SEM and EDS were used to observe the surface morphology of the as-prepared coatings and the atomic composition of the as-prepared coatings, respectively. The influences of the current density on the as-plated NiCu coatings are systematically researched. It was found that the moderate current density is beneficial to the compactness of the coatings. The content of the copper decreased and that of the nickel increased with the increasing of the current density. When the current density is smaller than 40 mA/cm², the contents of nickel and copper vary apparently. When the current density is larger than 40 mA/cm², the contents of nickel and copper vary slightly. That means the copper is more easily deposited at low current density and the nickel is more easily deposited at high current density.

Abstract: This work examines the processing and some mechanical properties of copper-electroplated graphite compacts. Shear and wear tests were conducted. Natural graphite (NG) flakes were compressed to make graphite compacts. No polymer binder was added in the compact. For reinforcing and preventing the NG particles from peeling off, a copper layer was electroplated on the compact. The density of green graphite compact approached a limit when the forming pressure was higher than 100 MPa. The results indicated that the shear strengths increase 150% and the wear resistance is improved more than ten times because of the copper layer. The induced damage mechanisms were examined, and the influence of the copper layer on the damage is discussed.

Abstract: The paper deals with nickel – cobalt coatings on the copper substrate prepared by electroplating process. The different Co content in the alloy coating depending on chemical composition of sulphate electrolyte and current density. The microstructure and composition of Ni-Co coating were observed with use of light and scanning electron microscopy. The mechanical properties were determined with use of the test according to EN ISO 6892-1:2009 standard and means of a Vickers microhardness tester. The results showed that under the same bath composition and technological parameters of process the Ni-Co alloy coating exhibited laminated structure. Their strength and hardness of the deposited coatings were higher than those for the Ni coatings.

Abstract: It is very important for micro-fluxgate to reduce its power consumption because higher power consumption causing serious cooling problem which will lead series of questions. In this paper the influence of core film magnetic properties (coercive force Hc and saturation field Hs) on optimum excitation current (OEC) and sensitivity are investigated theoretically. The expressions of optimum excitation magnetic and maximum sensitivity were given. In the field of magnetic material, lower Hc means better soft magnetic properties, but when analyze the effect of Hs and Hc on the OEC and corresponded sensitivity we find that low Hs and high Hc bring low OEC and high sensitivity. Applied magnetic fields at different angles during electroplating and annealing are introduced to improve magnetic properties of electroplated core films. In subsequent experiment we test the OEC, sensitivity, linear range and magnetic noise of fluxgate utilize these core films. Plating with θ=0° (θ is the angle between applied magnetic field and long edge of the core) samples obtain lowest OEC and highest sensitivity, plating with θ=90° and annealed samples obtain large linear range, annealed samples obtain lowest magnetic noise.

Abstract: In this paper, the NiCu alloy coatings were electroplated on the 304 stainless steel coupon. The XRD was used to identify the phase structure of the as-prepared products. The SEM and EDS were used to observe the surface morphology of the as-prepared coatings and the atomic composition of the as-prepared coatings, respectively. The influences of the temperature on the as-plated NiCu coatings are systematically researched. It was found that the lower of the temperature, the more compact of the coatings. With the increasing of the temperatures, the content of the nickel decrease and that of the copper increase. When the temperature is lower than 35 °C the contents of nickel and copper do not vary apparently. When the temperature is larger than 40 °C, there are significant increases of the copper content while apparent decreases of the nickel content.