Papers by Keyword: Electroplating

Abstract: This study evaluates and compares the corrosion resistance of zinc coatings deposited on mild steel using three different techniques: electroplating, TREFISSOUD Company hot-dip galvanization, and conventional hot-dip galvanization. Coated and uncoated samples were characterized by electrochemical polarization, microscopic analyses (optical microscopy and SEM), and X-ray diffraction (XRD). Electrochemical results demonstrated a significant decrease in corrosion current density (Icorr) for all zinc-coated specimens compared to bare steel, confirming the protective effect of the coatings. Among the coatings, hot-dip galvanization exhibited superior performance, with the TREFISSOUD Company method achieving the lowest corrosion current and the highest polarization resistance, indicating enhanced corrosion protection. Electroplated zinc, although thinner, provided adequate resistance in moderately aggressive environments. XRD analysis revealed zinc oxide (ZnO) and iron oxide (Fe₂O₃) as the main corrosion products. Their intensity was more pronounced in galvanized coatings than in electroplated zinc. Microscopic observations confirmed uniform and adherent coatings, with hot-dip galvanization producing thicker layers and stronger adhesion than electroplating. Overall, the findings demonstrate that hot-dip galvanization, particularly the TREFISSOUD Company method, provides the best long-term protection for mild steel exposed to harsh conditions. Electroplated zinc, while less durable, remains suitable for applications where a thinner, uniform coating is required. These results highlight the importance of selecting the coating method according to specific service conditions in industrial applications such as construction, pipelines, and marine environments. This study provides a new comparative analysis between conventional and TREFISSOUD company hot-dip galvanization methods, which has not been reported previously in the literature. The results highlight the distinctive performance of the TREFISSOUD Company process in improving coating uniformity, adhesion, and corrosion resistance. This novelty contributes to a better understanding of industrial zinc coating optimization for mild steel.

Abstract: To improve the reliability of solder joint, Ni–Cu alloy plating films with three-dimensional structures were fabricated on Cu substrates via electroplating. By varying the plating potential, the morphology of the Ni–Cu alloy plating films was controlled, and their effect on solder joint microstructure and mechanical properties was investigated. Sn–5Sb lead-free solder was used to join the plated Cu substrates, followed by aging at 200°C for up to 100 h. Surface observations revealed that more negative plating potentials promoted the formation of larger and more numerous three-dimensional structures. Cross-sectional analysis showed that Cu–Ni–Sn and Cu–Sn reaction layers formed at the solder interface and thickened with aging. Shear test showed that the joint strength decreased after 25 h of aging and remained nearly constant thereafter. In addition, joints with Ni–Cu alloy plating exhibited lower shear strength than those without plating. Fractographic analysis showed that fracture initially occurred within the solder and Cu–Ni–Sn reaction layers, whereas prolonged aging induced fracture propagation through the solder, Cu–Ni–Sn, and Cu–Sn reaction layers.

Abstract: This study investigates the bonding properties of transient liquid phase diffusion bonding using Cu/Sn electroplated films. A Cu substrate was electroplated with Cu and Sn films, followed by TLP bonding with a Ni substrate at 280°C under air atmospheric conditions without bonding pressure. Bonding times of 1, 3, and 30 min were employed to evaluate the effect of bonding duration on interfacial microstructure and shear strength. Cross-sectional microstructural analysis using EPMA revealed the formation of a Cu–Ni–Sn reaction layer at the bonded interface, with the thickness of this layer increasing as bonding time increased. Voids were observed at all bonding times, particularly at 30 min, where extensive void formation led to incomplete bonding. Shear test showed that shorter bonding times yielded higher average strengths, while longer bonding times resulted in a reduction due to void-induced degradation. Fracture surface observations confirmed that failure occurred within both the Sn and reaction layer, regardless of bonding time.

Abstract: The increasing demand for metals has led to the growth of the metal industry in Indonesia. This has resulted in a rise in the amount of waste generated. Various methods can be used in the treatment of metal waste, such as flotation, flocculation-coagulation, and adsorption. One biopolymer that can be used for metal removal is chitosan. This study aims to synthesize chitosan from shrimp shell waste, which is then modified with silica to enhance its mechanical strength and stability in acidic conditions using the sol-gel method. The chitosan-silica composite is then immobilized using dithizone to increase the adsorption capacity through immersion variations of 4, 6, and 8 hours. The adsorbent, characterized using Fourier Transform Infrared, showed the presence of bonds in chitosan at wavenumbers 3454 cm^-1 (N-H) and 1647 cm^-1 (C=O), chitosan-silica at wavenumbers 966 cm^-1 (Si-O in Si-OH), 798 cm^-1 (Si-O in Si-O-Si), and 466 cm^-1 (Si-O-Si), and chitosan immobilized with dithizone at wavenumbers 2343 cm^-1 (S-H) and 1083 cm^-1 (S=C). Adsorption was performed by mixing the adsorbent with the waste for 1 hour, then the waste was added with 0.25 ml of phosphoric acid and analyzed using a UV-Vis Spectrophotometer. Based on the results of the study, the highest adsorption efficiency was obtained with the adsorbent variation of 8 hours immersion at 59%, while the adsorption efficiency for immersion times of 4 and 6 hours was 0.3% and 6%, respectively.

Abstract: This study investigated the electrochemical behavior of Ni–Cu alloy plating baths during plating and dealloying reactions. Furthermore, the potential and plating time effects on the shape of three-dimensional structural Ni–Cu alloy plating film and its adhesion to epoxy resin were investigated. Nodules were observed on the surface of the plating film generated at potentials from-0.5 V to-1.0 V. When the plating films formed at potentials of-1.0 V to-1.5 V were dealloyed, the formation of pores was observed. The shear test results showed that the average shear strength of the specimen joined with epoxy resin between two Cu plates with Ni–Cu alloy plating film formed at a potential of-1.0 V was the highest under all conditions.

Abstract: Carbon steel was coated with Cr-multi-walled carbon nanotube (MWCNTs) coatings via electrodeposition. In this article, the impact of a combination of MWCNTs into the chromium coating on the morphology of the coating surface and corrosion characteristics was inspected. The MWCNTs seem to be evenly distributed across the chromium layer, according to scanning electron microscopy (SEM). Electrochemical measurements were used to conduct corrosion tests on samples of MWCNTs– chromium composite coated and pure chromium coated samples in aqueous NaCl (3.5 wt.%). The outcomes demonstrated a considerable increase in the resistance of corrosion due to the inclusion of MWCNTs during the chromium deposition procedure. In addition, the mechanism of anti-corrosion of the composite coating is also presented. Using an electrolyte bath containing various concentrations of dispersed MWCNTs (0.5, 1, and 1.5 g/L), crack-free and compact coating of Cr-MWCNT composite were electrodeposited on the substrates of the mild steel. The potentiodynamic polarization technique was used to examine the coatings corrosion performance subjected to a 3.5 weight percent of NaCl medium. When compared to chromium coating, the Cr-MWCNT composite coating showed the lowest corrosion rate (1.045x10⁸ mpy) compared to chromium coating (4.891x10⁸ mpy).

Abstract: The article describes a method to improve the uniformity of electroplating using fuzzy logic. This method provides for the replacement of the non-stationary model of the process dynamics in distributed coordinates with the quasi-stationary model of the process dynamics in lumped coordinates. The production knowledge model with "IF-THEN" rules is developed for the stochastic influences taken into account. The dynamic choice of the defuzzification method is justified by solving the problem of minimizing the absolute deviation of the coating thickness average value obtained from the non-stationary model from the predicted value according to the quasi-stationary model at const values of stochastic influences. As an example, fuzzy control of the current for nickel coating is considered, taking into account the stochastic influence of the electroplating time, detail area, temperature and acidity of the electrolyte. The experimental results prove the effectiveness of the combined defuzzification method in comparison with their independent use in the control process.

Abstract: The spread of disease by bacteria and viruses is very susceptible to outbreaks in public facilities through direct and indirect contact. Indirect contact occurs through intermediate such as housing equipment made of aluminum. One thing that people touch the most is door handles and frames. Aluminum frames are generally anodized to give a color effect because painted directly is difficult. Anodized products generally have a pore structure so that they can easily become an ideal place to grow and colonize bacteria and viruses. To overcome this, the coating process is carried out by electroplating. In this study, aluminum was treated with anodization and non-anodization. The concentration of sulfuric acid solution used was 0.5 M; 1M and 2M. The current used is 0.6A; 0.9A and 1.2M. Increasing the sulfuric acid concentration will increase the efficiency of the cathodic current and increase the mass of the deposit per unit area. Observation of the microstructure with an optical microscope shows the structure formed is dendritic in which the nucleus is continuous. The smooth and flat surface makes aluminum safe to be used and does not become a medium for bacteria or viruses to stick at aluminum surfaces.

Abstract: A comparative analysis of the occupational hazard was done when working with widely known cyanide electrolytes and new thiocarbamide and citrate acid-based electrolytes. For this purpose, we made use of available reference data on maximum permissible substance concentrations, i.e. process solution components. Appropriate computations were done to define the environmental hazard of the electrolytes used for the application of silver, gold and copper coatings and also for the electrochemical silver polishing. Consideration was given to the reactions that proceed in cyanide and thiocarbamide-citrate bathes. The main drawbacks and advantages of given electrolytes have been established. Special attention was paid to the quality of galvanic products. It was proved that the suggested electrolytes are highly competitive with cyanide analogues as for their visual appearance, density and other characteristics of the condition of treated surface. These turned out to be labor saving and energy efficient and have substantially lower harmful effect on the human health and environment.

Abstract: Preservation of materials using liquid nitrogen media has been widely used. One of them is used in the medical field, namely cryonic technology. Cryonics is a method of preservation at cold temperatures using a cryoprotectant in liquid nitrogen. To maintain the quality of the material, a sensor that can detect the temperature of liquid nitrogen is needed. Low temperature sensors with Cu and Ni based Resistance Temperature Detector with layers (RTD) have been made, but these sensors have a layer of Ni deposits that are not yet homogeneous. So quality improvement is needed by adding an external magnetic field. Based on this, the aim of this research is to synthesize a thin layer of Cu / Ni using electroplating method assisted by external magnets parallel to the ion currents