Plating Film Research Articles

Al Electroplating on Etched CFRP Surfaces in AlCl3-EmImCl Ionic Liquids

To improve the wear resistance of CFRP, Al electroplating on the surface was proposed. Etching of the resin on the CFRP surface in sulfuric acid solution was investigated to improve the adhesion of the Al plating film on CFRP. As a result of the etching treatment, more carbon fibers were found on the CFRP surface. Al film was electroplated to the etched CFRP in AlCl3-EmImCl ionic liquid; the adhesion strength of the Al plated film to the CFRP surface increased with etching time.

Battery-free flexible wireless temperature sensing for food storage

The method of monitoring food temperature during food storage needs to be improved to continuously and accurately perceive the temperature of the food in the package to ensure the quality and safety of the food during storage. This paper proposes and develops a battery-free flexible wireless temperature sensing system (BFTS) for food storage. The BFTS consists of a battery-free flexible wireless temperature sensing tag (BFTT), a wireless reader, and a personal computer (PC). The BFTT developed in this paper has good flexibility and can be placed inside the food package to realize the continuous monitoring of temperature changes. The flexible circuits of the BFTT were fabricated by laser engraving laser-induced graphene (LIG) −copper (Cu) plating film made with Cu plating on LIG. The LIG-Cu plating film has good thickness uniformity, electrical conductivity, and laser engraving processability. The antenna of BFTT has good performance. The wireless reader is connected to the PC using a data line, and the BFTT communicates wirelessly with the wireless reader using ultra-high frequency (UHF) radio frequency identification (RFID). The BFTT was realized by the wireless radio frequency (RF) as the supply power from the wireless reader. The BFTS could realize the temperature monitoring of food stored at 0℃ and −18℃, and it has the advantages of low cost, simple manufacturing process, and low energy consumption, which could be used to continuously and accurately monitor the inside temperature of the food packages. Overall, the LIG-Cu plating film developed in this paper could be used in the fabrication of flexible circuits, and the temperature monitoring inside food packages realized by the BFTS has potential applications in actual food storage.

Electrochemical aging model of lithium-ion battery with impedance output and its parameter sensitivity analysis and identification

The electrochemical model of the battery has gained widespread recognition due to its clear physical interpretability. However, achieving an accurate electrochemical model heavily relies on precise parameter settings. To address this challenge, various model-based parameter optimization methods have been developed. Currently, most research relies on model reduction techniques and heuristic random search methods for parameter identification. These approaches often lead to time-consuming processes and a loss of physical interpretability in the electrochemical model. To overcome these limitations, we propose a novel technical framework that directly parametrizes the electrochemical model. First, we establish a battery electrochemical model that accounts for lithium plating and SEI film thickening, serving as the main focus of this study. Secondly, in order to expedite parameter identification without compromising the model's physical interpretability, we innovate by performing comprehensive sensitivity analysis using voltage and impedance characteristics. This allows us to identify the most influential parameters, which become the key for subsequent research. Finally, to ensure reasonable initialization of finite element computations and to avoid convergence issues in the identification algorithm, we combine machine learning and optimization algorithms into a two-step parameter identification method. By utilizing the proposed method to identify the model parameters, the simulations exhibit high accuracy.

Energy-saving Hydrogen Generating Electrode Based on Nickel-based Nano Plating Film

Energy-saving Hydrogen Generating Electrode Based on Nickel-based Nano Plating Film

Fabrication of High-Temperature Solder by Zn Plating Films Containing Al Particles

This study investigated the microstructure and melting point of the Zn–Al composite electroplating film. The cross-sectional microstructure and shear strength of the joints made from the plating films were also evaluated. Zn and Al were confirmed in the plating films from initial microstructure observation. The plating film prepared by a plating bath without cationic surfactant melted near the melting point of Zn and the eutectic point of Zn–Al. When jointed at a joining temperature of 443°C, joining pressure of 5 MPa, and holding time of 5 min, multiple intermetallic compounds, Zn–Al eutectic layers, and unreacted Al particles were observed in the joint layer. From quantitative analysis, the multiple intermetallic compounds were estimated to be Zn–Ni and Zn–Al–Ni intermetallic compounds. The shear strength of the joints increased with increasing joining pressure but was lower than that of Sn–5Sb solder. Fracture after the shear test was observed at the interface between unreacted Al particles and Zn–Al–Ni intermetallic compounds, and inside unreacted Al particles.

Effect of Plating Potential on Three-Dimensional Structural Plating Films and their Adhesion to Epoxy Resin

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.

Effect of Special Plating Films on Galvanic Corrosion Behavior between Metal and CFRTP

In this study, electrochemical measurements and observations investigated galvanic corrosion behavior between various metals with or without projection-shaped Ni–Cu alloy plating film and carbon-fiber-reinforced thermoplastic (CFRTP) of corroded areas. Stainless steel, aluminum alloy, and CFRTP plates were prepared. Ni and Ni–Cu alloy electroplating were performed on the stainless steel plate. Electroless zinc plating, Ni, and Ni–Cu alloy electroplating were performed on the aluminum alloy plate. The galvanic current between the metal and CFRTP plates was measured using an electrochemical measurement system. The test solution was 0.06 mol/L NaCl aqueous solution. For Stainless steel/CFRTP, the galvanic current flow was negligible with and without the Ni–Cu alloy plating film. For aluminum alloy/CFRTP without the Ni–Cu alloy plating film, the galvanic current ranged from-80 to-120 μA/cm2 at a test temperature of 60°C. For aluminum alloy with the Ni–Cu alloy plating film, the galvanic current ranged from-60 to-80 μA/cm2. The galvanic current for the aluminum alloy plate with Ni–Cu alloy plating was lower than that of the aluminum alloy plate without Ni–Cu alloy plating film. The result suggests that the formation of the Ni–Cu alloy plating on the aluminum alloy improves corrosion resistance.

Preparation of platinum-free manganese oxide (MnOx) catalyst film for H2O2 decomposition in contact-lens cleaning

A platinum (Pt)-free manganese oxide (MnOx) catalyst film for H2O2 decomposition was prepared on an aluminum (Al) substrate (MnOx/Al) by a hydrothermal impregnation method to decrease the cost of a container used in contact lens cleaning and effectively using Pt materials as other several catalysts. Scanning electron microscopy with energy dispersive X-ray spectroscopy images confirmed that the Al substrate was covered with MnOx. The thickness of the MnOx film was about 300 nm. X-ray diffraction spectra showed that the MnOx film consisted of MnO2 and Mn2O3. The catalytic activity for H2O2 decomposition was estimated by measuring the residual H2O2 concentration, and the target value was ≦100 ppm. The MnOx/Al catalyst was immersed in 35,000 ppm H2O2 solution for 360 min, then the H2O2 concentration decreased to 737 ppm. This result indicated that the MnOx catalyst had a high catalytic activity for H2O2 decomposition but it was not enough for practical use. To improve the catalytic activity, an Al substrate was roughened to increase the specific surface area before preparing an MnOx film. A method with the highest effect of increase in surface roughness was a combination of sandblasting and chemical etching. An MnOx catalyst film was prepared on the roughened Al substrate (MnOx/roughened-Al). When the MnOx/roughened-Al catalyst was immersed in 35,000 ppm H2O2 solution for 360 min, the H2O2 concentration decreased to 38 ppm. When the catalyst was used repeatedly for 10 times, the residual H2O2 concentration was 66 ppm, which indicated that the Pt-free catalyst also had high catalytic durability. These results demonstrated that a roughening was extremely effective in improving both the catalyst activity and durability of a MnOx film catalyst, and a conventional catalyst of a Pt plating film can be replaced with the developed catalyst of the MnOx film on the roughened Al substrate.

Considering agitation in ultrasonic electroplating through observation of cavitation

Ultrasonic electroplating produces various effects, including refinement of the plating film structure, by generating localized agitation through cavitation bubbles. However, details of the agitation mechanism have not been clarified because ultrasonic cavitation is very small in scale and occurs rapidly, and its reproducibility is low. Therefore, using laser-induced cavitation, which can generate cavitation similar to ultrasonic waves with high reproducibility, the author attempted to elucidate the conditions and frequency of cavitation generation that affect the agitation phenomenon in ultrasonic electroplating. By controlling the laser irradiation position, three different cavitation conditions were established, and the microstructures of the plated films produced were compared. Microstructural refinement was the most advanced under the condition of microjet generation. The frequency of cavitation generation at any position in the ultrasonic electroplating was estimated to be < 1 Hz.

Investigation of electroless copper plating with high plating coverage in small BVH for next generation fine pattern SAP

Printed wiring board (PWB) used for package substrates are required to have higher circuit densities. We anticipate that PWB circuit patterns and blind via hole (BVH) will continue to be miniaturized due to higher density requirements. The electroless copper plating solution generally used has less chemical material supply to the inside of the BVH than the surface of the substrate. As a result, the copper thickness at the bottom of the BVH tends to be thinner than that on the surface of the substrate. It is difficult to uniformly deposit the electroless copper plating in the BVH on the package substrate by the semi-additive process (SAP), especially when the BVH are becoming smaller. Therefore, we investigated additives that suppress the electroless copper plating deposition on the surface of the substrate and additives that improve the permeability of the plating solution into the BVH. Two additives have been discovered that dramatically improve the plating uniformity in the small BVH compared to the conventional bath. In addition, we used this plating solution with the new additives to evaluate the internal stress and peel strength of the electroless copper plating film. As a result, it was confirmed that both internal stress and peel strength were improved compared to the conventional bath.

Effect of Microcracks Formed in Zn-Ni Alloy Plating Films on Hydrogen Embrittlement of High Strength Steel

Zn-Ni alloy plating from sulfuric acid baths has excellent hydrogen embrittlement resistance for high strength steels. In this study, we investigated the factors that contribute to the hydrogen embrittlement resistance of Zn-Ni alloy plating. In Zn-Ni alloy plating, microcracks are formed in the coating. Hydrogen embrittlement was accelerated by mechanical sealing of these microcracks, and the microcracks that form in the coating were a pathway for hydrogen release. Therefore, these microcracks are found to play an extremely important role in suppressing hydrogen embrittlement. It is suggested that a gap in the plating film that can release hydrogen-induced vacancies is important to suppress hydrogen embrittlement due to plating.

Evaluation of Hydrogen Embrittlement of Electroless Ni-P Plated 6061-T6 Aluminum Alloy by Three-Point Bending and Rotating Bending Fatigue Tests

In this study, 6061-T6 aluminum alloys were plated with electroless Ni-P with different phosphorus content and three-point bending and rotary bending fatigue tests. The effects of hydrogen due to plating on mechanical properties were investigated. It was shown that the ductility decreased immediately after low-phosphorus type and high-phosphorus type Ni-P plating by three-point bending test because a hydrogen was introduced into the alloys. The fatigue strength of the low-phosphorus type Ni-P plated specimen was higher than that of the untreated specimen, while that of the high-phosphorus type plated specimen was much lower. It is clear that the fatigue strength differs greatly depending on the phosphorus content in the plating film. 6061-T6 aluminum alloy have been reported to exhibit no hydrogen embrittlement in low strain rate tensile tests under wet condition. However, it was found that hydrogen embrittlement occurred when 6061-T6 aluminum alloy was plated with the high-phosphorus type electroless Ni-P and fatigue-tested on rotary bending machine.

Development of electroless NiSnP plating with excellent bath stability using nickel hydroxide

ABSTRACT In general, NiSn alloys are known as plating films with elegant lustre and excellent corrosion resistance. Electroplating methods have already reached a practical application level because high Sn-containing films can be obtained. On the other hand, electroless plating methods have not yet reached the level of practical application because the Sn content in the deposited film is not only low but also the corrosion resistance is not sufficient. The authors have studied in detail the composition of electroless plating baths to obtain NiSnP films with Sn content above 50 wt%. In particular, the plating bath using nickel hydroxide instead of nickel sulphate as the Ni source increased bath stability and obtained high Sn content. The effects of Ni source in the bath on the deposition films were studied. The bath using nickel hydroxide as the Ni source was almost unaffected by the bath ratio. Furthermore, the amount of dissolved oxygen (DO) in the plating bath also varied depending on the Ni source, affecting the composition of the deposited film and the bath stability. It was confirmed that electroless plating baths using nickel hydroxide have excellent bath stability and can be applied to a relatively wide range of plating operation conditions to obtain high Sn-containing films. In addition, the corrosion resistance was improved by increasing the Sn content in the film. It was also confirmed that the NiSnP with high Sn content does not dissolve in nitric acid.

Surface atomic structures of nickel plating films reacted with methane at high temperature

The surface structure of Ni plating films that were reacted with methane at 800°C was investigated using scanning electron microscopy and transmission electron microscopy (TEM). The surface of the Ni plating film was eroded by the reaction with methane, resulting in a nano‐roughened surface with a hexagonal close‐packed structure with a thickness of ~ 3 nm. The carbon layer deposited on the Ni plating film was evaluated by electron energy loss spectroscopy. An increase in the π + σ bonding energy and full width at half maximum of the π* peak was observed on moving toward the Ni plating film surface, indicating an increase in the hydrogenated or oxidized carbon atoms on the surface of the Ni plating film.

Development of high copper concentration, low operating temperature, and environmentally friendly electroless copper plating using a copper ‐ glycerin complex solution

Few researchers have studied high metal ions concentration electroless plating solutions since increasing metal ions concentration shortens the solution life considerably. Nevertheless, as the required thickness of the electroless plating film reduces gradually, the limited solution life will not be a large problem. There are no detailed studies on the influence of high copper concentration electroless copper plating solution and their composition on the plating rate and decomposition time. Therefore, this paper explores the plating characteristics of high copper concentration from a copper‐glycerin complex solution. Taguchi's approach was used to optimize the plating rate and decomposition time based on an L18 orthogonal array with six main effect parameters and three levels. Main effect response tables and plots were employed to investigate the parameter influence. The significant factors of plating rate are temperature and pH, and the concentration of copper sulfate has much influence on the decomposition time. Temperature and copper sulfate concentration are the key factors to optimize the formulation of the plating solution. The optimized results were obtained at 0.18 M copper sulfate, 0.133 M formaldehyde, 0.36 M glycerin, 3.2 × 10−5 M 2,2’-dipyridyl, 29 °C, pH = 12.8. The copper concentration was more than four times higher than the conventional electroless copper plating solution, and the critical factors of high copper concentration in the electroless copper plating solution were revealed. It was found that copper formed 1:2 complexes with glycerin at a pH value of 12.8. In addition, the surface morphology and the uniformity of the plating layer were included as well.

Effects of pH and Plating Bath Temperature on Formation of Eco-Friendly Electroless Ni-P Plating Film on Aluminum

Effects of pH and Plating Bath Temperature on Formation of Eco-Friendly Electroless Ni-P Plating Film on Aluminum

Machine learning-based analysis of overall stability constants of metal–ligand complexes

The stability constants of metal(M)-ligand(L) complexes are industrially important because they affect the quality of the plating film and the efficiency of metal separation. Thus, it is desirable to develop an effective screening method for promising ligands. Although there have been several machine-learning approaches for predicting stability constants, most of them focus only on the first overall stability constant of M-L complexes, and the variety of cations is also limited to less than 20. In this study, two Gaussian process regression models are developed to predict the first overall stability constant and the n-th (n > 1) overall stability constants. Furthermore, the feature relevance is quantitatively evaluated via sensitivity analysis. As a result, the electronegativities of both metal and ligand are found to be the most important factor for predicting the first overall stability constant. Interestingly, the predicted value of the first overall stability constant shows the highest correlation with the n-th overall stability constant of the corresponding M-L pair. Finally, the number of features is optimized using validation data where the ligands are not included in the training data, which indicates high generalizability. This study provides valuable insights and may help accelerate molecular screening and design for various applications.

Formation of Cu–Ni Alloy Plating Film for Improving Adhesion between Metal and Resin

Formation of Cu–Ni Alloy Plating Film for Improving Adhesion between Metal and Resin

The effect of fluoride on the formation of an electroless Ni–P plating film on MAO-coated AZ31B magnesium alloy

This study adds fluoride to the electroless nickel-phosphorus (Ni–P) plating solution to prevent the deterioration of MAO-coated AZ31B Magnesium alloy after contact with an electroless plating bath. During the electroless Ni–P plating process, fluoride reacts with Ni2+ ions and the MAO coating to form interphases (NaMgF3), which exhibit good bonding and corrosion resistance. NaMgF3 buffers H+ ions formed from the initiation of Ni–P deposition, preventing the interface of materials from damaging the MAO coating with H+ ions. As immersion time increases, nickel is scattered over the coating.The fundamental data for MAO/Ni–P coated AZ31B Mg alloy determines whether there is fluoride in the electroless Ni–P plating solution. The results show that the coating for a fluoride-containing solution is more resistant to corrosion than those in fluoride-free solution. The compositions, structure and morphology of the MAO/Ni–P coatings that formed for different working parameters are determined using energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The corrosion resistance of the MAO/Ni–P coatings is calculated in a 3.5 wt.% NaCl solution using a potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS) and a salt spray test (SST).

Study on Lithium-Ion Battery Degradation Caused by Side Reactions in Fast-Charging Process

With the development of electric vehicles, fast-charging is greatly demanded for commercialisation on lithium-ion batteries. The rapid charging process could lead to serious side reactions on the graphite anodes, such as lithium plating and solid electrolyte interface (SEI) film growth, which severely affect the battery performances. However, there is a lack of quantitative research on their contribution ratio to battery performance and the occurrence thresholds. In this work, a P2D model of a lithium-ion battery with the correction of SEI film growth and lithium plating was built. A cyclic charge/discharge experiment was also designed to analyze the changes of SEI film and lithium plating under high charge-rate conditions. It was found that under such conditions, the battery capacity attenuation in the early stage was mainly caused by lithium plating. In the middle and late stages, as the lithium plating tended to be stable, the capacity attenuation was largely caused by the growth of the SEI film. The study provides theoretical support for the improvement of the charge/discharge strategy of lithium-ion batteries.