Nickel Electroplating Research Articles

PTFE layer formation during brush electroplating of nickel

Brush electrodeposition of Ni/PTFE composite coatings was explored using a nickel high speed solution and polytetrafluoroethylene (PTFE) particles 6–9 μm in diameter. A novel bilayer-like, partially intercalated structure was produced, consisting of a rough nickel sublayer covered by an outer, compact, smooth PTFE layer. The study of the coating growth revealed that the PTFE particles bind together on the nickel coating valleys and grow until all the surface is covered by a polymer layer without the need of a baking stage. The resulting coating presents a hydrophobic surface with a low coefficient of friction (0.10) and higher corrosion resistance to salt spray testing than the nodular nickel coating. The coatings were produced using an aqueous nickel plating solution, where the hydrophobic PTFE particles were suspended using different substances: cetrimonium bromide (CTAB) cationic surfactant, isopropyl alcohol premixed with the particles, and ethanol premixed with the particles. High concentrations of the suspending products were detrimental for the deposition process, but optimal values of 0.1 g/l, 3 ml/l and 3 ml/l respectively were found. All compounds successfully suspended the PTFE particles and both alcohols produced the Ni/PTFE coating described before, but the CTAB failed to co-deposit the polymer.

Gluconate solutions for nickel electrodeposition and nickel electroless plating

Nickel electroplating has found a wide range of industrial applications as a technique for creating protective and decorative coatings of metallic and non-metallic surfaces, protecting materials against corrosion at elevated temperatures in both alkaline environments and organic acid solutions, forming a sublayer for obtaining coatings of other metals on steel, enhancing the hardness and wear resistance of surfaces, as well as for improving solderability. Such coatings can be obtained from weakly acidic aqueous and weakly alkaline complex electrolytes. In this review, we analyze the available literature on complexation of nickel(+2) with D-gluconate ion CH2OH(CHOH)4COO‾, along with that on compositions and some technological characteristics of complex D-gluconate solutions for nickel electrodeposition and electroless plating. Thus, a corrosion-resistant smooth light-colored nickel coating, tightly adhered to a copper substrate, was obtained from an electrolyte with a pH level of 8, containing 53 g/dm3 of NiSO4 •6H2O, 44 g/dm3 of D-C6H11O7Na, 25 g/dm3 of H3BO3, 53 g/dm3 of (NH4)2SO4, and 0.5–3 g/dm3 of CO(NH2)2, at a temperature of 25 °C, a cathodic current density of 2.5 A/dm2 with a current efficiency of 96.4%. An electroless Ni-P(3–18 wt%) alloy coating on copper was obtained from a solution with a pH level of 9, containing 5–30 g/dm3 of NiSO4 •6H2O, 10–60 g/dm3 of D-C6H11O7Na, 5–40 g/dm3 of NaH2PO2 •H2O, 3 g/dm3 of HOOCCH2CH2COOH, 0.5 g/dm3 of CH3(CH2)11OSO3Na, 0.002 g/dm3 of Pb(CH3COO)2•3H2O, at a temperature of 90 °C and a deposition rate of up to 0.75 μm/min. The review also discusses methods for preparing D-gluconate electrolytes for nickel plating using sodium D-gluconate, D-glucono-1,5-lactone, and nickel D-gluconate. One advantage of D-gluconate nickel plating solutions consists in the absence of toxicity and low cost of D-gluconates.

Effect of bath temperature on electroplating of nickel on a copper substrate

ABSTRACT Nickel electroplating is known to be industrially effective for enhancing various substrate properties. In the present work, nickel coatings were developed on copper substrates by electroplating using standard nickel plating solution at various electrolyte bath temperatures ranging from 40 ± 2°C to 60 ± 2°C in steps of 10°C. Energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to study the composition, phase structure and morphology of the coatings. The coatings were also analysed for hardness and porosity, and process current efficiency was measured. The electrolyte bath temperature has a profound effect on the nature of the developed nickel coatings, and is observed to have an impact on the surface morphology, crystallographic direction, and hardness, as well as deposition current efficiency.

Optimizing Nickel Electroplating in Low-Ni Environments for Efficient Source Production in Small Plating Baths

Electroplating nickel-63, a radioactive isotope used in betavoltaic batteries and random number generators, requires precise control due to its limited availability and the generation of radioactive waste. To minimize waste and ensure effective plating, small plating baths are employed, optimizing the process within constrained conditions. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were utilized to determine the optimal plating conditions and limiting conditions for nickel electroplating in a small plating bath. This study focuses on the use of low-concentration nickel solutions and small plating equipment, in contrast to the common industrial practice of using high concentrations of nickel. Here, it is important to optimize the plating parameters, especially the nickel concentration, current density, and bath temperature. An average thickness of 1.8 μm was found when plating with a nickel concentration of 0.06 M, a current density of 5 mA/cm2, and a solution temperature of 40 °C, while ideal conditions were found to achieve the theoretical maximum energy and 90% release rate when plating with nickel-63 instead of Ni.

Performance degradation due to thermal cycling in soldered Faraday and SuperPower HTS tape stacks

Soldering stacks of high temperature superconducting (HTS) tapes results in a current carrying matrix with high electrical, thermal, and mechanical stability. In some applications, these tape stacks may be exposed to elevated temperatures during thermal heat cycles. Previous research on thermal degradation of high temperature superconductors has been performed with isolated crystals or individual HTS tapes, showing that oxygen-out diffusion from the rare-earth barium copper oxide (REBCO) results in a reduction of the superconducting performance. In this work, the performance of Pb37Sn63 soldered HTS tape stacks with thermal cycling to 170∘ C is quantified through determination of the critical current Ic , the n-value, the linear resistance R in the pre-transition region of the tape stack current–voltage (I–V) traces, and the diffusion coefficient D associated with oxygen-out diffusion. The effect of tape manufacturer and nickel electroplating were considered; three soldered stacks each of unplated Faraday, nickel electroplated Faraday, unplated SuperPower, and nickel electroplated SuperPower tapes were fabricated. Across 20–30 one hour thermal cycles, there are no significant differences in degradation profiles observed between the unplated and nickel electroplated tape stacks for a given manufacturer. There is however a marked difference in degradation profiles observed between the SuperPower and Faraday tape stacks. For the unplated and plated SuperPower tape stacks, the degradation in Ic generally follows the model to describe oxygen-out diffusion from the superconducting REBCO layer. Significantly less degradation is observed in the unplated and plated Faraday tape stacks, and in some sections Ic even increases slightly across cycles. Further, cases of increasing Ic accompanied with decreasing n are observed, a decoupling between the two parameters. Across all samples, the linear resistance was highest in current-redistribution regions near the leads. Consistent with the model of oxygen-out diffusion and the formation of an increasingly wide oxygen deficient layer in the REBCO, the linear resistance increased with cycle number.

Synthesis and characterization of open cell Ni-Cr foam developed using Pulse electro deposition technique for filtration applications

Nickel–Chromium (Ni-Cr) foam is a highly versatile material, combining excellent high-temperature and corrosion resistance with lightweight and energy absorption properties, making it a popular choice for a wide range of applications. This study explores the development of Ni-Cr foam using Pulse electrodeposition techniques, specifically ultrasonic-assisted pulse electroplating of nickel (UAPEPN) and ultrasonic-assisted pulse electroplating of chromium (UAPEPCr). The study evaluates the surface morphology, coating thickness and minimum mass gain of Ni-Cr foam after each process. A dedicated test rig was designed to measure the pressure drop across the foam, revealing a pressure drop of 0.29 bar at an input pressure of 70 PSI and a flow rate of 17.53 LPM of oil. The porosity percentage and permeability of the foam were evaluated at each developmental stage, with values noted as 91% and 1.0032 × 10−8 m2, respectively, after the UAPEPCr stage. Uniaxial tensile and compression tests were conducted to measure the foam’s maximum strength and energy absorption per unit volume, yielding valuable insights into the material’s performance characteristics.

MEASUREMENT OF ADHESION PROPERTIES OF Ni2Al3 COATING WITH A MICRO SCRATCH TESTER AND AUTOMATIC SCRATCH TESTER

A functionally graded Ni2Al3 coating, prepared with a two-step method of nickel electroplating and pack aluminizing, can improve the hardness of low-carbon steel and other surface performance features. However, the adhesion between the coating and the substrate is an important factor affecting these properties. The primary purpose of this study was to introduce a test for determining the adhesion of the Ni2Al3 coating, which included two tools, namely a micro scratch tester (MST) and a WS-2000 automatic scratch tester, used for measuring the coating adhesion and observing the scratch morphology. Results show that the adhesion is about 14 N according to the MST, which is equivalent to 56 N obtained with WS-2000. As the load increases, the scratches gradually become larger and deeper. Finally, the surface morphology shows cracks, indicating that the coating has failed.

Investigation of Effects of Electroplating Conditions on TEMPO-Oxidized Cellulose Nanofiber Composited Nickel Electroplated Films

The effects of plating conditions on nickel (Ni) electroplated films composited with 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized CNFs (CNFs) were investigated. Plating experiments were performed by varying the amount of CNFs added to the Watt's bath, the current density, and the stirring speed. The plated film obtained at 3 g/L, 2.5 A/cm2, and 300 rpm of them respectively, reached an average 483 HV of the surface hardness, which was the highest in this study. The surface hardness of the conventional Ni film without CNFs plated under the same conditions was an average of 239 HV, and the hardness improvement effect was more than twice as high. The hardness improvement effect due to dispersion enhancement tended to increase as more CNFs were more finely and densely composited into the Ni film, although different trends were observed when the current density was varied.

Nickel electroplating of 6061-T6 aluminum alloy using anodizing process as the pretreatment

Typically, aluminum and its alloys fail to be coated by the electroplating process due to the existence of an inherent oxide layer on the surface which reduces the adhesion between the coatings and the substrate. In this regard, suitable surface preparation is required before the electroplating process. In this study, the anodizing process is chosen as the surface pretreatment. For this purpose, the soft anodizing process was done in a 0.3 M oxalic acid electrolyte at 25 °C and 90 V for different duration. AAO dissolving process was performed to increase the diameter of the pores. Finally, electroplating of nickel was performed in a Watts bath at 40 °C, pH of 3, and different current densities. Three variable of anodizing and dissolving durations and electroplating current density were optimized by a response surface methodology to form a continuous layer of electroplated nickel on the surface. FE-SEM surface morphology, SEM cross-sectional observations, surface XRD characteristics and Daimler-Benz adhesion test were performed to characterize and evaluate the coatings. The optimization of the three variables led to a sequence process of a 9 min anodizing treatment, followed by a 100 min dissolving stage, then electroplating under a current density of 20 mA/cm2. The formation mechanism of the electroplated layer is thoroughly discussed.

A Planar-Type Micro-Biopsy Tool for a Capsule-Type Endoscope Using a One-Step Nickel Electroplating Process.

Millimeter-scale biopsy tools combined with an endoscope instrument have been widely used for minimal invasive surgery and medical diagnosis. Recently, a capsule-type endoscope was developed, which requires micromachining to fabricate micro-scale biopsy tools that have a sharp tip and other complex features, e.g., nanometer-scale end-tip sharpness and a complex scalpel design. However, conventional machining approaches are not cost-effective for mass production and cannot fabricate the micrometer-scale features needed for biopsy tools. Here, we demonstrate an electroplated nickel micro-biopsy tool which features a planar shape and is suitable to be equipped with a capsule-type endoscope. Planar-type micro-biopsy tools are designed, fabricated, and evaluated through in vitro tissue dissection experiments. Various micro-biopsy tools with a long shaft and sharp tip can be easily fabricated using a thick photoresist (SU8) mold via a simple one-step lithography and nickel electroplating process. The characteristics of various micro-biopsy tool design features, including a tip taper angle, different tool geometries, and a cutting scalpel, are evaluated for efficient tissue extraction from mice intestine. These fabricated biopsy tools have shown appropriate strength and sharpness with a sufficient amount of tissue extraction for clinical applications, e.g., cancer tissue biopsy. These micro-scale biopsy tools could be easily integrated with a capsule-type endoscope and conventional forceps.

The Effect of Nickel Electroplating Time on Alumunium 2024 to ITS Mechanical Property

The purpose of this nickel electroplating research on aluminum is to determine the effect of time on mechanical properties in the form of hardness values from specimens and then the SEM-EDX Test is carried out on specimens with the highest hardness test values to find out the microstructure and composition in the coating. The materials used in this study are nickel as the coating and aluminum 2024 as the coated material. The fixed variables used in this study include voltage (25 V), electrode distance (20 cm), water (2400 ml), salt (40gr), vinegar (1600 ml), aluminum 2024, and nickel. The free variables are variation in coating time, namely 10, 15, and 20 minutes. The results of this study showed that the highest hardness value was found in specimens with 10 minutes of immersion time with a value of 198.31 HV and the lowest in specimens with 20 minutes of immersion time with a value of 132.81 HV. After the SEM-EDX test, it was found that the micro layer structure contained pitting (defects) and the element with the highest presentation in the layer was Ni with a mass of 84.07% and an atomic number of 55.29%.

Improving the thermal stability of sintered NdFeB magnets with nickel electroplating by high temperature treatment

Sintered NdFeB magnets with nickel electroplating are widely used in the fields of new energy vehicles, wind generators, elevators and so on. A critical issue that the NdFeB industry is faced with is the poor magnet thermal stability, i.e., a large amount of magnetic flux irreversible loss occurs when experiencing high temperature exposure. One way to address the issue is by adding heavy rare earth (RE) elements, while their scarcity, high cost, and negative effect on Br are unignorable. In this paper, by a simple heat treatment of the NdFeB substrate at 450 ℃, the thermal stability of the final coated NdFeB is significantly improved with the irreversible loss of magnetic flux decreasing from 3.49 % in the original sample to 1.85 % in the optimized sample, while maintaining excellent magnetic properties. Relations between microstructure and thermal stability are further analyzed. This study provides an easy and low-cost method of improving the thermal stability of NdFeB magnets.

Development and Mechanical Characterization of Ni-Cr Alloy Foam Using Ultrasonic-Assisted Electroplating Coating Technique

Metal foams and alloy foams are a novel class of engineering materials and have numerous applications because of their properties such as high energy absorption, light weight and high compressive strength. In the present study, the methodology adopted to develop a Ni-Cr alloy foam is discussed. Polyurethane (PU) foam of 40PPI (parts per inch) pore density was used as the precursor and coating techniques such as electroless nickel plating (ELN), ultrasonic-assisted electroplating of nickel (UAEPN), and pack cementation or chromizing were used to develop the Ni-Cr alloy foam. The surface morphology, strut thickness and minimum weight gain after each coating stage were evaluated. It was observed from the results that the adopted coating techniques did not damage the original ligament cross-section of the PU precursor. The minimum weight gain and the coating thickness after the UAEPN process were observed to be 42 g and 40–60 μm, respectively. The properties such as porosity percentage, permeability and compressive strength were evaluated. Finally, the pressure drop through the developed foam was estimated and verified to determine whether the developed foam can be used for filtering applications.

The optimization of nickel electroplating process parameters with artificial intelligence methods

The optimization of nickel electroplating process parameters with artificial intelligence methods

Improving the wear resistance of aluminum by a nickel-filled anodized porous alumina layer

Anodizing is a widely used method for increasing the wear and corrosion resistance of aluminum alloys. However, it is known that the porous brittle alumina layer can easily crack during tribological stresses, which results in the detachment of large particles from the worn surface. Electroplating, on the other hand, can produce a compact ductile metallic coating with enough wear resistance, though a specific pretreatment like the zincate process is needed for an aluminum substrate. In this paper, a combination of the two methods, anodizing and electroplating, is applied on the surface of pure aluminum intending to improve the wear resistance. Anodizing was performed in oxalic acid by applying a constant current density of 2 A/dm2. The anodized samples were then immersed in phosphoric acid for up to 10 h to increase the diameter of the pores. Nickel electroplating was carried out on the anodized samples at a current density of 0.5 A/dm2 in a Watts solution. Cross-sectional studies show that there is an optimum pore widening time that establishes a good adhesion between nickel and anodic oxide layers, while the structure of the oxide film is largely preserved. Sliding wear tests were performed on the samples using a ball-on-disk reciprocating tribometer. The results show much higher wear life for all Ni/Al2O3 composite coatings as compared with the alumina layer. The maximum wear life was obtained for the sample etched for an optimum pore widening time of 4 h.

Noise Energy Adopted to Understand Nickel Electroplating Process

Electrochemical noise (EN) coupled with chronoamperometry and cyclic voltammetry techniques were adopted to investigate the influences of substrate, temperature (T), current density (D K) and Ni2+ concentration (c i) on nickel electroplating process. The results show that the noise energy (E D) is weakly affected by c i as far as the concentration range concerned, and is limitedly influenced by the substrate, D K and T. The influence of D K on E D is achieved by its effect on the nucleation behavior of the initial deposit monolayer (the D K-depended nucleation behavior). E D mainly reflects the foreign work consumed in the procedure of formation of the initial deposit monolayer but not that in its subsequent growth process, and E D may be used as an index of EN to characterize the difficulty level of localized attacks (such as the formation of initial monolayer of crystallites and pits) for a defined area.

Electrochemical noise energy generated by nickel electroplating process

AbstractThe effects of current density (Jk) and bath temperature on the structure of deposition layer of nickel and electrochemical noise energy (ED) are studied, and the relationship between the structure of the deposit and ED is also discussed in detail using electrochemical noise technique in coupled with the scanning electron microscopy and the glancing angle X-ray diffraction techniques. The results show that ED theoretically mainly reflects the severity or rate of the local cathodic reaction rather than the integral cathodic reaction, and is markedly influenced by the electroplating current density (Jk)-depended nucleation/growth kinetics of the nickel deposit film. The proceeding of the nucleation (or the formation of new phase)/growth process of crystal nucleus on a foreign substrate possesses much more effect on ED value than the subsequent homogenous growth of the already formed film particles, and the factors which can accelerate the drastic change of the electrode surface state should result in large ED value.

Live-current electrodeposition of Nickel on Zinc from modified Watt’s bath

ABSTRACT The zinc-nickel alloy coating has a better combination of corrosion and wear resistance compared to galvanised steel. Electrodeposition of multilayer zinc-nickel alloy coating on steel is an important industrial process. However, in the case of multilayer deposition, the plating of nickel over the zinc layer has an inherent problem owing to the corrosion of zinc in the conventional acidic nickel electrolytes. Conventionally a copper strike layer is introduced over zinc followed by nickel electroplating. The present work aims at understanding the effect of both Ni2+ ion concentration and live currents on the feasibility and quality of Ni deposition on Zn from a modified Watt’s bath such that nickel can be directly deposited on zinc without a copper strike layer. The coating appearance, thickness and roughness are found to be strongly dependent on nickel-iron concentration and the extent of live current which prevent Zn corrosion by offering cathodic protection while simultaneously depositing nickel on zinc.

THE EFFECT OF NICKEL ELECTROPLATING ON THE SURFACE HARDNESS OF LOW CARBON STEEL

Electroplating on steel is basically done with the aim of protecting the steel surface from corrosion attack. However, it is necessary to know the quality surface hardness of steel that has undergone electroplating. This research is determining the electroplating time and the best anode and cathode distance to surface hardness in the nickel electroplating process on low carbon steel. The method was done by placing the specimen into a electrolyte solution. Then the hardness test was carried out on the specimen. The results shown that the ST-37 steel coating with nickel with a variation of the plating time of 12 minutes and the distance between the anode and cathode of 150mm,has highest hardness number of 246.7kg/mm2. By ANOVA analysis the coating time greatly affects the surface hardness.

Fatigue crack behaviour of composite- and mono-coated marine structural components

ABSTRACT In this study, experimental and numerical studies of fatigue crack growth (FCG) mechanisms in coated and uncoated structural components of EN8 steel (EN8) and aluminium alloy 6063 (AA6063) samples were compared. Electroplating (EP) (of nickel (Ni) and chromium (Cr)) and physical vapour deposition technique (PVD) (of aluminium nitride (Al-N) and nanocrystalline layers of titanium aluminium nitride (Ti-Al-N)) methods were used for mono and composite metallic coatings of EN8 and AA6063. The present study focuses on the implications of the coating-substrate interface during FCG initiation and propagation by considering the loading-bearing ability of the coating. Fatigue cracking mechanism depends on coating fracture toughness (FT) at the interface of mono-composite coating and its thickness. In comparison, composite-coated PVD samples proved better than mono-coated electroplated samples due to the delayed plastic deformation process on the surface of the substrate sample.