Brush Plating Process Research Articles

Establishing industrial Zn‑Ni brush electroplating process without post-plating hydrogen embrittlement relief baking

Transitioning from carcinogenic cadmium (Cd) to zinc‑nickel (Zn‑Ni) coating in aircraft components to prevent corrosion poses a challenge of hydrogen embrittlement (HE) of the substrate. While post-plating baking addresses HE in Zn‑Ni coated components, the economic repair of damaged coatings using the Zn‑Ni brush plating process without baking remains problematic. Therefore, in this work, the HE susceptibility of Zn‑Ni brush electroplating, both with and without baking has been investigated by subjecting plated notched specimens to a sustained load test (SLT) in accordance with ASTM F519. Baked specimens after plating passed the SLT, while unbaked specimens exhibit severe HE and fail. Adjusting electroplating parameters alone, such as plating current density and total plating electric charge, did not reduce HE vulnerability of the Zn‑Ni brush plating process without baking. However, optimizing the pre-plating grit blasting process (pressure, working distance), along with reducing the total plating electric charge, and introducing a 72 h delay between electroplating and subsequent SLT, enable plated specimens to exhibit no HE and to pass SLT without requiring baking.

Brush plating process and study on corrosion resistance and hardness of modified graphene on copper-based silver-graphene composite coating

Brush plating process and study on corrosion resistance and hardness of modified graphene on copper-based silver-graphene composite coating

Optimization of Plating Process on Inner Wall of Metal Pipe and Research on Coating Performance.

An innovative brush plating process for preparing coatings on the inner wall of metal pipes is proposed, which aims to solve the limitations of current electroplating technology and improve the performance of the inner walls of metal pipes. While optimizing the process, the effect of working voltage on the microhardness, thickness, surface morphology, corrosion resistance, and elastoplasticity of the Ni coating on the inner wall of the tube was studied under the new process. The results indicate this technique can produce high-quality coatings on the inner wall of pipes in a simple and efficient manner. As the working voltage increases, the surface quality and comprehensive performance of the coating show an increasing trend followed by a decreasing trend. At 12 V, the coating exhibits the highest surface density and uniformity, the lowest surface roughness, the best corrosion resistance, and the maximum microhardness of 575.8 HV, with a corrosion current density of 1.040 × 10-5 A·cm-2, a corrosion rate of 0.122 mm·a-1, the maximum elastic recovery ratio he/hmax of 0.36, and the best deformation resistance. This study demonstrated the effectiveness of this method in improving the durability and functionality of metal pipes and its potential for various industrial applications.

Friction and wear mechanism analysis of the electro brush plating Ni-Mo alloy

The Ni-Mo coating as a replacement for hard chrome plating has gained popularity due to its low environmental pollution. This thesis aims to investigate the characteristics of a Ni-Mo alloy brush coating on a 45# steel base material using the brush plating process. The composition of the plating solution was varied to analyze the effects on the surface morphology, microstructure, hardness, and wear resistance of the Ni-Mo coating. The experimental results demonstrate that the surface morphology of the brush coating is significantly influenced by the composition of the plating solution. As the concentration of nickel sulfate and sodium molybdate varies, the coating exhibits a clear preferential growth tendency. Higher nickel sulfate concentration leads to the growth of coating grain along the (111) crystal plane, while higher sodium molybdate concentration encourages the growth of coating grain along the (220) crystal plane. Increased nickel sulfate concentration results in refined coating grains, while increased sodium molybdate concentration causes more distortion and dislocation of the coating layer. It was observed that the brush plating coating of Ni-Mo alloy, with a nickel sulfate concentration of 400–500 g/L and a sodium molybdate concentration of 25–30 g/L, exhibits not only good surface morphology but also higher micro-hardness and wear resistance. Overall, the analysis of the effects of plating composition on the characteristics of Ni-Mo coating is crucial in developing a high-quality and effective coating for industrial applications.

Improved Adhesion Strength for Electrodeposited Nickel Onto Titanium Alloys Via the Brush Plating Method

Titanium and titanium alloys are attractive materials in a variety of industries such as aerospace due to a high strength to weight ratio and a surface which is naturally resistance to many forms of corrosion. However, tribological properties such as poor abrasion resistance and high friction during metal-to-metal contact have proven difficult to handle without additional treatments. Application of coatings onto the material’s surface is one means of protecting it from those poor tribological properties.Electroplated nickel coatings retain much of the corrosion resistance desired of titanium alloys while also exhibiting better abrasion and wear resistance. Electroplating onto titanium and its alloys is prohibitively difficult due to the propensity of the material to form a tenacious oxide coating on any fresh surface instantaneously after its exposure. The oxide surface acts as a barrier between the solution and the titanium surface reducing the adhesion strength of the resulting deposit. The oxide layer is most commonly removed and the surface modified by hydrofluoric acid (HF) based treatments. HF is considered highly dangerous to workers and to the environment and work is being done to heavily limit its use.For this work, a proprietary chloride-based solution was used during the preparatory steps. Brush or selective plating was chosen as the application technique due to its ability to perform the entire operation with the substrate exposed to solution and under potential control. In most applications of electroplating, the surface/part to be plated must be transferred between multiple tanks containing each preparatory solution used to etch and activate the surface which would involve exposure to air at several points. In addition, the brushing action inherent in brush or selective plating creates a surface environment which can be optimized to promote strong adhesion at the nickel/titanium interface.This presentation will discuss how SIFCO’s brush plating process technology and automation capabilities were used to achieve strong adhesion to the titanium surface without the use of HF. Focus was specifically placed on achieving strong adhesion of a nickel pre-plate onto the titanium surface which allows for a multitude of other coatings to be applied thereafter. The method was performed using a single anode through which the solutions for each step flowed. The samples were under applied potential and immersed in solution throughout the entire process. Applied potential and solution delivery were automated to maximize process consistency.Samples were measured for tensile adhesion strength via the specification ASTM C633. Several variables related to the preparatory procedure were optimized during the study including the flow rate of the solution, the voltage/current conditions, and the evaluation of preparatory steps taken before the electrochemical procedure.

Effect of brush plating process variables on the microstructures of Cd and ZnNi coatings and hydrogen embrittlement

Brush plated ZnNi coating is evaluated for replacement of Cd coating during repair of sacrificial coatings on high strength steel components. Plating parameters such as deposition voltage, surface preparation and type of anode for coating deposition are used to study the risk of Internal Hydrogen Embrittlement (IHE). Coating characterization using Transmission Electron Microscopy (TEM) is correlated with Incremental Step Load (ISL) testing, permeation measurements and Thermal Desorption Spectroscopy (TDS) to evaluate the effect of microstructure and crystallographic defects within the coating on the risk of internal hydrogen embrittlement (IHE) of the substrate steel. It is observed that the coating microstructure plays an important role in mitigating IHE. Brush plated ZnNi coatings at 6 V deposition voltage with grit blast method of surface preparation and graphite anode, or deposition at 12 V with scotch-brite™ method of surface preparation and either of platinized Ti or graphite anode can suitably replace Cd coating. Presence of twin boundaries within the coating proved to be beneficial to decrease the risk of IHE by minimizing the H diffusion to the substrate. On the other hand, stacking faults and dislocations within the ZnNi coating do not sufficiently trap hydrogen and therefore do not mitigate the IHE risk when plated at 10 V and 12 V. Coating deposited at 6 V generates low amount of hydrogen, and does not cause IHE irrespective of the microstructure. TDS measurements performed to quantify the hydrogen desorption from different plating conditions indicate a direct correlation between the amount of hydrogen generated during plating and degradation of mechanical strength by IHE cannot always be established, principally because of the influence of microstructure.

Highlighting the Use of Brush Plating for Plating on Titanium, Nickel Plating, and Metal Matrix Composite Materials

Selective or brush plating is an application method for electrodeposition which can be used for coating an array of pure metals, alloys, and composite materials. The ‘brush’ in brush plating describes a porous, non-conductive, flexible material which wraps the anode to keep it separated from the part to be plated. The plating solution is applied by rubbing the anode, covered with the brush material and saturated by the plating solution, against the area to be plated. This is done in lieu of dipping the entire part in a large tank of plating solution. Brush plating has seen its most advantageous use in plating smaller areas of larger parts because the amount of masking used can be reduced, and smaller volumes of solution can be utilized compared to traditional tank plating methods. Brush plating is portable and repair plating can be performed in the field, sometimes without even disassembling equipment. Brush plating is currently used for numerous specialty applications in the fields of aerospace, oil and gas, marine environments, manufacturing, and many others.The process of brush plating will be presented in terms common to all electroplating processes. The effects of facets particular to brush plating shall be clarified in terms of their contributions to the molecular level and to the properties of the resulting deposit. Applying solution by brushing it onto a part leads to different formulations of the plating solution compared to other plating methods. The application method (brushing) promotes fast solution replenishment at the electrode surface and dissipation of species generated by side reactions at the work surface. The type of brush material used on the anode will affect the type of surface finish or even the structure of the deposited material.The presentation will include a summary of a brush plating process for depositing nickel pre-plate on titanium with strong adhesion, highlighting advancements made to the plating process for a classic sulfamate nickel plating solution formulation, and evaluating differences in solution composition focusing on particle loading.M. Rubinstein, Electrochemical Metallizing, Vinmar Press, New York, NY (1987)D. Vanek, Met. Finish., 108, 25-32 (2010) Figure 1

Process and Equipment Improvement for Nickel Brush Plating Application

The purpose of this paper is to provide an overview of process and equipment improvements for nickel brush plating applications. At the beginning of this project the company used methodology from a subsidiary which does nickel brush plating. Over time, it turned out that it would require a total redesign of the process, because it wasn't compliant with Czech legislation. We knew that without improvements the process could not move forward, therefore, we mainly focused on safety, equipment, accuracy and better quality. In this work we have been using many elements from quality management such as 6Sigma methodology, Ishikawa diagrams, 5why methods, 5S, etc.This project included many people from different sectors such as designers, technicans, material engineers, facility and maintenance, production, quality engineers, EHS engineers etc. This team came with a completely new and unique technical solution for the covered equipment which had never been built in the past in this company or by brush plating process.

Microstructural Modification of Brush-Plated Nanocrystalline Cr by High Current Pulsed Electron Beam Irradiation

Cr layer was fabricated on 40Cr steel by electric brush plating process and then treated by high current pulsed electron beam irradiation technique. Surface microstructures of specimens before and after the irradiation were investigated. Results show that Cr surface is composed of uniformly distributed small nodule units which are composed of fine Cr particles smaller than 100nm. After high current pulsed electron beam treatment, many cracks are found on surface. The main reason is possibly due to the quasi-static thermal stresses accumulated along the surface of the specimens during the electron beam treatment. The surface grain grow from Cr particles because of heating by electron beam, and their size is less than 200nm.

Study of the Nickel-Tungsten and Nickel-Cobalt Coatings Plated on Ductile Iron

Hard coatings such as nickel, chromium and tungsten can improve the surface properties of the substrate. The coating surfaces have been developed for increase of the wear resistance, hardness or corrosion resistance for industrial applications. Electroplating methods generally used to obtain producing these hard coatings and a novel brush plating process has the potential as an alternative of electroplating for industrial applications. In the present work, nickel–tungsten and nickel–cobalt alloys are coated on ductile iron by brush plating for surface characterization. Scanning electron microscopy and energy dispersive spectrometry were used to investigate the coating microstructures, surface morphology. The hardness of plating layers was measured. The results indicated that the nickel–tungsten coating was harder than nickel–cobalt coating. Excellent adhesion was obtained after nickel–cobalt plating. The tribological resistances were also significantly improved, as confirmed by the decrease friction coefficient and wear rate.

The Study of Brush Plating Process on Polyamide Engineering Plastics Surface

The oxidation polymerization simplifies the brush plating process, by which a conductive polymer film is formed on Polyamide Engineering Plastics surface before direct brush plating. In the article, analysis is made on the various process parameters and the influence of the brush plating solution composition on deposition rate . And discussion has been done on the polyamide engineering plastics brush plating process , which includes three phases, namely preprocess, catalysis and brush-plating. the demand on brush-plating process is as following: The workpiece is connected to the positive; the working voltage is 14 V; the movement speed of the brush is from 0.04 m/s to 0.06 m/s; the temperature of brush-plating solution should remains at 80 °C; PH value is between 4.3 to 4.5.The test consequence shows that there are many advantages of brush-plating nickel-phosphorus alloy on the polyamide engineering plastics surface such as simple operating , brush-plating layer with high strength, no stripping and no cracks,and high abrasive resistance, all of which have greatly extended the life of polyamide engineering plastics service.

Nickel–tungsten alloy brush plating for engineering applications

Hard coating can improve the surface properties of a material beyond the capability of the substrate. For a long time, coatings such as hard nickel, hard chromium, hard alloys and hard composites have been developed for engineering applications due to the improved wear resistance. A newly-developed nickel–tungsten brush plating process has the potential as an alternative of electroplating of hard chromium for engineering application.The nickel–tungsten solution is based on the ammoniacal citrate bath, which can be conveniently brush plated just as brush plating of other metals or alloys. On the other side, hard chromium cannot be brush plated due to the exposure of hazardous hexavalent chromium exceeding the Occupational Safety and Health Administration (OSHA) limits.The nickel–tungsten alloy coating has been developed for engineering application. It is of nanocrystalline structure (~2nm crystallite size) and demonstrates excellent hardness and wear resistance. The coating is 60% nickel, 40% tungsten by weight. Due to high tungsten content in the alloy, it is thermally stable. Moderately elevated temperatures (200–500°C) do not cause grain size growth and softening as the case of most other hard coatings (such as hard chromium, nickel phosphorus). Actually, the nickel–tungsten alloy coating can be further hardened by exposure to high temperature of 200–500°C for a short period of time. Beyond the hardness and wear properties, the coating has been further characterized by XRD, electronic and optical microscopy, hydrogen embrittlement, salt spray corrosion, tribology, axial fatigue, and other testing.

Effect of bath temperature on corrosion resistance and structure of Cu–Ni alloy electrodeposited by brush plating method

The preparation of Cu–Ni alloy deposits by a brush plating process, and their corrosion, structure, morphology and composition are addressed. The study reveals that the composition, crystalline size and corrosion potential of the films can be controlled by the bath temperature. X-ray fluorescence analysis confirms that Cu–Ni alloy deposits of stoichiometry Cu50·65Ni49·35, Cu45·11Ni54·89, Cu41·95Ni58·05, Cu30·95Ni69·05 are obtained at 30, 40, 50 and 60°C. X-ray diffraction study reveals that the crystalline size varies in the range of 46 to 21 nm when the deposition temperature is varied from 30 to 60°C. The corrosion study revealed that the alloy deposits at higher temperatures show good corrosion resistance. The surface morphology study shows that the higher temperature deposits have smooth surface morphology and small grain size.

Structure, microstructure and corrosion properties of brush-plated Cu–Ni alloy

Cu–Ni alloy coatings on copper substrate by the brush-plating process have been investigated using XRD and AFM. The X-Ray diffraction analysis revealed that the brush-plated Cu–Ni alloy was heterogeneous and composed of cubic Cu3.8Ni phases. Uniform surface coverage of the substrate by granular morphology was observed from AFM. The corrosion protection performance of the brush-plated Cu–Ni alloy on copper substrate has been assessed using electrochemical corrosion tests. These results indicated a high charge transfer and low I corr for the alloy system compared with copper deposits and the copper substrate.

Structural, microstructural and corrosion properties of brush plated copper–tin alloy coatings

Cu–Sn alloy coatings on mild steel substrates produced by the brush plating process have been investigated using XRD, SEM and AFM. X-ray diffraction analysis revealed that the brush plated Cu–Sn alloy was heterogeneous and composed of hexagonal η-Cu 6Sn 5, orthorhombic ε-Cu 3Sn, tetragonal β-Sn and cubic Cu phases. Uniform surface coverage of the substrate by granular morphology was observed from SEM and AFM. The alloy composition was determined from atomic absorption spectroscopy (AAS). The corrosion protection performance of brush plated Cu–Sn alloy on mild steel has been assessed using salt water immersion and electrochemical corrosion tests. The results indicated a high charge transfer resistance and very low I Corr for the alloy system comparing with that of individual elements on the substrate and the mild steel substrate.

The application of brush-plated cobalt alloy coatings to hot- and cold-work dies

A new solution formulation has been developed which permits the rapid electrodeposition of wear-resistant cobalt—molybdenum alloys by brush or selective area plating. This technique enables the electroplating of selected areas of a die which are subjected to high wear. These areas include the flash-land of a hot-forging die and the radiused edges of a press-forming tool. The brush-plating process has the additional advantage of portability, which allows large dies to be treated in-situ. Industrial trials of these coatings have been carried out in two main metal working areas — hot forging and cold pressing. The hot-forging trials have been carried out in collaboration with forging companies in the Midlands, and the cold pressing trials in collaboration with a large British car manufacturer. The results of these trials have shown that hot-forging die life may be increased by up to 100% and that “down-time” due to metal pick-up on cold pressing tools can be reduced, or even eliminated. In consequence, significant savings can be made in both direct and indirect costs.