Electroless Nickel Plating Research Articles

Improving surface finish and wear resistance of electroless nickel plating using flexible abrasive tool

Electroless nickel plating has a variety of useful properties, including high hardness, high stability, and better corrosion and wear resistance when compared with the stainless steel substrate used in the present work, which make it useful in different fields such as aerospace, optics, defence, etc. However, these applications require very high level of surface finish. This work presents the finishing of electroless nickel plating by flexible abrasive tools fabricated by solvent dissolution method. The flexibility of the tool allows for better adaptability to the workpiece surface, thus protecting the surface from excessive abrasion from abrasive particles. The topographical and morphological studies of the as-plated surface are carried out and compared with the finished surface. Surface roughness, material removal rate and forces are measured to understand the material removal mechanism. Tool loading is also analysed to understand the tool performance. Final finishing is carried out using the best set of input parameters, with or without tool conditioning. A final surface roughness of 9 nm is achieved in 24 min when finishing is carried out using tool conditioning. The wear test and hardness testing of the as-plated and final finished surfaces is carried out to understand the performance of the component. The final finished surface has the lowest coefficient of friction and the maximum wear resistance.

Study of Electroless Nickel Plating on Super Duplex Stainless Steel for Lithium-Ion Battery Cases: Electrochemical Behaviour and Effects of Plating Time

With increasing demand for Li-ion batteries, studies are focusing on enhancing battery performance and safety. However, studies on battery cases remain scarce. Herein, we propose the use of super duplex stainless steel SAF2507, which is a two-phase (austenite + ferrite) steel, for battery casings. Unlike conventional AISI304, SAF2507 maintains its corrosion resistance and strength at high temperatures and precipitates a secondary phase at approximately 975 °C. However, the effects of Ni plating on this secondary phase are not well documented. Therefore, the electroless Ni plating of SAF2507 after secondary-phase precipitation was studied. Briefly, heat treatment at 1000 °C was used to induce precipitation, and the electroless Ni plating behaviour over varying plating periods was analysed using open-circuit potential, potentiodynamic polarisation, and electrochemical impedance spectroscopy measurements. The plating state and corrosion behaviour were examined using scanning electron microscopy. Heat-treated SAF2507 steel with a secondary phase exhibited excellent electroless Ni plating behaviour, which enhances the safety and durability of Li-ion batteries. Furthermore, uniform plating and electrochemical behaviour were achieved after 180 s, suggesting that SAF2507 is superior to AISI304. These findings contribute to the development of safer and more efficient batteries and address the growing demand for Li-ion battery case materials.

Performance and oxidation mechanism of VUV photo–Fenton in simultaneous removal of Ni-EDTA and hypophosphite: decomplexation, low-valent phosphorous oxidation and DFT calculation

The photo–Fenton process offers a promising alternative for the oxidation of complex heavy metals. However, the potential influence of coexisting substrates may be overlooked. The •OH radicals generated in the photo–Fenton process ensure superior oxidation ability. In this study, we used a vacuum ultraviolet (VUV) light-assisted photo–Fenton (VPF) process to explore its performance in the synergistic oxidation of Ni-ethylenediaminetetraacetic acid (EDTA) and coexisting hypophosphite, typical pollutants in electroless nickel plating (ENP) wastewater. Based on electron spin resonance (ESR) and DMSO-probing results, •OH was the predominant reactive oxygen species, and VPF possessed the highest •OH concentration compared to other photochemical processes under identical conditions (pH, Fe, H2O2). Enhanced •OH generation in VPF was attributed to various photochemical reactions, including photo–Fenton, UV/H2O2, and VUV/H2O. Consequently, VPF exhibited efficient Ni-EDTA decomplexation and hypophosphite oxidation. Notably, the evolution and rate-limiting steps during hypophosphite oxidation were demonstrated by experimental results and density functional theory calculations. Hypophosphite was initially oxidized to phosphite, which subsequently oxidized to phosphate. The oxidation of phosphite could be considered the rate-limiting step as it exhibits higher energy barriers than hypophosphite oxidation. Adequate •OH generation in the VPF process could overcome this energy barrier, indicating its potential for application in pollutant removal and resource recovery from ENP wastewater.

Effect of laser welding strategy for reducing intermetallic compound formation and residual stress

Reductions in automobile weight and carbon dioxide emission are critical for the further development of the automobile industry. Aluminum is a lightweight material that can replace copper in automobile electronic equipment; therefore, laser welding of aluminum and copper is a subject of extensive research. This study investigates the influence of the laser strategy on the laser welding of aluminum and copper while preventing the formation of brittle Al–Cu intermetallic compounds. Aluminum and copper plates with a length of 20 mm and thickness of 0.3 and 1 mm, respectively, are used for the experiment. A continuous-wave laser with a power of 500 W and a spot beam radius of 150 μm is employed to irradiate the aluminum surface at different scan speeds. An electroless-plated nickel layer is used as a buffer between aluminum and copper, and the experimental results show that it can prevent copper surface damage and the formation of Al–Cu compounds during laser welding. In addition, the simulation and experimental results reveal that the residual thermal stress after laser welding can be reduced by heat treatment at different temperatures prior to laser irradiation.

Electrochemical activity of electroless Ni-P coatings in the hydrogen evolution reaction

The purpose of this study was investigation of the electrochemical activity of Ni-P coatings, differing in phosphorus content and structure, in the hydrogen evolution reaction (HER) and the identification of the reasons for their high activity in the reaction being studied. The coatings were deposited from an electroless nickel plating solution, the phosphorus content in the coatings (from 4.8 to 8.0 wt. %) varied by changing the pH of the solution. It was found that during cathodic polarization in 0.5 M H2SO4 additional surface activation occurs as a result of dissolution of the surface layer of the coating, removal of phosphorus from the surface layer, and development of the electrode surface. Of all the coatings studied coatings containing 4.8% phosphorus were most susceptible to cathodic activation. Coatings with a phosphorus content of 8.0% were least susceptible to cathodic activation. The similar electrochemical activity of the studied coatings (taking into account the roughness factor) in HER indicates that, as a result of cathodic polarization, the composition of the thin surface layer on which the cathodic reaction occurs is approximately the same, regardless of the initial phosphorus content

Fabrication of conductive polymeric films with metallic luster by electroless plating of silver, copper, and nickel onto polymethyl methacrylate beads

Fabrication of conductive polymeric films with metallic luster by electroless plating of silver, copper, and nickel onto polymethyl methacrylate beads

Surface Finishing and Coating Parameters Impact on Additively Manufactured Binder-Jetted Steel-Bronze Composites.

In this paper, electroless nickel plating is explored for the protection of binder-jetting-based additively manufactured (AM) composite materials. Electroless nickel plating was attempted on binder-jetted composites composed of stainless steel and bronze, resulting in differences in the physicochemical properties. We investigated the impact of surface finishing, plating solution chemistry, and plating parameters to attain a wide range of surface morphologies and roughness levels. We employed the Keyence microscope to quantitatively evaluate dramatically different surface properties before and after the coating of AM composites. Scanning electron microscopy revealed a wide range of microstructural properties in relation to each combination of surface finishing and coating parameters. We studied chempolishing, plasma cleaning, and organic cleaning as the surface preparation methods prior to coating. We found that surface preparation dictated the surface roughness. Taguchi statistical analysis was performed to investigate the relative strength of experimental factors and interconnectedness among process parameters to attain optimum coating qualities. The quantitative impacts of phosphorous level, temperature, surface preparation, and time factor on the roughness of the nickel-plated surface were 17.95%, 8.2%, 50.02%, and 13.21%, respectively. On the other hand, the quantitative impacts of phosphorous level, temperature, surface preparation, and time factor on the thickness of nickel plating were 35.12%, 41.40%, 3.87%, and 18.24%, respectively. The optimum combination of the factors' level projected the lowest roughness of Ra at 7.76 µm. The optimum combination of the factors' level projected the maximum achievable thickness of ~149 µm. This paper provides insights into coating process for overcoming the sensitivity of AM composites in hazardous application spaces via robust coating.

Environmentally friendly and facile Mg(OH)2 film for electroless nickel plating on magnesium alloy for enhanced galvanic corrosion inhibition

Electroless amorphous nickel (Ni)–phosphorus (P) (NiP) alloy coatings were successfully achieved on magnesium alloys using an environmentally friendly and facile Mg(OH)2 conversion film, followed by AgNO3 activation. The success of the coating was confirmed through scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction characterizations. Electrochemical tests showed that the charge transfer resistance of the newly developed electroless NiP plating coating, which had a horizontally stacked Mg(OH)2 nanosheet primer (Mg(OH)2/pH 14/ENP), was significantly higher than that with a vertically grown Mg(OH)2 nanosheet underlayer (Mg(OH)2/pH 10/ENP) or that with a phosphate pretreatment (ENP). The measured corrosion current density of the Mg(OH)2/pH 14/ENP coating was 1.08 μA cm−2, one magnitude smaller than that of the ENP coating. Notably, the ENP coating exhibited severe galvanic corrosion, peeling off after only 24 h of the neutral salt spray (NSS) test. In contrast, the Mg(OH)2/pH 14/ENP surface showed no visible corrosion cavities or signs of galvanic corrosion even after 120 h of the NSS test or 21 d of exposure to a NaCl solution. These results indicate that the as-prepared coating possesses a strong inhibition capability against galvanic corrosion between the Ni layer and the magnesium alloy, providing long-lasting corrosion protection.

Highly Conducting Surface-Silverized Aromatic Polysulfonamide (PSA) Fibers with Excellent Performance Prepared by Nano-Electroplating.

In this work, bilayer nanocoatings were designed and constructed on high-performance aromatic polysulfonamide (PSA) fibers for robust electric conduction and electromagnetic interference (EMI) shielding. More specifically, PSA fibers were first endowed with necessary electric conductivity via electroless nickel (Ni) or nickel alloy (Ni-P-B) plating. Afterward, silver electroplating was carried out to further improve the performance of the composite. The morphology, microstructure, environmental stability, mechanical properties, and EMI shielding performance of the proposed cladded fibers were thoroughly investigated to examine the effects of electrodeposition on both amorphous Ni-P-B and crystalline Ni substrates. The acquired results demonstrated that both PSA@Ni@Ag and PSA@Ni-P-B@Ag composite fibers had high environment stability, good tensile strength, low electric resistance, and outstanding EMI shielding efficiency. This indicates that they can have wide application prospects in aviation, aerospace, telecommunications, and military industries. Furthermore, the PSA@Ni-P-B@Ag fiber configuration seemed more reasonable because it exhibited smoother and denser silver surfaces as well as stronger interfacial binding, leading to lower resistance (185 mΩ cm-1) and better shielding efficiency (82.48 dB in the X-band).

High-efficiency nickel recovery from spent electroless nickel plating solution: effective degradation of high-concentration nickel complexes to form a nickel ferrite nanomaterial via Fe3O4 catalytic oxidation

High-concentration organic nickel complexes were efficiently degraded and converted into NiFe2O4 nanomaterials via Fe3O4 catalytic oxidation under alkaline conditions, with high removal efficiency of nickel (99.99%) and TOC (81.94%), respectively.

Effect of Compliant Tool Finishing on Mechanical Properties and Surface Topography of Electroless Nickel Plating

Effect of Compliant Tool Finishing on Mechanical Properties and Surface Topography of Electroless Nickel Plating

Flexible metalized polyimide nonwoven fabrics for efficient electromagnetic interference shielding

Designing and fabricating efficient electromagnetic interference shielding materials has become a significant and urgent concern. Hence, a novel lightweight and flexible metallized polyimide nonwoven fabric is successfully prepared by polydopamine roughening, palladium-free activation of chloroplatinic acid, electroless nickel plating, and octadecanethiol corrosion-resistant treatment. As a result, the efficient construction of metallized surface on polyimide fibers facilitates the formation of multiple scattering for incident electromagnetic waves, leading to an excellent electromagnetic interference performance. More importantly, the strong binding force between nickel plating and polyimide fiber substantially improves the high/low-temperature resistance, endowing the composite with excellent stability and durability in electromagnetic interference performance. Meanwhile, the self-assembly modification of octadecanethiol on the surfaces of nickel plating effectively achieves the inhibition of metal corrosion. Additionally, the high electrical conductivity of metallized polyimide nonwoven fabric endows it with a rapid-responsiveness Joule heating performance, which makes it promising to become an efficient electromagnetic interference shielding material with a distinct competitive advantage in the cold environment.

Effect of interlayer interfaces enriched with multi-walled carbon nanotubes network on microstructure and mechanical properties of carbide-based composite coatings

In this paper, a WC-20Cr3C2-7Ni/multi-walled carbon nanotubes (MWCNTs)-Ni composite powder with a core-shell structure was prepared by surface modification and electroless nickel plating. After high-velocity oxy-fuel (HVOF) spraying, MWCNTs enriched in the shell and reinforced the interlayer interface of the composite coating. The addition of 0.2 wt% MWCNTs increased the reduced modulus and energy dissipation capacity of the composite coating by 12.6 % and 25.0%, respectively. The HRTEM results showed that MWCNTs formed a network structure at the interface. During the deformation process, stress was effectively transferred to network MWCNTs due to the strong metallurgical bond between MWCNTs and the binder phase. It allowed MWCNTs to absorb more energy and promoted stress to be transferred to the interior along the interlayer interface. The influence of MWCNTs on the elastic deformation process of the coatings was analyzed by numerical simulation.

Microstructure, mechanical properties and hermeticity of W-Cu/HTCC brazed joints with surface metallization

WCu alloy and high temperature co-fired ceramic (HTCC) were metallized through electroless nickel plating, then one series of W-Cu/Ni/AgCu/Ni/HTCC joints were successfully brazed with AgCu filler. The microstructure, mechanical properties, and hermeticity of W-Cu/HTCC joints were systematically investigated, and the fracture paths of the joints were summarized. The results revealed that the interface microstructure of the joints consisted of Ni(Cu)-W, Ni3P, CuNi, Cu(s,s), and Ag(s,s) phases. As the brazing temperature increased, Ni atoms gradually diffused from the NiP layer into the filler layer and substrate. At 900 °C, the NiP layer dissolved, and Cu atoms from the WCu alloy diffused into the solder layer, leading to a sharp growth in joint thickness. The shear tests indicated that the promotion of Cu content in the filler layer effectively alleviated the residual stress in the joints, resulting in higher joint strength. The maximum shear strength of 73.57 MPa was reached when the joints brazed at 840 °C. The hermeticity measurement results showed that the joints brazed at 900 °C for 10 min exhibited exceptional hermeticity, with a helium leakage rate of 2.51 × 10−11 Pa·m3/s. This work provided a reference for the connection of metal packaging materials with high temperature co-fired ceramics.

Strengthening phase and mechanical property analysis of artificially aged Al7075 – Ni coated Al2024 composites

This technical paper demonstrates the possibilities of nickel (Ni) coated Al2024 powder reinforcement in an Al7075 matrix using the liquid stir casting technique. Additionally, the paper focuses on achieving stable properties by implementing artificial aging heat treatment. To apply the Ni coating, the electroless nickel plating technique was utilized, and a minimum coating thickness of 8 μm was determined to effectively prevent the dissolution of Al2024 powder reinforcements within the Al7075 matrix. Stir casting facilitated the uniform dispersion of the coated Al2024 powder up to a weight percentage of 7%. Subsequently, the Al7075 alloy and composites underwent artificial aging through solution heat treatment (SHT) at 450 °C for 4 h, followed by water quenching and aging at temperatures of 120, 150, and 180 °C. Aging at 120 °C was found to yield superior results compared to aging at 150 and 180 °C, thus identified as the optimum aging temperature. When the Ni coating thickness was increased beyond the optimal 8 μm, the resulting enhancements in hardness for both as-cast and peak-aged specimens, as well as the tensile strength, were not significant. The improvements observed were only marginal, ranging between 2 to 3%. Fracture surface analysis revealed that the predominant fracture mode in the Al7075 alloy was ductile, characterized by dimple rupture. In the as-cast Al7075-(7%, 8 μm) Al2024 composite, a mixed fracture mode comprising both brittle and ductile characteristics was observed. In the peak-aged (120 °C) Al7075-(7%, 8 μm)Al2024 composite, the overall fracture mode exhibited a dominant brittle nature. Analytical techniques including XRD, TEM, and EDS confirmed the presence of Mg2Si, MgZn2, CuAl2, and CuAl2Mg phases in the peak-aged (120 °C) Al7075-(7%, 8 μm) Al2024 composite. These phases contributed to the enhancement of the properties of both the Al7075 alloy and its composites. The developed composites can be used in automobile parts and aerospace applications.

Machine Learning-Enabled Quantitative Analysis of Optically Obscure Scratches on Nickel-Plated Additively Manufactured (AM) Samples.

Additively manufactured metal components often have rough and uneven surfaces, necessitating post-processing and surface polishing. Hardness is a critical characteristic that affects overall component properties, including wear. This study employed K-means unsupervised machine learning to explore the relationship between the relative surface hardness and scratch width of electroless nickel plating on additively manufactured composite components. The Taguchi design of experiment (TDOE) L9 orthogonal array facilitated experimentation with various factors and levels. Initially, a digital light microscope was used for 3D surface mapping and scratch width quantification. However, the microscope struggled with the reflections from the shiny Ni-plating and scatter from small scratches. To overcome this, a scanning electron microscope (SEM) generated grayscale images and 3D height maps of the scratched Ni-plating, thus enabling the precise characterization of scratch widths. Optical identification of the scratch regions and quantification were accomplished using Python code with a K-means machine-learning clustering algorithm. The TDOE yielded distinct Ni-plating hardness levels for the nine samples, while an increased scratch force showed a non-linear impact on scratch widths. The enhanced surface quality resulting from Ni coatings will have significant implications in various industrial applications, and it will play a pivotal role in future metal and alloy surface engineering.

Induction Heating Characteristics of Electroless Ni-Coated CFRP for Deicing and Anti-Icing

Ice accumulation on the surface of aircraft is a serious threat to flight safety and a fatal factor causing air accidents. However, traditional aircraft deicing methods no longer meet the requirements of safe flight due to changes in aircraft structural materials. In recent years, the application of carbon fiber-reinforced polymer (CFRP) materials in the aviation structure industry has increased. In this study, we demonstrate an economical, easy-to-prepare, and pollution-free approach to deice an aircraft through induction heating. The nickel-coated carbon fiber-reinforced polymer used as the induction heater for aircraft deicing is obtained by electroless nickel plating on the surface of the CFRP. The result shows that it takes just 110 s to achieve a temperature of 205 °C on the nickel-plated CFRP when the input voltage is 30 V, as well as melting the ice layer with a thickness of 30 mm, while the temperature of this material can reach up to 81 °C by electric heating when the input voltage is 1.5 V. Meanwhile, the nickel-plated CFRP exhibits good repeatability during the induction heating. Based on the excellent electrothermal properties, the nickel-plated CFRP polymer shows a prominent deicing ability, which provides a promising strategy for the deicing of aircraft.

Peak hardness stability analysis of Al7075 alloy dispersed with Ni coated duralumin powder during natural aging phenomena

This technical paper presents the successful reinforcement of nickel (Ni) coated duralumin powder in an Al7075 matrix using the liquid stir casting technique and property stability obtained by heat treatment. Ni coating is performed by electroless nickel plating technique where 8 μm coating thickness was observed to be the minimum required to prevent dissolution of the reinforcements (duralumin powder) in the matrix (Al7075). During stir casting it was observed to uniformly disperse the coated duralumin powder up to 7 wt.%. Al7075 alloy and composites were artificially aged with solution heat treatment (SHT) performed at 450 °C for 4 h, water quenched and then aged at 120, 150 and 180 °C. Al7075 alloy and composites were naturally aged for 24 weeks in atmospheric temperature after peak aging. Composites aged at 120 °C exhibited superior results and considered as optimum aging temperature compared to those aged at 150 and 180 °C. Peak hardness values in 7075-7Dp+8T composite improved by 108% and 7075-7Dp+10T composite improved by 110% when compared to peak aged (at 120 °C) Al7075 alloy. Moreover, composites with coated reinforcement displayed a higher resistance to natural aging, with reductions of 53.5 and 54.4% in natural aging tendency compared to the naturally aged Al7075 alloy for 7075-7Dp+8T and 7075-7Dp+10T composites respectively. However, an increase in Ni coating thickness beyond the optimal 8 μm did not significantly improve as cast and peak hardness or natural aging resistance. XRD analysis confirmed that there is presence of CuAl2, CuAl2Mg, Mg2Si, and MgZn2 phases in peak-aged (120 °C) 7075-7Dp+8T sample. Considering the limited impact on property enhancement and the financial burden associated with thicker coatings, a coating thickness of 8 μm is recommended as compared to 10 μm.

Design Optimization and Mechanical Properties of SiC Particle Reinforced Ti-Based Metallic Glass Matrix Composite.

Ti-based bulk metallic glass (BMG) alloys have attracted widespread attention due to their strong glass forming ability, high specific strength, and good corrosion resistance. However, the poor plasticity of BMGs limits their further application in the aerospace and aircraft fields, as well as others. We optimized the composition of SiC-reinforced, Ti-based metallic glass matrix composites (MGMCs) through finite element modeling (FEM). FEM of MGMCs containing irregularly shaped SiC particles with different contents was conducted. Stress and strain analyses were conducted to evaluate the effect of the particle volume fraction on the mechanical behavior of MGMCs, and an optimization value of 30% was obtained, which is conducive to plasticity improvement. Arc melting copper mold injection casting was used to verify the optimized SiC content. The results show that the electroless nickel plating treatment effectively improves the wettability between SiC particles and the amorphous matrix, enabling the successful preparation of SiC/MGMC with a volume fraction of 29.5% through traditional injection casting. The volume fraction of SiC plays a crucial role in the transition of fracture mode from splitting to shear in MGMCs. After adding lightweight SiC particles, the yield strength, plasticity, modulus, and specific strength were improved by 25%, 1471%, 46%, and 33%, indicating that the use of nickel-plated SiC particles in MGMCs is an effective strengthening and toughening method for BMGs.

Effect of humidity on radiolysis-enhanced corrosion by gamma irradiation on electroless nickel plating

The study reveals that water vapor can cause corrosion of electroless nickel plating under gamma irradiation, even in the absence of dew condensation. To control relative humidity during gamma irradiation, a simple apparatus utilizing saturated salt solutions was developed and validated by cold tests. Irradiation testing of electroless nickel plating was conducted under humidity control at relative humidity of 20%, resulting in surface degradation after 1 MGy total dose. Conversely, no degradation was observed on samples exposed to dry condition with relative humidity of less than 10% after a 5 MGy total dose. Humidity-uncontrolled irradiation tests, where condensation could occur, resulted in more severe corrosion than the humidity-controlled tests. A comparison of the chemical composition of corrosion products between the humidity-controlled and humidity-uncontrolled environments showed nitrate corrosion products were prevalent in the former while hydroxides were dominant in the latter.