Electroless Ni-P Research Articles

ZnO-Doped gC3N4 Nanocapsules for Enhancing the Performance of Electroless NiP Coating-Mechanical, Corrosion Protection, and Antibacterial Properties.

A carbon nitride (C3N4) nanomaterial has superior mechanical, thermal, and tribological properties, which make them attractive for various applications, including corrosion-resistant coatings. In this research, newly synthesized C3N4 nanocapsules with different concentrations (0.5, 1.0, and 2.0 wt %) of ZnO as a dopant were incorporated into the NiP coating using an electroless deposition technique. The nanocomposite coatings either ZnO-doped (NiP-C3N4/ZnO) or undoped (NiP-C3N4) were heat-treated at 400 °C for 1 h. The as-plated and heat-treated (HT) nanocomposite coatings were characterized by their morphology, phases, roughness, wettability, hardness, corrosion protection, and antibacterial properties. The results indicated that the microhardness of as-plated and heat-treated nanocomposite coatings was significantly improved after the incorporation of 0.5 wt % ZnO-doped C3N4 nanocapsules. The outcomes of electrochemical studies revealed that the corrosion resistance of the HT coatings is higher than the corresponding as-plated ones. The highest corrosion resistance is achieved on the heat-treated NiP-C3N4/1.0 wt % ZnO coatings. Although the presence of ZnO in the C3N4 nanocapsules increased its surface area and porosity, the C3N4/ZnO nanocapsules prevented localized corrosion by filling the microdefects and pores of the NiP matrix. Furthermore, the colony-counting method used to evaluate the antibacterial behavior of the different coatings demonstrated superior antibacterial properties, namely, after heat treatment. Therefore, the novel perspective C3N4/ZnO nanocapsules can be utilized as a reinforcement nanomaterial in improving the mechanical and anticorrosion performance of NiP coatings in chloride media, together with providing superior antibacterial properties.

The effect of candle-soot reinforced electroless Ni-P particle interface on tribological performance in copper-based materials produced by flake powder metallurgy method: Transfer of candle-soot from waste to solid-lubricant

The softness and ductility of copper can lead to high levels of wear and friction when it encounters other surfaces, which can be detrimental in certain applications. Therefore, improving the tribological properties of copper, such as by coatings or surface treatments, can help to mitigate these issues and make copper even more versatile and useful in a wider range of applications. Accordingly, in this study, functional particles were produced by electroless coating process by providing an electroless Ni-P/candle-soot (CS) nanoparticle (1%vol.) coating layer around each of the flake copper powders followed by production of final materials by flake powder metallurgy including hot-pressing. The wear surfaces were thoroughly analysed using SEM and EDS techniques which allows for the examination of morphological and microstructural characteristics. Due to the homogeneous distribution of Ni-P/CS additives on the interface, the tensile and wear resistances have shown approximately 250% and 1300% increase, respectively, compared to the additive-free Cu materials. While the Ni-P interface in Cu materials caused a decrease in electrical conductivity, the addition of CS resulted in approximately 14% improvement in electrical conductivity. It was showed that electroless Ni-P coatings provide a hard, wear-resistant surface with lubricative CS that protects against wear, making them ideal for use in applications such as aerospace, automotive, and electronic industries.

傾斜切削による無電解Ni-Pめっき金型の表面粗さの改善

Ultraprecision aspheric cutting process using a monocrystalline diamond tool is widely used in the manufacturing process of the optical components and their molds/dies. Plastic lenses are molded by the injection molding using an amorphous electroless Ni-P plated molds/dies and decreasing of the lens surface roughness is required. Generally, the oblique cutting is one of the methods to decrease the cutting force and the burr, and to decrease the surface roughness. In this study, the oblique cutting was applied to aspheric mold materials to decrease the surface roughness. In the experiments, plunge cut by oblique cutting was applied to the electroless Ni-P plated molds, aluminum, oxygen free copper, and brass to clarify the burr behaviors. Finally, flat surface was diamond-turned by changing the oblique angle of the tool, the cut surface was evaluated, and the effects of the oblique angle to the surface roughness were evaluated.

Corrosion characteristics of microwave and furnace annealed electroless Ni-P-TiO2 coatings

The Co-deposition of TiO2 particles (anatase type) of 200–300 nm with Ni-P electroless coatings on low carbon steel. The coated specimen was annealed by microwave and common electric furnace. The effects of microwave and furnace annealing temperatures on these coatings were characterized via. XRD, SEM, EDAX, and the corrosion performance was characterized through electrochemical polarization technique. The corrosion medium used for this work was sodium chloride (NaCl) solution and which contains 3.5 wt-% in distilled water. The result showed that, the microwave annealing method was enhanced the corrosion performance of the coating by diffused TiO2 particle into the matrix and reduced the micro voids presented in the matrix. Further, the corrosion mechanisms of the non-treated and the annealed coated materials have been explained in the consideration of crystallization, transformation of phases, grain size, and micro strain.

Effect of sodium dodecyl sulfate surfactant on the surface properties of electroless NiP-TiO2-ZrO2 composite coatings on magnesium AZ91D substrate

This research incorporated nano TiO2 and ZrO2 particles into the NiP electroless bath to produce NiP-TiO2-ZrO2 composite deposits on magnesium AZ91D substrates. The impact of sodium dodecyl sulfate (SDS) (anionic surfactant) was utilized for deposition to minimize the agglomeration and clustering of particles in the electroless bath. Surface properties such as atomic force microscopy, energy dispersive X-Ray analysis, scanning electron microscopy, and X-ray diffraction are used to evaluate the surface morphologies of coating, surface roughness, elementary composition, and crystalline structure of the deposits. Furthermore, the impact of SDS surfactant on the corrosion properties of deposits was also studied using potentiodynamic polarization in a 5 wt% NaCl solution. The overall results reveal that incorporating anionic surfactant SDS at the optimum concentration of 1.5 g/L (CMC value) improved wettability, deposition rate, and surface roughness compared to the deposits developed without surfactant. The proposed mechanism is that the molecules of SDS surfactant could come into contact with the surface of NiP-TiO2-ZrO2 composite coating in the bath, increasing nanoparticle dispersion and resulting in a uniform coating. Furthermore, the electrochemical results show improved corrosion protection efficiency (PE%) of NiP-TiO2-ZrO2 composite coatings by increasing the concentration of SDS surfactant, achieving ∼87.9% at (1.5 g/L) CMC value.

Comparison of Electroless Ni-P and Co-W-P Diffusion Properties Against GaAs Substrate

Comparison of Electroless Ni-P and Co-W-P Diffusion Properties Against GaAs Substrate

Comparison of interfacial reactions and isothermal aging of cone Ni-P and flat Ni-P with Sn3.5Ag solders

Electroless Ni-P plating has good prospects for application as a diffusion barrier layer for interfacial reactions. In this study, the interfacial reaction between the microcone-structured Ni-3.5%P coating with high crystallinity and the Sn3.5Ag solder was investigated and compared with Sn3.5Ag/flat-Ni-(2%, 5%, 10%)P couples. Wettability experiments of Sn3.5Ag on four types of Ni-P coatings were carried out. Reflow at 250 °C for various minutes was performed, as well as isothermal aging experiments at 175 °C for various durations. The results showed that the Sn3.5Ag achieved the best wettability on cone Ni-3.5%P due to the pyramidal morphology that provides an additional driving force for wetting. During isothermal aging, the growth of intermetallics (IMCs) in the Sn3.5Ag/cone-Ni-3.5%P couple was attributed to the contribution of boundary diffusion mechanism to the rate control process, while that in the remaining three couples was a grain boundary diffusion-limited process. After reflow and isothermal aging, fewer microvoids and no harmful Ni-Sn-P layers were detected in the interface of Sn3.5Ag/cone-Ni-3.5%P couples, while they were detected in the other three couples, indicating that the cone Ni-3.5%P couple could inhibit the formation of Ni-Sn-P layer and microvoids. As a result, Sn3.5Ag/cone Ni-3.5% couples exhibited better shear resistance.

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.

Corrosion behaviour of electroless NiP coating in artificial blood plasma

ABSTRACT Electroless NiP coatings are well known for their excellent properties and vast area of applications. In the present investigation, electroless NiP coating is applied on AISI 420 substrate, which is used for manufacturing medical instruments. As blood is a strong electrolyte, the steel, when comes in contact with blood for a long time, tends to corrode very fast. The primary objective of this work is to enhance the corrosion resistivity of AISI 420 stainless steel by the application of electroless NiP coating. The corrosion resistance of coated steel was investigated using both potentiodynamic polarisation and electrochemical impedance spectroscopy in artificial blood plasma. Detailed microstructural investigation using scanning electron microscopy (SEM), X-ray diffraction and energy dispersive X-ray spectroscopy has been done. Microhardness measurement has been performed. The SEM images revealed the coatings to be primarily amorphous and changed to crystalline when heat treated at 300°C for 2 h. Microhardness of the as-plated coating was 592 HV and increased to 677 HV after heat treatment. Corrosion rate decreased from 4.694 × 10−4 mm/year of bare steel to 4.104 × 10−5 mm/year for coated and heat-treated steel.

Erosion–Corrosion of Novel Electroless Ni-P-NiTi Composite Coating

The lifespan of low-carbon steel petroleum pipelines can often be shortened by the erosion–corrosion damage caused by their service conditions. Applying electroless Ni-P coating is a promising option to protect the steel from the environment due to its high hardness and corrosion resistance. However, electroless Ni-P has a low toughness but can be increased by the addition of NiTi ductile particles. This work produced electroless Ni-P and Ni-P-NiTi coatings of different thicknesses on AISI 1018 substrates and compared their erosion, corrosion, and erosion–corrosion behaviors. The methodology involved conducting slurry pot erosion–corrosion tests on AISI 1018 steel substrate, the monolithic Ni-P coatings, and the composite Ni-P-NiTi coatings. Erosion resistance was highly influenced by coating thickness, presumably because of the relationship between the erosion-induced compressive stresses and the coating’s as-plated internal stresses. The NiTi nanoparticle addition was highly effective at improving the erosion–corrosion resistance of the coating. Pitting corrosion and cracking were present after erosion–corrosion on the monolithic Ni-P coatings. However, the Ni-P-NiTi composite coating had a relatively uniform material loss. Overall, the AISI 1018 steel substrate had the worst erosion–corrosion resistance and 25 μm thick Ni-P-NiTi coating had the best.

Electroless deposition of Ni-W-Mo-Co-P films as a binder-free, efficient and durable electrode for electrochemical hydrogen evolution

In this study, the manufacture of Ni-W-Mo-Co-P, Ni-Mo-Co-P, Ni-W-Co-P, Ni-W-Mo -P, Ni-Co-P, Ni-Mo-P, Ni-W-P, and Ni-P alloying coatings through electroless method on the copper substrate was investigated. The elemental and structural tests showed that the alteration of the Ni-P electroless basic bath composition by introducing sodium tungstate, sodium molybdate, and cobalt chloride additives enabled the deposition of alloying coatings. Linear Sweep Voltametry (LSV) tests revealed that the Ni-W-Mo-Co-P sample (NWMCP) coated in an alkaline bath with 18 g/l Nickel (II) sulfate, 12 g/l Ammonium acetate, 12 g/l Sodium citrate, 12 ml Lactic acid, 12 g/l Sodium hypophosphite, 8 g/l Sodium tungstate, 0.2 g/l Sodium molybdate, and 10 g/l Cobalt (II) chloride was featured with the best electrocatalytic properties with η10 = −41, η20 = −46, η100 = −67 mV and tafel slope of 38 mV.dec−1. Scanning Electron Microscope (SEM) observations and Cyclic Voltametry (CV) electrochemical tests showed that morphology had a negligible effect on electrocatalytic performance of the coating. In addition, the presence of alloying elements improved the coating intrinsic properties by changing its electronic structure. Electrocatalytic stability was assessed using chronoamperometry, cyclic voltammetry, and stepwise chronoamperometry tests, introducing NWMCP sample a durable electrode generation with good stability.

Friction and Wear of Electroless Ni-P-CS Composite Coating

Carbon nanoparticles have excellent lubricating properties, however, they are less involved in metal protection. In this study, easily prepared candle soot was added to electroless nickel-phosphorus plating as a re-enforcement particle. Ball-disc friction and wear tests were conducted to evaluate the wear-resistance capabilities of the electroless Ni-P coating and Ni-P-CS (Candle Soot) composite coatings. The parameters for the friction coefficient, wear amount, and friction morphology of the Ni-P-CS composite coatings were studied after being heat-treated (300 °C, 400 °C, 500 °C, and 600 °C). The surface morphology and phase composition of the Ni-P-CS composite coatings after thermal treatment at various temperatures were also investigated. The results are as follows: heat treatment strengthens the local hardness of the Ni-P-CS composite coating but does not further enhance wear resistance. Compared with the Ni-P coating and the heat-treated Ni-P-CS composite coating, the Ni-P-CS composite coatings without heat treatment have a lower friction coefficient (0.35) and better wear resistance.

α-Fe2O3/Fe3O4@GO nanosheets boost the functionality of Ni[sbnd]P thin film deposited by electroless method

The highly active heterogeneous iron oxide@graphene oxide (α-Fe2O3/Fe3O4@GO) composite was produced using a simple assembly method to incorporate into the electroless NiP thin film to enhance its performance. It was thoroughly characterized using X-ray diffraction (XRD), Raman Spectroscopy, Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and N2 adsorption-desorption tests. The outcomes showed that the α-Fe2O3/Fe3O4 nanoparticles were uniformly and densely distributed on the GO sheets, with a tiny diameter of about 160 nm.Ni-P/α-Fe2O3/Fe3O4@GO composite coatings were created on low-carbon steel using an acidic electroless plating bath containing various α-Fe2O3/Fe3O4@GO nanosheets. The protective effect of co-deposited nanosheets on the corrosion behavior of the coatings was examined in a 3.5 % NaCl solution. Electrochemical techniques, including electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization investigations, were used to evaluate the layers' corrosion resistance. The outcomes demonstrate that adding α-Fe2O3/Fe3O4@GO significantly increases the coatings' ability to resist corrosion. Maximum corrosion resistance was achieved at a dosage of 50 mgl−1 α-Fe2O3/Fe3O4@GO nanosheets in the plating bath. According to the SEM images the α-Fe2O3/Fe3O4@GO were implanted in the NiP matrix and were evenly disseminated over the coated surface. Moreover, the incorporation of α-Fe2O3/Fe3O4@GO enhances the mechanical properties of NiP thin film.Because of its improved performance, ease of synthesis, and low cost, this coating layer warrants more consideration as a good option for possible application to safeguard carbon steel utilized in the atmosphere.

FEA Based Design and Stability Study of Electroless Ni-P Coating Plated over a Stepped Shaft under Thermal Load

ABSTRACT Modelling of Ni-P coating and substrate assembly is done using the finite element analysis framework. Coating having a thickness of 50 µm is applied over a stepped shaft made of stainless steel and analysed in Ansys Workbench at an elevated temperature of 200°C. The thermal effect on the system is studied and results are discussed in detail with respective figures. Elastic modulus of Ni-P coating required for the analysis is evaluated from the nanoindentation test under 10 mN load. The analysis focuses on the evaluation of the critical design parameters such as equivalent stress, total deformation, strain energy and thermal strain over the entire body. Besides, four separate paths are created on the model to study the difference of induced stress and strain energy between the contacting surfaces of the shaft and the coating. It is found that there is a sharp discontinuity in these values and this discontinuity is further interpreted as a measure of the stability of coating over the substrate. It is found that the higher the difference of stress and strain energy, lower is the stability of the assembly which is considered to be realistic and in accordance with the elasticity principles. .

Ultra-precision Cutting Characteristics of Convex Blazed Gratings with Electroless NiP

Ultra-precision Cutting Characteristics of Convex Blazed Gratings with Electroless NiP

Optimization of Lead-Free Electroless Ni-P Coatings

Optimization of Lead-Free Electroless Ni-P Coatings

Wearable nonwoven fabric decorated with Fe3O4/rGO/PANI/Ni-P for efficient electromagnetic interference shielding

The design of three-dimensional (3D) architectures with different multi-interface and the identification of suitable nanomaterials have significantly progressed in recent years. However, balancing increasing electrical conductivity and optimising impedance matching is substantially important and requires special architecture. Here, we devised lightweight wearable electromagnetic interference (EMI) shielding materials with promising microwave absorption performances. Layer-by-layer integration of conducting and magnetic nanomaterials onto the porous structure of the nonwoven fabric was performed using dielectric and magnetic loss to enhance the absorption capability of the composite. The EMI shielding effectiveness of the 1-layer, 2-layer, and 3-layer reach up to 27, 42, and 81 dB, respectively, revealing excellent performances in the X-band. The synthesis of hierarchical Ni-P nanospheres on fibres with heterojunctions and multi-interfaces as polarisation centres results in excellent microwave absorption performance. Furthermore, Ni-P electroless plating and Ni-B chemical deposition were conducted to improve permittivity, conductivity, and permeability in addition to increasing the impedance matching of the EM shielding material. It provides an avenue for the architecture of promising wearable functional materials with superior absorption activity, flexibility, durability, and breathability.

Effect of Heat Treatment and Passivation on Corrosion Behavior of Electroless Ni-P Coating on 20# Steel in Simulated Soil Solution

Effect of Heat Treatment and Passivation on Corrosion Behavior of Electroless Ni-P Coating on 20# Steel in Simulated Soil Solution

IMPROVING CORROSION RESISTANCE OF MAGNESIUM NANOCOMPOSITES BY USING ELECTROLESS NICKEL COATINGS

The present study aims at improving corrosion resistance of magnesium nanocomposites through autocatalytic Ni-P coating. Electroless Ni-P coatings with different concentration of sodium hypophosphite are deposited on 2% WC incorporated magnesium nanocomposites (AZ31-2WC) and the coated samples are further heat-treated. Basic characterizations and compositional analyses are done by using scanning electron microscope (SEM), energy dispersive x-ray analysis (EDAX), and X-ray diffraction analysis (XRD). Microhardness values of the developed materials are also evaluated. The attempt is made to improve corrosion resistance of AZ31-2WC by modifying surface roughness. Corrosion characteristics of Ni-P coated AZ31-2WC nanocomposites are examined by performing potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). Corrosion resistance improves with enhancement of surface quality. Corrosion resistance of AZ31-2WC nanocomposite also improves due to application of Ni-P coating. Finally, corrosion morphologies are scrutinized by SEM micrographs of corroded surface.

Contact resistance measurement methods for PEM fuel cell bipolar plates and power terminals

The electrical contact resistance is a key parameter for optimising both the bipolar plate of the polymer electrolyte membrane fuel cell (PEMFC) and the electrical contact of the power terminal of the stack. The contact resistance is affected by the conductivity, roughness, and hardness of the two contacting surfaces. Here, new, application-specific contact resistance measurement methods are proposed for both the stack power terminal, and the bipolar plate. The proposed methods are compared to methods from references as well as standards, and it is concluded that the uncertainty of the measurements can be reduced by changing the measurement setup, and that the influence of probe resistance on measurement results can be eliminated. Furthermore, the effect of different accelerated durability tests on the contact resistance of the power terminal is examined both on test coupons and on a prototype screw connection with an electroless NiP and an electroplated NiSn coatings. As expected, the NiSn coupons gives lower contact resistance after ageing as compared to the NiP. However, the increase in contact resistance seen on coupons after ageing is not observed on the prototype screw connection.