Ni Coatings Research Articles

Tribological Properties of Attapulgite Nanofiber as Lubricant Additive for Electric-Brush Plated Ni Coating

In order to expand the application field of attapulgite in tribology, the tribological properties of attapulgite as a lubricant additive on electric-brush plated Ni coating were investigated using the ball-disc contact mode of a SRV-IV friction and wear tester. The worn surfaces were characterized and analyzed via scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Results indicated that the friction-reducing and antiwear properties of 150 SN lubricating oil on the Ni coating were remarkably improved by an appropriate amount of attapulgite. Tribofilm mainly composed of Ni, NiO, SiO2, Al2O3, graphite, and organic compounds was formed on the worn surface under the action of attapulgite, which was responsible for the reduction of friction and wear.

Electrochemical and immersion corrosion performance improvement of electrodeposited Fe–Ni coating: Effect of laser-induced periodic current on microstructure evolution

This study developed a new electrodeposited Fe–Ni coatings using the laser-induced current waveform. This process refined grains accomponied with a mixed nanocrystalline size and alternate element content. The electrochemical and immersion corrosion performance at 3.5 wt% NaCl was improved, which is still pitting corrosion. The corrosion pits are more likely to spread around rather than in the depth direction. The enhancement mechanism is mainly attributed to the richer grain boundaries. This microstructure increases the interface transfer resistance and makes the corrosion more uniform. This study provides a potential process for preparing nanocrystalline coatings with better performance.

Cavitation-silt erosion behavior and mechanism in simulated sea water slurries of cermet coatings manufactured by HVOF spraying

Understanding the interaction between the sea water slurries and flow-handling components is important for enhancing the cavitation-silt erosion (CSE) resistance of the ocean power generation systems. In this manuscript, two cermet coatings (i.e., Cr3C2-25(NiCr) coating and WC-10(Ni) coating) were manufactured via a high-velocity oxygen fuel (HVOF) spraying method, and influences of sand concentrations (SCs) as well as flow velocities (FVs) on their CSE characteristics in simulated sea water slurries (SSWS) were investigated. Results indicated that the Cr3C2-25(NiCr) coating exhibited larger porosity, lower hardness (H) and elastic modulus (E), stronger ability to resist corrosion in 3.5 wt.% saline solution as well as worse CSE resistance in SSWS, and its CSE resistance was more affected by both the SC and FV by comparison to the WC-10(Ni) coating. Both SC and FV had a positive effect on the CSE damage for the Cr3C2-25(NiCr) and WC-10(Ni) coatings, while SC had more influence on their CSE resistances than FV. The CSE deterioration mechanisms in SSWS under different SCs and FVs of the Cr3C2-25(NiCr) and WC-10(Ni) coatings were also compared and revealed.

Superhydrophobic Ni nanocone surface prepared by electrodeposition and its overall performance

This study investigated the electrodeposition of a three-dimensional nanocone-shaped surface structure on SUS304 stainless steel substrates. Different electrodeposition parameters were adopted to generate nanocone-shaped Ni coatings. A detailed description of the coating microstructure and composition is proposed to understand how Ni nanocones develop throughout electrodeposition. A series of wetting tests compared the superhydrophobicity of the Ni nanocone coating. Wear tests were used to verify their mechanical stability. The best superhydrophobic and mechanical performance is achieved after 25 min electrodeposition, where the newly formed Ni nanocones grow to provide additional air cushion to support surface water droplets and promote wear resistance. The superhydrophobic Ni coating also has good anti-icing properties. Water droplets begin to freeze from the contact points between the water and the sample surface. Surface damage, such as scratches and holes, reduces superhydrophobic samples' anti-icing properties.

Lightweight and thermal insulation fabric-based composite foam for high-performance electromagnetic interference shielding

With the rapid development of electronic devices, electromagnetic interference (EMI) has posed serious threats to human health. Therefore, wearable materials with high EMI shielding performance are urgently required for protecting people from electromagnetic radiation. Herein, electroless plating and compression molding methods were utilized to fabricate sandwich structured composite foam. Aramid-carbon blend fabrics with Co–Ni coatings were selected as the surfaces, and the porous polyurethane (PU) foam doped with diverse content of carbon nanotubes (CNTs) served as the core lightweight layer. With the CNTs doping content of 3 wt%, a 3D conductive network is precisely constructed in the core foam with a tested 13.82 GPa tensile strength. Through a “reflection-absorption-reflection” triple-loss mechanism, the resulting composite foam possesses a favorable average EMI shielding effectiveness (SE) of 73.9 dB in the X band (8–12 GHz), which was far more than the requirement of 30 dB for common commercial EMI SE. In addition, the porous structure exhibits excellent thermal insulation properties within a wide range of temperature (0–150 °C) while presenting a low thermal conductivity of 0.0695 W/(m·K). Finally, the prepared composites were applied to the simulation scene of electromagnetic protection to explore its reliability and practicability as a wearable electromagnetic wave proof material. With the good combination of mechanical properties, thermal properties and excellent electromagnetic shielding properties, the prepared composites have a great application prospect in electromagnetic protective materials.

Effect of spraying time on mechanical and tribological performances of HVOF-sprayed WC–Co and WC–Cr3C2Ni coatings on AISI 1095 steel

Purpose This paper aims to compare the wear behavior, surface roughness, friction coefficient and volume loss of high-velocity oxy-fuel (HVOF) sprayed WC–Co and WC–Cr3C2–Ni coatings on AISI 1095 steel with spraying times of 10 and 15 s. Design/methodology/approach In this study, the pin-on-disc testing technique was used to evaluate the wear characteristics at a speed of 0.24 m/s, load of 40 N and test time of 60 min under dry conditions at room temperature. The wear characteristics were examined and analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy. The surface roughness of a coated surface was measured, and microhardness measurements were performed on the cross-sectioned and polished surfaces of the coating. Findings Spraying time and powder material affected the hardness of HVOF coatings due to differences in the porosity of the coated layers. The average hardness of the WC–Cr3C2–Ni coating with a spaying time of 15 s was approximately 14% higher than that of the WC–Cr3C2–Ni coating with a spraying time of 10 s. Under an applied load of 40 N, the WC–Co coating with a spraying time of 15 s had the lowest variation in the friction coefficient compared with the other coatings. The WC–Co coating with a spraying time of 10 s had the lowest average and variation in volume loss compared to the other coatings. The WC–Cr3C2–Ni coating with a spraying time of 10 s exhibited the highest average volume loss. The wear features changed slightly with the spraying time owing to variations in the hardness and friction coefficient. Originality/value This study investigated tribological performance of WC–Co; WC-Cr3C2-Ni coatings with spraying times of 10 and 15 s using pin-on-disc tribometer by rotating the relatively soft pin (C45 steel) against hard coated substrate (disc).

Effect of Mo Content on Microstructure and Fatigue Properties of Ni60 Coating Produced by Plasma Cladding

Effect of Mo Content on Microstructure and Fatigue Properties of Ni60 Coating Produced by Plasma Cladding

A comprehensive experimental study and numerical analysis of coefficient of friction of nanocomposite coatings

A comprehensive study of nanocomposite coating friction behaviour in oscillating-reciprocating simulations with steel balls is presented. Graphene/Nickel (Ni/GPL) and pure Nickel (Ni) coatings have been studied. SEM, EDS, and AFM analyses of coatings pre-test were performed to characterise the coatings in addition to tests to compare the coefficients of friction ‘COF’ between pure Ni and Ni/GPL. Based on microscopic characterisation of wear tracks, wear on counter carbon steel balls, and “U-shaped” wear depth profiles of wear tracks, it was determined that Ni had a higher coefficient of friction than Ni/GPL. A novel 2-D predictive numerical model was developed to examine the wear of nanocomposite coatings that integrates the microstructural and lubrication concepts. Predictions from newly developed model and the experimental results are in close agreement. While significant research has been conducted to understand the frictional performance of nanocomposite coatings, a novel and reliable predictive model is still needed for analyzing nanocomposite coatings COF in the context of design. The research will impact the automotive, aerospace, renewable energy, high-end manufacturing, and renewable energy sectors.

Electrodeposited Ni/C-SnO2 composite electrode materials for hydrogen evolution reaction in alkaline electrolyte

The high performance Ni/C-SnO2 composite electrodes were successfully prepared for hydrogen evolution reaction (HER) in alkaline media by an easy and low cost composite electrolytic deposition method. The Ni/C-SnO2 composite coating was physically examined by using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive analysis of X-ray (EDX). The XRD and EDX results showed that C-SnO2 particles prepared by high temperature hydrolysis method were successfully incorporated in Ni coatings. The preferred orientation of Ni particle in composited coatings had been altered to (111) crystal plane which was more benefit for HER. The SEM and XRD results indicated that the addition of C-SnO2 particles refined Ni crystallization in composite coatings. The catalytic activity and stability of the composite coatings for hydrogen evolution reaction were examined by steady-state polarization, Tafel plots, electrochemical impedance spectroscopy (EIS) and chronopotentiometry technique. Compared to Ni coating, the Ni/C-SnO2 composite coatings exhibited higher hydrogen evolution performance. The abundant OHads on C-SnO2 surface accelerated the water molecular decomposition and Hads formation which determined the rate of HER (Volmer step). The carbon in C-SnO2 improved the conductivity of composite electrode, which was also helpful for HER.

Joining of Cast Iron and Phosphor Bronze Through Liquid–Solid Interaction: Effect of Ni and Cu Coating on Interfacial Microstructures and Mechanical Properties of Bimetallic Composites

Joining of Cast Iron and Phosphor Bronze Through Liquid–Solid Interaction: Effect of Ni and Cu Coating on Interfacial Microstructures and Mechanical Properties of Bimetallic Composites

Microstructure and Tribo-Behavior of WC–Cr3C2–Ni Coatings by Laser Cladding and HVAF Sprayed: A Comparative Assessment

SK5 steel is the base material used for the preparation of the wrinkle scraper, whose service life strongly affects the working efficiency and economic benefits. In this work, WC-Cr3C2-Ni coating was deposited on the SK5 steel substrate by using High-velocity air fuel spray (HVAF) and Laser cladding (LC) processes respectively, named HVAF-WC coating and LC-WC coating. The microstructure and wear resistance of both coatings were analyzed, and were compared with the substrate sample. Results showed that the coatings were adhesive well onto the substrate. More WC with fine crystals is retained in HVAF-WC coating due to low flame flow temperature, while WC of LC-WC coating is characterized by columnar crystals. The wear rate of HVAF-WC and LC-WC coating was 4.00 × 10-7 mm3/(N•m) and 3.47 × 10-6 mm3/(N•m), respectively, which was two and one orders of magnitude lower than SK5 steel with 3.54 × 10-5 mm3/Nm. HVAF-WC coating exhibited the best wear resistance because of significant fine grain strengthening, which wear mechanism is mainly dominated by abrasive wear. Thus, it was thought that HVAF-WC coating is more effective ways to improve the wear resistance of SK5 steel, comparing with LC-WC coating.

Investigation on fretting wear of NiCrAlY coatings at elevated temperature

Tribological properties of MCrlAlY (M = Ni, Co, or Ni and Co) coatings are well established under sliding conditions. However, the tribological properties of MCrAlY coatings under fretting conditions, typically encountered in blade-disk dovetail connection of aero engines, are yet to be further studied. The present study aims to investigate the elevated-temperature fretting wear behaviors and mechanisms of a NiCrAlY coating deposited on a γ-TiAl substrate. Scanning electron microscope, energy dispersive spectrometer, and Raman spectrometer were utilized to study the wear scars and tribolayers. Transmission electron microscope and nanoindentation tests were utilized to elucidate the structural and mechanical properties of the tribolayers. The results revealed that, large areas of sea-shape tribolayers formed on the NiCrAlY coating and resulted in the low wear rate and friction coefficient. While for the γ-TiAl substrate, small areas of island-shape tribolayers formed, and insufficient to protect the alloy from severe abrasive wear, delamination, and adhesive wear. The formation of the sea-shape tribolayers was found to be derived from the high diffusion coefficients in the oxides. In addition, the wear of the counterpart nickel alloy was not aggravated with the NiCrAlY coating, since sea-shape tribolayers also formed on the counterpart.

The soft X-ray and XUV split-and-delay unit at beamlines FL23/24 at FLASH2.

A split-and-delay unit for the extreme ultraviolet and soft X-ray spectral regions has been built which enables time-resolved experiments at beamlines FL23 and FL24 at the Free-electron LASer in Hamburg (FLASH). Geometric wavefront splitting at a sharp edge of a beam splitting mirror is applied to split the incoming soft X-ray pulse into two beams. Ni and Pt coatings at grazing incidence angles have been chosen in order to cover the whole spectral range of FLASH2 and beyond, up to hν = 1800 eV. In the variable beam path with a grazing incidence angle of ϑd = 1.8°, the total transmission (T) ranges are of the order of 0.48 < T < 0.84 for hν < 100 eV and T > 0.50 for 100 eV < hν < 650 eV with the Ni coating, and T > 0.06 for hν < 1800 eV for the Pt coating. For a fixed beam path with a grazing incidence angle of ϑf = 1.3°, a transmission of T > 0.61 with the Ni coating and T > 0.23 with a Pt coating is achieved. Soft X-ray pump/soft X-ray probe experiments are possible within a delay range of -5 ps < Δt < +18 ps with a nominal time resolution of tr = 66 as and a measured timing jitter of tj = 121 ± 2 as. First experiments with the split-and-delay unit determined the averaged coherence time of FLASH2 to be τc = 1.75 fs at λ = 8 nm, measured at a purposely reduced coherence of the free-electron laser.

Electrocatalytic Performance of Ethanol Oxidation on Ni and Ni/Pd Surface-Decorated Porous Structures Obtained by Molten Salts Deposition/Dissolution of Al-Ni Alloys.

Ni coatings with high catalytic efficiency were synthesised in this work, obtained by increasing the active surface and modifying Pd as a noble metal. Porous Ni foam electrodes were obtained by electrodeposition of Al on a nickel substrate. Deposition of Al was carried out with potential -1.9 V for a time of 60 min in NaCl-KCl-3.5 mol%AlF3 molten salt mixture at 900 °C, which is connected with the formation of the Al-Ni phase in the solid state. Dissolution of Al and Al-Ni phases was performed by application of the potential -0.5 V, which provided the porous layer formation. The obtained porous material was compared to flat Ni plates in terms of electrocatalytic properties for ethanol oxidation in alkaline solutions. Cyclic voltammetry measurements in the non-Faradaic region revealed the improvement in morphology development for Ni foams, with an active surface area 5.5-times more developed than flat Ni electrodes. The catalytic activity was improved by the galvanic displacement process of Pd(II) ions from dilute chloride solutions (1 mM) at different times. In cyclic voltammetry scans, the highest catalytic activity was registered for porous Ni/Pd decorated at 60 min, where the maximum oxidation peak for 1 M ethanol achieved +393 mA cm-2 compared to the porous unmodified Ni electrode at +152 mA cm-2 and flat Ni at +55 mA cm-2. Chronoamperometric measurements in ethanol oxidation showed that porous electrodes were characterised by higher catalytic activity than flat electrodes. In addition, applying a thin layer of precious metal on the surface of nickel increased the recorded anode current density associated with the electrochemical oxidation process. The highest activity was recorded for porous coatings after modification in a solution containing palladium ions, obtaining a current density value of about 55 mA cm-2, and for a flat unmodified electrode, only 5 mA cm-2 after 1800 s.

Experimental Investigations on Erosion-Corrosion Characteristics of HVOF-Sprayed WC-10% Ni Coatings Deposited on Aluminum Alloy

The current work investigates the erosion-corrosion behaviour of thermally sprayed tungsten carbide-10% nickel (WC-10% Ni) coatings placed on the AA6061 aluminum alloy. The AA6061 aluminum alloy was coated with tungsten carbide –10% nickel coatings utilising a high-velocityoxy-fuel (HVOF) spray method. The microstructure and hardness of thermally sprayed coatings were examined using a scanning electron microscope (SEM) and a Vickers hardness tester. The slurry erosion-corrosion wear tests were carried out by varying the parameters of the slurry erosion process, such as testing time, slurry content, slurry speed, and impinging particle size, on the erosion testing equipment. The data demonstrated that when slurry concentration, slurry speed, and impinging particle size increased, so did the slurry erosion-corrosion wear loss. The wear processes of uncoated and thermally sprayed tungsten carbide –10% nickel have been examined using SEM and a 3-D confocal microscope.

Effect of Ni Coating on Microstructure and Property of Al Alloy/Steel CMT Welding-Brazing Joints

The cold metal transfer (CMT) welding-brazing process was chosen to join Al alloy and Ni-coated steel using AlSi12 as the filler wire. The macrostructure and microstructure of the joints were tested by using an optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). The tensile properties and corrosion properties of the joints were also tested. The results showed that Ni coating could improve the wettability and spreadability of molten AlSi12 filler metal on the steel surface, resulting in a good appearance for the Al alloy/steel joint. Ni coating could hinder the chemical metallurgical reaction between Al atom and Fe atoms to inhibit the formation of brittle Fe-Al intermetallic compounds (IMCs) and reduce the thickness of the IMCs layer. Meanwhile, the Ni atom reacted with the Fe and Al atoms to form Al3Ni2, (Fe, Ni) Al3 and (Fe, Ni)2Al3, which improved the tensile strength of the joints. All joints with Ni coating cracked near the Al alloy. When the Ni-coating thickness was 5 μm, the tensile strength of the joint reached a maximum of 202.5 MPa. The addition of Ni could also improve the corrosion resistance of the joints. Significantly, when the Ni-coating thickness was 10 μm, most of the Ni coating was still solid, and the interface reaction layer was mainly composed of α-Ni solid solution and some (Fe, Ni)2Al3.

Hydrogen Evolution Reaction Performance of Ni-Co-Coated Graphene-Based 3D Printed Electrodes.

Additive manufacturing has been a very promising topic in recent years for research and development studies and industrial applications. Its electrochemical applications are very popular due to the cost-effective rapid production from the environmentally friendly method. In this study, three-dimensional (3D) printed electrodes are prepared by Ni and Co coatings in different molar ratios. Different Ni/Co molar ratios (x:y) of the Ni/Co/x:y alloys are prepared as 1:1, 1:4, and 4:1 and they are named Ni/Co/1:1, Ni/Co/4:1, and Ni/Co/1:4, respectively. According to the results, when the 3D electrode samples are coated with Ni and Co at different molar ratios, the kinetic performance of the NiCo-coated 3D electrode samples for hydrogen evolution reaction is enhanced compared to that of the uncoated 3D electrode sample. The results indicate that the Ni/Co/1:4-coated 3D electrode has the highest kinetic activity for hydrogen evolution reactions (HERs). The calculated Tafel's slope and overpotential value (η10) for HER are determined as 164.65 mV/dec and 101.92 mV, respectively. Moreover, the Ni/Co/1:4-coated 3D electrode has an 81.2% higher current density than the other electrode. It is observed that the 3D printing of the electrochemical electrodes is very promising when they are coated with Ni-Co metals in different ratios. This study provides a new perspective on the use of 3D printed electrodes for high-performance water electrolysis.

Production of a superhydrophobic frame-cone structure by laser etching and Ni electrodeposition

ABSTRACT Metal components in microelectromechanical systems are prone to failure and corrosion due to droplet adhesion in wet environments. Several multi-level structures on the micro-nano scale may induce effective superhydrophobicity to prevent such adhesion. This study proposes a hybrid manufacturing process to generate ‘frame-cone’ textures on the surfaces of metals by combining ultra-fast laser etching and electrodeposition. Periodically distributed frame recesses and pits were coated with nano-submicron Ni coatings with conical shapes, and the pit depth and cone height were controlled by tuning the laser scanning time and current density, respectively. The surface adhesion force was reduced to 22.8 μN, and the static contact angle was maintained at 156.7° using the hybrid process, while the adhesion forces of laser etched samples with the same depth were 164.7 μN. The multi-level ‘frame-cone’ structure stored more air and reduced the contact areas between the bottoms of the pits and droplets. The hybrid process of ultra-fast laser etching and electrodeposition aided in improving the superhydrophobicity, with less damage to the substrate.

Стойкость режущего инструмента с осажденными керамико-металлическими покрытиями (Ti,Al)N – Cu и (Ti,Al)N – Ni при точении и фрезеровании сталей

The study shows the results of comparative resistance tests of a carbide cutting tool with (Ti,Al)N – Cu and (Ti,Al)N – Ni nanostructured arc-PVD coatings deposited on its working surfaces under conditions of continuous and interrupted cutting of 13Mn6 (09G2S) and 10Cr15Ni9Si3Nb1-SH (EP302-Sh) steels, respectively. Under milling conditions of 10Cr15Ni9Si3Nb1-SH steel, when using WC – Co (6 wt.% Co) inserts with (Ti,Al)N – Cu and (Ti,Al)N – Ni coatings, tool life increases by 3.1 and 1.7 times, respectively. When turning steel 13Mn6 using WC – Co inserts coated with (Ti,Al)N – Cu and (Ti,Al)N – Ni, tool life increases by 7.6 and 10.8 times, respectively, and cutting forces Fz, Fx, Fy decrease nearly by 20 %. This effect is determined by the presence of a nanostructure in the formed coatings, the presence of a highly hard ceramic component and ductile metal, which determine their hardness (more than 35 GPa) and fracture toughness (the relative work of plastic deformation during indentation is more than 60 %), increased tribological characteristics (friction coefficient ~ 0.5 according to comparison with uncoated carbide ~ 0.7). The study noted an increased resistance of (Ti,Al)N – Ni coatings on a hard alloy to continuous cutting of steel, which is determined by their high hardness and lower friction coefficient compared to (Ti,Al)N – Cu coatings, which are characterized by better performance in interrupted cutting operations, where the determining value of resistance is the fracture toughness.

Effect of ultrasonic shot peening on electrodeposited Ni and Cu coatings on Cu substrate

In this study, the effect of ultrasonic shot peening (USSP) on bilayered Ni and Cu coatings on Cu substrate was studied. On the Cu substrate, Ni and Cu coatings were sequentially electrodeposited followed by ultrasonic shot peening with a varying shot diameter and peening time. Apart from phase analysis and microscopy study of the coatings (before and after peening), hardness, compressive residual stress, wear, and corrosion resistances are also examined. Improvement of surface-mechanical properties and electrochemical properties were observed in specific peening conditions. There was also a noticeable improvement in residual compressive stress as an effect of peening.