Ni Coatings Research Articles

Structural modifications induced by ultrasonic vibration during plasma spray deposition Ni coating on Al substrate

In this study, a 28 kHz ultrasonic vibration was applied to the Al substrate during plasma spraying of Ni coatings. The microstructure, mechanical properties, and wear resistance of the coatings were investigated. With application of the ultrasonic vibration, the bonding between splats increased and porosity of the coatings decreased from 6.2 % to 3.4 %. Grain size in the coatings also decreased. The hardness and Young's modulus of the coating increased from about 2.8 GPa and 111.5 GPa to about 4.4 GPa and 183.4 GPa, respectively, by application of the ultrasonic vibration. The width and depth of the wear trace and the wear rate of the Ni coating sprayed using ultrasonic vibration also significantly decreased. These results are ascribed to the effects of acoustic pressure and acoustic streaming, cavitation, and heating of the ultrasonic vibration that promote wetting and filling ability and affect solidification of molten Ni droplets during the spraying process.

Malic acid pathway of constructing high-performance Ni anticorrosive coatings using supercritical-CO2 electrodeposition

We presented the fabrication of nickel (Ni) coatings from malic acid-supported Ni electrolyte (M/Ni-E) as an alternative for boric acid by supercritical-CO2 (SC–CO2) electrodeposition. The surface roughness, morphology, and crystal phase structure of the prepared coatings were analyzed with an atomic force microscope (AFM), field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) techniques. Corrosion resistance was evaluated through standard electrochemical methods such as linear polarization and electrochemical impedance spectroscopy (EIS) techniques with 1 M HCl solution. Based on the FESEM, AFM, and XRD results, the film prepared by a malic acid-supported electrolyte exhibits a compact coating with smaller grains (21.6 nm) and lower surface roughness (RMS = 7.59 nm). The corrosion resistance of the film prepared with M/Ni-E by SC-CO2 method shows a higher corrosion resistance of 570 Ω/cm2. Thereby, malic acid is suggested as a suitable replacement for boric acid and SC-CO2 electrodeposition process as an environmental-friendly approach.

Effect of Heat Treatment and NC Ni Coating on Electrochemical and Hydrogen Embrittlement Behaviour of a High Strength Low Alloy (HSLA) Steel

Effect of Heat Treatment and NC Ni Coating on Electrochemical and Hydrogen Embrittlement Behaviour of a High Strength Low Alloy (HSLA) Steel

Analysis and Control of Cracks in Ni60 Coating of 7050 Aluminum Alloy by Electron Beam Cladding

Ni60 electron beam cladding can play an important role in improving the properties of 7050 aluminum alloy. The cracking of the cladding layer, however, greatly affects the cladding quality. To solve this problem, the optimum range of cladding process parameters is determined by an experimental method: electron beam current [25–30 × 10−3 A], scanning speed [10–12 mm/s] and focusing current [700–720 × 10−3 A]. Through range analysis of the experiment results, the primary and secondary order of the influence of the cladding process parameters on the crack areal density is determined as follows: electron beam current > scanning speed > focusing current. A mathematical model of the crack areal density of the cladding layer is established based on the method of nonlinear regression, which is y = 4.1553 × 104 I2.2887V−0.8379I210.2675. It is shown that the model has obvious significance in the results of variance analysis, which can provide a basis for the selection of electron beam cladding process parameters.

Microstructure and Soil Wear Resistance of a Grey Cast Iron Alloy Reinforced with Ni and Cr Laser Coatings.

The goal of the presented investigation was to assess the impact of surface laser modification with the implementation of nickel and chromium on the microstructure and tribological behaviour of grey iron. Surface laser modification consisted of remelting the surface layer with simultaneous implementation of selected elements. In the first variant of treatment only nickel was implemented and in the second one, a combination of nickel with chromium together. This treatment was performed on an agriculture machine part made of grey iron and working in intensive friction conditions. The constituted surface layer was characterized by about 0.45 mm of depth and a 160 mm2 area of the most exposed to wear of the treated part. In the case of both types of variants, the achieved surface layer microstructure was identified as homogenized with small grains. It involved nickel in the first variant of modification and nickel and chromium in the second one. The attained microstructure with nickel addition was characterized by nearly 800 HV0.1 of hardness (a 3.6-fold increase in comparison to its core material). The approximate hardness of 900 HV0.1 was achieved in the case of the microstructure enriched with nickel and chromium (over a 4-fold increase in comparison to the core material). The roughness of the surface after laser modification was reduced (nearly 3-fold) in comparison to the original surface of the part that was characterized by quite substantial coarseness. The wear test showed that Ni and Cr laser coatings increased resistance to abrasive wear resulting from the modification of the microstructure by the formation of martensite and grain fragmentation. Laser modified parts had a 2.5-fold smaller mass loss than untreated parts. Both types of performed variants: with the implementation of nickel and a combination of nickel and chromium gave comparable effects.

Effect of geometrically necessary dislocations induced strain on the corrosion behavior of Ni coatings with different surfactants

Ni coatings were electrodeposited using surfactants of different polarities. Pole figures analysis showed similar surface texture ({110} surface plane) for all coatings. Coating with cationic (CTAB) surfactant contained the highest fraction of low energy low angle grain boundaries (LAGBs) but showed the highest corrosion rate due to geometrically necessary dislocations (GNDs) distribution. GNDs in coating with cationic surfactant promoted high grain orientation spread (GOS) values, suggesting increased coating strain. Coatings with anionic (SLS) surfactants showed higher corrosion resistance than other coatings because of the presence of GNDs as strings along the boundaries, which yielded lower coating strain.

Compressive Property and Energy Absorption Capacity of Mg-Ceramic-Ni Foamsat Various Temperatures

Mg–Ceramic–Ni hybrid foams were fabricated via continuousdepositing micro-arc oxidation (MAO) ceramic coating and electroless Ni coating on the surface of the AZ91D foam struts. Mechanical tests from room temperature (RT) to 300 °C were carried out to evaluate the compressive properties and energy absorption capacities of two types of foams, i.e., AZ91D alloy foams and corresponding hybrid foams. The effect of composite coatings and test temperature on the compressive property of the foams was studied. The experimental results show that the MAOand Ni coatings enhance the Mg foam struts, resulting in high compressive strength and energy absorption capacity at each testing temperature. In addition, the compressive properties are also depending on testing temperature. The different mechanical responses of the composite foams under various temperature conditions are mainly attributed to the different deformation behaviors and failure modes of the foam struts, which are confirmed by scanning electron microscopy (SEM) observation.

Interface Reaction between Tin Solder and Nanocrystalline Ni and Ni-Mo Coatings Obtained by Electrodeposition

Interface Reaction between Tin Solder and Nanocrystalline Ni and Ni-Mo Coatings Obtained by Electrodeposition

Effect of Fe content on the tribological properties of Ni60 coatings applied by pulsed magnetic field assisted supersonic plasma spraying

In order to study the effect of magnetic field on the spraying process, a thermal spraying technique of ferromagnetic metal powder assisted by pulsed magnetic field is presented. The Ni60 coating with different Fe content was prepared by pulsed magnetic field assisted supersonic plasma spraying. This process can improve the microstructure, porosity, mechanical properties and tribological properties of the coating. In this paper, a diagram depicting the mechanism for coating formation by pulsed magnetic field assisted spraying was prepared according to the test results for the coatings. We found that the pulsed magnetic field formed at the edge of the poles, and, compared with the Ni base material, the Fe phase material was easily attracted by the magnetic poles, which accelerated its downward movement. During this downward movement, a mixing effect developed within the coating that decreased the coating porosity, made the Cr strengthening phase more uniform, and, as the matrix provided many nucleation sites, further promoted the production of amorphous nanocrystalline phases. Finally, the service performance of the coatings was continuously improved. This process provides a new approach to the design and development of advanced coatings, and it shows great promise for applications in next-generation ferromagnetic metal-based coatings. • Pulsed magnetic field assisted supersonic plasma spraying coating was prepared. • The effect of Fe in the coating under magnetic field was analysed. • The magnetic field can induce the formation of amorphous nanocrystalline phase. • The strengthening phase is gradually homogenized with the pulsed magnetic field.

Microstructure, Mechanical, and Nanotribological Properties of Ni, Ni-TiN, and Ni90Cu10-TiN Films Processed by Reactive Magnetron Cosputtering

In this study, nanocrystalline Ni, Ni-TiN, and Ni90Cu10-TiN coatings were processed using reactive magnetron cosputtering of Ni, Cu, and Ti targets under Ar and N2 gas environment. The phase evolution and structure of coatings were analyzed by the X-ray diffraction (XRD) technique. The morphology of the as-prepared nanocomposite films were investigated by high-resolution transmission electron microscopy (HRTEM). The elastic modulus, nanohardness, and scratch resistance of the investigated films were measured using the nanoindentation technique and compared. The results showed that Ni, Ni-TiN and Ni90Cu10-TiN coatings exhibited nanocrystalline structure. The Ni90Cu10-TiN nanocomposite films showed optimum nanohardness and tribological properties due to the additional TiN additives which enhanced the dispersion hardening of the composite matrix significantly.

Fabrication of Nickel Coatings on Zirconia Balls by Mechanical Ball Milling and the Process Analysis

The Ni coatings were prepared from nickel metal powder and zirconia ceramic balls by mechanical coating technique. The relationship between rotation speed and coatings thickness was studied, the thickness of the coatings was characterized by the weight increase of the zirconia balls after mechanical coating. The composition and microstructure of the coatings with maximum thickness were analyzed by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray Diffraction (XRD). The results revealed that the formation of coatings consists of thickening from the cold welding between Ni particles and the thinning from the exfoliation of coatings work hardening. The thickness of the coatings reaches the maximum when the above two process progress are close to each other. The results proved that higher speed was favor of the coatings formation, the maximum thickness was obtained at the 15 h for rotation speed of 240 rpm, and microscopic images show that the average thickness was about 20 μm.

Salt spray corrosion behavior and electrochemical performance of Al and Ti reinforced Ni60 coating by laser cladding

AbstractNi60 coatings with the additions of Al and Ti were prepared on S355 steel by laser cladding. The microstructure and phases of obtained coatings were analyzed using an ultra‐depth of field microscope and X‐ray diffraction, respectively. The effects of Al and Ti additions on the salt spray corrosion and electrochemical performances were investigated using a salt spray corrosion chamber and electrochemical workstation, and the corrosion mechanism was also discussed by the models of defect reactions and pitting corrosion. The results show that the crystal microstructure of Ni60 coatings with the Al and Ti additions is changed from dendritic to massive and granular. After the neutral salt spray test, the corrosion forms of Ni60, Ni60–Al, and Ni60–Al–Ti coatings are mainly pitting and intergranular corrosion in which the Ni60–Al–Ti coating exhibits the highest anti‐corrosion performance. The improvement of electrochemical performance for the Ni60–Al–Ti coating is attributed to the high compact structure and passive film, which provides fewer oxygen vacancies in the corrosion process due to the additions of Al and Ti.

Effect of Cr3C2 Content on Microstructure and Properties of Laser Cladding Ti(C, B)/Ni Coatings

Effect of Cr3C2 Content on Microstructure and Properties of Laser Cladding Ti(C, B)/Ni Coatings

Effect of grain size on the thermal stability of electrodeposited nanocrystalline nickel: X-ray diffraction studies

Nanocrystalline (NC) Ni coatings have widespread engineering applications, many of which are in high-temperature environments. Therefore, it is important to study the thermal stability of NC Ni. The present study compares the thermal stability of electrodeposited (ED) NC Ni of varying grain sizes: 20 nm, 50 nm, and 100 nm. In-situ high-temperature X-ray diffraction (XRD) investigations have been employed to follow the grain growth behavior of 〈111〉 and 〈200〉 grains under isochronal annealing up to 550 °C. Based on the calculated activation energies, the anisotropic growth mechanisms of 〈111〉 and 〈200〉 grains are evaluated. The studies revealed that the onset of grain growth occurred at progressively higher temperatures with increasing initial grain sizes. While near uniform grain size distribution is observed for the 20 nm grain size variant, bimodal distributions are observed for its counterparts. Electron Backscatter Diffraction studies of NC Ni samples in the final-processing temperature of XRD showed that <100>//ED texture is preserved during the annealing process. While high fractions of Σ3 coincidence site lattice (CSL) boundaries are observed in the 20 nm sample, reduced fractions with no particular trend is observed for the 50 nm and 100 nm grain-sized samples. It is shown here that the incomplete recrystallization arising from inhomogenous strain distribution is the reason for the observed bimodal distribution and deviation from an expected trend in the formation of Σ3 CSL as a function of initial grain size.

FexNi(1-x) coatings electrodeposited from choline chloride-urea mixture: Magnetic and electrocatalytic properties for water electrolysis

Fe, Ni, and FexNi(1-x) coatings were successfully electrodeposited on Cu substrates from a choline chloride-urea eutectic solution without the addition of complexing agents. In addition, its magnetic properties and electrocatalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were fully investigated. X-ray diffraction and Mössbauer spectroscopy analyses characterized the formation of Fe-Ni alloys in the following coatings: Fe89Ni11, Fe69Ni31, Fe47Ni53, and Fe28Ni72. The magnetic measurements showed that all electrodeposits presented low coercivity, characterizing the coatings as soft magnetic materials. The Fe coating presented the best electrocatalytic performance for HER and OER in 0.5 mol L−1 NaOH and at 298.15 K. However, the Fe coating detached from the substrate when it was submitted to a long-term test. Among the FexNi(1-x) coatings, the Fe89Ni11 coating displayed the best performance for HER since it exhibited the lowest overpotential of 152 mV at an applied current density of 10 mA cm−2. For OER, the Fe69Ni31 and Fe47Ni53 were the best electrocatalysts, which presented the highest exchange current densities about of 7 × 10−4 mA cm−2 and overpotential values around 374 and 377 mV to provide 10 mA cm−2. Furthermore, the Ni and FexNi(1-x) coatings presented good stability in 120 h long term tests at 50 mA cm−2. Finally, the experimental results showed that the manufacture of electrocatalysts based on Fe, Ni and Fe-Ni coatings via electrodeposition conducted in the presence of choline chloride-urea is very promising and environmentally friendly process.

Optimization of electrodeposition nanocrytalline Ni-Fe alloy coatings for the replacement of Ni coatings

Fabricating nanocrystalline Ni-Fe alloy coatings with excellent brightness and corrosion resistance could reduce the use of Ni and benefit economically. Nanocrystalline Ni-Fe alloy coatings were electrodeposited on steel substrates and the coatings with 34.55% Fe content were achieved at the optimized conditions with the current efficiency high up to 80.30%. The electrodeposition behavior of Ni-Fe coatings was investigated by cyclic voltammetry (CV), chronopotentiometry and chronoamperometry. CV tests illustrate that Ni2+ and Fe2+ are co-electrodeposited to form single phase and the deposition of Ni is inhibited by the presence of Fe2+ while the deposition of Fe is boosted by the Ni2+ according to chronopotentiometry. The nucleation and growth of nanocrystalline Ni-Fe alloy coatings is 3D diffusion-controlled instantaneous nucleation process. Intermetallic compound, namely Ni3Fe phase, was formed according to XRD analysis and TEM analysis, while the mean grain size is 4.79 nm. SEM and AFM images demonstrate that nanocrystalline and compact surface were fabricated and the roughness is lower than 5 nm, better than pure Ni coating. Due to the nanocrystalline and compact surface, the icorr and Rct of nanocrystalline Ni-Fe alloy coating are 0.7544 μA cm−2 and 8560 Ω respectively, indicating that Ni-Fe alloy coating is of good corrosion resistance.

Enhancement of electrical conductivity and corrosion resistance by gold-nickel coating of additively manufactured AlSi10Mg alloy

Gold-nickel coatings (Au–Ni) were applied by electrodeposition (ED) and electroless deposition (ELD) on additively manufactured (AM) AlSi10Mg alloy to improve the electrical conductivity and electrochemical behavior. Characterization of the Au–Ni coatings was performed by a scanning electron microscope equipped with energy dispersive X-ray spectroscopy (EDS) and x-ray diffraction to study the tiny features. The surface indentation hardness of the coated alloy was evaluated to study the coating strength. The electrochemical behavior of the as-built part and its counterpart, Au–Ni coated surfaces, were evaluated by conducting potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution.The results revealed that the Au–Ni coatings with layers thickness of ∼2 and 10 μm, respectively, could overcome the surface critical defects, i.e., pores and flaws. The surface hardness of the coated AM alloy has significantly increased six times due to the hard Ni layer. The electrochemical measurements showed a significant decrease in the anodic dissolution rate and increase in pitting corrosion resistance for the Au–Ni coated surfaces compared to the bare AM AlSi10Mg alloy with the as-built and polished surface condition in chloride solution. This was attributed to the stability of the Au–Ni coatings against the anodic overpotential. Moreover, it was observed that the Au–Ni coatings reduce the electrical resistance of the studied AM alloy by 40%. Consequently, the surface electrical conductivity property of the AM AlSi10Mg alloy was enhanced by both Au–Ni coating procedures.

Synergistic effect of L-cysteine and iodide ions during electrodeposition of nanocrystalline nickel from a Watts bath

ABSTRACT Nickel deposited from the Watts bath with L-cysteine (L-Cys) as a new organic brightener additive, and/or iodide ion was accomplished on a copper cathode. Cathodic polarisation, anodic linear stripping voltammetry, i-t transients, throwing power and cathodic current efficiency were investigated thoroughly. The surface of the produced Ni coatings was analysed using scanning electron microscope and X-ray diffraction (XRD) methods. The results showed that the inhibition of nickel reduction was observed in the presence of L-Cys or in the presence of iodide ions individually. Excellent inhibition was achieved with the addition of a mixture of L-Cys and I− ions due to their co-adsorption on the cathode surface (in a synergistic effect). Moreover, the TP value of the Watts bath in the presence of a mixture of L-Cys and I− ions is four times its value in the absence of this mixture. XRD measurements showed that the (200) level was the most preferred direction for growth and the intensity of all peaks increased considerably with a combination of L-Cys and I− ions. Fine-grained and pit-free deposits that were firmly adherent to the substrate were produced using a combination of L-Cys and NaI.

Electrochemical method for obtaining of composite graphite powder

An electrochemical method for producing a composite graphite powder by depositing nickel, copper and Cu—Ni coatings on graphite powder grade GL-1 is proposed, which ensures the production of a clad powder material. An installation, a technological scheme was developed, and a cyclic method of electrochemical metallization of graphite was proposed, which makes it possible to obtain a composite graphite powder of a given chemical composition. An electrochemical method for producing a composite graphite powder by depositing nickel, copper and Cu-Ni coatings on graphite powder grade GL-1 is proposed, which ensures the production of a clad powder material. An installation, a technological scheme was developed, and a cyclic method of electrochemical metallization of graphite was proposed, which makes it possible to obtain a composite graphite powder of a given chemical composition. The graphite powder nickel plating process was optimized, a regression equation was obtained, and the results of the dispersion analysis of regression coefficients were presented, indicating the adequacy and statistical significance of the obtained regression model. The thickness of nickel, copper and combined Cu-Ni coatings was determined by optical microscopy. It is shown that the electrolytic method of graphite powder metallization makes it possible to deposit continuous coatings with the formation of a shell (capsule) for each graphite particle. Presents the results of a study of the physicochemical properties of nickel-plated graphite powder (bulk density, fluidity, granulometric and chemical composition).

Study on Corrosion Behaviour of Nanostructured Ni Coating Electrodeposited from Deep Eutectic Solvent at Different Current Densities on Medium Carbon Steel

Study on Corrosion Behaviour of Nanostructured Ni Coating Electrodeposited from Deep Eutectic Solvent at Different Current Densities on Medium Carbon Steel