Electrochemical codeposition of inert particles in a metallic matrix

Production of Cu/Diamond Composite Coatings and Their Selected Properties

This article presents Cu/diamond composite coatings produced by electrochemical reduction on steel substrates and a comparison of these coatings with a copper coating without diamond nanoparticles (<10 nm). Deposition was carried out using multicomponent electrolyte solutions at a current density of 3 A/dm2 and magnetic stirring speed of 100 rpm. Composite coatings were deposited from baths with different diamond concentrations (4, 6, 8, 10 g/dm3). This study presents the surface morphology and structure of the produced coatings. The surface roughness, coating thickness (XRF), mechanical properties (DSI), and adhesion of coatings to substrates (scratch tests) were also characterized. The coatings were also tested to assess their solderability, including their spreadability, wettability of the solder, durability of solder-coating bonds, and a microstructure study.

The Effect of Nano-ZrO2 Dispersed Phase into Cobalt Plating Electrolyte on Layer Thickness and Current Efficiency

The aim of this work is to obtain nanocomposite layers having a cobalt matrix with zirconium oxide nanoparticles (mean diameter 30 nm) through the electrodeposition process. The plating electrolyte suspension is prepared by adding ZrO2 nanoparticles in a sulfate-chloride cobalt electrolyte at a concentration of 0 and 10 g·L−1. The electrodeposition is performed at room temperature, using three current densities of 23, 48 and 72 mA·cm−2 and three deposition times of 30, 60 and 90 min. The influence of current density, time and nanoparticles concentrations on the characteristics of the obtained nanostructured layers are also discussed. ZrO2 ceramic nanoparticles as a dispersed phase in the cobalt deposition electrolyte modify the mechanism of its electro-crystallization, so they participate in this process by increasing the rate of cobalt deposition, confirmed by the thickness of the nanocomposite layers obtained. The paper presents some of the comparative results obtained regarding the thickness of the layers, the current efficiency and the inclusion of the nanoparticles into nanocomposite layers depending on the current density and time of the electrodeposition process. The analysis of Co/nano-ZrO2 nanocomposite layers with the help of optical light microscopy and electronic microscopy in cross-section highlights the good degree of adhesion of the layers to the metallic substrate made of 304L stainless steel. The results of the study show that as the current density and time increase, the thickness of the composite layers increases. The efficiency of the process is improved compared to the electrodeposition of pure cobalt layers. The degree of inclusion of ZrO2 nanoparticles increases with time and decreases with increasing of imposed current density on the electrodeposition process. The distribution of the dispersed phase in the cobalt metallic matrix is uniform. The layers obtained in this study can be applied in aircraft technology, in the automotive industry, as well as in biomedical applications in order to improve the properties and to increase the corrosion or tribocorrosion resistance in a specific environment.

Fabrication of Metal/Carbon Nanotube Composites by Electrochemical Deposition

Metal/carbon nanotube (CNT) composites are promising functional materials due to the various superior properties of CNTs in addition to the characteristics of metals, and consequently, many fabrication processes of these composites have been vigorously researched. In this paper, the fabrication process of metal/CNT composites by electrochemical deposition, including electrodeposition and electroless deposition, are comprehensively reviewed. A general introduction for fabrication of metal/CNT composites using the electrochemical deposition is carried out. The fabrication methods can be classified into three types: (1) composite plating by electrodeposition or electroless deposition, (2) metal coating on CNT by electroless deposition, and (3) electrodeposition using CNT templates, such as CNT sheets and CNT yarns. The performances of each type have been compared and explained especially from the view point of preparation methods. In the cases of (1) composite plating and (2) metal coating on CNTs, homogeneous dispersion of CNTs in electrochemical deposition baths is essential for the formation of metal/CNT composites with homogeneous distribution of CNTs, which leads to high performance composites. In the case of (3) electrodeposition using CNT templates, the electrodeposition of metals not only on the surfaces but also interior of the CNT templates is the key process to fabricate high performance metal/CNT composites.

Improvement of the Adhesion and Diamond Content of Electrodeposited Cu/Microdiamond Composite Coatings by a Plated Cu Interlayer

Diamond-incorporated copper metal matrix layers were fabricated on brass substrates by using electrodeposition technology in this study. To improve the adhesion of the composite coatings on the brass substrate, a plated copper was applied as the interlayer between the multilayers and the substrate. The surface morphologies of the interlayer and the diamond-incorporated copper composite layers were studied by scanning electron microscopy. The effect of the copper interlayer on the incorporation and the distribution of the diamond content in the coatings was analyzed by surface roughness, electrochemical impedance spectroscopy, and cyclic voltammetry. The diamond content of the composite coating was measured by energy-dispersive X-ray. The film thickness was evaluated by the cross-sectional technique of focused ion beam microscopy. The element, composition, and crystallization direction of diamond with Cu matrix was measured by X-ray diffraction and transmission electron microscope. The adhesion of the multilayers was studied by scratch tests. The experiment results indicated that the diamond content and distribution of the coating were higher and more uniform with the Cu interlayer than that without one. The plated copper interlayer reduced the electrical double-layer impedance and enhanced the adsorption of diamond particles by the surrounding Cu ions, which promoted the diamond content in the composite coatings. The roughened surface caused by the plated Cu interlayer also improved the substrate’s mechanical interlock with the composite coating, which contributed to the strong adhesion between them.

Electro-codeposition of CeO2 nanoparticles into cobalt matrix to improve the tribocorrosion performances of Co/nano CeO2 composite layers in biological solution for medical applications

Co/nano-CeO₂ composite layers were developed by electro-codeposition method from a cobalt electrolyte containing dispersed CeO₂ nanoparticles. The tribocorrosion performances of both Co/nano-CeO₂ and pure Co layers were comparatively investigated by sliding friction tests under lubricated condition in biological Hank solution. The effect of embedded nano-CeO₂ on the corrosion electrochemical response, friction coefficient and wear loss volume is analyzed. The results show that the codeposited of nano-CeO₂ particles into cobalt matrix reduce the friction coefficient and wear weight loss as well as the shift of open circuit potential to active state, increasing the polarization resistance and reducing the corrosion damages.

Electrodeposition of Co-B/SiC Composite Coatings: Characterization and Evaluation of Wear Volume and Hardness

In this research work, Co-B/SiC composite coatings were synthesized by electrochemical deposition from colloidal suspensions with different content of SiC. The Co-B/SiC films obtained were heat treatment at 350 °C. The composition, morphology, and structure of the Co-B/SiC composite coatings were analyzed using glow discharge spectrometry (GDS), scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Hardness and tribological properties were also studied. The results showed that an increase in the SiC concentration in the colloidal suspensions resulted in both an increase in the SiC content and a decrease in the B content in the obtained Co-B/SiC coatings. The Co-B/SiC coatings were adherent, glossy, and soft, and exhibited a homogeneous composition in all thicknesses. Besides, an increase in the SiC particle content of the Co-B/SiC composite coating from 0 to 2.56 at.% SiC reduced the hardness of the film from 680 to 360 HV and decreased the wear volume values from 1180 to 23 μm3 N−1 m−1, respectively (that is, the wear resistance increased). Moreover, when the Co-B/SiC coatings with SiC content ranging from 0 to 2.56 at.% SiC were subjected to a heat treatment process, the obtained coating hardness values were in the range of 1200 to 1500 HV, and the wear volume values were in the range of 382 to 19 μm3 N−1 m−1.

Enhanced Wear Performance of Cu-Carbon Nanotubes Composite Coatings Prepared by Jet Electrodeposition

Cu-carbon nanotubes (CNTs) composite coatings with high CNT content and uniformly distributed CNTs were successfully prepared via jet electrodeposition. Pristine CNTs, without any treatment like acid functionalization, were used. Anionic surfactant sodium dodecyl sulfate (SDS) was used to increase the wettability of the CNTs and improve the content of incorporated CNTs. With an appropriate SDS concentration (300 mg/L) in the electrolyte, the incorporated CNT content is as high as 2.84 wt %, much higher than the values reported using conventional electrodeposition (0.42–1.05 wt %). The high-content CNTs were uniformly distributed in the composite coating. The surface morphology of this composite coating (2.84 wt % CNTs) was flat due to the uniform electric field in jet electrodeposition. In the wear test a with load of 1 N and sliding speed of 0.02 m/s, the wear rate of this composite coating was 1.3 × 10⁻² mg/Nm, 85.4% lower than that of pure Cu. The enhanced wear performance of Cu-CNTs composite coatings can be attributed to high CNT content and flat surface morphology.

Preparation and properties of nanocrystalline Ni/graphene composite coatings deposited by electrochemical method

The paper presents results of studies of composite nickel/graphene coatings produced by electrodeposition method on a steel substrate. The method of producing composite coatings with nanocrystalline nickel matrix and dispersion phase in the form of graphene is presented. For comparative purposes, the study also includes nano-crystalline Ni coatings produced by electrochemical reduction without built-in graphene flakes. Graphene was characterized by Raman spectroscopy, transmission and scanning electron microscopes. Results of studies on the structure and morphology of Ni and Ni/graphene layers produced in a bath containing different amounts of graphene are presented. Material of the coatings was characterized by SEM, light microscopy, X-ray diffraction. The microhardness of the coatings was examined by Knoop measurements. The adhesion of the coatings with the substrate was tested using a scratchtester. The influence of graphene on the structure and properties of composite coatings deposited from a bath with different graphene contents was determined.

Corrosion inhibiting action of Ni–Mo alloy coatings in the presence of mixed metal oxide nanocomposites

Enhanced anti-corrosion properties of Ni–Mo alloy coatings by addition of mixed metal oxide nanoparticles via an electrodeposition method.

Effect of Nano-TiC Dispersed Particles and Electro-Codeposition Parameters on Morphology and Structure of Hybrid Ni/TiC Nanocomposite Layers

This research work describes the effect of dispersed titanium carbide (TiC) nanoparticles into nickel plating bath on Ni/TiC nanostructured composite layers obtained by electro-codeposition. The surface morphology of Ni/TiC nanostructured composite layers was characterized by scanning electron microscopy (SEM). The composition of coatings and the incorporation percentage of TiC nanoparticles into Ni matrix were studied and estimated by using energy dispersive X-ray analysis (EDX). X-ray diffractometer (XRD) has been applied in order to investigate the phase structure as well as the corresponding relative texture coefficients of the composite layers. The results show that the concentration of nano-TiC particles added in the nickel electrolyte affects the inclusion percentage of TiC into Ni/TiC nano strucured layers, as well as the corresponding morphology, relative texture coefficients and thickness indicating an increasing tendency with the increasing concentration of nano-TiC concentration. By increasing the amount of TiC nanoparticles in the electrolyte, their incorporation into nickel matrix also increases. The hybrid Ni/nano-TiC composite layers obtained revealed a higher roughness and higher hardness; therefore, these layers are promising superhydrophobic surfaces for special application and could be more resistant to wear than the pure Ni layers.

Tribological behavior of a Ni matrix hybrid nanocomposite reinforced by titanium carbide nanoparticles during electro-codeposition

TiC nanoparticles (50 nm mean diameter) were successfully electro-codeposited with nickel to obtain Ni/nano-TiC hybrid nanocomposite layers on a 304L stainless steel support with increased properties of nanohardness and wear resistance.

Electrodeposition Mechanism of Composite Coatings

The mechanism of co-deposition of solid particles with metal ions has not been thoroughly explained so far. This, among others, results from a number of factors that influence the process and their mutual relations. Therefore, the present paper aims at deeper understanding of the mechanism of electrolytic co-deposition and the mathematical models developed over the years to describe the incorporation of solid particles into electrodeposited metals. In this review, three mechanisms explaining the process of co-deposition of solid particles with the metal matrix have been discussed: (i) the electrophoretic, (ii) the mechanistic, and (iii) the adsorption ones.

The monitoring of coating health by in situ luminescent layers

The work is to develop a sensing system based on luminescent coatings in order to monitor deterioration during service.

Existence of a lower critical radius for incorporation of silica particles into zinc during electro-codeposition

Recently, it was shown that the surface modification of silica particles with -SH functional groups enables their electro-codeposition with zinc. Here, however, we report that no incorporation into Zn can be observed for such modified particles with diameters of <100 nm, while incorporation is possible for particles with diameters of 225 nm and larger. Furthermore, when silica particles are functionalized with mixtures of -SH and -Cl functional groups, which affect the interface energy at the particle/metal interface differently but have similar interfacial energies for the particle/electrolyte interface, it is found that, for successful incorporation of the particles, a minimum amount of -SH functional groups is needed. An explanation for these observations has been derived based on energetic considerations regarding the interfaces involved in the process.

Microstructure and Deposition Relations in Alumina Particle Strengthened Ni-W Matrix Composites

The nanostructured Ni-W/Al2O3 composite coatings were prepared by electrodeposition technique on ferritic steel substrates from aqueous electrolyte solutions containing ultrafine alumina particles in suspension. The effects of plating parameters like current density, inert particle concentration in plating bath and ultrasonic field frequency on the incorporation of α-Al2O3 particles (TM-DAR Taimicron) into an Ni-W matrix were investigated. The MMC coatings microstructure, phase and chemical composition were studied by means of scanning (E-SEM FEI XL-30) and transmission (TECNAI G2 SuperTWIN) electron microscopies, as well as XRD measurements (Bruker D8 Discover). SEM and TEM observations of composite cross-section microstructure showed that the presence of ultrasounds considerably reduces the particles agglomeration and enables a uniform distribution of particles in the Ni-W matrix. The electron diffraction pattern analysis revealed that the composite metallic matrix consists of an α-Ni(W) solid solution. The matrix was characterized by quasifibrous, nanocrystalline grains of an average size about 10 nm.

Study of Zn-Ni Alloy Coatings Modified by Nano-SiO2Particles Incorporation

The aim of this research work was to codeposit nano-SiO2particles into Zn-Ni alloy coatings in order to improve some surface properties. It had been investigated the effect of loading the plating bath with nanoparticles on composition, morphology, phase structure of deposits, and their subsequent influence on the corrosion process in corrosive solution of 3% NaCl and the thermal stability of deposits at200°C. It was found that Zn-Ni alloy composites contain a higher percentage of Ni with incorporation in the deposit of 1.54% of silica. X-ray diffraction measurements revealed that the alloys consisted of two phases, pure zinc andγphase. Electrochemical characterization of the composites had been carried out through potentiodynamic polarization and electrochemical impedance spectroscopy. The composites exhibited higher values of microhardness and better corrosion resistance in corrosive media.

Synthesis and Characterization of Nickel-Iron-Silicon Nitride Nanocomposite

Nickel-iron-silicon nitride nanocomposite thin films were prepared by electrodeposition technique. The deposition was performed at current density of 11.5 A dm-2. Nano-size silicon nitride was mixed in the electrolyte bath as dispersed phase. The effects of silicon nitride nanoparticulates in the nickel-iron nanocomposite thin films were investigated in relation to the amount of silicon nitride in the plating bath. X-ray diffraction (XRD) analysis showed that the deposited nickel iron film has face-centered cubic structure (FCC). However, a mixture of body-centered cubic (BCC) and face-centered cubic (FCC) phases were observed for nickel iron-silicon nitride nanocomposite films. The crystallite size of Ni-Fe nanocomposite coating decreased with increasing amount of silicon nitride in the film. From elemental mapping procedure, Si3N4 nanopaticles were uniformly distributed in the Ni-Fe film. The presence of silicon nitride increased the hardness of the film. The microhardness of the nickel-iron nanocomposite increased from 495 HV for nickel-iron film to 846 HV for nickel-iron nanocomposite film with 2 at. % Si. The coercivity of Ni-Fe nanaocomposite films increases with decreasing crystallite size.