Characterization of Composite Coatings Obtained by Electrodeposition (original) (raw)
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Transactions of the IMF, 2014
Following a brief overview of their history, which dates back to the 1920s with marked developments during the 1960s and 1970s, the principles of composite coatings, achieved by including particles dispersed in a bath into a growing electrodeposited metal layer, are considered. The principles and role of electroplating compared to other techniques for realising such coatings, are considered. A good quality particle dispersion (often aided by a suitable type and concentration of surfactants) appropriate choice of work-piece shape/geometry and controlled agitation in the bath are seen to be prerequisites for achieving uniform coatings having a well-dispersed particle content by electroplating. Examples are provided to illustrate the influence of bath composition and plating conditions on deposit properties. Engineering applications of included particle composite layers are illustrated by examples of hard ceramic, soft ceramic and polymer inclusion composite coatings from the recent literature. Current trends in the development of composite plated coatings are summarised and their diverse applications are seen to include the use of finely structured (especially nanostructured) and functionally active particles together with hybrid and more complex, e.g. hierarchical, structures for applications ranging from tribology to speciality electronics, magnetic and electrochemical energy conversion materials.
Electrodeposition of Ni P composite coatings: A review
Surface and Coatings Technology, 2019
NieP coatings produced by electrodeposition have important mechanical, tribological and electrochemical properties. They can also exhibit catalytic activity and beneficial magnetic behaviour. With subsequent thermal treatment, the hardness of such NieP coatings can approach or exceed that of hard Cr coatings. Electrochemical codeposition of homogeneously dispersed second phase particles within the NieP matrix can enhance deposit properties and meet the challenging demands on modern engineering coatings. A general overview of research work on the electrodeposition of NieP composite coatings containing included ceramic or solid lubricant particles is provided. Advances in research into NieP composite layers reinforced by SiC, B 4 C, WC, Al 2 O 3 , SiO 2 , TiO 2 , CeO 2 , MWCNT, MoS 2 , WS 2 , TiN, hexagonal BN, PTFE and their combinations are considered. Major models proposed for the codeposition of particles, the influence of bath hydrodynamics and control of operational parameters are illustrated by examples. Important trends are highlighted and opportunities for future R & D are summarised.
Rev. Adv. Mater. Sci, 2007
Composite Ni+Mo coatings were obtained by electrodeposition of Ni with Mo particles on a steel substrate from the nickel bath in which metallic powder was suspended by stirring. The deposition was conducted under galvanostatic conditions. Deposits were characterized by the presence of Mo microsize particles embedded into the nanocrystalline nickel matrix. The influence of the metal powder amount in the bath, as well as the deposition current density on the chemical composition of the coatings was investigated. The content of incorporated Mo increases with the increase in the amount of metal powder in the bath, and diminishes with the increase in the deposition current density. The mechanism of metallic particles embedding is explained on the base of Ni 2+ ions adsorption process. Incorporation of Mo particles into electrolytic nickel matrix causes an increase in the real surface area of deposits. Thermal treatment of deposited coatings leads to chemical reactions in the solid state and in a consequence exerts significant influence on their phase composition and surface morphology. As a result of the interaction between the nickel matrix and incorporated Mo particles Ni 3 Mo intermetallic phase and Ni-Mo solid solution are arising. The obtained composite coatings were tested as electrode materials for hydrogen evolution in alkaline environment. Electrochemical characterization of the composites was carried out by steadystate polarization method. It was ascertained, that as-deposited Ni+Mo coatings are characterized by enhanced electrochemical activity for this process, which was confirmed by considerable decrease in the hydrogen evolution overpotential, by a nearly 170-260 mV compared to nickel electrode. Thermal treatment decreases the electrochemical activity of the investigated materials, as the values of hydrogen evolution overpotential on heated coatings are much higher.
Mechanisms for the Formation of Electrodeposited Composite Coatings
Transactions of the IMF, 1974
Measurements of the streaming potentials of alumina have been made in different electrolyte solutions and the effect of concentration studied. The codeposition of alumina with electroplated copper and nickel is discussed in terms of these results, and it is concluded that electrokinetic effects could not cause the observed behaviour. An alternative explanation is offered which considers the electro-adsorption of the particles at the cathode a5 the controlling process.
The Characteristics of Electrodeposited Nickel composite coatings-A Review
IRJET, 2022
For a long time, environmental protection of metallic components has become a pressing concern for the engineering and manufacturing industries. Coating technology has gained prominence to meet the needs of industrial demands. The coating is used to protect the metals and ensure the product's performance for a long time. Among other coating processes such as thermal spray, spark plasma sintering, and chemical vapour deposition, the electrodeposition process has proven to be the most costeffective and simple. The paper discusses the properties of various Nickel composite electrodeposited Protective coatings.
Electrodeposition of composite coatings containing nanoparticles in a metal deposit
Surface and Coatings Technology, 2006
Recent literature on the electrodeposition of metallic coatings containing nanosized particles is surveyed. The nanosized particles, suspended in the electrolyte by agitation and/or use of surfactants, can be codeposited with the metal. The inclusion of nanosized particles can give (i) an increased microhardness and corrosion resistance, (ii) modified growth to form a nanocrystalline metal deposit and (iii) a shift in the reduction potential of a metal ion. Many operating parameters influence the quantity of incorporated particles, including current density, bath agitation (or movement of work piece) and electrolyte composition. High incorporation rates of the dispersed particles have been achieved using (i) a high nanoparticle concentration in the electrolyte solution, (ii) smaller sized nanoparticles; (iii) a low concentration of electroactive species, (iv) ultrasonication during deposition and (v) pulsed current techniques. Compositional gradient coatings are possible having a controlled distribution of particles in the metal deposit and the theoretical models used to describe the phenomenon of particle codeposition within a metal deposit are critically considered.
Surface & Coatings Technology, 2007
Composite Ni + Ti, Ni + V and Ni + Mo coatings were prepared by codeposition of Ti, V or Mo particles in an Ni matrix on a carbon steel substrate from the nickel bath in which metallic powder was held in suspension. The influence of the metal powder amount in the bath, as well as the deposition current density on chemical composition of obtained coatings has been investigated. It was stated that the content of incorporated Ti, V and Mo increases with the increase in the particle concentration in the electrolyte, and diminishes with the increase in the deposition current density. The mechanism of metallic particles embedding was explained on the base of Ni 2+ ions adsorption process. Deposits exhibited a presence of Ti, V or Mo microsize particles embedded into the nanocrystalline nickel matrix. Incorporation of metallic powder into electrolytic nickel matrix results in the significant increase in the real surface area of the deposits. Electrodeposited composite coatings were tested as electrode materials for hydrogen evolution reaction (HER) in an alkaline environment. Electrochemical characterization was carried out by steady-state polarization method. All composite materials showed enhanced electrochemical activity for HER compared to the nickel electrode. Based on determined values of exchange current density-j 0 and the values of hydrogen evolution overpotential at 100 mA cm − 2 -η 100 the variation in the electrochemical activity of Ni + Ti, Ni + V and Ni + Mo composites in dependence on their chemical composition and the kind of incorporated component was evaluated. Comparison of the investigated materials leads to the statement that the highest activity towards the HER exhibit Ni + Mo deposits.
2017
Nanocomposite films of polyaniline and functionalized carbon nanotubes (FCNTs) with different additives have been electrochemical deposition from synthesis solutions such that constituents were deposited simultaneously onto metallic substrate. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques established that these composite films had electrochemical like respond rates to pure polymeric films however a reduced resistance and much improved mechanical integrity. The morphology of composite films has been investigated by scanning electron microscopy (SEM). The negatively charged functionalized carbon nanotubes (CNTsF) and additives utilized as anionic dopant through the electropolymerization to obtain polymer/CNTsF composite films. The electrochemical and physical properties like specific electrochemical capacitance of the composite films is a meaningful bigger value than that for pure polymer films obtained likewise. The additives substances used were...
Characteristics of electrodeposition of Ni-polyethylene composite coatings
Nickel polyethylene composites were produced by electrodeposition technique using Watt's nickel bath. The effect of operating conditions such as current density, pH, temperature and the effect of particle concentrations on the volume percent incorporation of polyethylene particles in the deposits were investigated. The properties of the composites such as micro-hardness, wear and corrosion resistance were also examined and compared with polyethylene-free nickel deposits. An optimum value of polyethylene (30 vol.%) was obtained at 30 g/l polyethylene particles in the electrolyte, at 7.5 – 9 A/dm 2 at pH 4 and temperature 50 B C. The microhardness wear resistance and corrosion resistance of the composite were found to be greater than free nickel deposits. D