Electroless Deposition of Nanolayered Metallic Coatings (original) (raw)
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Electroless nickel, alloy, composite and nano coatings – A critical review
Journal of Alloys and Compounds, 2013
The development of metal deposition processes based on electroless nickel, alloy and composite coatings on various surfaces has witnessed a surge in interest among researchers, with many recent applications made possible from many excellent properties. In recent years, these coatings have shown promising corrosion and wear resistance properties and large number of newer developments became most important from macro to nano level 1 applications. After a brief review of the fundamental aspects underlying the coating processes, this paper discusses in detail about different electroless nickel alloy, composite, nano plating, bath techniques, preparation, characterization, new depositing mechanism and their recent applications, including brief notes on difficult substrate and waste treatment for green environment. Emphasis will be on to their recent progress, which will be discussed in detail and critically reviewed.
electroless, nikel coating, nano coating, alloy coating, wear, corrosion
The development of metal deposition processes based on electroless nickel, alloy and composite coatings on various surfaces has witnessed a surge in interest among researchers, with many recent applications made possible from many excellent properties. In recent years, these coatings have shown promising corrosion and wear resistance properties and large number of newer developments became most important from macro to nano level applications. After a brief review of the fundamental aspects underlying the coating processes, this paper discusses in detail about different electroless nickel alloy, composite, nano plating, bath techniques, preparation, characterization, new depositing mechanism and their recent applications, including brief notes on difficult substrate and waste treatment for green environment. Emphasis will be onto their recent progress, which will be discussed in detail and critically reviewed.
Electrochemistry role in production of nano-coatings
Out of numerous synthesis methods of nano-coatings, electrochemical techniques have gained much interest, mainly because of their versatility. By means of advanced electrochemical strategies it is possible to obtain nano-coatings of diverse forms. Rapidity of the process, purity of products as well as production of coatings on widely varying surfaces are the most noticeable advantages of electrochemical synthetic methods. In this chapter we will present two principal electrochemical techniques: electrochemical deposition and electrophoretic deposition, together with less popular alternatives, such as plasma electrolytic deposition, laser-assisted electrodeposition and alternating current electrophoretic deposition. The fundamentals of each technique will be followed by specific examples illustrating details of the synthetic methods.
Development of Hybrid Electro-Electroless Deposit (HEED) Coatings and Applications
Journal of the Electrochemical Society, 2014
Since the discovery of electroless deposition within the electroplating process, the two techniques have grown as two separate, yet parallel, means of deposition. This paper demonstrates the reunification of the two processes in what is herein named hybrid electroelectroless deposition, or HEED. Specifically, the novel reunification as outlined within this study demonstrates that electroplating and electroless deposition can be achieved from a single solution wherein each process specifically targets a different metal ion within the electrolyte. The successful production of a compositionally modulated Au/Co/Au tri-layer from a single electrolyte using modulated electroless and electro-plating is described. Additionally, the practical application of producing compositionally modulated Ni-Zn-P alloy layers on AZ91D Mg alloys is demonstrated.
Factors affecting the adhesion of electroless coatings
Surface and Coatings Technology, 1993
In this paper, we study the factors affecting the first stage of autocatalytic (electroless) growth: the nucleation processes. The initiation of the process was achieved with the nickel electroless method on iron and copper substrates. Both acidic and alkaline baths were used for generalization of the layers.
A Review on the Corrosion Behaviour of Nanocoatings on Metallic Substrates
Materials
Growth in nanocoatings technology is moving towards implementing nanocoatings in many sectors of the industry due to their excellent abilities. Nanocoatings offer numerous advantages, including surface hardness, adhesive strength, long-term and/or high-temperature corrosion resistance, the enhancement of tribological properties, etc. In addition, nanocoatings can be applied in thinner and smoother thickness, which allows flexibility in equipment design, improved efficiency, lower fuel economy, lower carbon footprints, and lower maintenance and operating costs. Nanocoatings are utilised efficiently to reduce the effect of a corrosive environment. A nanocoating is a coating that either has constituents in the nanoscale, or is composed of layers that are less than 100 nm. The fine sizes of nanomaterials and the high density of their ground boundaries enable good adhesion and an excellent physical coverage of the coated surface. Yet, such fine properties might form active sites for corr...
Optimization Studies on Electroless Nickel Coatings
International Journal of Manufacturing, Materials, and Mechanical Engineering, 2014
Electroless nickel coating is a novel method of coating which can be developed in various combinations of alloys and composites each having its unique set of characteristics. Electroless nickel coatings are mainly used for wear and corrosion resistant properties. However, additional characteristics like smoothness of deposit, low friction, descent plating rate, electrical and magnetic properties also make them suitable for a host of applications. The properties of electroless nickel coatings depend mainly on the electroless solution ingredients as well as deposition conditions. Important deposition parameters include bath temperature, concentration of nickel source, concentration of reducing agent, pH of the solution, concentration of surfactants, and so on. Moreover, heat treatment is found to modify the microstructure of the coating and influence certain properties viz. hardness, wear resistance, corrosion resistance, etc. A large number of works have been published by the researc...
Improvement of electroless nickel coatings
This paper describes research and technology developments that enable to improve nickel electroless coating properties. This work deals with: (a) different methods in order to achieve Ni-P-Mo coatings. (b) Other development is related with coatings with addition of hard particles such as SiC, WC or Al 2 O 3 ,(c) Electroless nickel deposits on PBT and austempered ductile iron (ADI). (d) In addition, nickel coatings were deposited on powder metallic pieces and finally, electroless nickel coatings, in conjunction with layers from thermal spray process were formed. Characterization of all coatings by means of optical microscopy, scanning electron microscopy, micro-hardness, wear and corrosion tests were carried out. Results indicate positive increment in both mechanical and electrochemical properties which enhance field applications in Mexican industry.
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.
Transactions of the IMF, 2015
In part 1 of this review, emerging practice to realise nanostructured metallic coatings by electrodeposition, anodising and electrophoresis has been considered. Conventional, aqueous electrolytes may be utilised in some cases if workpiece preparation and process conditions are well controlled. Such coatings can provide wear and corrosion resistance or a catalytic or high active area compared to more conventional coatings. An overview of the principles involved in deploying electrochemical techniques to produce nanostructured surfaces and factors influencing developments in this rapidly emerging field were considered. The strategies, which can be adopted to electrodeposit nanostructured metallic coatings, include grain refinement, application of a pulsed current, inclusion of nanoparticles into the coating and the use of nanoporous templates. In part 2, examples of nanostructured coatings and their properties are illustrated with research findings from the authors' laboratory and the literature. Nanostructured metallic coatings include nanocrystalline, functionally graded, nanocomposite and recently introduced hierarchical structures. The potential uses for these coatings in engineering industries (including tribology and energy conversion) are summarised. Finally, future developments necessary to realise and deploy the coatings in increasingly demanding environments are considered.