Composite coatings can demonstrate improved property performance as compared to metals and alloy materials. One category of composite coatings is composed of metal or metal alloys with a dispersed phase of nonmetallic nanoparticles. The addition of these nanoparticles has been found to improve corrosion, wear resistance, and hardness. Producing metal composite coatings using electrochemical techniques can be advantageous due to reduced production cost, lower working temperatures, and precise control of experimental parameters. Metal coatings such as zinc have been successfully co-deposited with TiO2, SiO2, CeO2 and mica particles and nickel has been co-deposited with a number of materials including TiO2, SiC, Al2O3, PTFE and silicates. Zinc-nickel alloys have long been studied for a number of properties, most notably corrosion resistance and recently their tribological properties. This chapter reviews the literature on electrodeposition of ZnNi nanocomposite coatings. Although there has been much work done on composite coatings, there is much less literature available on composite coatings with zinc-nickel alloys. So in this review, we look at the general trends for nanoparticle incorporation, deposition mechanisms, system stability, microstructures of the coatings and general corrosion trends.

"Sacrificial metallic coatings, such as those based on Zn and Cd are used to protect steel components against corrosion. Growing environmental and health concerns have limited the use of Cd in any form since Cd plating bath is cyanide based and Cd compounds are carcinogenic. This thesis investigates Zn-Ni as a potential replacement for Cd and Cd based alloy coatings used in aerospace industries and Zn in automotive industries with respect to their tribological, corrosion and tribocorrosion resistance and hydrogen embrittlement susceptibility. In situ tribometry and additional ex situ analyses revealed that Zn-Ni coatings had superior resistance to adhesive wear compared to cadmium coatings. The microhardness of Zn-Ni coatings was higher than Zn and Cd coatings. Hardness on the wear track of Zn-Ni coatings showed the formation of strain hardened tribo layer. Zn-Ni coatings had higher polarization resistance after wear testing as compared to zinc and cadmium coatings. The mass loss due to wear enhanced corrosion was less with Zn-Ni than with Zn and Cd coatings. Zn-Ni coatings are a suitable replacement to Cd coatings when the surfaces are subjected to simultaneous wear and corrosion. Zn-Ni coatings had higher polarization resistance after the 24 hour immersion tests compared to zinc and cadmium coatings. Zn-Ni coatings offer better sacrificial corrosion protection because of low corrosion rates, and are a suitable replacement for Cd coatings. The Passivated Zn-Ni coatings showed lower corrosion resistance when heat treated due to localized damage of passive films while there was no effect of heat treatment on corrosion resistance of as plated Zn-Ni coatings. During the electrodeposition of metals, hydrogen is evolved due to electrolysis. The evolved hydrogen may diffuse outward and become trapped in the substrate/coating interface or migrate inward into the steel lattice causing delayed embrittlement when the component is subjected to stress. This study reports two principal variables for Zn, Zn-Ni, and Cd coatings: (i) quantity of hydrogen absorbed by the coating and substrate, by vacuum thermal desorption (ii) permeability of the coating material to hydrogen, by electrochemical permeation. The findings were analyzed in correlation with microstructural characteristics of both the coating material and the coating/substrate interface. With Zn-Ni, both coating process and coating material combined to significantly reduce the risk of internal hydrogen embrittlement by: (i) introducing the least amount hydrogen during the electrodeposition process, and (ii) by the ease with which hydrogen can be extracted by baking due to the presence of cracks in the coating.Keywords: Zn-Ni, Cd, Cd-Ti, Zn, EIS, insitu tribology, tribocorrosion, hydrogen permeation, TDS" --

Nanocomposite coatings have various properties that can be utilized for corrosion protection and tribological improvements. Synthesis of the nanocomposite coatings using an electrodeposition method allows unique control of the experimental parameters. By fine tuning the experimental parameters, various compositions and properties can be obtained for the nanocomposite coatings. This book covers some of the electrochemical methods used for nanocomposite coating deposition as well as discusses in detail examples of several nanocomposite coating. The corrosion and tribological performance of the nanocomposite coatings are also covered and some nanocomposite coatings are discussed for specific technological areas, such as fuel cells and microelectronics.

Electrodeposition of Alloys: Principles and Practice, Volume I covers the general and theoretical aspects of the electrodeposition of alloy containing silver and/or copper. This book is organized into three parts encompassing 21 chapters. The first part considers first the history of electrodeposition, the applications of electrodeposited alloys, and the practical considerations involved in electrodeposition. This part also deals with the effect of operating variables on composition of electrodeposited alloys, and the physico-chemical properties of the alloy. The second part focuses on the theoretical aspects of alloy electrodeposition. This part includes discussions on the role of cathode diffusion layer, the effects of complexing agents, and the concept of alloy plating. The third part discusses the practical aspects of the electrodeposition of alloys, focusing primarily on the electrodeposition of alloys from aqueous solutions. This part examines first brass and bronze plating, followed by the electrodeposition of copper-tin, silver, and iron containing alloys. This book is directed toward electrochemists and researchers.

This book reviews research activities around fabrication of these kinds of two dimensional nanostructured coatings with examples of enhanced mechanical properties, corrosion resistance, and physical characteristics. As one of the useful and simple methods for fabrication of nanocomposite coatings, electrochemical deposition (electroplating) techniques are a strong focus in this book. The relation among nanotechnology and these kinds of nanostructures that come from "size effect" and "distribution effect" is discussed through different chapters of this book. Nanocomposite coatings have numerous advantages.

Zinc electrodeposition has long been utilised as a sacrificial coating to protect steel from corrosion. However, the life span of such coatings is limited due to the aggressive nature of some environments, particularly those containing industrial pollutants. Consequently, considerable efforts are being made to improve their corrosion resistance. In order to improve the technological properties of these coating, zinc composite coating is considered as an alternate and effective method. Electrodeposition is a low-temperature process used to fabricate nanocomposite coatings in a single step without secondary treatment. Nanocomposites have attracted research interest due to their unique functional properties such as improved corrosion and wear resistance, lubricity semiconductor properties, magnetic properties and superconduction. This Book highlights the production of Zinc/ Zinc alloy- Nano particles composites by electrodeposition method. In this work all the coatings are characterized by different spectral and electrochemical methods. Corrosion behaviors of these composite coatings were studied by chemical and electrochemical methods.