**1. Introduction**

Nanocoatings are one of the most important topics within the range of nanotechnology. Through nanoscale engineering of surfaces and layers, a vast range of functionalities and new physical effects can be achieved. Some application ranges of nanolayers and coatings are summarized in table 1 [1].


**Table 1.** Some applications of nanocoatings

Many synthesis techniques for production of nanostructured coatings have been developed such as sputtering, laser ablation, sol/gel technique, chemical vapour deposition, gas-conden‐

© 2013 Abdel-Karim and Waheed; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 Abdel-Karim and Waheed; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

sation, plasma spraying, and electrochemical deposition [1]. Chemical vapour deposition includes chemical reaction of input materials in the gas phase and deposition of the product on the surface. Physical vapour deposition (PVD) includes transforming the material into the gaseous phase and then deposition on the surface [2]. The impact of an atom or ion on a surface produces sputtering from the surface. Unlike many other vapour phase techniques there is no melting of the material. Sputtering is done at low pressure on cold substrate. In laser ablation, pulsed light from an excimer laser is focused onto a solid target in vacuum to boil off a plum of energetic atom. A substrate will receive a thin film of the target material. The sol-gel process is well adapted for ceramics and composites at room temperature [1].

**2.1. Electrodeposited nanocrystalline Ni-Fe alloys**

**Figure 1.** Two stages of electro crystallization according to Bockris et al. [6]

According to R. Abdel-Karim et al. [10], nanocrystalline Ni-Fe deposits with different compo‐ sition and grain sizes were fabricated by electrodeposition. Deposits with iron contents in the range from 7 to 31% were obtained by changing the Ni2+/Fe2+ mass ratio in the electrolyte. The deposits were found to be nanocrystalline with average grain size in the range 20–30 nm. The surface morphology was found to be dependent on Ni2+/Fe2+ mass ratio as well as electroplating time. Figure 2 represents SEM of electrodeposited Ni base layers at longer electrode position time (100 min) as a function of Ni2+/Fe2+ mass ratio in the electrolytic bath. From Figure 2(a), in case of Ni2+/Fe2+ mass ratio equal to 20.7, SEM image displayed well defined nodular coarse and fine particles with no appearance of grain boundaries. This nanosized particles can be better illustrated by using higher magnification (100000x), as shown in Figure 2(b). From Figure 2(c), sample of Ni2+/Fe2+ mass ratio equal to 13.8 displayed clusters of fine particles embedded

Nanostructured Ni-Fe alloys, produced by electro-deposition technique provide material with significant improved strength and good magnetic properties, without compromising the coefficient of thermal expansion (CTE). Such properties made these alloys to be used in many of the applications where conventional materials are currently used. For such applications a special attention has been made to study the physical, mechanical and chemical properties of such alloys because of the potential for performance enhancement for various applications of Ni-Fe alloys arising from the enhanced properties due to the ultra-fine grain size of these alloys [7-9].

Nanocoatings

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http://dx.doi.org/10.5772/55776

The superiority of electrochemical deposition techniques in synthesizing various nanomate‐ rials that exhibit improved compared with materials produced by conventional techniques, will be discussed. Nanocoatings can be obtained either directly on substrates or by using porous templates.
