**1. Introduction**

Nanotechnology is based on the knowledge and mastery of the infinitely small. They constitute a multidisciplinary field of research and development involving the fabrication of new materials and devices from tools or techniques that can be used to structure matter at the atomic, molecular, or supramolecular level. The typical scales of nanotechnology range from 1 to 100 nm.

The nanomaterials thus derived from these nanotechnologies are materials composed or constituted for all or part of nano-objects which confer to them improved or specific properties of the nanometric dimension. In this context, we speak of nanocharged or nanoreinforced materials. These materials are developed by incorporating nano-objects in an organic or mineral matrix to provide new functionality or to modify mechanical, optical, magnetic, or thermal properties. Nanocomposites are one example. Nano-objects (**Figure 1**) that have two different forms, nanotubes (e.g., MWNT: multi wall carbon nanotubes) or spherical particles (e.g., alumina powder) are incorporated in the porous matrix by several techniques, among which and the most interesting is that of electrophoresis. In this chapter, we are interested in presenting a work whose main objectives consisted in developing a model anodizing layer on the 5754 aluminum alloy, then a stable suspension of nanometric titanium dioxide, then composite coatings based on TiO<sup>2</sup> nanoparticles by electrophoretic impregnation of the anodizing layer, and finally rigorously examine the impact of TiO<sup>2</sup> localization on the tribological behavior of the composite coating already developed.

**Figure 1.** Different shapes of nano-objects (a) multi-wall carbon nanotubes and (b) spherical nanoparticles of alumina [1].

obtained are illustrated in **Figure 3**. Indeed the Al5754 aluminum substrate has an initial roughness (Ra = 740 nm and Rz = 7 μm) and a roughness after electrochemical polishing

nanoparticles in the pores of anodic layer.

Improving Tribological Behavior of Porous Anodic Film by Electrophoretic Impregnation by…

http://dx.doi.org/10.5772/intechopen.75782

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It should be noted that the anodization consists in carrying out the anodic polarization surface conversion of the base metal, immersed in a suitable electrolyte (generally an aqueous solution of a mineral acid). **Figure 4** shows an experimental setup of anodizing and the reactions

Different kinds of electrolytes such as sulfuric acid, phosphoric acid, and oxalic acid can be used for anodization. Although sulfuric anodizing, which is nowadays the most commonly used process [3], phosphoric acid was used in the case of this study because it produces a

that take place on the surfaces of the anode (Al5754) and the cathode.

(Ra = 140 nm and Rz = 1.5 μm).

**Figure 2.** Incorporation flowchart of TiO<sup>2</sup>

**2.2. Two-step anodization**
