Tenue à l’usure d’un alliage de surface AlNi sur un substrat d’aluminium

Abstract

The work undertaken in this thesis focused on the improvements brought by electrodeposition of nickel on an aluminum alloy substrate on the microstructural, mechanical and tribological level. The characterization of the surface of the substrate and the coating layer has given rise to the use of different techniques: microhardness, XRD, optical microscopy and tribometry. This is considered to be the crux of this characterization. We have shown that the coating brought a significant improvement in terms of microhardness such that it went from 85Hv to 400Hv. From a microstructural point of view, the surface has changed from a unique Al-4.3%Cu composition to a surface layer containing aluminum, nickel, Al3Ni and Al3Ni2. By a tribological study, we have shown that the coefficient of friction of the coating marks a remarkable stability of the coating than that of the substrate. The profilometric data showed that the wear of the substrate is of the adhesive type while that of the coating is of the abrasive type. These results are consistent with the tribological behavior of the material