Protection of metal and alloy surfaces using corrosion resistance nanostructured superhydrophobic coatings /

Abstract

Dans notre travail actuel, le processus de fabrication de surfaces de cuivre superhydrophobe est simplifié en une simple étape. L'application d'une tension continue entre deux plaques de cuivre immergé dans une solution diluée d'acide stéarique éthanolique transforme la surface de l'électrode de cuivre anodique en superhydrophobe due à la formation de micronano fibres de stéarate de cuivre à faible énergie de surface, tel que confirmé par rayons X diffraction (XRD) et microscopie électronique à balayage (MEB). L'augmentation du potentiel de modification, ainsi que la temps de modification conduit à l'augmentation de la valeur de la faible énergie de surface des micronanostructures ainsi que l'augmentation de la superhydrophobicité des surfaces telle que mesurée par l'angle de contact de l'eau. ABSTRACTSuperhydrophobic surfaces, which demonstrate high water-repellency, have recently become a very popular field because of its scientific and technological importance and wide range of applications in diverse areas. Preparation of nanostructured superhydrophobic surfaces requires both an optimum roughness and low surface energy; therefore, superhydrophobic surfaces are conventionally prepared employing two steps: roughening a surface and lowering its surface energy.In our present work, the fabrication process of superhydrophobic copper surfaces is simplified as just one-step. The application of a direct voltage between two copper plates immersed in a dilute ethanolic stearic acid solution transforms the surface of the anodic copper electrode to superhydrophobic due to the formation of micro-nanofibors low surface energy follower-like copper stéarate as confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The increase of the modification potential as well as the modification time leads to the increase of the amount of the low surface energy micro-nanostructures as well as the increase of the superhydrophobicity of the surfaces as measured by water contact angle.The nanostructured superhydrophobic aluminum alloy surfaces have also been prepared by the similar procedure as it was performed on copper surfaces. However, stearic acid modified aluminum alloy surfaces didn't show the superhydrophobic properties. Therefore, the aluminum surfaces were firstly coated with copper films followed by electrochemical modification with stearic acid solution. The copper grows as microdots on AA6061 Al alloy surfaces. The surface densities of the microdots increase with the increase of the negative deposition potentials. On the other hand their sizes as well as the distances between the microdots reduce with the increase of the negative deposition potentials. The surface roughness and water contact angle of electrodeposited copper film followed by electrochemical modification in ethanolic stearic acid solution increase with the increase in negative copper deposition potentials. The stearic acid modified copper films deposited at -0.6 V provides a surface roughness of 6.2 /un with a water contact a...