Effect of Laser Treatment and Hydrophobization on the Corrosion-Electrochemical Behavior of Aluminum

Abstract: The effect of laser treatment of aluminum samples on the properties of the surface hydroxide oxide layer is studied. It is shown that treatment in air leads to an increase in the thickness of the oxide layer and the almost complete disappearance of hydroxide forms, which results in deterioration of the protective properties of this layer due to its higher defectiveness and porosity. It is found that the optimal treatment regime for aluminum, the surface of which is covered by an oxide layer with a significant fraction of hydroxides, is laser irradiation in an inert argon gas medium with small (1–2 vol %) oxygen content. Laser treatment leads to the formation of a protective surface layer that effectively inhibits the anodic dissolution of aluminum in a model corrosion medium, borate buffer solution at pH 7.4. It is shown that the initial hydroxide oxide film and the oxide film formed during laser treatment processing are hydrophilic, that is, they are well moistened with water. The surface treatment of aluminum in the initial state and after laser irradiation with a solution of vinyltriethoxysilane (VTES) leads to the formation of a hydrophobic adsorption layer and a significant decrease in the currents of anodic dissolution. Using X-ray photoelectron spectroscopy, it is shown that silane adsorption occurs both with the participation of silicon atoms and carbon atoms of an alkene bond. The hydrophobic layer of adsorbed silane on the laser-treated surface has a greater thickness and has a higher inhibiting effect on the anodic dissolution of aluminum than in the case of the initial aluminum surface. © 2020, Pleiades Publishing, Ltd.