Effect of the Coating Deposition Technique on the Protective Properties of Hybrid Sol-Gel on AA2024

Abstract

The deposition technique effect on the corrosion properties of thin films applied on AA2024 was evaluated. The deposition techniques were spin-dip coating and brush-spray painting. For each technique different parameters were varied in accordance with its nature of deposition. The coating was synthesized by the sol-gel method of copolymerization of 3-Glycydoxypropyltrimethoxysilane, and tetra-n-propoxyzirconium was deposited on an AA2024 substrate. Scanning electron microscopy and atomic force microscopy revealed that the spincoating method formed a more homogenous film than the dipcoating method. The time deposition and the surface finishing significantly modified the bond strength between substrate and solgel coating. The corrosion properties were assessed by Electrochemical Impedance Spectroscopy. These results revealed that the spin-coating technique provides not only better corrosion properties of the sol-gel but also a marked improvement of the corrosion resistance on aluminum at longer immersion times in NaCl. The combination of ground finishing in conjunction with time deposition modifies the properties of sol-gel significantly.

Correlation of high‐hydrophobic sol‐gel coatings with electrochemical and morphological measurements deposited on AA2024

“…Furthermore, the incorporation of nanoparticles either in the form of sols or as solid particles (clay, pigments, and fibers) enhances the physical and chemical properties [7] of the coating. Specifically concerning the corrosion protection of aluminum, previous results have evidenced that the protection properties of aluminum substrates are strongly influenced by the deposition technique and the surface finishing of the metal [8] . Therefore, in order to guarantee an adequate level of protection against the corrosion phenomenon, in the sol-gel formulation, not only the proper selection of metal alkoxides, chelating agents, hydrolysable OR groups, or inhibitive species but also the physical media of deposition that provide a free-defect coating with an optimal anchoring profile should be considered.…”