Síntesis, caracterización y evaluación de la resistencia a la corrosión de recubrimientos híbridos Sol-Gel base TEOS/MPS sobre la aleación AA2050-T8

The aim of the present work was to synthesize, characterise and evaluate the corrosion resistance of TEOS/MPS hybrid sol-gel coatings applied on the AA2050-T8 aluminium alloy attending to two experimental variables: the sol synthesis conditions (type of solvent and aging time), and the inorganic/hybrid (TEOS/MPS) ratio. The aging process was monitored by infrared spectroscopy (FTIR) and viscosity measurements. The hybrid coatings were obtained by dip-coating and then characterized by scanning electron microscopy (SEM-EDX). The evaluation of corrosion resistance was performed by anodic potentio dynamic polarization testing in aerated 0.1 M NaCl solution. The results showed that ethanol as solvent promoted better stabilization of the hybrid precursor and favoured polymerization of the methacrylate groups of the MPS precursor. Further, an increase of the TEOS/MPS ratio allowed obtaining more continuous and uniform coatings. Nevertheless, all the hybrid coatings showed a significant increase in corrosion resistance of the AA2050-T8 alloy, being more evident for those synthesized with the TEOS:MPS 80:20 ratio.