Obtenção de revestimentos de alumínio-silício para a proteção química de aço inoxidável

Abstract

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Al2O3-SiO2 sol-gel coatings of different compositions have been deposited on 316L stainless steel by dip-coating from a sonocatalyzed sol made by the mixture of Al(OC4H9)3 e Si(OC2H5)4 as precursors and ethanol and acetic acid as solvents. The coatings were densified at 600, 800 and 1000°C and characterized by X-rays diffraction. The influence of the coatings on the corrosion behavior of the substrate was tested in 3% NaCl by potentiodynamic polarization curves at 1 mV s(-1). The electrochemical results showed that the films densified at 800 and 1000°C have a better electrochemical behavior than the films densified at 600°C. An increase in the aluminium content improves the behavior of the coatings.