Óxidos Mistos de Al2O3/ZrO2 como Inibidores de Corrosão do Aço SAE 1020

Abstract

<p class="orbitalabstract"><span>This paper describes the use of Al₂O₃/ZrO₂ mixed oxides synthesized by sol-gel process with different amounts of ZrO₂ (5%, 10%, 15% and 20% by mass) in the Al₂O₃ matrix and different temperatures of calcination, such as interesting inhibitor materials of corrosive processes of SAE 1020 steel. The materials were characterized by Infrared Spectroscopy Fourier Transform (FTIR) and X-Ray Diffraction (XRD) techniques. FTIR spectra show the typical Al-O and Zr-O bonds vibrations in the mixed oxides. The XRD patterns of the samples calcined at 800 °C and 1000 °C shows the ZrO₂ tetragonal and γ-Al₂O₃face-centered cubic (FCC) phases. The corrosion tests showed that the SAE 1020 steel covered with mixed oxides have an anodic passive region, thereby inhibiting the corrosive processes on the metal surface. Furthermore, the found values for steel coated with mixed oxide synthesized indicate a decrease in corrosion potentials (E_cor) and corrosion current (i_cor). With respect to different samples of mixed oxides, the sample with 20 % of ZrO₂ in the Al₂O₃ matrix proved to be the best inhibitor of steel corrosion, with the lowest values of corrosion potential and corrosion current, - 1.32 V and 0.31 μA cm^-2, respectively.</span></p