IMPROVEMENT OF CORROSION RESISTANCE OF 2024 ALUMINUM ALLOY BY Y(NO₃)3⋅6H₂O MODIFICATION AND HOLE SEALING TREATMENT

In order to obtain better corrosion resistance, the micro-arc oxidation (MAO) coating after adding (Y(NO 3 )[Formula: see text]H 2 O was sealed by TiO 2 sol–gel method. Dynamic polarization curves and electrochemical impedance spectroscopy show that the prepared samples (Y(NO 3 )[Formula: see text]H 2 O content was 1.5[Formula: see text]g/L) have good corrosion resistance ([Formula: see text]A[Formula: see text]) in 3.5[Formula: see text]wt.% NaCl aqueous solution. Afterward, the samples with a concentration of 1.5 g/L of Y(NO 3 )[Formula: see text]H 2 O were sealed by TiO 2 sol–gel. Through SEM, XRD and electrochemical test, it is found that the surface of the film is smooth, the phase is mainly in the form of Anatase-TiO 2 and has better corrosion resistance ([Formula: see text]A[Formula: see text]). This showed that sealing the doped 2024 aluminum alloy MAO film can significantly reduce the corrosion sensitivity and corrosion rate of the film.