Influence of Silane Sol Sealing Treatment on the Anti-Corrosion of Micro-Arc Oxidation Coating

Silane sol was applied to seal the pores in a micro-arc oxidation coating, with the results proving that the treatment increased the anti-corrosion characteristics of aluminium alloy. Moreover, an electrochemical workstation was employed to test the open-circuit voltage, polarisation potential, and polarisation current of the samples. According to the results, after the aluminium alloy was treated with the micro-arc oxidation coating and underwent subsequent sealing treatment, the open-circuit potential increased from −0.64 to −0.44 V, the corrosion potential from −0.54 to −0.31 V, and the corrosion current density from 56.23 × 10−7 to 7.76 × 10−7 A. However, when samples were corroded by 1 mol/L HCl, the corrosion potential and corrosion current density decreased to −0.34 V and 20.42 × 10−7 A, respectively, proving that sealing the pores on the micro-arc oxidation coating only prevented substrate corrosion for a short time. In addition, slow-strain-rate stretching experiments were conducted to explore the mechanical performances of the samples, determining that the surface treatment had an insignificant effect on the stress of the aluminium alloy but had an important effect on its elongation, and when the surface of the alloy was treated with micro-arc oxidation coating, its elongation decreased from 28% to 26%.