Study of Sealing of Anodized Aluminium in Mixed Titanium-Cerium Salt Solutions

Abstract

5052 aluminium alloy as building structure material was used as the substrate to be anodized and then sealed respectively in boiling deionized water, titanium salt solution, cerium salt solution, and mixed titanium-cerium salt solutions to further improve the corrosion resistance of anodized aluminium and prolong the service life of 5052 aluminium alloy. The experimental results show that, the anodized aluminium sealed in boiling deionized water, titanium salt solution, cerium salt solution, and mixed titanium-cerium salt solutions shows different morphology features with different elemental composition and hydrophobic performance which can reduce the corrosion rate of 5052 aluminium alloy to significantly improve the corrosion resistance. Ti(OH)2, Ti(OH)4, Ce(OH)3 and Ce(OH)4 precipitates and gel film can be formed during synergetic effect between ammonium hexafluorotitanate and cerium(III) nitrate as a mixed sealing solution, which can play a combination of physical filling and covering effect. After sealing in mixed titanium-cerium salt solutions, the anodized aluminium is more flat and compact and exhibits hydrophobic performance, with the lowest weight loss of 0.62 mg/cm2, the highest charge transfer resistance of 4.06×103 Ω·cm2 and the highest low-frequency impedance of 6.34×103 Ω·cm2. The aluminium sealed in mixed titanium-cerium solutions shows excellent corrosion resistance and can provide better corrosion protection for 5052 aluminium alloy.