Properties of UV-irradiated TiO2, ZrO2, and TiO2-ZrO2 films as pore-sealing layers on micro-arc-oxidized aluminum alloys

In this paper, the UV-assisted sol–gel route was employed to fabricate the TiO 2 pore-sealing films on the micro-arc-oxidized (MAO) aluminum alloys (MAO/Al). As compared with the TiO 2 film derived from traditional sol–gel method, the UV-irradiated TiO 2 film showed a structure with less cracks, resulting in enhanced electrode potential, higher impedance, and lower corrosion current. Further, we investigated and compared the properties of the UV-treated amorphous oxides, including the TiO 2 , ZrO 2 , and TiO 2 -ZrO 2 films on MAO/Al. It was found that their corrosion resistances were related to the metallic–oxygen–metallic (M–O–M) lattice in the films. The MAO/Al sealed with UV-irradiated ZrO 2 pore-sealing film showed higher corrosion resistance than the samples sealed with UV-irradiated TiO 2 film or TiO 2 -ZrO 2 film, which was owing to the fact that a larger amount of M–O–M lattice formed in the UV-ZrO 2 film during the UV irradiation. Highlights UV-assisted sol-gel ZrO 2 , TiO 2 , and TiO 2 -ZrO 2 layers were prepared on micro-arc oxidized aluminum alloys. The ZrO 2 pore-sealing layer showed enhanced anti-corrosion properties than that of TiO 2 , and TiO 2 -ZrO 2 layers. The formation of M-O-M bonds was contributed to the enhancement of anti-corrosion properties.