Effects of porous hydrous oxide layer on the microstructure and dielectric properties of TiO2-coated aluminum foil

The porous hydrous oxide layer obtained from the hydrothermal treatment of etched aluminum foil was used for fabricating the composite TiO 2 -Al 2 O 3 oxide film during anodization of the TiO 2 -coated aluminum foil. The results indicated that the TiO 2 -coated film obtained in the etched tunnels containing hydrous oxide layer was more tightly adsorbed with a more consistent compactness. The porous hydrous oxide layer facilitates the anchoring of TiO 2 sol particle, resulting in the tight coupling of the coated-TiO 2 film and the anodized alumina . Moreover, the porous hydrous oxide layer is beneficial to the migration of the Ti element to form the composite layer. It is indicated from the performance testing that the etched aluminum foil with hydrothermal treatment, and then 2 coating cycles, can improve the specific capacitance observably.