Preparation And Characterization Of Alumina Films With Nanopore

Anodic Aluminum Oxide (AAO) is a kind of transparent template with high-ordered nano-pores. The diameter of the pores was controlled between 5nm and 200nm. The density of the pores is between 109 singleton·cm-2 and 1011 singleton·cm-2. In recent years, it is more interested in Anodic Aluminum oxide with the unique hole-structure. As a template, it has potential application in functional materials such as optical components, magnetic materials, and selectly absorbable films and so on.Aluminum Oxide templates were firstly prepared by aluminum anodizing in given electrolyte oxalic acid with new two-step methods (firstly steady current, then voltage). The condition optimization of the templates preparation such as purity of the aluminum sample, the anodic voltage, the oxidizing temperature, the concentration of the electrolyte solutions,the oxidizing time and the expanding time was confirmed. At the same time, the large-area membrane was obtained with the voltage reduction sequence method. The porous Alumina template was gained by dissolving the barrier of the membrane with phosphoric acid. The area of oxidizing temperature on the preparation of anodic aluminum oxide templates was extended from (15.0～20.0℃) to (15.0～40.0℃) by the new anodic technique.The microstructure and mechanism of the porous Alumina membrane had been investigated by SEM, AFM and TEM. According to the fluctuating voltaic, the dynamics of the pores of AAO templates was discussed. The elements and crystalline state were determined by XRD and EDX, the results showed that the Alumina membrane is not crystalloid and the alumina templates calcined at 900℃possessed theγ-Al2O3 structure.The results indicated that the porous Alumina template was made of two layer films. One layer was porous alumina film in the surface of the template and other barrier layer was the barrier layer, compacting and no-hole. The porous layer contained high-density holes, which were parallel, no-crossing and homogeneous. The parameters of porous alumina template such as aperture, hole density, aspect ratio and membrane thickness were affected by the factors mentioned above.