Production And Application Of Alumina Template With 3D Nano-tapered Array Structure

With the development of nano-tech and the functional materials, porous alumina membranes with many advantages like good chemical stability, controllable structure, low process cost, have become widely used templates for various functional materials. Among these,3D tapered alumina arrays are competitive candidates. The fabrication of tapered porous alumina may be accomplished by combining the multi-step anodization and etching processes with the two-step mild anodization, ion etching, photo fabrication, or other nano-manufacture approaches. However, the complicated processes cannot content the requirement of easy, rapid and low cost fabrication process for controllable 3D tapered alumina array.Bases on the analyses above, we focus on the formation mechanism of the tapered alumina membrane, and have fabricated various tapered porous alumina with various morphologies. The result shows there is close relationship between the interpore distance of the tapered pore and its nanopits. The application potential of the as-prepared tapered alumina membranes was investigated on development of the tapered copper materials. The results of this thesis are as follows:1. In the oxalic acid-ethanol mixed electrolyte, hard anodization was used to fabricate the porous alumina with different interpore distance by changing anodization voltage, anodization time, anodization temperature and ratio of the electrolyte. Adding ethanol can effectively reduce the anodization current, and the reaction heat decreases accordingly, which has a great effect upon the increase of the critical voltage.2. On the basis of the aluminum substrate with a nanopit-array structure, the tapered alumina templates were prepared by the multi-step anodization and etching processes. The morphology of the tapered alumina membrances could be controlled by varying the anodization voltage, the etching time and the distance of the nanopits.3. The performance of the surface enhanced Raman scatting (SERS) and the hydrophobicity of the surface of the sample were studied. Additionally, a tapered copper material with inter-hollow structure was obtained successfully using the tapered alumina membranes as templates.