Electrochemical anodizing, structural and mechanical characterization of nanoporous alumina templates

摘要

Highly ordered Anodic Aluminum Oxide (AAO) structures produced from aluminum byusing an electrochemical anodizing method were developed towards its application for the nextgeneration of micro/nano medical and energy devices. In addition of analyzing the anodizingcurrent profile, the surface morphology was characterized by using Scanning Electron Microscopy(SEM), the crystalline structure by X-Ray Diffraction (XRD) and the mechanical properties bynanoindentation experiments. The anodizing time and applied potential determines the nanoporesregularity and their size, although the effect of the potential is more pronounced than the effect oftemperature in the transformation from crystalline alumina to amorphous alumina. Optimum poregrowth was achieved with an applied potential of 17 V which led to a pore fraction - P(f) - of about17.5%. The experimental Berkovich nanoindentation method was used to determine the AAOhardness as a function of the indenter depth, during the loading stage, using mechanical responseand deformation behaviour of the nanopores structure. From the experimental data of the loaddisplacementcurves, this method allows the calculation of the indenter contact depth at eachreloading point, thus leading to the estimation of the material’s hardness. The results reveal that thehardness depends on the processing conditions used for the production of the AAO samples thatalso strongly influences the organization and pore size uniformity.