Research porous alumina template and electrodeposition of metals
|School||Central South University|
|Course||Physical Chemistry of Metallurgy|
|Keywords||porous anodic aluminum oxide growth process situ disolving conductive adhesive deposition|
With the development of nanotechnology, the preparing of ordered nanowire arrays via templates have been drawing more and more attention.A highly ordered porous AAO (anodic aluminum oxide) template was prepared by the two-step anodic oxidation in oxalic acid in the present work. Composed of AI2O3, it had evenly distributed nanopores arranged with the haxagonal honeycomb-shape on the surface. All the straight nanopore channels were parallel completely without any intersection.It was studied that the self-assembly process of preparing ordered pores of alumina by controlling the oxidation voltage. According to I-t curves of the procedure, the formation of the template could be divided into three stages, barrier formation, pore in the bud and stable growth of ordered pores.It was analyzed the dependence of the anodic oxidation process on the electrolytic voltage and stirring. The diameter of pore enlarged linearly with the increase of the anodic oxidation voltage, while its density decreased. In the case of no-stirring, the stripes or even patterns were present on the sample surface because of local higher temperature due to the heat released from the reaction.A study was made on situ dissolving of barrier without removing the aluminum base by a reverse voltage method. A new technology of the phosphate pore-enlarging process combined with the reverse voltage method was proposed. The uniformly distributed Ni nanowire arrays in diameter of 60-80nm were obtained by DC deposition on the electrode made of the treated template.Element Co nanowires that grow on the preferred orientation were prepared via AC deposition. SEM and XRD detection showed the diode-like rectifier effect of the barrier, and a loose material caused by the discontinuity of the surplus deposition.In addition, in order to increase the conductivity of template, a new technology where the conductive adhesive was used to replace thin gold film was studied. This method was easier to operate and could avoid template damage caused by gilt. The examination on SEM showed that the platy Ni element with the content of 21.82% was deposited on the bottom of the template.