Papers by Keyword: Two-Step Anodization

Abstract: Anodic Aluminum Oxide (AAO) membrane has been successfully fabricated from two-step anodization with aluminum low grade (Al6061). The pore density, the pore diameter, and the interpore distance can be controlled by varying anodization process conditions. However, there are limits to control the mechanical strength and growth of AAO arrays, such as pore density, pore diameter and interpore distance. In this research the self-organized two-step anodization is carried out varying time at 24, 48 and 72 hours, respectively with 40V at the low temperature 2-5°C. The optimum conditions of AAO with two-step anodization is 40V for 48 hr. Finally, AAO substrate is separated from aluminum low-grade and enlarged pore diameter with pore widening process by 5% H₃PO₄. The physical properties were investigated by mean of field emission scanning electron microscope (FE-SEM) show that the average pore diameter and average interpore distance increase with the anodization time. Al6061 Aluminum substrate can be used to fabricate a nanoporous AAO film with an average pore diameter and average interpore distance larger than 70 and 90 nanometers, respectively but less mechanical stability.

Abstract: TiO₂ nanotube arrays were fabricated through anodization in the glycol electrolyte system. The new composite structures of the bottom nanotube and the upper nanowire with a length of 15 um to 20 um were prepared. The influence of the water contents in the electrolyte with respect to the composite structure was studied through two-step anodization. The results show that the composite structure can be obtained based on the moderate etching rate of the electrolyte and the selective etching of the nanotube when the glycol system electrolyte contains 0.4wt% NH₄F and 2 vol% H₂O.

Abstract: Oxide membranes are one kind of porous materials with many nano-sized pores. In our work, the two-step anodization method was used to fabricate Anodic aluminum oxide (AAO) membranes. The surface, cross-section micrographs and chemical composition were analyzed by field emission scanning electron microscopy (FESEM). From the FESEM micrographs, it can be easily seen that the self-ordered hexagonal pore channels were parallel and perpendicular to the surface of membrane when AAO membrane was prepared in oxalic acid at 0.2mol/L for 4h. In addition, the biggest pore diameter was 78nm, and the thickness ranged from a few microns to tens of microns in the suitable preparation parameters.

Abstract: Effects of annealing treatments of aluminum substrate for ordered nanopore arrays formed by self-organized anodization have been investigated. To observe the relationship between microstructures of aluminum substrate and nanopore regularity formed after anodization of the aluminum substrate, aluminum specimens were annealed at 300, 400, and 500 °C. The anodic alumina layer was prepared by two-step anodizing process in oxalic acid at 40 V. The ordered arrays of nanopore on anodic alumina were shown to be strongly dependent on the annealing conditions, and nanopore regularity on alumina template increased with increasing annealing temperature and time.