Nanoporous Aluminum Oxide Layer Research Articles

Evaluation of Sealing Process on the Surface Properties of Nanoporous Aluminum Oxide Layers Electrochemically Growth on 1050 Aluminum Alloy Surface

Thanks to its low density, aluminum and its alloys are extensively used in the transport and construction industries. The improving of aluminum and its alloys corrosion resistance is an extensively studied topic. Different methods are applied to improve the corrosion resistance of aluminum and its alloy: painting, waxing, zinc-chromate priming, conversion coatings and also anodic oxidation. The anodic oxidation is the most used method to fabricate nanoporous aluminum oxide layers, with controlled thickness and pores diameters, on aluminum and its alloys surfaces. The aim of this work is to evaluate the influence of the sealing process of the nanoporous aluminum oxide layers obtained by anodic oxidation on 1050 aluminum alloy surface. Scanning electron microscopy (SEM) was used to observe the morphological structure of untreated and modified surfaces. Corrosion behavior of oxidized 1050 aluminum alloy, sealed oxide layer and untreated 1050 aluminum alloy were investigated using electrochemical methods such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD). The experimental results show that the anodic oxidation process improve the corrosion resistance of 1050 aluminum substrate and the sealing process improve even more the anticorrosive properties.

Nanopatterned Silicon Emitters of a Solar Cell Fabricated by Anodic Aluminum Oxide Masks

We investigated the nanopattern transferring process by a template of anodic aluminum oxide and the formation of a nanoporous aluminum oxide layer on a Si solar cell by the anodization process of Al thin films. The anodization process provided a template to transfer the nanopattern onto the Si surface. The small-sized nanoporous alumina template was attached to be covered on the textured surface and played the role of etching mask in the F-based dry etching process. Furthermore, we deposited an Al thin film onto the Si surface and the subsequent anodization process was performed. The alumina formulated on the deposited Al thin film did not show the array of nanoporous structure and no nanopatterns were transferred onto the surface. The large-areal alumina deposited on the Si surface showed enhanced photo-absorption in the ultraviolet spectral region of 243 nm, but increased the photo-reflectance in the visible and infrared spectral regions when compared to the Si-bare sample.

Effects of Thin-Film Structural Parameters on Laser Desorption/Ionization from Porous Alumina

Nanoporous aluminum oxide layers, grown by anodization of aluminum thin films on glass and then sputter-coated with gold, were used to study the effects of the thin-film structural parameters on laser desorption/ionization (LDI) mass spectrometry (MS) of peptides. Variation of MS signal intensity was examined as a function of alumina pore depth, pore width, and gold layer thickness. Peptide molecular ion intensity was optimal with porous alumina formed from aluminum films of approximately 600-nm thickness; thinner or thicker films gave significantly lower signals. Signals decreased when pore sizes were increased beyond the as-formed width of approximately 100 nm. The MS signal also varied with the thickness of the sputtered gold layer with an optimum thickness being approximately 90 nm. The results of these studies provide values for empirical optimization of LDI MS performance as well as potential clues to the LDI mechanism.