Tubular alumina formed by anodization in the meniscal region

Abstract

A method to fabricate tubular nanoporous alumina layers by anodization of aluminum at current densities up to 1400 mA/ cm 2 and anodization rates up to 70 m / min has been developed. It implies anodization in the meniscal region of the sample dipping into an electrolyte. The formed porous alumina has been found to be selforganized nanotube cells when the anodization current excides 100 mA/ cm 2. The formation of nanotubes is supposed to be controlled by the increased volume expansion factor ͑more than 2͒ at high forming current densities. The meniscal anodization allows fabrication of porous alumina nanotubes with desired tilt angles in the range of 0°-16°.

Variable Thickness Porous Anodic Alumina/Metal Film Bilayers for Optimization of Plasmonic Scattering by Nanoholes on Mirror

“…If the anodization would be performed during dipping rather than withdrawal, the meniscal region would continuously remain in the initial anodization phase, characterized by a high current density. 18 However, this approach increases the risk of local breakdown, likely caused by inhomogeneities of the natural passivation layer that leads to local heating and uncontrolled oxidation.…”

Peculiar Porous Aluminum Oxide Films Produced via Electrochemical Anodizing in Malonic Acid Solution with Arsenazo-I Additive

“…The ratio of simultaneously occurring self-organized processes of metal oxidation with the formation of oxide and dissolution plays an important role in the formation of porous and tubular anodic oxides of valve metals. Different kinds of metal dissolution during anodic oxidation of aluminum and other valve metals lead to the formation of oxide films with different morphologies: barrier layers, quasi-regular porous layers, high degree self-ordering porous layers as well as tubular and nanocomposite structures [ 6 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The anodizing electrolyte is, aside from other process parameters, the main factor that determines this morphology.…”

“…The composition of the electrolyte for anodizing aluminum [ 79 , 80 , 81 ], and the modes of the experiment [ 23 , 81 , 82 ] significantly affect the properties and composition of the PAOF. So far, there is no clear idea on how these acids and organic additives interact with the anodizing process and how this leads to the observed modifications in PAOF growth.…”

Анодный Оксид Алюминия, Сформированный В Водных Растворах Хелатных Комплексных Соединений Цинка И Кобальта

“…Нужно сказать, что формирование пористых и трубчатых оксидов этих металлов стало возможным благодаря добавлению в электролиты анодирования небольших количеств фторид-ионов, являющихся лигандами, образующими прочные комплексные соединения со многими ионами металлов [15]. Состав электролита анодирования алюминия [16][17][18], и режимы проведения эксперимента [18][19][20] также существенно влияют на свойства и состав его анодного оксида. С точки зрения дополнительных возможностей для управления составом АОА большой интерес вызывают процессы получения АОА в электролитах, в составе которых присутствуют комплексные соединения и/или лиганды, способные образовывать устойчивые комплексные соединения [21].…”