Effects of anodizing conditions on anodic alumina structure

Zhao, Naiqin; Jiang, Xiaoxue; Shi, Chunsheng; Li, Jiajun; Zhao, Zhiguo; Du, Xi‐Wen

doi:10.1007/s10853-006-0410-3

Cited by 55 publications

(41 citation statements)

References 19 publications

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“…For example, in their experiments D int was independent of the electrolyte pH at constant anodization voltage [99], whereas the former two models predict that D int (in nm) should vary with the pH according to 2.96V 0 /(2.31-1.19 pH), where V 0 is the constant anodization voltage. Although some of the predictions of these models do not agree with the experimental observations by Friedman et al [99], in some aspects [98,99], this does not necessarily mean that electric field is not the driving force for AAO growth and self-ordering, because previous models may not reflect the nature of electric-field assisted process correctly. Most recently, van Overmeere et al [127] performed an energy-based perturbation analysis for pore growth in AAO, and they concluded that the electrostatic energy, rather than the mechanical strain energy-induced surface instability, was the main driving force for pore initiation as well as a controlling factor for pore spacing selection.…”

Section: Electric Field Assisted Pore Growthmentioning

confidence: 77%

“…Here, we assume that ion migration across the oxide/electrolyte interface is the rate-determining step, because the oxygen and aluminum ions are weakly bound under the effect of the high electric field [94]. It should be noted that ionic migration in the bulk oxide has been proposed previously as an alternative rate-determining step [153], but recent experiments revealed that an increase in the acid concentration of the electrolyte, which should play a role directly at the oxide/electrolyte interface, can influence the anodization process significantly, such as increasing the pore diameter [98], the current density [154], and the oxide growth rate [99]. These profound changes of the anodization process should be due to changes in the anodization conditions at the oxide/electrolyte interface, and this is the basis of the present assumption that the rate-determining step is at this interface.…”

Section: Electric Potential Distribution Within Aaomentioning

confidence: 99%

“…A thin scallop-shaped oxide barrier layer exists between the porous AAO layer and Al substrate. It has been demonstrated for decades that the barrier layer thickness D b , D p , and D int have linear relationships with anodization voltage [2,3,94,[97][98][99]. The dependence may vary slightly with temperature and acid concentration.…”

mentioning

confidence: 99%

“…The dependence may vary slightly with temperature and acid concentration. For example, under mild anodization (MA) conditions, the voltage dependence of D p and D b is about 1 nm V −1 , and that of D int is 2.5 nm V −1 [93,98]. Recently, Lee et al [92].…”

mentioning

confidence: 99%

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Theoretical Pore Growth Models for Nanoporous Alumina

Cheng

Ngan

2015

Nanoporous Alumina

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Nanoporous alumina has been extensively used in a wide range of applications, including template materials for various types of nanomaterials, high surface-area structures for energy conversation and storage, bio/chemo sensors, electronic/photonic devices, and so on. However, the formation mechanism of the nanopores and the subsequent pore growth process towards self-ordered pore arrangements have been under investigation for several decades without clear conclusions. The present models may be divided into two main groups in terms of the driving force for pore initialization, as well as the subsequent pore growth process. One group considers that the driving force is the high electric field across the oxide barrier layer at the bottom of the pore channels, which assists metal oxidation at the metal/oxide interface, and oxide dissolution at the oxide/electrolyte interface. The other group of models assumes that the driving force is mechanical stress originating from the volume expansion of the metal oxidation process. This chapter reviews the development of these models for nanoporous alumina formation, and discusses their advantages and shortcomings. A recent model proposed by us is also described, and potential directions for further development are discussed.

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Section: Electric Field Assisted Pore Growthmentioning

confidence: 77%

Section: Electric Potential Distribution Within Aaomentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Theoretical Pore Growth Models for Nanoporous Alumina

Cheng

Ngan

2015

Nanoporous Alumina

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“…A thin scallop-shaped oxide barrier layer exists at the pore bottom which separates the metal substrate from the electrolyte in the pore channels during the anodization. It has been known for several decades that the barrier layer thickness and interpore distance are primarily linearly dependent on the anodization voltage, while the pore diameter also depends on the electrolyte concentration and temperature, in addition to the voltage [2,3,95,[102][103][104]. For example, under traditional mild anodization (MA) conditions in which the oxide growth rate is several micrometers per hour, the voltage dependency is about 1 nm V −1 for both the pore diameter and the barrier layer thickness, and 2.5 nm V −1…”

mentioning

confidence: 99%

Research Background and Motivation

Cheng

2015

Electro-Chemo-Mechanics of Anodic Porous Alumina Nano-Honeycombs: Self-Ordered Growth and Actuation

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Anodic porous alumina, which exhibits a characteristic nano-honeycomb structure, has received increasing attention both experimentally and theoretically . Due to the quasi-periodic arrangement of the nanopore channels, narrow distribution of pore sizes, and interpore distances, relative ease to control the porous scales and self-ordering qualities by anodization conditions, excellent thermal stability, and very low-cost anodic porous alumina has been extensively used as templates for fabrication of various nanostructured materials such as nanodots [22][23][24], nanowires [25][26][27][28][29], nanotubes [30][31][32], and many other types [33][34][35], especially to realize the collective functioning of arrays of nanoelements which may not be realized by individual nanoelements [5,36], for applications in high-density magnetic media [37][38][39][40][41][42] [95,96]. For neutral electrolytes with pH in the range of 5-7, such as boric acid solution, ammonium borate, or tartrate aqueous solution, only barrier-type anodic alumina films with a uniform thickness will be formed by anodization [1,97]. The configuration of anodic porous alumina is composed of closely packed arrays of nanopore channels perpendicular to the aluminum substrate with pore diameters on the order of several to hundreds of nanometers [58,[93][94][95]98]. When viewed from the top, the nanopores are usually arranged in a quasi-hexagonal porous pattern. The in-plane arrangement of pore channels generally exhibits local variations with ordered zones separated with disordered zone boundaries, which is much similar to the crystallographic grains and grain boundaries of the Al substrate. However, the perfect ordered zones are at most several micrometers big even for highly self-ordered patterns, while the grain

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Effect of coupling agent quantity on composite interface structure and properties of fiber metal laminates

et al. 2021

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Epoxy silane coupling agent A‐187 and amine silane coupling agent A‐1387 were used to modify the interface of carbon‐reinforced aluminum laminates (CARE), respectively. The effects of the type and content of coupling agent on the microstructure and mechanical properties of CARE were investigated. Results show that with the increase in the content of two coupling agents, the wettability first increases and then decreases. When the mass fraction of the two coupling agents is 1%, good wetting property is obtained, and the interlaminar shear and flexural strengths of the CARE plate are the best. Compared with epoxy coupling agent A‐187, amine coupling agent A‐1387 had better wettability to aluminum alloy surface and highly contributed to the improvement of interface structure and properties, which then increased the interlaminar shear and flexural strengths by 19.1% and 8.9%, respectively.

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Effects of anodizing conditions on anodic alumina structure

Cited by 55 publications

References 19 publications

Theoretical Pore Growth Models for Nanoporous Alumina

Theoretical Pore Growth Models for Nanoporous Alumina

Research Background and Motivation

Effect of coupling agent quantity on composite interface structure and properties of fiber metal laminates

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