The formation of streak defects on anodized aluminum extrusions

Zhu, Hanliang; Zhang, Xinquan; Couper, Malcolm J.; Dahle, A. K.

doi:10.1007/s11837-010-0077-8

Cited by 21 publications

(34 citation statements)

References 6 publications

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“…Surface gloss is considered to be the amount of incident light that is reflected at the specular reflectance angle of that surface, and streaking is typically characterised by narrow bands with a different surface gloss than the surrounding material [1][2][3][4][5]. The origin of streaking is a difference in intensity and diffuse nature of the reflected light.…”

Section: Introductionmentioning

confidence: 99%

“…The origin of streaking is a difference in intensity and diffuse nature of the reflected light. Hence, the formation of streak defects is dependent on surface topography of the final anodized products [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…Previous research indicates that the gloss after anodising correlates strongly with the metal surface roughness and to a lesser degree with the oxide surface roughness [2,6]. The reason is that aluminum oxide is transparent and the metal/oxide interface is therefore the prevailing reflecting surface whose surface characteristics have a greater effect on the gloss of the anodized part [2,6].…”

Section: Introductionmentioning

confidence: 99%

“…The reason is that aluminum oxide is transparent and the metal/oxide interface is therefore the prevailing reflecting surface whose surface characteristics have a greater effect on the gloss of the anodized part [2,6]. Hence, any surface imperfections in the metal/oxide interface will increase the diffuse part of the reflected light and any inhomogeneous distribution of these surface imperfections results in the occurrence of streak defects [2].…”

Section: Introductionmentioning

confidence: 99%

“…Surface imperfections are created on the extrusion surfaces during etching [2,3]. It has been found that the most common surface imperfections are etching pits, grain boundary grooves and grain etching steps [2,3].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effect of Process Variables on the Formation of Streak Defects on Anodized Aluminum Extrusions: An Overview

Zhu

Couper

Dahle

2012

High Temperature Materials and Processes

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Abstract. Streak defects are often present on anodized extrusions of 6xxx series aluminum alloys, increasing the fabrication cost of these products. Moreover, streaking often only becomes visible after etching and anodizing treatments, rather than in the as-extruded condition, making it difficult to identify the original causes and influencing factors of these defects. In this paper, various process variables that influence the formation of streak defects on anodized aluminium extrusions are reviewed on the basis of a literature review, industrial practice and experimental results. The influencing factors involved in various processing steps such as billet quality, extrusion process, die design and etching process are considered. Effective measures for preventing the formation of streak defects in industrial extrusion products are discussed.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Process Variables on the Formation of Streak Defects on Anodized Aluminum Extrusions: An Overview

Zhu

Couper

Dahle

2012

High Temperature Materials and Processes

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Anodizing of AA6063 aluminium alloy profiles: Generation of dark appearance

Zhou

Thompson

et al. 2013

Surface & Interface Analysis

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The generation of dark appearance on an anodized AA6063-T6 aluminium alloy profile has been investigated. Plan and cross-sectional views of the anodic films of normal and dark samples revealed a distinct layer, of 1-2 mm thickness, decorated with characteristic features in the outer film regions of the dark sample, contrasting with typical porous anodic film of the normal sample. Additionally, it was revealed that the alloy substrate of the dark sample was over-aged and the characteristic features in the outer film regions of the dark sample are related to preferential anodizing of coarsened b 0 (Mg2Si) precipitates. Further, it is suggested that the over-aged microstructure is not the sufficient condition for the occurrence of dark appearance, and the anodizing conditions in the early stages also play an important role in the generation of dark appearance.

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