High frequency pulse anodising of aluminium: Anodising kinetics and optical appearance

Jensen, Flemming; Gudla, Visweswara Chakravarthy; Kongstad, Ib; Ambat, Rajan

doi:10.1016/j.surfcoat.2018.12.117

Cited by 10 publications

(4 citation statements)

References 75 publications

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“…al. [27] showed that pulsing from zero to 15 V at 1 kHz, results in very dramatic current peak of approximately 30 A/dm 2 . As soon as the barrier layer is fully charged (during one pulse cycle), the current drops to approximately 4 A/dm 2 ; i.e.…”

Section: Figurementioning

confidence: 99%

High frequency pulse anodising of recycled 5006 aluminium alloy for optimised decorative appearance

Jensen

Kongstad

Dirscherl³

et al. 2019

Surface and Coatings Technology

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High frequency (HF) pulse anodising of a recycled AA5006 Aluminium alloy has been investigated to understand the effect of pulse anodising on improvements in optical quality of anodised surfaces in a sulphuric acid bath. The investigation includes the effect of applied voltage potential and pulse frequency on the anodising kinetics and optical properties of the recycled alloy with high number of intermetallic phases. The effect is compared with anodised surfaces produced using conventional DC anodising. Both the anodising kinetics and optical properties are largely dependent on the applied pulse frequency and amplitude of the anodising voltage. Surface gloss of the layer is generally improved upon using pulses compared to DC and improved by lowering the anodising voltage potential and increasing the pulse frequency. Improved kinetics under pulse mode allows for getting good anodic layers even with voltage levels lower than 10V, however the surface gloss worsens when anodising below 10 V. The benefit from pulse anodising is found to be largely due to metal-oxide interface roughness rather than on the structure and composition of the anodised layer.

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Section: Figurementioning

confidence: 99%

High frequency pulse anodising of recycled 5006 aluminium alloy for optimised decorative appearance

Jensen

Kongstad

Dirscherl³

et al. 2019

Surface and Coatings Technology

Self Cite

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“…When applying a low current density, the dissolution of the Al 2 O 3 predominates over the formation of this layer. The influence of the current density value, duty factor, and pulse frequency on the forming anode layer of Al 2 O 3 has been presented, among other studies, in research [9][10][11]. The study of the pore composition and structure as well as the mechanical properties of anodic alumina layers obtained by the impulse method are presented in [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Influence of Research Factors and Al2O3 Layer Production Parameters on Tribological and Microstructural Properties

Korzekwa,

Matczuk,

Hubkiewicz

et al. 2023

Lubricants

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The exclusion of systems supplying the lubricant from the outside makes it necessary to replace traditional sliding pairs with materials containing a lubricant component. Such solutions are carried out to prevent the formation of material tacks and, consequently, of adhesive wear, which must be avoided. The article presents the influence of research factors and parameters of Al2O3 layer production on tribological and microstructural properties. The input variables for the tests were the admixture of WS2 to the electrolyte, the type of sputtering of the samples for SEM tests, and the load on the oxide coating—TG15 material friction node. The surface morphology and cross-section of the oxide coatings as well as the tribological properties of the rubbing pair have been studied. Interactions between the input variables and the obtained test results have been analyzed using DOE—a 2k factorial design with one repetition. Pareto charts and two-way ANOVA were used to determine the relationship. The analysis of variance shows the influence of sample preparation on the calculation values of the size of nanopores and Al2O3 walls on the SEM image. Statistical analyzes also show that both the load and the type of electrolyte affected the values of the coefficient of friction and wear of the TG15 material; those values are the result of appropriate adhesion of the sliding film to the surface of the layer.

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“…The cell size has a linear relationship with voltage, as the voltage is increasing the cell size gets bigger too and the number of pores is decreasing, respectively. The layer of Al₂O₃ forms, and chemically bonds perfectly to the metal base also the thickness of the film is increasing as the treatment operates for a longer time (16,118,119,(124)(125)(126). system (1,121) which can be linked according to the previously reported orientation relationship (16).…”

Section: Anodising Processmentioning

confidence: 88%

“…Each specific grain illustrated identical position of maximum intensity with respect to the analyser rotations. Also, the data showed each specific grain to maintain identical value for the difference between maximum and minimum intensity unconventionally to the anodised layer(16,(124)(125)(126).…”

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confidence: 85%

Quantitative polarised light microscopy of metals

Safaie¹

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For most engineering metals a material’s crystal structure can play a significant role in its performance in service. This is particularly relevant for materials that display pronounced differences in their physical properties depending on the arrangement and orientation of these crystals. Examples of such alloys are titanium and aluminium which are employed in a wide range of applications from medical to structural. Conventionally, the crystal structure of these materials is measured using various X-ray and electron diffraction techniques. Unfortunately, these are generally costly, time-consuming and therefore impractical in an industrial quality assurance setting. On-going research at Swansea University has demonstrated that a simpler alternative offers a solution to this problem. The project aimed to build on this research to develop a semi-automated method to conduct this analysis. The work involves extensive characterisation of various materials using optical and electron microscopes; this will focus on the direct correlation of electron diffraction data to polarised light microscopy. The project will concentrate on developing this apparatus to provide high quality, reliable information on material crystal structures. Electron Backscatter Diffraction (EBSD) is the most well-known approach to investigate the crystal orientation of polycrystalline material. However, when compared to optical microscopy EBSD is an expensive approach, very time consuming and complex laboratory technique needed to plot a crystal orientation map. The research offers a novel approach for optically anisotropic (titanium) and isotropic (aluminium) material to plot the crystal orientation map. The aim of the research is to offer a simpler, cheaper, and less time-consuming method which can be affordable by a middle-class company to have access to the crystal orientation map.

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High frequency pulse anodising of aluminium: Anodising kinetics and optical appearance

Cited by 10 publications

References 75 publications

High frequency pulse anodising of recycled 5006 aluminium alloy for optimised decorative appearance

High frequency pulse anodising of recycled 5006 aluminium alloy for optimised decorative appearance

Influence of Research Factors and Al2O3 Layer Production Parameters on Tribological and Microstructural Properties

Quantitative polarised light microscopy of metals

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