Control of scale effects in the localized anodic oxidation of aluminium based materials – lokO
Joining and Separation Technology
Synthesis and Properties of Functional Materials
Final Report Abstract
The investigation of the innovative anodizing technique using an electrolyte jet allows for the production of defined, localized oxide layers on surfaces of aluminum alloys. In addition to oxalic acid, sulfuric acid was successfully applied as electrolyte in this project. Due to the oxide growth rates of more than 5 µm/min, the desired minimum layer thickness of 5 µm was achievable on structured functional surfaces. The coaxial jet of electrolyte and deionized water phases ensures the dilution of the effluent acid, resulting in increased localization and simplified handling. This development enables the production of laterally confined, sharpcontoured oxide layers with a high layer thickness in the center. The results show that compact and transparent oxide layers are achieved up to a voltage of 25 V, while higher voltages up to 60 V led to increasing burning effects and finally to the detachment of the oxide layer in the center of the anodized area. Relevant electrical parameters were determined for various substrate materials by in-situ measurements during electrochemical impedance spectroscopy (EIS) and incorporated into the simulation-assisted process design. Experimental investigations with the derived input parameters showed significant increases of the maximum oxide layer thickness through pulsation of the direct voltage. Tribological investigations showed that anodized surface structures in the form of curved lines and square-arranged spots enable a significant reduction of the coefficient of friction compared to non-anodized surfaces and entirely anodized surfaces in an immersion process.
Publications
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Downscaled anodic oxidation process for aluminium in oxalic acid. IOP Conference Series: Materials Science and Engineering, 181, 012044.
Sieber, M.; Morgenstern, R.; Kuhn, D.; Hackert-Oschätzchen, M.; Schubert, A. & Lampke, T.
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Localised anodic oxidation of aluminium material using a continuous electrolyte jet. IOP Conference Series: Materials Science and Engineering, 181, 012042.
Kuhn, D.; Martin, A.; Eckart, C.; Sieber, M.; Morgenstern, R.; Hackert-Oschätzchen, M.; Lampke, T. & Schubert, A.
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Heat treatment condition of EN AW-7075 influencing the anodic oxidation process and coating properties. IOP Conference Series: Materials Science and Engineering, 373, 012021.
Morgenstern, R.; Scharf, I. & Lampke, T.
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“Multiphysics simulation of localised anodisation of aluminium,” Eur. Soc. Precis. Eng. Nanotechnology, Conf. Proc. - 18th Int. Conf. Exhib. EUSPEN 2018, pp. 429–430, 2018
N. Lehnert et al.
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Strategien zur Lokalisierung der Schichtbildung bei der anodischen Oxidation mittels Elektrolytfreistrahl. In: ZVO-Oberflächentage Leipzig, Kongress für Galvano- und Oberflächentechnik, 2022
R. Morgenstern; S. Quitzke; I. Danilov; A. Martin; T. Mehner; A. Schubert & T. Lampke
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Simulation-Assisted Process Design and Experimental Verification of Laterally Confined Oxide Areas Generated with Continuous Electrolytic Free Jet on EN AW-7075 Aluminum Alloy. Micromachines, 14(2), 293.
Quitzke, Susanne; Danilov, Igor; Martin, André; Morgenstern, Roy; Lampke, Thomas & Schubert, Andreas
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“Concentric jet for confined mask-less anodic dissolution and oxidation of aluminium,” in euspen´s 23rd International Conference & Exhibition, no. June, pp. 99–102, 2023
A. Martin; S. Quitzke; R. Morgenstern; A. Schubert & T. Lampke
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Lokales Anodisieren mit koaxialem Elektrolytstrahl: Schwefelsäureprozess mit hoher Schichtbildungsrate für tribologische Anwendungen. In: ZVO-Oberflächentage, Kongress für Galvano- und Oberflächentechnik, 2024
R. Morgenstern; S. Quitzke; A. Martin; T. Mehner; A. Schubert & T. Lampke
