Formation of Alumina Nanotubes and Jet Effect during High‐Voltage Local Anodization of Aluminum
Using an improved heat sink from the barrier layer, the voltage of anodic electrochemical oxidation of aluminum in sulfuric electrolytes is successfully increased from the conventional limit of about 40 to 200 V. This is done by localization of the anodized regions within the windows in the niobium...
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| Published in: | Advanced engineering materials Vol. 24; no. 1 |
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| Main Authors: | , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
01-01-2022
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Using an improved heat sink from the barrier layer, the voltage of anodic electrochemical oxidation of aluminum in sulfuric electrolytes is successfully increased from the conventional limit of about 40 to 200 V. This is done by localization of the anodized regions within the windows in the niobium thin film masks with the diameters of 0.3 μm to 2.5 mm. High‐voltage anodization in water solutions of sulfuric acid is observed to be accompanied by a reproducible formation of densely packed alumina nanotubes and intense gas propulsion from the pores of the forming alumina. The latter is proposed and experimentally confirmed for use as an efficient driving agent in micro‐ and nanoengines. Test samples are accelerated to the velocities up to 1 cm s−1, demonstrating a thrust‐to‐weight ratio of about 1000.
Localization of electrochemically anodized regions of aluminum within windows 0.3 μm to 2.5 mm in diameter allows for increase of anodic voltages to 200 V. Such high‐voltage anodization results in the formation of alumina nanotubes and intense gas propulsion from their pore channels. The injected gas bubbles produce a jet effect suitable for micro‐ and nanoengines. |
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| ISSN: | 1438-1656 1527-2648 |
| DOI: | 10.1002/adem.202100691 |