2024-03-28T10:32:08Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/842102022-11-17T02:08:08Zhdl_2115_20045hdl_2115_139Fabrication of a plasma electrolytic oxidation/anodic aluminum oxide multi-layer film via one-step anodizing aluminum in ammonium carbonate1000060374584Kikuchi, TatsuyaTaniguchi, Taiki1000080179275Suzuki, Ryosuke O.1000070706879Natsui, Shungoopen access© <2020>. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 InternationalAnodizingAluminumAmmonium CarbonatePlasma Electrolytic OxidationAnodic Aluminum Oxide431A plasma electrolytic oxidation (PEO)/anodic aluminum oxide (AAO) multi-layer film was fabricated via onestep galvanostatic anodizing of high-purity aluminum in 0.3-2.0 M ammonium carbonate ((NH (4))(2)CO3) solutions at 283-333 K and 25-400 Am-2. Anodizing at higher concentrations and higher temperatures caused the formation of relatively uniform anodic oxide film on the aluminum substrate. Characteristic voltage-time curves with two high-plateau voltages at approximately 250 V and 375 V were obtained during galvanostatic anodizing. A mull-layer structure of an outer PEO layer with a crystalline gamma-Al2O3 structure and an inner amorphous AAO layer with nano-cylinerical pores was formed by continuous visible sparking occurring after passing the first voltage plateau region. The whole aluminum surface was covered with the multi-layer structure after reaching the second voltage region. The thickness of the mull-layer increased with time via the further anodizing process at the second plateau voltage. Pore sealing of the inner nanoporous film was achieved by immersion post-treatment in boiling water.Elsevier2020-03-01engjournal articleAMhttp://hdl.handle.net/2115/84210https://doi.org/10.1016/j.tsf.2020.1377990040-6090Thin solid films697137799https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/84210/1/PEO.pdfapplication/pdf833.49 KB2020-03-01