open access

https://hdl.handle.net/2115/84210

Fabrication of a plasma electrolytic oxidation/anodic aluminum oxide multi-layer film via one-step anodizing aluminum in ammonium carbonate

英語

Anodic Aluminum Oxide

2020-03-01

Elsevier

Thin solid films

697

137799

A 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.

学術雑誌論文

Accepted Manuscript

Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

© <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/

0040-6090