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Dielectric properties of Al-Si composite oxide films formed on electropolished and DC-etched aluminum by electrophoretic sol-gel coating and anodizing
Title: | Dielectric properties of Al-Si composite oxide films formed on electropolished and DC-etched aluminum by electrophoretic sol-gel coating and anodizing |
Authors: | Sunada, M. Browse this author | Takahashi, H. Browse this author | Kikuchi, T. Browse this author | Sakairi, M. Browse this author →KAKEN DB | Hirai, S. Browse this author |
Keywords: | Aluminum | Electrolytic capacitor | Electrophoretic deposition | Sol-gel coating | Composite oxide film |
Issue Date: | Oct-2007 |
Publisher: | Springer Berlin / Heidelberg |
Journal Title: | Journal of Solid State Electrochemistry |
Volume: | 11 |
Issue: | 10 |
Start Page: | 1375 |
End Page: | 1384 |
Publisher DOI: | 10.1007/s10008-007-0316-2 |
Abstract: | Highly pure aluminum specimens (99.99%) after electropolishing and DC-etching were covered with SiO2 films by electrophoretic sol-gel coating and were anodized in neutral boric acid/borate solutions. Time-variations in cell voltage during electrophoretic sol-gel coating and in anode potential during anodizing were monitored. Structure and dielectric properties of the anodic oxide films were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and electrochemical impedance spectroscopy (EIS). It was found that electrophoretic sol-gel coating forms uniform SiO2 films on the surface of both electropolished and DC-etched specimens. Anodizing of specimens after electrophoretic coating lead to the formation of anodic oxide films consisting of two layers: an inner alumina layer and an outer Al–Si composite oxide layer. The anodic oxide films formed, thus, had slightly higher capacitances than those formed on aluminum without any coating. Higher heating temperatures after electrophoretic deposition caused the increase in capacitance of anodic oxide films more effectively. Anodizing in a boric acid solution after SiO2 coating on DC-etched foil allowed the anode potential to reach a value higher than 1,000 V, resulting in 39% higher capacitances than those on specimens without SiO2 film. |
Rights: | The original publication is available at www.springerlink.com |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/28635 |
Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 高橋 英明
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