Formation and dielectric properties of anodic oxide films on Zr-Al alloys

Shun Koyama, Yoshitaka Aoki, Shinji Nagata, Hiroki Habazaki

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Zr-Al alloys containing up to 26 at.% aluminum, prepared by magnetron sputtering, have been anodized in 0.1 mol dm -3 ammonium pentaborate electrolyte, and the structure and dielectric properties of the resultant anodic oxide films have been examined by grazing incidence X-ray diffraction, transmission electron microscopy, Rutherford backscattering spectroscopy, and AC impedance spectroscopy. The anodic oxide film formed on zirconium consists of monoclinic and tetragonal ZrO 2 with the former being a major phase. Two-layered anodic oxide films, comprising an outer thin amorphous layer and an inner main layer of crystalline tetragonal ZrO 2 phase, are formed on the Zr-Al alloys containing 5 to 16 at.% aluminum. Further increase in the aluminum content to 26 at.% results in the formation of amorphous oxide layer throughout the thickness. The anodic oxide films become thin with increasing aluminum content, while the relative permittivity of anodic oxide shows a maximum at the aluminum content of 11 at.%. Due to major contribution of permittivity enhancement, the maximum capacitance of the anodic oxide films is obtained on the Zr-11 at.% Al alloy, being 1.7 times than on zirconium at the formation voltage of 100 V.

Original languageEnglish
Pages (from-to)2221-2229
Number of pages9
JournalJournal of Solid State Electrochemistry
Volume15
Issue number10
DOIs
Publication statusPublished - 2011 Oct 1

Keywords

  • Anodic oxide
  • Anodizing
  • Capacitor
  • Crystalline ZrO
  • Dielectric oxide

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Electrochemistry
  • Electrical and Electronic Engineering

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