TY - JOUR
T1 - Formation and dielectric properties of anodic oxide films on Zr-Al alloys
AU - Koyama, Shun
AU - Aoki, Yoshitaka
AU - Nagata, Shinji
AU - Habazaki, Hiroki
N1 - Funding Information:
The present work was supported in part by the Global COE Program (Project No. B01: Catalysis as the Basis for Innovation in Materials Science) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
PY - 2011/10
Y1 - 2011/10
N2 - 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.
AB - 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.
KW - Anodic oxide
KW - Anodizing
KW - Capacitor
KW - Crystalline ZrO
KW - Dielectric oxide
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U2 - 10.1007/s10008-010-1238-y
DO - 10.1007/s10008-010-1238-y
M3 - Article
AN - SCOPUS:80054734743
VL - 15
SP - 2221
EP - 2229
JO - Journal of Solid State Electrochemistry
JF - Journal of Solid State Electrochemistry
SN - 1432-8488
IS - 10
ER -