Anodic oxidation of Al-Cr alloys and the valence state of chromium

被引：13

作者：

Habazaki, H ^{[1
]}

Skeldon, P ^{[1
]}

Thompson, GE ^{[1
]}

Wan, J ^{[1
]}

Wood, GC ^{[1
]}

Zhou, X ^{[1
]}

DeLaet, J ^{[1
]}

Shimizu, K ^{[1
]}

机构：

[1] KEIO UNIV,UNIV CHEM LAB,YOKOHAMA,KANAGAWA 223,JAPAN

来源：

JOURNAL OF THE ELECTROCHEMICAL SOCIETY | 1997年 / 144卷 / 12期

关键词：

D O I：

10.1149/1.1838169

中图分类号：

O646 [电化学、电解、磁化学];

学科分类号：

081704 ;

摘要：

The anodic oxidation of Al-4 atom percent (a/o) Cr [7.4 weight percent (w/o) Cr] and Al-10 a/o Cr (17.6 w/o Cr) sputtered-deposited alloy films was investigated by transmission electronmicroscopy and by x-ray absorption studies. The oxidation behavior of both alloys is explained by initial formation of a chromium-free anodic alumina film with accumulation of chromium in a thin underlying alloy layer. On sufficient enrichment of the alloy, chromium and aluminum are oxidized at the alloy/film interface in their approximate alloy proportions. The resultant Cr3+ ions migrate outward through the film more slowly than Al3+ ions. Oxidation of chromium is followed by production of what is probably oxygen gas within the film, which is likely to generate a high pressure, leading to film rupture and gas release. Consequently, a complex, irregular film morphology, associated with voids, channels and cracks, develops. X-ray absorption studies reveal that Cr(VI) species are detected in significant quantities only after the mechanical breakdown of the film. Such species probably form as a result of the high electrochemical potential of the alloy that is freshly exposed to the environment following film rupture.

引用

页码：4217 / 4222

页数：6

共 12 条

[1] USE OF RUTHERFORD BACKSCATTERING TO STUDY BEHAVIOR OF ION-IMPLANTED ATOMS DURING ANODIC-OXIDATION OF ALUMINUM - AR, KR, XE, K, RB, CS, CL, BR, AND I [J].