The effect of pre-oxidation treatment on the corrosion behavior of amorphous Al_{1∿span style='font-style: italic'>x}Zr_x solid-solution alloys

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• 作者：K. Weller^a ; ^{k.weller@is.mpg.de" class="auth_mail" title="E-mail the corresponding author} ; T. Suter^b ; Z.M. Wang^a ; ^c ; L.P.H. Jeurgens^b ; E.J. Mittemeijer^a ; ^d
• 关键词：corrosion ; oxidation ; amorphous Al-Zr ; microstructure ; potentiodynamic polarization
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 January 2016
• 年：2016
• 卷：188
• 期：Complete
• 页码：31-39
• 全文大小：1929 K

文摘

The electrochemical behavior of as-deposited and pre-oxidized amorphous Al_1−xZr_x solid-solution alloys (x = 0.25, 0.32, 0.49, 0.65, 0.74) in 1 M HCl was investigated by the micro-electrochemical technique. It was found that, for higher Zr alloying contents, x ≥ 0.49, the class="boldFont">as-deposited Al_1−xZr_x alloys exhibit passive corrosion behavior due to the formation of a protective Zr-rich passive film on the Zr-rich alloy surface. The native oxide layer on the as-deposited Al-rich Al_1−xZr_x alloys (x < 0.49) is much less stable, which rapidly results in a total break-down of the protective character of the native Al-rich oxide layer upon anodization in 1 M HCl. The class="boldFont">pre-oxidized am-Al_1−xZr_x alloys all exhibited superior corrosion behavior as compared to their as-deposited pendants, attaining passive current densities as low as 3.5× 10⁻² μA/cm² at 1000 mV. The superior corrosion resistance of the pre-oxidized alloys is attributed to a combination of characteristics of the thermally-grown amorphous (Al_0.33Zr_0.67)O_1.83 overlayer: (i) a relatively high Zr fraction, (ii) a structurally and chemically uniform microstructure, (iii) a stable, minimal residual growth defect structure (in the surface region) established by a sufficiently large time of oxidation.