Electrochemical Corrosion Behavior of Oxidation Layer on Fe30Mn5Al Alloy
The Fe30Mn5Al alloy was oxidized at 800℃ in air for 160h, the oxidation-induced layer about 15μm thick near the scale-metal interface was induced to transform to ferrite and become enriched in Fe and depletion in Mn. The effect of the oxidation-induced Mn depletion layer on the electrochemical corro...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Journal of Materials Engineering
2017-08-01
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| Series: | Cailiao gongcheng |
| Subjects: | |
| Online Access: | http://jme.biam.ac.cn/CN/Y2017/V45/I8/83 |
| Summary: | The Fe30Mn5Al alloy was oxidized at 800℃ in air for 160h, the oxidation-induced layer about 15μm thick near the scale-metal interface was induced to transform to ferrite and become enriched in Fe and depletion in Mn. The effect of the oxidation-induced Mn depletion layer on the electrochemical corrosion behavior of Fe30Mn5Al alloy was evaluated. The results show that in 1mol·L<sup>-1</sup> Na<sub>2</sub>SO<sub>4</sub> solution, the anodic polarization curve of the Mn depletion layer exhibits self-passivation, compared with Fe30Mn5Al austenitic alloy, and the corrosion potential <i>E</i><sub><i>vs</i> SCE</sub> is increased to -130mV from -750mV and the passive current density i<sub>p</sub> is decreased to 29μA/cm<sup>2</sup> from 310μA/cm<sup>2</sup>. The electrochemical impedance spectroscopy(EIS) of the Mn depletion layer has the larger diameter of capacitive arc, the higher impedance modulus|<i>Z</i>|, and the wider phase degree range, and the fitted polarization resistant <i>R</i><sub>t</sub> is increased to 9.9kΩ·cm<sup>2</sup> from 2.7kΩ·cm<sup>2</sup> by using an equivalent electric circuit of <i>R</i><sub>s</sub>-(<i>R</i><sub>t</sub>//CPE). The high insulation of the Mn depletion layer leads to an improved corrosion resistance of Fe30Mn5Al austenitic alloy. |
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| ISSN: | 1001-4381 1001-4381 |