Influence of MAO Treatment on the Galvanic Corrosion Between Aluminum Alloy and 316L Steel

Journal Article · Fri Dec 15 04:00:00 EST 2017 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-017-3037-4· OSTI ID:22860741

Yang, Yuanhang; Gu, Yanhong ^[1]; Zhang, Lei ^[2]; Jiao, Xiangdong; Che, Juntie ^[1]

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1. Beijing Institute of Petrochemical Technology, School of Mechanical Engineering (China)
2. University of Alaska Fairbanks, Department of Mechanical Engineering (United States)

To slow down the galvanic corrosion of aluminum alloy and 316L stainless steel in subsea water, a micro-arc oxidation (MAO) coating was prepared on the surface of the Al alloy, and no treatment was performed on the surface of the 316L. The surface morphology of MAO-coated Al alloy was evaluated using a scanning electron microscope (SEM) before and after corrosion. A micro-hardness tester was used to measure the micro-hardness. Corrosion behaviors were evaluated by open-circuit potential (OCP), potentiodynamic polarization (PDP) and electrode impedance spectroscopy (EIS) tests in a 3.5 g/L NaCl solution. The results of PDP testing show that the corrosion potential of the MAO-coated galvanic pair was more positive than that of the uncoated galvanic pair and that the corrosion current density was smaller than that of the uncoated galvanic pair. EIS results show that the impedance of the galvanic pair increased after MAO coating. SEM images show that the corrosion damage of the uncoated Al alloy was more severe than that of the MAO-coated one, and the post-corrosion images of the surface of the 316L connected with MAO-coated Al alloy were more compact than those of the 316L connected with uncoated Al alloy. A physical model was developed to discuss the influence of MAO treatment on the galvanic corrosion process and corrosion mechanism.

• OSTI ID: 22860741
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 12 Vol. 26; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CURRENT DENSITY
ELECTROCHEMICAL CORROSION
HARDNESS
IMPEDANCE
MATHEMATICAL SOLUTIONS
POLARIZATION
SCANNING ELECTRON MICROSCOPY
SPECTROSCOPY
STAINLESS STEEL-316L
SURFACES