A novel fabrication method of surface-porous Mg-Al alloy and its corrosion property

• Published in: Materials today communications Vol. 27; p. 102415
• Main Authors: Wu, Peng-Peng, Zhu, Yi-Xing, Feng, Zhen-Liang, Song, Guang-Ling, Zheng, Da-Jiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2021
• Subjects: EIS; Mg alloy; Porosity; Porous surface; Surface alloying; Porosity; Mg alloy; Surface alloying; Porous surface; EIS
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2021.102415

[Display omitted] •A alloy precursor surface was obtained via surface alloying.•A porous surface was formed through chemically etching the alloy precursor.•Corrosion resistance of the surface-porous Mg alloys and its precursor was studied. The specific stiffness, strength and damping capacity of a Mg alloy may be further enhanced if the Mg alloy has a specifically porous surface layer. However, it is not practical to use a faveolated brittle alloy precursor to generate such a porous microstructure. Hence, in this study, surface alloying was employed for the first time to fabricate the precursor of Mg-Al alloys with porous surfaces. The porous surface could be obtained via chemical etching of the precursor. The corrosion performance of the precursor alloy before and after the etching was measured and the corrosion mechanism was analyzed. It was found that in the alloyed surface layer of the precursor, the α-Mg was Al-supersaturated and potential difference of the α-Mg from the secondary phase was relatively small, which was helpful to form a uniform surface film to suppress micro galvanic corrosion. The porous surface had a high ratio of cathodic-to-anodic area and thus showed poor corrosion resistance compared with the surface of the precursor Mg-Al alloy.