SVET Study of Galvanic Corrosion of Al/Mg2Si Couple in Aqueous Solutions at Different pH. Issue 6 (1st January 2017)

• Record Type: Journal Article
• Authors: Li, L. L.; Zhang, B.; Tian, B.; Zhou, Y.; Wang, J. Q.; Han, E. H.; Ke, W.
• Is Part Of: Journal of the Electrochemical Society. Volume 164:Issue 6(2017)
• Page Start: C240
• Page End: C249
• Publication Date: 2017-01-01
• Subjects: Dealloying -- Galvanic corrosion -- Mg2Si phase -- SVET -- XPS; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0671706jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The galvanic corrosion behavior between pure Al and synthesized bulk Mg2 Si in 0.01 M NaCl solution at different pH values has been investigated by the scanning vibrating electrode technique (SVET). At pH 2, bulk Mg2 Si actively dissolves and it acts as an anode. With the increase of exposure time, the anodic activity of Mg2 Si decreases drastically and eventually anodic activity appears on Al surface. In alkaline solution, Mg2 Si phase always acts as the cathode. The preferential dissolution of Mg and enrichment of Si found by energy dispersive X-ray spectroscopy are responsible for the observed anodic activity decay of Mg2 Si in acidic solution. At pH 6, the galvanic corrosion current of Al/Mg2 Si couple is much less than those at pH 2 and pH 13, and Mg2 Si mainly undergoes self-dissolution. These results indicate that the dealloying of binary Mg2 Si phase depends on the solution pH value and corrosion time, which subsequently have a great influence on the galvanic corrosion current of Al/Mg2 Si couple.