Electrochemical dealloying of a ternary Al67Cu18Sn15 alloy compared with that of a binary Al75Cu25 alloy

This paper reports on the electrochemical dealloying of a ternary Al67Cu18Sn15 (in at.% throughout the paper) alloy consisting of a-Al, Al2Cu and Sn using potentiodynamic and potentiostatic polarization measurements. When the applied potential (-0.5 V) was below the critical potential of the Al2Cu phase (-0.41 V), complete electrochemical dealloying of the binary Al75Cu25 alloy (consisting of a-Al and Al2Cu) occurred, leading to the formation of a nanoporous (52 ± 10 nm) copper (Cu) structure. However, under the same condition dealloying only occurred partially to the α-Al phase in the ternary Al67Cu18Sn15 alloy due to the suppressing influence of Sn. The electrochemical dealloying of the ternary Al67Cu18Sn15 alloy was potential dependent and involved the concurrence of dealloying and realloying as evidenced by the formation of Cu6Sn5.