Electrochemical Dealloying of a Ternary Al67Cu18Sn15 Alloy Compared with that of a Binary Al75Cu25 Alloy  

Wednesday, 27 May 2015: 16:40
Marquette (Hilton Chicago)
T. Song, M. Yan (RMIT University), Z. Shi, A. Atrens (The University of Queensland), and M. Qian (RMIT University)
Chemical de-alloying of binary Al75Cu25 (at.%) alloy (consisting of α-Al and Al2Cu) can be used to prepare bulk nanoporous Cu which shows promise for a number of applications. Chemical de-alloying of ternary Al67Cu18Sn15 alloy (consisting of α-Al(Cu), Al2Cu and β-Sn(Al,Cu)) can result in nanoporous Cu3Sn-Cu-Cu6Sn5composites where re-alloying between Cu atoms released from de-alloying and Sn atoms in the precursor is involved.  Compared to chemical de-alloying in toxic and expensive solutions, electrochemical de-alloying in neutral salt solution has the advanategs of being pollution-free, inexpensive and readily available.

This paper reports the results obtained from electrochemical dealloying of binary Al75Cu25 alloy and ternary Al67Cu18Sn15 alloy by using potentiodynamic polarization, cyclic voltammetry (CV) and potentiostatic polarization measurements. For electrochemical de-alloying of the binary Al75Cu25, the asynchronous dealloying behaviour and the final size of the porous structure are both potential dependent. For de-alloying of the ternary Al67Cu18Sn15, the concurrence of de-alloying and re-alloying is potential dependent. In addition, when the applied potential (-0.5 V) is below the critical potential of the Al2Cu phase (-0.41 V), electrochemical de-alloying of Al75Cu25 can be complete leading to nanoporous Cu (52 ± 10 nm). However, complete de-alloying does not occur to the ternary Al67Cu18Sn15 alloy under the same condition due most likely to the existence of β-Sn(Al,Cu) phase.