Investigation of anodic dissolution behaviour of intermetallic compound in Sn-3Ag-0.5Cu solder alloy by cyclic voltammetry

The purpose of this paper is to study the mechanism of electrochemical dissolution of SAC305 solder in mild acid solution.

Cyclic voltammetry (CV) was used to obtain electrochemical dissolution peaks followed by chronoamperometery (CA) to investigate the dissolution mechanism at each peak. Structural and microstructural characterization was performed to verify the CA analysis. Potentiodynamic polarization was performed afterwards to determine the corrosion potential of every phase in SAC305.

The early cycle of CV exhibits only dissolution peaks of β-Sn until intermetallic compound (IMC) peaks emerged at a later cycle. CA performed for 24 h at selected potentials reveals that β-Sn can be removed completely from the sample without disrupting the IMC network at a suitable potential. This was later verified by XRD and SEM. Potentiodynamic polarization determined the corrosion potential of IMC as −0.36 V.

The mechanism of anodic dissolution of SAC305 was studied and proposed.