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Electrochemical corrosion behaviour of Sn–Ag–Cu (SAC) eutectic alloy in a chloride containing environment
Author(s) -
Rosalbino F.,
Zanicchi G.,
Carlini R.,
Angelini E.,
Marazza R.
Publication year - 2012
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201005979
Subject(s) - eutectic system , materials science , metallurgy , corrosion , alloy , scanning electron microscope , dielectric spectroscopy , electron microprobe , chloride , electrochemistry , soldering , composite material , electrode , chemistry
The corrosion behaviour of the Sn 94.5 Ag 3.8 Cu 1.5 (SAC) eutectic alloy was investigated in 0.1 M NaCl solution by potentiodynamic polarization and impedance spectroscopy measurements and compared with that of the conventional Sn 73.9 Pb 23.1 eutectic solder employed for a long time in the packaging of microelectronic components and devices. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were used to characterize the SAC eutectic alloy prior to and after the electrochemical tests. The electrochemical results indicated that the Sn–Ag–Cu eutectic alloy exhibits better corrosion behaviour than the Sn–Pb eutectic solder in NaCl solution. The presence of a corrosion products layer constituted by tin oxy‐chloride was detected at the surface of both alloys investigated after the electrochemical tests. The better corrosion behaviour of SAC eutectic alloy compared to Sn–Pb eutectic solder is ascribed to the formation of a more compact surface film of corrosion products with improved protective properties owing to the presence of copper and silver, as revealed by EPMA.