The role of Zn precipitates and Cl− anions in pitting corrosion of Sn–Zn solder alloys

• DOI: 10.1016/j.corsci.2014.12.014
• Publication Date: 2014-12-24T04:47:53Z
• Authors: Jian-Chun Liu; SungWon Park; Shijo Nagao; Masaya Nogi; Hirotaka Koga; Ju-Sheng Ma; Gong Zhang; Katsuaki Suganuma
• Keywords: Pitting Corrosion

Abstract Electrochemical corrosion behavior of Sn–Zn solder alloys in aerated and quiescent 0.5 M NaCl solution was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques, aiming to assess the role of Zn precipitates and Cl− anions in pitting corrosion. The results reveal that increasing in Zn contents leads to increasing in pitting susceptibility, ascribed to the coarsening Zn precipitates with larger intergranular boundaries between Zn-rich precipitates and Sn matrix. The EIS results provide a quantitative description of the electrochemical interface behavior. The mechanism of pitting and the role of Cl− anions are discussed.