Insight into influence of temperature on electrochemical corrosion behavior of SAC305 tin-based solder alloy in NaCl solution

In this work, the corrosion behavior of Sn-3.0Ag-0.5Cu (SAC305) tin-based solder alloy at relatively lower temperature is firstly investigated using electrochemical methods. Effects of temperature and sodium chloride (NaCl) concentration on the corrosion behavior are discussed in detail. Results indicate that the anti-corrosion ability decreased when temperature rising at the same NaCl concentration. On the other hand, the corrosion resistance of SAC305 alloy increased with a lager chloride concentration at relatively lower temperatures, whereas the opposite conclusion was reached at high temperatures. X-ray diffraction meter (XRD) and scanning electron micrograph (SEM) studies revealed that at low temperature, chloride ion reacted with SAC305 alloy forming insoluble basic tin chloride with tin alloy, which covered on metal surface and inhibited corrosion process. However, this process is disrupted at relatively higher temperatures due to chloride ions attacked the tin-oxide protective film on the metal surface, further promoting pitting corrosion. Relevant mechanism has been proposed to clarify the roles of temperature and NaCl concentration in the corrosion process for SAC305 alloy in NaCl solution.