Effects of reflowing temperature and time on alloy layer of tinplate and its electrochemical behavior in 3.5% NaCl solution
(1. R&D Centre of Wuhan Iron and Steel Co., Wuhan 430080, China;
2. Department of Chemistry, Zhejiang University, Hangzhou 310027, China;
3. State Key Laboratory for Corrosion and Protection, Shenyang 110015, China)
2. Department of Chemistry, Zhejiang University, Hangzhou 310027, China;
3. State Key Laboratory for Corrosion and Protection, Shenyang 110015, China)
Abstract: Effects of reflowing temperature and time on the alloy layer of tinplate and its electrochemical behavior in 3.5% NaCl solution were investigated by electrochemical measurements and surface characterization. It is found that the amount of alloy layer increases with the increase of reflowing temperature and time. Then the corrosion potential of detinned tinplate shifts positively and the corrosion rate decreases. After being coupled with tin, the detinned tinplate acts as cathode and tin acts as anode initially. However, after being exposed for some time, the potential shifts of both detinned tinplate and tin reverse the polarity of the coupling system. The galvanic current density decreases with the increase of reflowing temperature and time.
Key words: tinplate; alloy layer; reflowing process; galvanic corrosion