电流密度对锡镀层结构及耐蚀性的影响

针对镀锡板合金层ATC(Alloy TinCouple)值受电流密度的影响较大这一情况 ,研究了电流密度对镀锡层、锡铁合金层及其耐蚀性的影响。采用扫描电镜 (SEM )观察了锡层以及软熔后镀锡板合金层的形貌 ,测试了镀锡板合金层的ATC值。结果表明 ,随着电流密度的增加 ,电沉积的锡晶粒度逐渐细化 ,合金层的晶粒度有变粗的趋势。此外 ,在实验过程中还发现 ,镀锡层的晶粒度越大 ,经软熔后生成的合金层晶粒度就越小 ,镀锡板耐蚀性也越差。并解释了出现这种现象的原因。

Effects of reflowing temperature and time on alloy layer of tinplate and its electrochemical behavior in 3.5%NaCl solution

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.