通过中性盐雾试验(NSST)和电化学试验对DX56热镀锌钢板及其合金化钢板进行耐腐蚀性能试验,得到了GI板和GA板产生红锈面积和失重随时间的变化关系,以及GI板和GA板在2% NaCl溶液中的Tafel极化曲线和电化学阻抗图谱(EIS).NSST结果显示,GA板出现红锈的时间明显早于GI板,且红锈面积增加迅速,但GA板的失重明显小于GI板.Tafel极化曲线表明GI板和GA板在2% NaCl溶液中均表现为活化溶解,未出现钝化,GA板的自腐蚀电位明显较GI板正移,在相同阳极电位下,GA板的极化电流密度小于GI板；由EIS及其等效电路拟合结果得到GA板镀层的电荷转移电阻明显大于GI板.试验结果表明GA板比GI板具有更好的耐腐蚀性能,用失重法衡量GA板的耐腐蚀性能比用红锈出现的时间及红锈面积增长速度更准确.

Neutral salt spray test(NSST) and electrochemical test of DX56 were performed to study its corrosion properties.The changes of red rust area and weightloss of GI sheet and GA sheet as well as the Tafel polarization curves and electrochemical impedance spectroscopy (EIS) in 2 wt.% NaCl solution were obtained.NSST showed that the red rust on GA sheet occurred much earlier than GI sheet and the weightloss of GA sheet was less than GI sheet obviously.Tafel curves showed that both of GI sheet and GA sheet′s corrosion behaved to be activated dissolution without passivation and that GA sheet′s corrosion potential moved to positive direction in contrast with GI sheet′s.At the same anodic potential,GA sheet′s polarization current density was obviously lower than GI sheet′s.It was obtained from the EIS diagrams and the simulation results of their equivalent circuits that the charge transfer resistance of GA sheet was obviously higher than that of GI sheet.It is shown that GA sheet has better corrosion resistance than GI sheet and using weightloss to judge the corrosion resistance of GA sheet is more accurate than using the time for red rust to occur or the growth rate of red rust area.