摘要
Cl-对镀锌钢在锈层环境中具有强烈的点蚀作用,易引起锌镀层的破坏,造成经济损失。探究其腐蚀机理和腐蚀过程有利于预防Cl-对镀锌钢的腐蚀。采用电化学阻抗谱(EIS)研究镀锌钢在锈层模拟溶液中的腐蚀行为,并应用电子扫描电镜(SEM)观察了镀锌钢在不同浸泡时间的腐蚀形貌。结果表明:镀锌钢在锈层模拟溶液中包含2个时间常数,分别对应锈层和界面的双电层;镀锌钢的阻抗谱随浸泡时间和锈层成分的变化而改变;在无Cl-的锈层溶液中,锈层可以提高镀锌钢的耐蚀性能,在含3.5%NaCl锈层模拟溶液中,Cl-逐步侵蚀并破坏了锈层结构,促使镀锌钢点蚀的发生。
The corrosion behavior of galvanized steel in rust-layer simulating solution containing Cl-was evaluated by means of electrochemical impedance spectroscopy. The morphology of the corroded steel surfaces after immersion in the simulating solution for different durations was observed with a scanning electron microscope. It was found that the corrosion process of the galvanized steel in the simulated solution involved two time constants which corresponded to the rust-layer and dielectric layer,respectively. The electrochemical impedance spectra of the galvanized steel varied with varying immersion time and rust-layer composition. Moreover,the rust layer was able to improve the corrosion resistance of the galvanized steel in the simulating solution without Cl-. However,in the rustlayer simulating solution of 3. 5% NaCl,Cl-gradually caused corrosion and structure destruction of the rust-layer thereby leading to pitting of the galvanized steel.
出处
《材料保护》
CAS
CSCD
北大核心
2013年第11期24-28,6,共5页
Materials Protection
基金
国家自然科学基金(41076046)资助
