Effect of SO2 Content on Corrosion Behavior of High-strength Steel E690 in Polluted Marine Atmosphere

Hongchi MA
2016 Journal of Mechanical Engineering  
摘要:采用干湿交替腐蚀试验方法,结合电化学测试、锈层截面和腐蚀产物 X 射线衍射(X-ray diffraction,XRD)分析,研究 Cr 合金元素在内锈层中的富集,大大促进锈层的致密化,使均匀腐蚀速率逐渐减低,并促进锈层底部点蚀坑的生长。随着 模拟溶液中 NaHSO 3 浓度的增加,E690 钢在 60 d 内的平均腐蚀速率逐渐增加,当 NaHSO 3 浓度达到 0.03 mol/L 时,又出现 一定程度的降低;同时,锈层底部的点蚀坑随 NaHSO 3 浓度的增加显著长大。 关键词:E690 钢;干湿交替腐蚀;SO 2 ;污染海洋大气;锈层 Abstract:Dry/wet cyclic corrosion tests, combined with electrochemical measurements, cross-sectional morphology observation of rust layer and X-ray diffraction (XRD) analysis of corrosion products, are conducted to
more » ... ate the effect of SO 2 content on corrosion behaviors of E690 steel in simulated polluted marine atmosphere. The results show that SO 2 can change the electrochemical corrosion mechanism of E690 steel in marine atmosphere. The anodic branch is transformed from weak passivation to active dissolution feature while the cathodic branch is transformed from oxygen diffusion process to mixed-control of oxygen reduction reaction and hydrogen evolution reaction, leading to great acceleration of anodic and cathodic reaction process. Meanwhile, SO 2 can significantly promote the formation of α-FeOOH and enrichment of Nickel and Chromium in the inner rust layer, resulting in the decrease of uniform corrosion rate and growth of corrosion pits under the rust layer. With the increase of NaHSO 3 concentration, the average corrosion rate of E690 steel within 60 days in simulated marine atmosphere is increased accordingly, and then appears a certain degree of decline when the concentration of NaHSO 3 obtained 0.03 mol/L. Meanwhile, the corrosion pits under the rust layer grew up significantly with the increase of NaHSO 3 concentration. Key words:E690 steel;dry/ wet cyclic corrosion;sulfur dioxide;polluted marine atmosphere;rust layer
doi:10.3901/jme.2016.16.033 fatcat:z53h3rcv6ngixhqgreykgzoqpm