论文部分内容阅读
采用模拟大气腐蚀系统,利用OM,SEM,XRD和局部交流阻抗测试(LEIS)等研究了20碳钢在高湿度SO_2大气环境中腐蚀产物的形态变化和生长过程.结果表明,20碳钢表面首先生成Fe(OH)_2膜,Fe(OH)_2膜在酸性介质中发生破裂形成头部为绿色的丝状物,丝状物沿晶界腐蚀并向铁素体内生长;空气中SO_2,O_2和H_2O不断进入破裂的Fe(OH)_2膜内,导致Fe不断溶解并形成FeSO_4巢穴,FeSO_4与O_2和H_2O作用在巢穴内生成FeOOH堆积物,最后形成胞状腐蚀产物.随腐蚀时间的延长,胞状腐蚀产物增多,锈层阻抗增加,腐蚀产物层厚度不均匀;继续腐蚀,腐蚀产物变得均匀致密SO_2含量越高,胞状物增加越快.
The morphology and growth process of corrosion products of 20-carbon steel in high-humidity SO 2 atmosphere were studied by using simulated atmospheric corrosion system and OM, SEM, XRD and local impedance test (LEIS). The results show that the surface of 20- Fe (OH) _2 film was formed, and the Fe (OH) _2 film was cracked in acidic medium to form a green filament. The filament corroded along the grain boundary and grew into the ferrite. SO_2, O_2 and H_2O continuously entered into the ruptured Fe (OH) _2 membrane, resulting in the continuous dissolution of Fe and the formation of FeSO_4 nests, FeSO_4 and O_2 and H_2O in the nest to generate FeOOH deposits, and finally the formation of cellular corrosion products. With the extension of the corrosion time, The product increased, the resistance of the rust layer increased, the thickness of the corrosion product layer was not uniform, and the corrosion products became uniform and dense due to continued corrosion. The higher the content of SO 2, the faster the cell material increased.