316L不锈钢在Cl^(-)与SO_(4)^(2-)协同作用下的腐蚀行为研究

Synergistic Effect of Cl^(-)and SO_(4)^(2-)on the Corrosion Behavior of 316L Stainless Steel

为了降低腐蚀对海洋油气管道正常运行的危害,利用电化学试验中的交流阻抗技术以及循化极化技术研究了模拟南海海洋环境中Cl^(-)与SO_(4)^(2-)的协同作用对316L不锈钢腐蚀行为的影响,并结合扫描电子显微镜(SEM)对316L不锈钢表面的腐蚀形貌进行表征。结果表明,当SO_(4)^(2-)含量恒定时,Cl^(-)含量的升高会使容抗弧半径、极化电阻R_(p)以及点蚀电位E_(b)均降低,当Cl^(-)含量从0升至50 g/L时,316L不锈钢表面出现了明显的腐蚀情况。当Cl^(-)含量恒定时,SO_(4)^(2-)含量的升高会使容抗弧半径、R_(p)以及E_(b)值均减小,同时试件表面的腐蚀坑直径扩大,深度出现逐渐加深的情况。

In order to reduce the harm caused by corrosion to the normal operation of offshore oil and gas pipelines,the effects of the synergistic effect of Cl^(-)and SO_(4)^(2-)on the corrosion behavior of 316L stainless steel in the simulated South China Sea marine environment were investigated through the AC impedance technique and the cyclic polarization technique in electrochemical tests,and the corrosion morphology of 316L stainless steel surface was characterized by scanning electron microscopy(SEM).Results showed that when the SO_(4)^(2-)content was constant,an increase in Cl^(-)content could reduce the capacitive arc radius,polarization resistance R_(p) and pitting potential E_(b).As the Cl^(-)content increased from 0 to 50 g/L,significant corrosion was observed on the surface of 316L stainless steel.When the Cl^(-)content was constant,an increase in SO_(4)^(2-)content reduced the capacitive arc radius,R_(p) and E_(b) values.At the same time,the diameter of the corrosion pit on the surface of the specimen expanded,and the depth gradually deepened.