摘要
通过动电位极化、电化学阻抗和浸泡失重等方法,考察了X80钢在含有不同浓度CO2的库尔勒土壤模拟溶液中的腐蚀行为,采用扫描电镜对腐蚀形貌进行了观察。结果表明:当土壤模拟溶液中通入的CO2和N2的体积比分别为CO2∶N2=10∶90,20∶80和30∶70时,不同浓度的CO2都促进了X80钢在库尔勒土壤介质中的腐蚀速率。这主要是因为通入的CO2使模拟溶液的p H值显著下降,导致溶液变为酸性,腐蚀过程由原来的氧控制变为了析氢反应为主,阴极反应过程进一步加快。另一方面,溶液中存在的CO2增加了X80钢表面腐蚀产物膜的缺陷,对基体的保护作用下降。这些因素导致X80钢的腐蚀速率增大。
The influence of CO2 concentration on corrosion behavior of X80 pipeline steel in a simulated soil solution of Ku'erle area was investigated by potentiodynamic polarization curves, electrochemical impedance spectroscopy(EIS) and weight loss, and then the corroded surface morphology was observed using scanning electron microscopy(SEM). It was found that the corrosion rate of X80 steel increased with increasing the volume proportion of CO2 to N2in the aerated gaseous flow in the simulated solution. It follows that the p H value of the solution could be decreased from9.1 to 4.7 by inducing CO2; therewith the control step of cathodic process of steel corrosion was transferred from the oxygen reduction to hydrogen reduction, which then resulted in the increase of cathodic reaction rate. On the other hand, defects in the corrosion product film also increased due to the presence of CO2, thus exhibited lower protectiveness to X80 steel. The above two factors all promote the corrosion of X80 steel in the simulated solution.
出处
《腐蚀科学与防护技术》
CAS
CSCD
北大核心
2014年第6期529-532,共4页
Corrosion Science and Protection Technology
基金
辽宁省教育厅一般科学研究项目(L2012127)资助
