20钢在CO2/水两相塞状流条件下的初期腐蚀行为

Corrosion Behavior of 20 Steel at Initial Stage under CO2/H2O Two-phase Plug Flow Condition

通过失重法、SEM、X射线光电子能谱分析(XPS)等方法研究了20钢在CO2/水气液两相塞状流条件下初始阶段的腐蚀行为。结果表明:腐蚀过程初期存在明显的腐蚀速率减速过渡阶段,不同CO2压力下腐蚀速率的差异随着腐蚀时间的延长而逐渐减小;腐蚀产物的沉淀从管壁表面的缺陷处或晶界处开始,进而向周围扩展直至腐蚀产物在管壁表面全部覆盖,管壁表面最初形成针状腐蚀产物层,而后在其表面逐渐形成絮凝腐蚀产物;腐蚀产物层中的主要组成相有Fe3C、FeCO3、FeOOH和Fe3O4。

The corrosion behavior of 20 steel at initial stage under CO2/H2O gas-liquid two-phase plug flow conditions was studied by wear mass loss method,SEM and XPS.The results indicate that there is an obvious deceleration transition of corrosion rate at the early stage of corrosion process.The difference of corrosion rate under different CO2 pressures decreases with the increase of corrosion time.The precipitation of corrosion products starts from the defects area of the pipe wall surface or the crystal interface,and the corrosion products spread until it is completely covered on the surface of pipe wall.The corrosion products grow into the flocculated corrosion products on the surface covered with acicular corrosion products layer preliminary with the corrosion time extending.The main phases of the corrosion products layer are Fe3C,FeCO3,FeOOH and Fe3O4.