长距离输水管道电化学腐蚀行为研究

Electrochemical Corrosion Behavior of Long‑distance Water Distribution Pipeline

长距离输水管道在原水输送过程中存在管道腐蚀的风险,水泥砂浆内衬的脱落和前置预氧化都将影响管道的腐蚀过程,进而影响供水水质。通过扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、电化学工作站研究了长距离输水管道内壁的腐蚀形貌、腐蚀产物和腐蚀趋势。根据电化学测试结果,管道的腐蚀电位和电化学阻抗谱存在一定的变化规律,与输水时间、管道内衬和预氧化作用有关。水泥砂浆内衬影响了电化学腐蚀过程中材料的阻抗,对输水管道的腐蚀过程具有明显的抑制作用。预氧化作用显著改变了电化学腐蚀过程中电子的转移途径,影响了管道腐蚀过程。

There is a risk of pipeline corrosion in the process of long‑distance raw water transportation.The falling off of cement mortar lining and pre‑oxidation will affect the corrosion process of pipeline,and then affect the water quality of the distribution system.The corrosion morphology,corrosion products and corrosion tendency of the inner wall of long‑distance transmission main were analyzed by scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X‑ray diffractometer(XRD)and electrochemical workstation.According to the electrochemical test results,the corrosion potential and electrochemical impedance spectrum of the pipeline changed regularly,and the reason was related to the water delivery time,pipeline lining and pre‑oxidation.The cement mortar lining affected the material impedance in the electrochemical corrosion process,and had obvious inhibition effect on the corrosion process of water pipeline.The pre‑oxidation significantly changed the electron transfer pathway in the electrochemical corrosion process and affected the corrosion process of the pipeline.