NaClO对再生水球墨铸铁管道腐蚀行为的影响

Effect of Sodium Hypochlorite on Corrosion Behavior of Ductile Cast Iron Pipe in Reclaimed Water

采用失重法和电化学方法研究再生水投加NaClO消毒剂对球墨铸铁管道腐蚀行为的影响,并结合扫描电镜(SEM)对腐蚀产物的结构和形貌进行测定,探讨了其腐蚀机理。结果表明:NaClO的投加会增大球墨铸铁管道的腐蚀速率,但是,在腐蚀初期(5d内)其影响比较微弱,在腐蚀稳定期(5d后),其促进作用比较明显;加氯环境下,ClO^-最终被还原为Cl^-,腐蚀垢层由于Cl^-的破坏作用变得疏松多孔进而降低了其对于管道的保护作用;NaClO的投加导致电化学阻抗谱半径明显减小,并且其主要通过影响电化学的阴极反应。

Effect of sodium hypochlorite（Na Cl O） on the corrosion of ductile cast iron pipe in reclaimed water was studied by means of mass loss method, electrochemical methods（polarization curve and electrochemical impedance spectroscopy（EIS）） and SEM. Results show that：（1） Sodium hypochlorite increased the corrosion rate of ductile cast iron, which had a relatively weak impact on the corrosion during the initial period（5-15 d） and then played a role as accelerator during the stable period（5-15 d）;（2） Hypochlorite was finally reduced to chloride ions by chlorination process, which made the corrosion layer become porous;（3） Due to the presence of Na Cl O,the radius of electrochemical impedance spectroscopy reduced seriously, which implied that Na Cl O involved in the cathodic reaction of electrochemical corrosion process thus affected the corrosion behavior of ductile cast iron.