流动对316L/2205和431/2205不锈钢在3.5% NaCl溶液中电偶腐蚀的影响
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摘要
采用动电位极化、电偶电流、腐蚀形貌分析等方法研究了在3.5%NaCl溶液中介质流动对316L/2205和431/2205不锈钢电偶腐蚀的影响。与42CrMo/316L偶对对比发现316L/2205、431/2205和42CrMo/316L电偶中316L、431和42CrMo均作为阳极,其腐蚀受到加速,三种偶对的电偶腐蚀倾向大小为:316L/2205<431/2205<42CrMo/316L;电偶电流测量发现介质流动可以增大三种偶对的电偶电流,偶对431/2205存在电偶电流和电位暂态峰。腐蚀形貌分析发现,静止条件下316L、2205和431不锈钢没有明显的腐蚀,42CrMo钢表面覆盖锈蚀层;流动条件下431不锈钢表面点蚀坑形成并附着腐蚀产物,42CrMo表面局部形成锈蚀层,结合形貌分析认为,431/2205偶对中电流暂态峰的出现与蚀坑中锈蚀层的形成有关。
Effect of flowing on galvanic corrosion of 316L/2205 and 431/2205 couples in 3.5% NaCl solution was investigated by potentiodynamic polarization,galvanic current and corrosion morphology analyses.The galvanic behavior of these couples was compared with that of 42CrMo/316 Lcouple.The results showed that 316 L,431and42CrMo were anode,respectively.The galvanic corrosion tendency of these couples was shown as follows:316L/2205< 431/2205< 42CrMo/316 L.The galvanic current measurement revealed that flowing increased the galvanic current.Oscillation peaks in both galvanic potential and current curves were observed under flowing condition for the431/2205 couple.Corrosion morphology analyses indicated that there were no obvious corrosion on 316 L,431and2205stainless steels in the static solution and a rust layer formed on the surface of 42 CrMo steel.Under flowing condition,pits covered with rust on 431 stainless steel were observed,surface of 42 CrMo steel was covered with corrosion products.It is considered that the oscillation peaks of current density for 431/2205 couples is possibly attributed to the formation of rust on the pits under flowing condition.
Effect of flowing on galvanic corrosion of 316L/2205 and 431/2205 couples in 3.5% NaCl solution was investigated by potentiodynamic polarization,galvanic current and corrosion morphology analyses.The galvanic behavior of these couples was compared with that of 42CrMo/316 Lcouple.The results showed that 316 L,431and42CrMo were anode,respectively.The galvanic corrosion tendency of these couples was shown as follows:316L/2205< 431/2205< 42CrMo/316 L.The galvanic current measurement revealed that flowing increased the galvanic current.Oscillation peaks in both galvanic potential and current curves were observed under flowing condition for the431/2205 couple.Corrosion morphology analyses indicated that there were no obvious corrosion on 316 L,431and2205stainless steels in the static solution and a rust layer formed on the surface of 42 CrMo steel.Under flowing condition,pits covered with rust on 431 stainless steel were observed,surface of 42 CrMo steel was covered with corrosion products.It is considered that the oscillation peaks of current density for 431/2205 couples is possibly attributed to the formation of rust on the pits under flowing condition.
引文
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[3]李君,董超芳,李晓刚,等.Q235-304L电偶对在Na2S溶液中的电偶腐蚀行为研究[J].中国腐蚀与防护学报,2006,26(5):308-314.
[4]ASTM G82 Standard guide for development and use of a galvanic series for predicting galvanic corrosion performance[S].
[5]SANCHEZ-TOVAR R,MONTANES M T,GARCIAANTON J.Contribution of the flowing conditions to the galvanic corrosion of the copper/AISI 316Lcoupling in highly concentrated LiBr solutions[J].Corros Sci,2013,68:91-100.
[6]OLSSON C O A,LANDOLT D.Passive films on stainless steels-chemistry,structure and growth[J].Electrochimica Acta,2003,48(9):1093-1104.
[7]WHARTON J A,WOOD R J K.Influence of flow conditions on the corrosion of AISI 304Lstainless steel[J].Wear 2004,256:525-536.
[8]CHENG C Q,ZHAO J,CAO T S,et al.Facile chromaticity approach for the inspection of passive films on austeniticstainless steel[J].Corr Sci,2013,70:235-242.
[9]SASSKI K,BURSTEIN G T.Erosion-corrosion of stainless steel under impingement by a fluid jet[J].Corr Sci,2007,49(1):92-102.
[10]DONG Z H,SHI W,GUO X P.Initiation and repassivation of pitting corrosion of carbon steel in carbonatedconcrete pore solution[J].Corr Sci,2011,53:1322-1330.
[11]HU Q,ZHANG G,QIU Y,et al.The crevice corrosion behaviour of stainless steel in sodium chloride solution[J].Corr Sci,2011,53:4065-4072.