接地镀锌圆钢土壤腐蚀原位监测方法的对比

Comparison of In-Situ Monitoring Methods for Soil Corrosion of Grounding Galvanized Round Steel

分别采用失重法、护环电极法和电化学阻抗法研究了埋设在武汉土壤环境中接地镀锌圆钢的腐蚀行为,对比了各监测技术的相关性。结果表明:埋设1~2月时,试样的腐蚀速率较大,随后逐渐减小;试样表面镀锌层溶解不均匀,埋设3月后残留的镀锌层已很少;电化学阻抗法测量的极化电阻与腐蚀速率之间的相关性较好,但由于镀锌层与Q235钢基体所形成电偶的影响,不能按传统方法直接计算得到腐蚀速率;在合适条件下,现场采用护环电极法得到的极化电阻与电化学阻抗谱法得到的极化电阻具有可比性。

The corrosion behavior of grounding galvanized round steel buried in soil environment of Wuhan was studied by weight loss method,guard ring electrode method and electrochemical impedance method,and the correlation of the monitoring techniques was compared.The results showed that the corrosion rate of the sample was large when buried for 1-2 months,and then gradually decreased.The dissolution of the zinc coating was uneven,and there was little residual zinc coating on the sample surface after 3 months of burial.The polarization resistance measured by electrochemical impedance method displayed a good correlation with corrosion rate.However,due to the influence of the galvanic couple between zinc coating and Q235 steel substrate,the corrosion rate cannot be directly calculated using traditional method.Under appropriate conditions,the polarization resistance obtained by guard ring electrode method could be comparable to that measured with electrochemical impedance method.