X80管线钢在洛阳土壤中的电化学腐蚀行为研究

Study on Electrochemical Corrosion Behavior of X80 Pipeline Steel in Luoyang Soil with Saturated Water

采用电化学测试、SEM及EDS微观分析等方法,对X80管线钢在洛阳水饱和土壤中的电化学腐蚀行为进行了研究。结果表明,在洛阳水饱和土壤中,随腐蚀时间延长,X80钢腐蚀趋势和腐蚀速率均明显增大,局部腐蚀面积和深度不断增加,腐蚀程度加剧,腐蚀机理为氧浓差腐蚀电池和局部腐蚀自催化效应,腐蚀速度主要受氧扩散过程控制;EIS图谱具有双容抗弧与Warburg阻抗特征,电荷传递和扩散传质的阻力随时间越来越大,而结合层电阻明显减小,腐蚀产物主要为铁的氧化物、硫化物和土壤中盐类的混合物。

The electrochemical corrosion behavior of X80 pipeline steel was investigated in luoyang soil with saturated water using electrochemical measurement,scanning electron microscopy（SEM） and energy dispersive spectrum（EDS） analysis.The results show that the corrosion tendency and corrosion rate of X80 steel significantly increases,pitting depth and area increase continuously,the degree of corrosion aggravates,the corrosion mechanism is oxygen-concentration corrosion cell and localized corrosion autocatalysis effect,the corrosion rate is controlled by oxygen diffusion process.The characters of double capacitive reactance arcs and Warburg impedance could be found in electrochemical impedance spectra,the resistance of charge transfering and diffusion mass transfering in pitting becomes bigger and bigger,the resistance of binding layer significantly decreases.The corrosion product is basically the mixture of iron oxides,iron sulfides and salts in soil.