College of Civil Engineering, Taiyuan University of Technology

【目的】探究毛细作用对X70钢在土壤中腐蚀的规律。【方法】基于非饱和土与电化学阻抗谱理论,结合极化曲线技术(PC)、电化学阻抗技术(EIS)、扫描电子显微镜(SEM)等测试方法,在室内条件下通过一维土柱仪的模拟试验研究了粉质黏土中毛细作用对X70钢的电化学腐蚀行为。【结果】试验结果表明,毛细作用对X70钢的电化学腐蚀行为具有一定的影响,即在土柱12cm、27cm高度位置处的钢片腐蚀速率随埋置时间先增大后减小,在土柱42cm、57cm高度位置处的钢片腐蚀速率随埋置时间先减小后增大;毛细水在粉质黏土中的上升速率满足先快后慢的规律。【结论】X70钢片表面的腐蚀类型以点蚀为主,且腐蚀产物表面伴有较深较宽的裂缝,随着土样高度的增加,腐蚀程度降低,整体上腐蚀坑的大小和数目均呈现出减小趋势;毛细水上升过程中,当X70钢片处于固-液-气三相界面(TPB)时,其腐蚀速率最快,腐蚀程度最严重。

【Purposes】 It is important to explore the law of capillary action on the corrosion of X70 steel in soil. 【Methods】 On the basis of the theory of unsaturated soil and electrochemical impedance spectroscopy, combined with polarization curve technology, electrochemical imped- ance technology, scanning electron microscopy, and other test methods, the electrochemical cor- rosion behavior of X70 steel caused by capillarity in silty clay was investigated through the simu- lation test of one-dimensional soil column instrument under indoor conditions. 【Findings】 The test results show that capillary action has a certain influence on the electrochemical corrosion be- havior of X70 steel, that is, the corrosion rates of steel sheet at the height of and cm of soil column first increase and then decrease with embedding time, and the corrosion rate of steel sheet at the height of and cm of soil column first decrease and then increase with embedding time; The rising rate of capillary water in silty clay meets the law of being first fast and then slow. 【Conclusions】 The corrosion type of X70 steel sheet surface is mainly pitting corrosion, and the corrosion product surface is accompanied by deep and wide cracks. With the increase of soil sample height, the corrosion degree decreases, and the size and number of corrosion pits show a decreasing trend on the whole. In the rising process of capillary water, when X70 steel sheet is at the solid-liquid-gas three-phase boundary, its corrosion rate is the fastest and the corrosion degree is the most serious.

何斌,梁登钦,兰茹蒙,等.非饱和粉质黏土中毛细作用对X70钢电化学腐蚀行为的影响[J].太原理工大学学报,2024,55(5):865-873.

HE Bin,LIANG Dengqin,LAN Rumeng,et al.Effect of capillarity in unsaturated silty clay on electrochemical corrosion behavior of X70 steel[J].Journal of Taiyuan University of Technology,2024,55(5):865-873.