利用电化学阻抗谱、动电位扫描测试技术、扫描电镜以及表面能谱分析方法在湿度为10%的土壤中,研究了尿素(0.05mass%)对Q235钢微生物腐蚀的影响。结果表明,在接菌土壤中尿素对Q235钢腐蚀起加速作用,在灭菌土壤中尿素对Q235钢腐蚀起抑制作用。在接菌土壤中,试验前期阻抗谱上出现一个时间常数;5d后变为两个时间常数,试件表面已生成一层腐蚀产物。试验后期出现Warburg阻抗,表明此时电极反应受扩散控制,并且接菌土壤中试样的腐蚀产物中存在S元素。
The effect of urea (0.05 mass%) on the microbial corrosion of Q235 steel in soil with humidity at 10% was investigated by electrochemical impendence spectroscopy(EIS), polarization curve, scanning electron microscopy (SEM) and EDX. The results showed that urea accelerated carbon steel corrosion in soil with SRB yet prevented the corrosion of steel in sterile soil. The results of EIS showed that in inoculated soil only one time constant appeared in primary experimental period, two time constants appeared after 5 d and corrosion product formed on the steel surface. Warburg impedance was found at the later stage, which indicated that the process was controlled by concentration polarization. Sulfur element was detected in corrosion product of carbon steel in soil with SRB by EDX, which confirmed the effects of SRB on the corrosion.