硫酸盐还原菌对Q235钢缝隙腐蚀行为影响

INFLUENCE OF SULPHATE REDUCING BACTERIA ON CREVICE CORROSION BEHAVIOR OF Q235 STEEL

应用矩形缝隙模拟装置,研究Q235钢在土壤浸出液中有无硫酸盐还原菌条件下,缝隙厚度为0.5mm时的缝隙腐蚀行为。电化学阻抗谱测试结果表明,随着实验时间的延长,Q235钢在有菌溶液中的容抗弧半径小于相同时期在无菌溶液中的容抗弧;Q235钢在有菌溶液中的腐蚀速率大于无菌溶液。硫酸盐还原菌促进了Q235钢在溶液中的腐蚀。同一时期,随着缝口距离的增加,有菌溶液及无菌溶液中的容抗弧都先增大后减小,其中在有菌溶液中的容抗弧较小,腐蚀速率比无菌溶液中的大。

The crevice corrosion mechanism of Q235 carbon steel in soil leaching solution was studied,using a rectangle blind side device.The width of its aperture is 0.5 mm.The soil leaching solution was prepared in two groups for comparison：with SRB（sulphate reducing bacteria） and without SRB,both being investigated separately.The corrosion behavior of the steel was studied by electrochemical,microbiological and surface analysis methods.Electrochemical impedance spectroscopy（EIS） was measured.The results show that,the capacitive arc of the steel in bacteria containing solution is smaller than that in the aseptic solution at the same stage and the corrosion rate in bacteria containing solution is smaller than that in the aseptic solution. The results declare that SRB promotes the corrosion of the steel.At the same time,along with the aperture increasing,the capacitive arc increases at first,then decreases,and the corrosion rate of the bacteria containing solution is greater.