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采用电化学阻抗、动电位极化及微观观察法,对比了有、无硫酸盐还原菌(SRB)的情况下X70管线钢在近中性p H溶液(NS4)中的腐蚀行为,研究了SRB生长周期对X70钢腐蚀行为的影响。结果表明:X70钢在无菌溶液中腐蚀速率随时间增加呈单一增大的趋势。SRB在NS4溶液中的生长周期分为对数繁殖期(1~3 d),稳定生长期(4~7 d)和衰亡期(7~14 d)3个阶段。SRB对X70钢在NS4溶液中腐蚀速率的影响与其在溶液中生长规律有关:当SRB处于对数繁殖期和稳定期时,X70钢表面覆盖一层致密的生物膜,对钢起到了保护作用,此时X70钢的腐蚀速率比无菌条件下低;当SRB进入衰亡期,X70钢腐蚀的程度比无菌介质中严重,钢表面腐蚀产物逐渐增多,生物膜出现破裂,腐蚀速率增大。
The corrosion behavior of X70 pipeline steel in near-neutral p H solution (NS4) with and without sulfate-reducing bacteria (SRB) was compared by electrochemical impedance, potentiodynamic polarization and microscopic observation. The effects of SRB Effect of Growth Cycle on Corrosion Behavior of X70 Steel. The results show that the corrosion rate of X70 steel in sterile solution increases with the increase of time. The growth cycle of SRB in NS4 solution was divided into three stages: logarithmic phase (1-3 days), stable phase (4-7 days) and decay phase (7-14 days). The effect of SRB on the corrosion rate of X70 steel in NS4 solution is related to its growth pattern in solution. When SRB is in logarithmic growth phase and stable period, the surface of X70 steel is covered with a dense biofilm that plays a protective role in steel. At this time, the corrosion rate of X70 steel was lower than that under aseptic conditions. When SRB entered the decay period, the corrosion rate of X70 steel was more serious than that in aseptic medium, the corrosion products of steel surface increased gradually, the biofilm ruptured and the corrosion rate increased.