海水及培养基中假单胞菌对45钢电化学腐蚀行为的影响

采用微生物分析、失重法、自腐蚀电位、EIS、动电位极化曲线和SEM等手段对比研究了45钢在无菌海水、无菌培养基、假单胞菌海水和假单胞菌培养基4种不同环境下的腐蚀行为。结果表明：腐蚀初期假单胞菌及培养基均对45钢有缓蚀作用。但随着时间的推移，假单胞菌新陈代谢作用引起了氧浓差腐蚀，且其代谢产物中的碱及铁载体的局部堆积加速了45钢的腐蚀。培养基环境对微生物腐蚀有促进作用。

Effect of Pseudomonas on Electrochemical Corrosion Behavior of S45C Steel in Seawater and a Culture Medium

The effect of pseudomonas on electrochemical corrosion behavior of 45 carbon steel was comparatively studied in seawater and a culture medium with and without the presence of pseudomonas, by means of microbiological analysis, weight loss method, corrosion potential measurements, EIS, potentialdynamic polarization curve and SEM, etc. The results showed that both pseudomonas and the medium exhibited inhibiting effect for the steel. Organic compounds in the medium could be absorbed onto steel surface and change the cathodic and anodic reaction of the corrosion process. The mechanisms of the effect of pseudomonas on corrosion behavior varied with immersing time: at the initial stage, the dissolved oxygen concentration in the environment was reduced by bacteria metabolism, which slowed down the corrosion rate. By prolonging the corrosion time, however, the partly quantitative accumulation of pseudomonas metabolites, which include alkalinesubstances and siderophores, finally accelerated the corrosion rate of the steel. Rich nutritious contents in the medium could promote mass propagation of pseudomonas, thus accelerated the influence of pseudomonas on corrosion behavior.