热带海洋气候下海水中氧化硫硫杆菌和假单胞菌协同作用对45钢腐蚀行为的影响

Synergistic Effect of Thiobacillus Thiooxidans and Pseudomonas sp.on Corrosion of 45 Steel in Tropic Seawater Condition

采用失重法、表面分析技术和电化学测试技术研究了45钢在硫杆菌和假单胞菌协同作用下的腐蚀行为。结果表明,与单种菌相比,腐蚀初期两种菌混合作用下45钢平均腐蚀速率受到明显抑制。随浸泡时间延长,30 d时混菌体系中电极电化学阻抗值较单菌体系减小,腐蚀电位降低,腐蚀电流密度增大,混菌逐渐加速了金属腐蚀。扫描电镜(SEM)分析结果表明,混合菌体系中45钢腐蚀产物膜存在大量裂纹且金属表面点蚀现象更为严重。

The microbe-induced corrosion of 45 steel in tropic seawaters was investigated in the presence of thiobacillus thiooxidans and pseudomonas sp.by means of mass loss method,surface analysis techniques and electrochemical measurement technology.The results showed that in comparison with the seawaters containing only one of the two bacterial species,the corrosion of 45 steel was evidently prohibited in seawaters with the presence of the two bacterial species at the initial stage,however after 30 d immersion 45 steel showed relatively smaller impedance,lower corrosion potential and higher corrosion current density.With the prolonging of immersion time,synergism of thiobacillus thiooxidans and pseudomonas sp.accelerated the corrosion of 45 steel,while a large numbers of cracks were observed in the corrosion product film formed on the surface of 45 steel and the pitting corrosion was rather severe.