通过对比25钢在自然海水和无菌海水中的腐蚀行为, 研究了微生物单因素对25钢腐蚀行为的影响. 结果表明, 微生物对25钢的腐蚀有显著影响, 微生物对25钢平均腐蚀速率的影响与微生物种类和含量密切相关. 锈层中的微生物主要由假单胞菌、弧菌、铁细菌、硫杆菌和硫酸盐还原菌组成, 浸泡365 d时还出现大量的黄杆菌. 其中好氧菌、兼性厌氧菌和厌氧菌的含量均随浸泡时间规律性变化, 这也导致在不同浸泡时间下微生物的作用及其作用机理的不同.

Biological elements have a significant impact on lifetime prediction of marine carbon steel facilities. Microbe can produce pitting, crevice corrosion, selective dealloying and stress–oriented hydrogen–induced cracking, which accelerate both localized and average corrosion rates of carbon steel.
The formation of microbe films can also reduce the corrosion rate of 25 steel through inhibition of oxygen diffusion and depletion of oxygen in the electrolyte and metal/solution interface. The research on the single effect of microbe on the corrosion behaviors of metal is insufficient up to now. In this work, the single effect of microbe on the corrosion behaviors of 25 steel was studied by comparing the corrosion behaviors of the carbon steel in natural seawater and in serile seawater. The results show that in most of mmerging periods, the bacterial activity at the interface accelerated the average corrosion rate of 25 steel. When the corrosion time was 365 d, the average corrosion rate of 25 steel immersed in natural seawater was 2.6 times that in sterile seawater. However, when the corrosion time was 28 d, the biofilms inhibited the corrosion of 25 steel. The species and contents of microbes significantly influenced the corrosion behavior of 25 steel. The microbes in the corrosion product mainly consisted of pseudomonas, vibrio, crenothrixandleptothrix, thiobacillus and sulfate–reducing bacteria. When the corrosion time was 365 d, flavobacterium also existed in the corrosion product. The contents of aerobe, facultative anaerobe and anaerobe reached the maximum vale when the corrosion time was 28, 91 and 184 d, respectively. The regular change of the contents of microbes with the immerging time led to the different microbe corrosion mechanisms of 25 steel.