微生物影响下不锈钢焊缝的腐蚀机理

从水化学、材料表面特征及微生物种类3方面研究了不锈钢304O焊缝微生物腐蚀，用微生物腐蚀实验台测量了试样的开路，结果表明，在有微生物的水介质中的试样产生了电位升，而无微生物的水介质中的试样没有电位升，当微生物腐蚀发生时，电位急剧下降，在几种焊接缺陷中，金黄色回火膜对微生物腐蚀最敏感，研究表明，当水中Cl^-含量较高时，容易发生微生物腐蚀，用SEM对点蚀坑进行观察，并用EDXA分析了部分腐蚀产物，微生物 腐蚀试样与未腐蚀试样表面最明显的区别是Mn-Fe氧化菌的数量。

MICROBIOLOGICALLY INFLUENCED CORROSION ON WELD OF STAINLESS STEEL

The influence of welding defects, water compositions and microbiological species on MIC (microbiologically influenced corrosion) was studied. The open circuit potential (OCP) was measured during MIC test. It was found that OCP shifted to a higher level when the system was inoculated with bacteria and it decreased dramatically when MIC started. As a contrast, the OCP kept stable in the system without bacteria. Among a series of welding defects,the golden heat tint was found to be the most susceptible to MIC. It was found that pitting corrosion happened when Cl- content in the water was high. The tubercles over pitting were observed with SAM. Some elements inside of the tubercles were measured with EDXA. Microbiological analysis of a corroded and a non- corroded samples revealed the significant difference to be number of the Mn-Fe oxidizing bacteria between them.