三种典型菌种复合环境下2A12铝合金的腐蚀行为研究

目的研究由硫酸盐还原菌、铁细菌、脱氮硫杆菌三种典型菌种复合环境下飞机常用材料2A12铝合金的腐蚀行为。方法实验室内菌种培养再现飞机内部封闭部位复合菌种环境,通过电化学交流阻抗、动电位极化曲线及体视显微镜对2A12铝合金的电化学性能和宏微观形貌进行表征,揭示2A12铝合金在复合菌落下腐蚀程度随时间和复合菌落的影响。结果与空白试验对比发现,复合菌种环境下,2A12铝合金表面出现明显裂缝与腐蚀坑,部分腐蚀孔隙中有腐蚀产物与微生物膜的残留。在复合菌液中,腐蚀电流密度最小为1.12×10~(-6)A/cm~2,最大为2.43×10~(-6)A/cm~2。结论三种典型菌种复合环境下,2A12铝合金的腐蚀速率是对照组的62.79倍,腐蚀深度是对照组的3.41倍,复合菌落对2A12铝合金的腐蚀影响规律与菌落种类、代谢特点及多种菌落间相互作用有关。

Corrosion Behavior of 2A12 Aluminum Alloy in Combined Environment of Three Typical Bacterial Species

The paper aims to study the corrosion behavior of 2A12 aluminum alloy, a common material for aircraft, under the compound environment with three typical strains, namely, sulfate reducing bacteria, iron bacteria and thiobacterium denitrifides. The compound bacteria environment in the internal closed parts of airplane was reproduced and the electrochemical properties and macro microstructure of 2A12 aluminum alloy were characterized through electrochemical impedance, potentiodynamic polarization curve and stered microscope, revealing the 2A12 aluminum alloy corrosion degree in conformity with colony and the effect of compound colony over time. Compared with the blank test, it was found that there were obvious cracks and corrosion pits on the surface of 2A12 aluminum alloy under the compound bacteria environment, and some corrosion products and microbial film residues were found in the corrosion pores. In the compound bacterial solution, the minimum corrosion current density was 1.12×10-6 A/cm2, and the maximum was 2.43×10-6 A/cm2. The corrosion rate of 2A12 aluminum alloy is 62.79 times as high as that of the control group and the corrosion depth is 3.41 times as high as that of the control group under the combined environment of three typical bacterial species. The rule of the influence of compound colonies on the corrosion of 2A12 aluminum alloy is related to the types of colonies, metabolic characteristics and the interaction among various colonies.