2205-Cu抗菌双相不锈钢在硝酸盐还原菌环境中的微生物腐蚀行为研究

Due to the limited study and knowledge about the mechanism of microbiologically influenced corrosion (MIC), many people are unaware that nitrate reducing bacteria (NRB) can be corrosive and cause serious MIC attack. Compared with some of the sulfate reducing bacteria (SRB), NRB are even more aggressive and corrosive than typical SRB in MIC pitting investigations. So it is rational to speculate that NRB may lead to serious MIC problems in marine applications, oil and gas industries where NRB and nitrate are ubiquitous. Based on the development of bioelectrochemistry and bioenergenetics, the corrosion behavior of NRB on 2205 and 2205-Cu duplex stainless steel will be investigated in this work, especially focusing on 2205 cu-bearing antibacterial stainless steel with broad-spectrum and strong antibacterial ability. In comparison of commericial 2205 duplex stainless steel, the antibacterial ability of 2205 cu-bearing antibacterial duplex stainless steel against various NRB will be tested in simulated environments such as marine and internal wall of pipeline where NRB are commonly present. The MIC resistance properties of antibacterial 2205-Cu duplex stainless steel will be studied, and the possible mechanisms of how 2205-Cu duplex antibacterial stainless steel inhibit NRB and prevent MIC due to NRB will be discussed. This work will provide the fundamental research data to better support the novel design of the anti-MIC and antibacterial 2205-Cu duplex stainless steel. This is a vital and meaningful project, which will promote the development of the application of the antibacterial stainless steel.

因为对微生物腐蚀机制了解的局限性,所以硝酸盐还原菌导致微生物腐蚀的可能性被忽略了。而硝酸盐还原菌导致点蚀的能力甚至超过了硫酸盐还原菌,所以NRB在其广泛存在的海洋和石油天然气等环境中可能导致严重的微生物腐蚀问题。本项目根据生物能量学和生物电化学，合理推测NRB是可能导致金属不锈钢材料的微生物腐蚀。本项目从研究2205-Cu抗菌双相不锈钢对NRB的抗菌性能和耐NRB导致的微生物腐蚀性能为出发点，通过模拟存在NRB的海洋和石油天然气壁道内壁等环境，以普通2205双相不锈钢为对比，系统和深入研究2205-Cu含铜抗菌双相不锈钢对各种环境中典型NRB的杀灭作用、抗菌不锈钢NRB微生物腐蚀行为及影响因素，并探讨其作用机理，为发展耐NRB微生物腐蚀的抗菌双相2205-Cu不锈钢新材料提供理论依据和奠定技术基础。本项目对推动抗菌不锈钢新材料的应用与发展也具有重要意义。

2205-Cu 抗菌双相不锈钢(2205-Cu DSS)对海洋腐蚀细菌 Pseudomonas aeruginosa和产酸菌Acetobacter aceti导致的微生物腐蚀具有明显的抑制作用。以2205 DSS为对比，采用电化学方法测试了2205-Cu DSS和2205 DSS试样在有菌和无菌环境下的开路电位（OCP）、线性极化电阻（LPR）、电化学阻抗谱（EIS）及极化曲线，采用扫描电子显微镜（SEM）、激光共聚焦显微镜（CLSM）、X射线电子能谱（XPS）等表面分析技术研究了生物膜形态、腐蚀形貌及腐蚀产物。结果显示和2205DSS相比，2205-Cu DSS具有良好的抗菌性能和较好的耐微生物腐蚀的能力。通过添加铜银元素赋予2205双相不锈钢协同抗菌效果，提高材料的抗菌性能和耐微生物腐蚀能力。发现了铜银的添加会改变2205双相不锈钢的两相比例、降低耐蚀性并使钝化膜致密性降低。但同时含用含银的材料具有明显的协同抗菌效果，能够有效抑制金属表面生物被膜的附着，显著提升了材料耐硫酸盐还原菌导致的微生物腐蚀性能。2205-Cu抗菌不锈钢对细胞外电子传递类型的微生物腐蚀（硫酸盐和硝酸盐还原菌）和代谢产物类的微生物腐蚀都具有明显的抑制作用。