海洋环境微生物附着的电化学检测技术

研究了采用电化学方法监检测海水环境中金属表面微生物附着状态．根据钝性金属在海水中开路电位随微生物膜形成正移的现象研制了不锈钢与Cu构成的微生物膜检测复合电极．它的电位差随微生物膜增长逐渐增大，标定后能够用于定量评价微生物膜生长程度．     

海水环境中微生物附着与钝性金属

对天然海水中微生物膜附着导致钝性金属开路电位正移现象及其作用机理的研究进行了综述.     

天然海水中微生物膜对316L不锈钢腐蚀行为研究

采用电化学技术包括开路电位、电化学阻抗谱、动电位极化、循环极化、表面表征技术、包括扫描电镜和能谱分析研究了316L不锈钢在天然海水中微生物膜影响的初期腐蚀行为。研究表明,海洋微生物在不锈钢表面发生附着形成生物膜。在天然海水中不锈钢的开路电位正移约450mV,而在灭菌海水中不锈钢的开路电位基本保持不变。电化学阻抗和极化实验结果指出,海洋微生物膜使不锈钢阻抗增加,点蚀电位升高,生物膜抑制了不锈钢的腐蚀发生。这种抑制作用经历了一个先变大后减小的过程。天然海水中,海洋生物膜的附着和其代谢产物作用使不锈钢的耐蚀性能得到提高,这一耐蚀性能的提高与生物膜影响的阳极抑制作用有关。     

海洋环境中微生物膜吸附动力学过程对钝态金属开路电位变化特征的影响

采用荧光显微技术研究了自然海水中微生物在两种钝态金属表面的吸附动力学过程与其开路电位正移之间的关系。高钼钢和1Cr18Ni9Ti电极在海水中浸泡了10d左右,1d后现金种钝态金属腐蚀电位正移约200mV。研究发现微生物向钝 态金属表面附着的初期对金属的开路电位影响最大,随后腐蚀电位增加缓慢,在吸附过程中微生物在钝态金属表面附着数量随时间增加呈负指数增长。给出了微生物附着的动力学方程,并对其进行了讨论。两种钝态金属开路电位的变化和其表面微生物数量增加有着相似的趋势。开路电位在微生物附着过程中迅速增加,微生物附着达到平衡后钝态金属开路电位增加缓慢。这说明在微生物附着初期对钝态金属电位正移影响最大,随后阶段影响逐渐减弱。     

天然海水微生物对5083铝合金初期腐蚀行为的影响

利用荧光电子显微镜,扫描电镜及能谱表面分析技术和开路电位,电化学阻抗谱,动电位极化电化学技术研究了在天然海水中浸泡初期,天然海水微生物对5083铝合金腐蚀行为的影响.结果表明,在天然海水中,铝合金表面形成良好的生物膜.电化学结果表明,在天然海水中铝合金腐蚀电位负移,点蚀电位正移,电荷转移电阻增大,说明短期浸泡时,天然海水生物膜的形成可以抑制其腐蚀,尤其对点蚀具有明显的抑制作用.在无菌海水中,随时间的增长,铝合金的腐蚀也受到一定程度的抑制,原因是锈蚀产物的形成对铝合金具有一定的保护作用.     

用丝束电极研究SRB微生物诱导腐蚀的电化学特征

应用丝束电极研究了半连续培养基中SRB及其生物膜对Q235低碳钢腐蚀的影响，采用电位、电流以及阻抗扫描技术测试了生物膜的不均匀性特性，以及电极开路电位和电化学阻抗谱（EIS）与培养时间的关系，发现微生物膜的成长，开路电位负移，由于生物膜中SRB代谢产生的硫化物具有导电性，使表面电位扫描已不能作为生物膜下局部腐蚀的判据，但表面阻抗扫描却可探测到膜下的局部腐蚀，EIS表明，生物膜电容极大（10^4－10^5μF／cm^2），且膜电容随时间呈S型增加，而溶液电阻和电荷传递电阻则呈指数下降。     

海水中小球藻对Q235碳钢腐蚀行为的影响

采用表面分析技术以及电化学测试技术研究了海水中小球藻对Q235碳钢腐蚀的影响。结果表明:在不含小球藻培养液中Q235碳钢发生均匀腐蚀,而在含小球藻培养液中碳钢发生不均匀腐蚀;在含小球藻体系中,开路电位随浸泡时间的变化呈周期振荡;小球藻及其代谢产物能够在材料表面附着并形成一层生物膜,减缓金属的腐蚀;小球藻光合作用产生的氧导致阴极氧去极化作用,加速了金属的腐蚀。     

天然海水中早期微生物附着对316L不锈钢腐蚀行为的影响

海水中的微生物附着对金属材料的腐蚀有重要的影响。采用电化学阻抗测试和动电位极化曲线测试,研究了316L不锈钢浸泡于天然海水中早期微生物附着对其腐蚀行为的影响。结果表明:在天然海水中,微生物附着初期316L不锈钢的腐蚀加剧,微生物膜生长形成期316L不锈钢在天然海水和灭菌海水中腐蚀速度差别不大;微生物膜成熟稳定期,天然海水中316L不锈钢的腐蚀与无菌时相比明显受到抑制。     

厌氧微生物对紫铜腐蚀行为的影响

采用开路电位、电化学极化曲线、电化学阻抗谱(EIS)研究了紫铜在海洋厌氧菌影响下的腐蚀行为。结果表明,扫描电子显微镜SEM形貌分析结果表明在紫铜上附着的SRB海洋微生物呈微弯杆状,材料表面形成较致密的半透明的生物细菌膜。电化学测试结果表明,紫铜在SRB细菌培养基海水中的腐蚀过程主要受活化极化控制,SRB微生物的存在导致紫铜的开路电位和活化极化率变小,从而加速了紫铜的腐蚀进程。     

缓蚀剂阳极脱附现象的研究──Ⅱ．缓蚀剂阳极脱附对电极阻抗的影响

使用交流阻抗方法研究了缓蚀剂阳极脱附对电化学阻抗谱及电化学界面参数的影响。在脱附电位附近，缓蚀剂阳极脱附使铁阳极过程阻抗响应中产生一附加感抗。界面电容在外加电位低于脱附电位时保持不变，达到脱附电位后迅速增加。电荷迁移电阻随电位正移逐渐降低，达到脱附电位后降至很小数值并减缓变化。弥散效应系数则随电位正移大体线性增加，与脱附电位无明显相关性。依据缓蚀剂在脱附电位Ｅｄｅｓ附近发生阳极脱附讨论了上述实验结果。     

Influence of biofilms growth on corrosion potential of metals immersed in seawater

The changes of corrosion potential (E_corr) of metals immersed in seawater were investigated with electrochemical technology and epifluoresence microscopy. In natural seawater, changes of E_corr were determined by the surface corrosion state of the metal. E_corr of passive metals exposed to natural seawater shifted to noble direction for about 150 mV in one day and it didn't change in sterile seawater. The in‐situ observation showed that biofilms settled on the surfaces of passive metals when E_corr moved in noble direction. The bacteria number increased on the metal surface according to exponential law and it was in the same way with the ennoblement of E_corr. The attachment of bacteria during the initial period played an important role in the ennoblement of E_corr and it is believed that the carbohydrate and protein in the biofilm are reasons for this phenomenon. The double layer capacitance (C_dl) of passive metals decreased with time when immersed in natural seawater, while remained almost unchanged in sterile seawater. The increased thickness and reduced dielectric constant of C_dl may be reasons.     

微生物附着对不锈钢钝化性能的影响

通过荧光显微镜研究了天然海水及无菌海水中不锈钢表面微生物的附着状态,同时利用扫描电镜和能谱仪对有微生物附着的不锈钢电极及对比试样表面成分进行了分析,根据不同浸泡时间内微生物附着以后极化曲线尤其是阳极钝化曲线的变化,解释了微生物附着对不锈钢钝化性能的影响.     

Influence of Static Low Electromagnetic Field on Copper Corrosion in the Presence of Multispecies Aerobic Bacteria

The effects of low electromagnetic field(EMF)( B = 2 mT) on the corrosion of pure copper in the absence and presence of multispecies marine aerobic bacteria were investigated in this work. The results showed that EMF has an inhibitory effect on copper metals and decreases the corrosion rate of copper metals in sterile artificial seawater. However, microbiologically influenced corrosion of Cu was increased in the presence of electromagnetic field due to its effect on the biofilm morphology and structure. EMF reduced the growth rate of bacteria and decreased bacterial attachment, thereby forming a heterogeneous and non-stable biofilm on the Cu surface in the presence of EMF. Moreover, the biofilm was dispersed throughout the surface after 7 days, whereas the scattered bacteria were observed on the surface after 10 days. Confocal laser scanning microscopy images showed large and deep pits on the surface in the presence of EMF and confirmed the acceleration of Cu corrosion in the presence of EMF and multispecies bacteria. Furthermore, XPS and FTIR results demonstrated that the corrosion products and metabolic by-products were significantly changed in the presence of EMF.     

Relationship between the ennoblement of passive metals and microbe adsorption kinetics in seawater

The relationship between microbial colonization of two kinds of passive metals and ennobling of their corrosion potentials (E_corr) were studied. Two types of passive metal coupons were exposed to natural seawater for about ten days. Under laboratory conditions, all corrosion potentials of the samples ennobled for about 200 mV. Epifluorescence microscopy showed that bacteria adsorption was the main process during about the first day immersion and bacteria reproduced in the following days. The bacteria number increased on the metal surface according to an exponential law and the kinetics of bacteria adsorption at the metal surface during this period was proposed. The ennoblement of E_corr was similar to the increasing bacteria number: E_corr increased quickly during the bacteria adsorption process and increased slowly after biofilms had formed.     

金属在海水中的腐蚀电位研究

获得了３８种金属在天然海水中浸泡１８０ｄ的腐蚀电位数据，列出了它们在海水中的腐蚀电位序，讨论了金属材料在海水中的腐蚀电位特性，分析了它们在海水中的腐蚀电位与耐蚀性的关系。结果表明，钝化能力强的金属，其腐蚀电位随浸泡时间变化较大，电位稳定时间较长，非钝化金属和钝化能力弱的金属则相反，对铝合金来说，初始电位，稳定电位较负，其耐蚀性较好，反之则较差。对不锈钢来说，稳定电位较正，其耐蚀性较好，反之则较差。     

The importance of live biofilms in corrosion protection

As observed before, Al 2024 was passive in artificial seawater (AS) in the presence of a protective biofilm of Bacillus subtilis WB600. When antibiotics were added to the AS to kill the bacteria in the biofilm, pitting occurred within a few hours as indicated by characteristic changes in the impedance spectra. The corrosion potential E_corr decreased at the same time to values observed in sterile AS. Addition of the antibiotics to sterile AS had no effect on corrosion behavior.     

海水环境中弧菌对45钢腐蚀行为及力学性能的影响

通过热带海洋气候条件下在海水中培养弧菌,并对比45钢在自然海水、无菌海水和弧菌海水中的腐蚀行为,研究了弧菌对45钢腐蚀行为及力学性能的影响。结果表明,弧菌可以接种于海水中大量培养至高浓度(非培养基中培养),避免了培养基成分的缓蚀作用,从而更接近碳钢的自然腐蚀状态。海水中弧菌对45钢的平均腐蚀速率及力学性能有显著的影响。弧菌能加速45钢的平均腐蚀速率,但微生物的协同作用比单种弧菌更能加速材料的平均腐蚀速率。弧菌能显著降低局部pH值,引起材料表面严重的局部腐蚀,材料表面局部腐蚀促使其在拉伸过程中应力集中而发生断裂。