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海藻希瓦氏菌对Zn-Al-Cd牺牲阳极的腐蚀性能影响 总被引:1,自引:0,他引:1
从锈层中分离出黄色细菌,经分子生物学技术鉴定为海藻希瓦氏(Shewanella algae,SA)菌.采用分光光度法研究了其生长曲线的变化,发现该细菌的生长分为3个阶段:指数生长阶段、稳定阶段和衰亡阶段.采用电化学交流阻抗技术、扫描电镜和荧光显微技术等方法研究了SA菌对Zn-A1-Cd牺牲阳极材料腐蚀行为的影响.结果表明,含SA菌培养基的试样的开路电位要高于无菌培养基中试样的电位,电荷传递电阻Rct值大于无菌培养基的Rct值,说明该SA菌能够抑制试样的腐蚀.分析原因是细菌在试样表面形成生物膜,隔离了腐蚀介质与试样的接触,同时,细菌的生长消耗了氧气,抑制了腐蚀的发生;试样在含SA体系中,5 d时,其表面覆盖比较致密的生物膜;而在不含细菌的体系中,试样表面有明显的腐蚀坑;试样在含SA体系中7 d时,生成比较完整的生物膜,随着体系中营养物质及氧气的减少,SA菌逐渐减少,11 d后试样表面附着的SA菌所剩不多. 相似文献
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用原子力显微镜研究铜合金微生物的腐蚀行为 总被引:1,自引:0,他引:1
用原子力显微镜(AFM)研究了HSn70-1A、HSn70-1B和HSn70-1AB等3种铜合金在硫酸盐还原菌(SRB)菌液中的微生物腐蚀行为.结果表明,3种铜合金表面形成的生物膜形貌各不相同.HSn70-1AB合金表面生物膜的粗糙度大于其余两种合金,表明其生物膜最不均匀.去除生物膜后,3种样品的腐蚀形貌也小相同,粗糙度均有所增加,这是微生物腐蚀作用的结果.研究证实,AFM的定量分析能力是研究材料微生物腐蚀的重要手段. 相似文献
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用腐蚀失重、X射线衍射等方法研究了AZ91、Q235、Al和Zn等材料的微生物腐蚀行为.结果表明,4种材料在无菌培养基中的平均腐蚀速度均大于在含菌培养基中的平均腐蚀速度;其中,AZ91的耐腐蚀性最差,Q235最好;各种材料在含菌培养基中,表面均形成生物膜,这层生物膜均抑制了4种材料的腐蚀. 相似文献
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原子力显微镜在微生物腐蚀研究中的应用 总被引:1,自引:0,他引:1
利用原子力显微镜(Atomic Force Microscopy,AFM)研究硫酸盐还原菌(Sulfate Reducing Bacteria,SRB)、微生物膜和腐蚀前后铜合金材料BFe30-1-1的表面形貌,得到了高分辨率的表面形貌图,测得SRB的大小、点蚀坑的深度和直径,分析了腐蚀后BFe30-1-1的表面粗糙度参数.结合电化学参数说明,浸蚀14d的铜合金表面形成了不均匀的微生物膜,加速了试片表面的局部腐蚀.AFM作为一种具有纳米级分辨成像能力的工具,是观察材料的表面特征和腐蚀形貌及测量材料表面纳米粗糙度的理想仪器. 相似文献
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目的研究需钠弧菌与芽孢杆菌分别单独培养以及混合培养时对海洋工程钢DH36腐蚀行为的影响,为海洋环境下材料的腐蚀发生规律探讨以及微生物腐蚀防治提供依据。方法通过扫描电子电镜、能谱仪、电化学设备等仪器,分析DH36钢在不同腐蚀体系中的腐蚀形貌信息以及电化学特征。结果SEM图显示,芽孢杆菌在DH36钢表面上的贴附量较大,需钠弧菌与混菌腐蚀体系中,生物膜、锈层构成的混合层存在很多的裂纹、缝隙,致密性较差。电化学结果显示,试样表面均出现两个时间常数,在低频处出现感抗特征。芽孢杆菌腐蚀体系中的腐蚀速率先增大后减小,浸泡3 d后需钠弧菌腐蚀体系中的腐蚀速率介于芽孢杆菌与混菌腐蚀体系之间。与单菌种腐蚀体系相比,混菌腐蚀体系中的开路电位最低,且浸泡7 d后的腐蚀速率最大,达到13.53μA/cm^2。结论在浸泡后期芽孢杆菌显示出腐蚀抑制效果,在需钠弧菌与混菌腐蚀体系中,由于细菌代谢产生了腐蚀性产物以及形成了致密性较差的混合层,试样腐蚀速率不断加快,但混菌的促进作用更显著。 相似文献
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应用原子力显微镜(AFM)研究硫酸盐还原菌(SRB)、微生物膜、腐蚀产物膜和A3钢腐蚀后的表面形貌,获得了高分辨率、清晰的图像.测得了SRB的大小,微生物膜、腐蚀产物膜的厚度和形成的点蚀孔深度.结果表明,A3钢的微生物腐蚀过程是先形成致密的硫化物膜,然后微生物在其上面聚集附着形成微生物膜;A3钢的微生物腐蚀主要以点蚀形式发生. 相似文献
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自然界中,微生物常常附着在材料表面形成生物膜,影响金属表面的电化学过程,从而诱发微生物腐蚀。生物膜与微生物腐蚀的发生密切相关,其结构组成、成膜过程对金属的腐蚀反应类型与速率有着很大的影响。由于微生物活动的复杂性以及缺乏生物膜与金属界面之间交互作用的深刻认识,微生物腐蚀的发生和发展机制尚不清晰。基于此,从生物膜的角度阐述了金属微生物腐蚀的作用机制。介绍了易引起材料腐蚀的常见菌种,如硫酸盐还原菌、硫氧化菌、铁氧化菌、硝酸盐还原菌及其他腐蚀菌,并对它们的腐蚀机理进行了概述。综合论述了生物膜的特征、生成步骤,以及它是如何随时间和外部环境进行动态演变的。着重讨论了影响生物膜生成和发展的因素,包括材料因素以及环境因素,如温度、溶解氧、pH值、Cl~-、Fe~(2+)、水体流速、营养介质、磁场。最后,针对外界影响因素的复杂性,阐述了生物膜研究过程中存在的问题,同时对模拟生物环境过程中合理设计实验方案的重要性进行了展望。 相似文献
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利用扫描电镜 (SEM)、能谱、X射线衍射仪 (XRD) 和超景深三维立体显微镜等表面分析手段,调查研究油田污水集输管线材料的腐蚀和结垢行为。实验结果表明,暴露在没有添加杀菌剂的污水中30 d的试样表面形成了大量的垢状沉淀物,局部放大可以发现以胞外聚合物为主的生物膜覆盖在试样表面,此时生物膜的厚度高达169.6 μm,生物膜中含碳酸盐垢和细菌代谢产物硫铁化合物,且膜下基体材料局部腐蚀孔深度达到23.96 μm。在连续添加100 mg/L有机胍类杀菌剂1个月后,试样表面覆盖物中以无机矿物为主,且膜层厚度较未添加的薄,厚度为48.6 μm,膜下腐蚀较均匀,局部腐蚀轻微。硫酸盐还原菌参与的生物作用是管线局部腐蚀穿孔的主要原因之一。 相似文献
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Xiaojian Gao Baoguo Ma Yingzi Yang Anshuang Su 《Journal of Materials Engineering and Performance》2008,17(4):543-549
Mortar prisms made with OPC cement plus 30% mass of limestone filler were stored in various sulfate solutions at different
temperatures for periods of up to 1 year, the visual appearance was inspected at intervals, and the flexural and compressive
strength development with immersion time was measured according to the Chinese standard GB/T17671-1999. Samples were selected
from the surface of prisms after 1 year immersion and examined by x-ray diffraction (XRD), Fourier transform infrared spectroscopy
(FTIR), laser-raman spectroscopy and scanning electron microscopy (SEM). The results show that MgSO4 solution is more aggressive than Na2SO4 solution, and Mg2+ ions reinforce the thaumasite sulfate attack on the limestone filler cement mortars. The increase of solution temperature
accelerates both magnesium attack and sulfate attack on the limestone filler cement mortar, and leads to more deleterious
products including gypsum, ettringite and brucite formed on the surface of mortars after 1 year storage in sulfate solutions.
Thaumasite forms in the mortars containing limestone filler after exposure to sulfate solutions at both 5 °C and 20 °C. It
reveals that the thaumasite form of sulfate attack is not limited to low-temperature conditions. 相似文献
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Stationary and non-stationary chloride diffusion coefficients of mortars prepared with ordinary Portland cement partially substituted by spent cracking catalyst (FC3R) and fly ash (FA) have been determined. An accelerated test of chloride migration through the mortar has been performed in order to determine these coefficients. The results show that the presence of FC3R improves chloride binding properties of mortars and the addition of FA reduces the total porosity, both factors leading to a higher resistance to chloride ingress. Corrosion rate of steels embedded in these ternary-binder mortars do not show significant differences compared to reference mortars (with plain cement), so a combined cement substitution as high as 45% by FC3R and FA do not lead to a higher risk of chloride-induced corrosion of steel when tested at an early age. 相似文献
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The present study investigates the influence of partial cement substitution with biomass ash on the corrosion behaviour of steel embedded in the mortar. To evaluate this influence, corrosion parameters of steel in mortar exposed to tap water and 3.5 wt% NaCl solution were monitored over a period of 50 days. The electrochemical cell consisted of a steel plate as a working electrode, covered with a layer of mortar that was exposed to the testing solution. Open-circuit potential and linear polarisation were used to monitor changes in corrosion behaviour, whereas electrical impedance spectroscopy was used to evaluate the conductivity of the matrix. Additional to corrosion parameters, the chloride migration coefficient was tested after 28 days. On the basis of the results, it was observed that mortars with biomass ash provide equal or better protection for embedded steel, compared with the reference mortar. Mortars that performed slightly better than the reference mortar and other mortars were prepared with ashes with a higher amount of pozzolanic oxides. 相似文献
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矿渣水泥混凝土抗海水侵蚀性能试验研究 总被引:2,自引:0,他引:2
水灰比和水泥用量是反映混凝土抗渗性的两个主要因素。制作相同水泥用量、不同水灰比和同一水灰比、不同水泥用量的两类矿渣水泥混凝土试块,测定了试块多次海水浸泡和烘干后的抗压强度、抗折强度、重量变化,并进行超声波无损检测。研究表明:随水灰比的减小,矿渣水泥混凝土耐久性提高;混凝土设计中存在最佳水泥用量,此用量时矿渣水泥混凝土抗侵蚀性最强。 相似文献
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F. Raupp-Pereira L. Silva A.M. Segades H. Paiva J.A. Labrincha 《Journal of Materials Processing Technology》2007,190(1-3):12-17
This work describes the study of the potential use of the sludge generated in potable water filtration/cleaning operations (waste material) as workability-aid in rendering/plastering mortars. A commercial mortar was used as reference and several formulations were investigated, containing sodium phosphate enriched waste material instead of the enriched bentonite traditionally used as workability-aid and setting retarder in cement-based compositions.
Fresh mortars were characterised in terms of plasticity as a function of elapsed time. Rheological behaviour was studied with a specific rheometer. The same setting delay can be obtained with the use of the enriched sludge even by using lower contents of the additive (0.25%), but the workability window tends to be narrower. Fluidity assured by the tested admixtures is mostly controlled by changes in yield stress values of the paste.
The replacement of bentonite by an equivalent amount of sodium phosphate-added waste material (ca. 0.25 wt.%) is technically feasible. 相似文献
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Multi-species biofilms are found in various bacterial habitats and have industrial relevance. These complex bacterial communities have synergetic effects, unlike a single species. Therefore, it is critical to evaluate these complex communities as a whole. Here, the inhibitory effect of single- and dual-species biofilms of Vibrio neocaledinocus sp. and Pseudoalteromonas piscicida for A36 carbon steel corrosion was investigated. The results demonstrated that the synergistic interactions of the monoculture increased the overall biomass production of the dual-species biofilm, but the growth rate was reduced in the presence of the dual-species culture due to a lack of nutrients. Field emission scanning electron microscopy images also confirmed the development of biofilms—they became more homogenized via exposure time in both the mono- and dual-species cultures. The corrosion resistance of A36 carbon steel positively increased because of the dual-species interactions. This reached the highest value after four weeks of exposure. The highest corrosion inhibition efficiency of 99.8% was achieved in the dual-species cultures. Microbial community analysis revealed the high relative abundance of Pseudoalteromonas piscicida during the initial days of exposure, demonstrating the dominant role of this bacterium in the biofilm structure. 相似文献
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Studies of the corrosion of mild steel in alkali-activated slag cement mortars with sodium chloride admixtures by a galvanostatic pulse method 总被引:2,自引:1,他引:1
Corrosion of mild steel reinforcement in an alkali-activated slag (AAS) cement mortar containing NaCl admixtures has been investigated using an improved galvanostatic pulse technique. Corrosion rates were monitored at 90% relative humidity over a period of several months. On first exposure highest corrosion rates are seen with the lowest chloride levels, but over time different behaviours are seen for different chloride levels. The complex pattern of current and potential variation has been analysed using Tafel plots. Tentative conclusions are put forward to account for the behaviour seen, based on a model where oxidation of sulphide anions to sulphur prevents potential rising into the pitting regime and leads to inhibition of the oxygen cathode reaction. 相似文献
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研究了水泥、粉煤灰、矿渣三种胶凝材料对新拌浆体、28天龄期硬化砂浆的氯离子固化能力,并探讨了这三种胶凝材料对氯离子的固化机理。 相似文献