Q235钢在假单胞菌和铁细菌混合作用下的腐蚀行为

采用腐蚀失重法、电化学阻抗谱(EIS)和表面分析技术研究了Q235钢在假单胞菌和铁细菌共同作用下的腐蚀行为.结果表明:与单种菌相比,两种菌混合作用下Q235钢腐蚀受到了抑制.混菌体系中金属电极自腐蚀电位升高,腐蚀电流密度减小,交流阻抗值随时间增大.扫描电子显微镜(SEM)分析结果表明混合菌体系中Q235钢表面形成了均匀致密的腐蚀产物膜.     

A3钢在氧化亚铁硫杆菌、链霉菌及其混合菌体系中的腐蚀行为

采用电化学方法和表面分析技术研究了A3钢在链霉菌(Stremptomyces)和氧化亚铁硫杆菌(Thiobacillus fer-rooxidans,T.f)单独及共同作用下的腐蚀行为.结果表明,试样在不同的含菌腐蚀体系中浸泡7d后,表面生成了不均匀的生物膜层,并表现出各不相同的形貌特征;A3钢在氧化亚铁硫杆菌和链霉菌单种菌作用下发生了局部腐蚀,而混合菌体系中的试样发生均匀腐蚀;混合菌体系中A3钢的腐蚀失重速率介于两种菌单独存在时的腐蚀失重速率之间;试样浸泡14d后的电化学阻抗谱(EIS)测试结果表明,A3钢电极在氧化亚铁硫杆菌-链霉菌混合菌体系中的阻抗值介于两种单菌腐蚀体系之间.以上研究结果表明,A3钢在链霉菌体系中腐蚀最重,混合菌体系其次,氧化亚铁硫杆菌体系中腐蚀最轻.     

N80油套管钢应力状态下的CO2腐蚀行为研究

利用交流阻抗技术研究了拉伸、压缩和弯曲三种应力状态下N80油套管钢在饱和CO₂地层水中的腐蚀过程. 结果表明, 三种状态下的阳极电化学阻抗谱均出现了高频容抗弧、中低频感抗弧和低频容抗弧三个时间常数, 其中高频容抗弧与双电层电容和传递电阻有关, 感抗弧对应膜的活性溶解, 低频容抗弧与试样表面膜的生成有关. 随着三种状态下应变的增加, 感抗弧逐渐扩大, 而低频容抗弧则逐渐缩小, 表明应力状态下N80钢的CO₂腐蚀会加剧. 三种状态下的阴极阻抗谱高频均由容抗弧组成, 中低频由Warburg阻抗和容抗弧共同组成, 三种状态下随着应变程度的增加, Warburg阻抗增加, 反应电阻减小, 双电层电容减小, 说明应力会加速阴极反应过程的进行, 从而增加N80钢的CO₂腐蚀速率.     

A3钢在链霉菌和诺卡氏菌共同作用下的腐蚀行为

采用腐蚀失重法、电化学交流阻抗法(EIS)和表面分析技术研究了A3钢在链霉菌(Stremptomyces)和诺卡氏菌(Nocardia sp)共同作用下的腐蚀行为. 结果表明, 与单种菌相比, 混合菌作用下试样表面的腐蚀倾向增大, 阻抗值降低, 腐蚀电流密度增加. 浸泡21天后, 混合菌溶液中A3钢的腐蚀失重速率大于两种微生物单独存在时的腐蚀失重速率之和. 扫描电子显微镜(SEM)分析结果表明, 混合菌溶液中A3钢表面发生了严重的局部腐蚀, 在链霉菌和诺卡氏菌的共同作用下, A3钢的腐蚀程度加剧.     

3.5% NaCl饱和Ca(OH)2溶液中醇胺缩聚物对碳钢腐蚀的抑制

利用动电位极化, 电化学阻抗谱(EIS)和表面形貌观察方法, 并结合量子化学计算, 在3.5% NaCl饱和Ca(OH)₂ 溶液中研究探讨了山梨醇与二乙烯三胺缩聚物(SDC)对碳钢腐蚀的抑制行为. 结果表明: SDC的加入可有效降低碳钢的腐蚀电流密度, 提高碳钢的点蚀电位, 表明阻绣剂对Cl^-诱导的局部腐蚀具有良好的抑制作用, 为混合型阻锈剂; 且在所研究浓度范围内, 随添加浓度增加, 缓蚀效率提高. 化合物对碳钢腐蚀的抑制主要源自阻锈剂分子在碳钢表面的静电吸附, 且吸附遵循Langmuir等温吸附规律.     

高温高压喷射湍流区中X70管线钢CO2腐蚀电化学特征

采用高温高压环路喷射装置并结合腐蚀微电极技术, 开展了湍流区中X70 管线钢CO₂腐蚀实验. 利用扫描电镜对不同实验时间的试样表面腐蚀产物微观形貌进行了观察和分析, 并进行了湍流区原位电化学测试和分析. 结果表明, 湍流区中X70 钢的CO₂腐蚀电化学特征与其表面所覆盖腐蚀产物膜层变化密切相关. 实验12 h内, 湍流区中X70钢表面从最初的基体与腐蚀产物共存, 转变为由疏松且不完整的膜层覆盖的特征. 实验12 h 后, 试样表面出现内外两层腐蚀产物膜, 内层膜堆垛致密, 外层膜疏松多孔, 同时湍流区中高切应力导致外层腐蚀产物脱落, 材料表面逐渐被完整致密的内层膜覆盖, 这是腐蚀速率持续下降的主要原因. 电化学结果表明, 实验12 h 内, 湍流区中X70 钢的腐蚀电位E_corr和线性极化电阻R_p不断下降; 电化学阻抗谱由高频容抗弧、中频容抗弧和低频感抗弧组成, 膜层电阻R_f缓慢增加, 电荷传递电阻R_t不断下降, 双电层电容C_dl和膜层电容C_f迅速下降; 12 h后, 腐蚀产物膜层对基体材料保护性随喷射时间延长逐渐增强, E_corr和R_p逐渐增大, 电化学阻抗谱中低频感抗弧逐渐收缩并在48 h 时消失, 最后转变为双容抗特征, R_f、R_t和C_dl随时间迅速增大, C_f趋于稳定.     

苯并三唑对水泥砂浆中钢筋的阻锈作用

应用腐蚀电位(E_corr)、极化电阻(R_p)和砂浆保护层电阻率(ρ_c)研究了苯并三唑(BTA)对钢筋电极腐蚀电化学行为的影响. 通过电化学阻抗谱(EIS)、循环极化(CP)和循环伏安(CV)结果对比了BTA与NaNO₂ (SN)对钢筋电极在未处理、预锈蚀和内掺氯盐3种状态下3.5% (w)氯盐浸泡360 d后的阻锈效率. 利用环境扫描电镜(ESEM)与能谱分析(EDS)解释了BTA对水泥基材料中钢筋的阻锈机理. 结果表明: 3种状态下BTA均能明显降低砂浆中钢筋的均匀腐蚀速率, 且其阻锈效率高于SN. 在未处理与预锈状态下, BTA抑制点蚀的能力稍弱于SN; 但在内掺氯盐的状态下, BTA表现出了较大的点蚀阻力. BTA除了能在钢筋表面形成复杂的保护膜, 从而有效抑制氯盐的破钝化作用. ESEM/EDS结果表明BTA还能与砂浆基体形成较多富钙C-S-H凝胶, 可能优化了钢筋/砂浆界面区的孔结构, 形成更致密的微观结构, 显著延缓了氯盐向钢筋表面的传输进程, 较好地保护了钢筋. 适量的BTA对砂浆360 d的基本力学性能无明显影响.     

共吸附剂修饰TiO2薄膜电极

共吸附剂修饰纳晶TiO₂薄膜电极是目前染料敏化太阳电池研究的一个热点. 本文通过平带电势和电化学阻抗研究了二(3,3-二甲基丁基)次膦酸和鹅脱氧胆酸两种共吸附剂修饰对TiO₂薄膜电极的平带电势和电极表面钝化能力的影响及其在染料敏化太阳电池中的应用. 结果表明, 二(3,3-二甲基丁基)次膦酸能更有效地钝化TiO₂薄膜表面, 并使TiO₂薄膜平带电势负移. 电化学阻抗谱测试结果表明, 在染料敏化太阳电池中, 相对于鹅脱氧胆酸, 二(3,3-二甲基丁基)次膦酸能更显著地提高器件的电子寿命和开路电压.     

镀锡薄钢板在功能饮料中的腐蚀行为

应用电化学阻抗谱(EIS)技术,结合扫描电镜(SEM)、能量散射X射线谱(EDS)、X射线光电子能谱(XPS)、扫描探针显微镜(SPM)等表面分析技术,研究了镀锡薄钢板在功能饮料中的腐蚀过程并探讨了腐蚀机制.结果表明:浸泡前期,EIS低频阻抗模值的增加与前31 h镀锡薄钢板表面形成的腐蚀产物膜有关;随着浸泡时间的增加,EIS低频阻抗模值有所下降,这与腐蚀产物膜的部分脱落以及暴露的基底金属碳钢的腐蚀有关.镀锡薄钢板在功能饮料中浸泡24天后其表面的腐蚀产物膜由外层的富锡层和内层的富铁层组成,XPS结果表明其成分主要是Sn(Ⅱ)/Sn(Ⅳ)与柠檬酸阴离子及Fe(Ⅲ)与柠檬酸阴离子组成的化合物,其腐蚀类型主要是功能饮料中的有机酸对镀锡薄钢板的腐蚀.     

Ti、Mg离子复合掺杂对LiNi0.4Co0.2Mn0.4O2性能的影响

采用SEM、XRD、恒电流充放电、交流阻抗谱等方法研究了钛镁离子复合掺杂对LiNi_0.4Co_0.2Mn_0.4O₂的结构及其电化学性能的影响. 结果表明材料的XRD图谱中部分特征峰的强度比值有较大的变化. 1%(摩尔分数) 的Ti、Mg离子复合掺杂能显著地改善LiNi_0.4Co_0.2Mn_0.4O₂的倍率放电能力, 平台保持能力和高倍率下的循环性能. 交流阻抗谱表明钛镁离子掺杂抑制了LiNi_0.4Co_0.2Mn_0.4O₂在高放电倍率下循环的电化学反应阻抗Rct的增加. 采用几种不同价态的金属离子复合掺杂是改善嵌锂的镍钴锰系金属氧化物的倍率放电能力的有效途径.     

Study of the electrochemical behaviour of a carbon steel electrode in sodium sulfate aqueous solutions using electrochemical impedance spectroscopy

The study of a plain carbon steel (AISI 1020) in Na₂SO₄ aqueous solutions at different concentrations was carried out by electrochemical impedance spectroscopy (EIS) in order to determine the corrosion mechanism and to obtain representative corrosion rates of the system. EIS was used to measure corrosion current densities at high concentrations in the range 0.1–1 wt% Na₂SO₄, but in the low concentration range, from 0.001 to 0.01 wt%, a scattered Nyquist plot was obtained. Other electrochemical techniques, such as polarization resistance (PR), Tafel plots and electrochemical noise (EN), were also used in this analysis. The charge transfer resistance was determined and compared with the PR and noise resistance. Electronic Publication     

Electrochemical study on corrosion process characteristics of the high-strength low-alloy steels in NaHSO3 solution

Electrochemical methods were used to study the characteristics of corrosion process for the high-strength low-alloy steel and carbon steel used as a huge oil storage tank in NaHSO₃ solution. The polarization curve results show that both steel samples take place in active solution, and the high-strength low-alloy (HSLA) steel has higher i _corr value than carbon steel, which is due to the small grain size that provides high density of active sites for preferential attack. The electrochemical impedance spectroscopy (EIS) results make known that the corrosion process presents two stages. In the first 136 h, one-time constant in EIS diagrams can be shown. Both steels have similar corrosion resistance due to the combination effects of the grain size and microstructure. After 240 h of immersion, a complete passive film forms on the specimen surface, and two-time constants can be shown in EIS diagram. The HSLA steel exhibited improved corrosion resistance when compared with the carbon steel, which is due to the effect of the shape Fe₃C in microstructure and the deposition of FeSO₄ on the electrode surface. The scanning electrode microscopy analyses show that both steels take place in homogenous corrosion, and the carbon steel shows higher surface roughness and many Fe₃C residues. XRD results show that both steels have similar phase constitutes of corrosion products.     

碳钢在N-甲基二乙醇胺介质中的电化学阻抗谱研究

应用电化学阻抗谱(EIS)研究碳钢在N-甲基二乙醇胺(MDEA)介质中的腐蚀行为.实验表明,未经预阴极活化处理的碳钢表面存在氧化膜,溶解氧促使它腐蚀速率增大,经活化处理去除氧化膜后则相反.在不含热稳定性盐(HSS)的MDEA溶液中,碳钢的腐蚀性随MDEA浓度的增加呈先上升后下降趋势;而在HSS高含量的溶液中,其腐蚀性则随MDEA浓度的增加而单调下降.在含有HSS模拟溶液中,碳钢的阳极极化EIS随极化电位由低到高分别出现感抗、负阻抗以及Warburg阻抗响应等特征,对应于孔蚀、活化状态向钝化状态过渡以及进入钝化的趋势,腐蚀反应的阴极过程表现为电化学反应和扩散传质混合控制,阳极过程为电化学反应控制.     

Kinetics of carbon steel dissolution in ammonium chloride solution containing sodium thiosulfate

The dissolution behavior of carbon steel in ammonium chloride (NH₄Cl) solution containing sodium thiosulfate (Na₂S₂O₃) of various concentrations (0.01 and 0.1 M) was investigated using electrochemical impedance spectroscopy (EIS) and other nonelectrochemical techniques. The weight loss and polarization measurements indicate a significant increase in the NH₄Cl corrosion rate of carbon steel on addition of Na₂S₂O_3. The EIS measurements exhibited two capacitive loops at multiple direct current (dc) potentials for both the concentrations. Electrical equivalent circuit (EEC) and reaction mechanism analysis (RMA) were employed to analyze the impedance data. A four-step mechanism with two intermediate adsorbate species of same charge was proposed to explain the dissolution behavior of carbon steel in the given system. The surface coverage values enumerated that the surface was entirely covered with adsorbed species unlike in the pure NH₄Cl system. Charge transfer resistance and polarization resistance values estimated from RMA parameters indicate the increase in a dissolution rate with dc potential. The surface morphology was inspected via field emission scanning electron microscopy, and the corrosion products including surface state of carbon steel electrode were analyzed using energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy.     

海生物附著对钢板管椿腐蚀之影响

为了解海生物对钢板管椿腐蚀之影响 ,将SS4 1金属试片浸渍于高雄港 #1 4码头水深 3m处及实验室人造海水中 .试验期间 ,以DC直流动电位极化曲线扫描与AC交流电阻抗分析现场量测各试片的瞬间腐蚀速率 .结果发现 :宏观地看 ,海生物在金属 (或锈层 )表面的附著可以减缓金属腐蚀 ,但从微观 (micro)的观点推论 ,海生物在金属表面的附著亦可以造成氧差或浓度差异电池 ,促成局部腐蚀 .此外 ,等效电路的模拟 ,有助于了解海生物附著对金属腐蚀的影响 ,即随浸渍时间的延长 ,金属表面因锈层增厚且趋于致密 ,以致锈层电阻增加 ;又因海生物种类不同 ,含水量不同 ,海生物电阻可能会有极大的差异     

Assessment of carbon steel microbiologically induced corrosion by electrical impedance spectroscopy

A methodology to analyse electrochemical impedance spectroscopy (EIS) data for the study of microbiologically induced corrosion is proposed. The proposed methodology is based on the loss tangent behaviour of EIS spectra for sterile and bacteria-inoculated environments. Loss tangent parameters were obtained by fitting the EIS data to the Cole–Cole dispersion model using a genetic algorithm. Two electrochemical cells were implemented to expose carbon steel probes to sterile and inoculated media for two bacteria consortia, acid-producing bacteria (APB) and sulphate-reducing bacteria (SRB). The APB tests were exposed for 96 h and the SRB tests for 144 h. A microbial count was carried out during each experiment. The EIS spectra were measured during exposure for sterile and inoculated media. The spectra were fitted to a multi Cole–Cole dispersion model, and loss tangent parameters were obtained.     

Experimental and theoretical studies of carbon steel corrosion protection in phosphoric acid solution by expired lansoprazole and rabeprazole drugs

The effects of expired lansoprazole and rabeprazole on the corrosion protection of carbon steel in phosphoric acid (3.0 ?M) solution were examined by Tafel polarization and electrochemical impedance spectroscopy (EIS). Lansoprazole and rabeprazole concentrations (0.5, 1.0, 5.0 and 10 ?mM) in acid solution were raised, which improved corrosion prevention. Both lansoprazole and rabeprazole as the mixed inhibitors retarded the anodic and cathodic processes, as indicated by polarization data. With the increasing temperature in the range of 25–55 ?°C, the inhibition efficiency drops from 92.9% to 69.3% for lansoprazole and from 94.8% to 74.2% for rabeprazole. The major decrease in the inhibition efficiency with ascending temperature proved the physisorption of the drugs. The activation energies for carbon steel corrosion in H₃PO₄solution were enhanced from 41.6 ?kJ ?mol^?1 to 81.9 ?kJ.mol^?1and 85.9 ?kJ ?mol^?1 for lansoprazole and rabeprazole, respectively. The influence of temperature on the corrosion process of carbon steel in the acid medium was used to derive the thermodynamic quantities of corrosion. The adsorption of both lansoprazole and rabeprazole on carbon steel followed the Langmuir adsorption isotherm. The polarization data yielded outcomes that were consistent with the results arising from impedance measurements. The theoretical study of both lansoprazole and rabeprazole was done by a density functional theory (DFT) approach to realize the effects of molecular structure on their inhibitive action. Both lansoprazole and rabeprazole contain a higher E_HOMO, a lower E_LUMO and a lower energy gap than some inhibitors earlier reported as good corrosion inhibitors in the literature.     

新型咪唑啉化合物在H_2S/CO_2共存条件下对Q235钢的缓蚀性能

合成了一种新型咪唑啉化合物1-(2-氨基-硫脲乙基)-2-十五烷基-咪唑啉(IM-S),并通过失重法、电化学方法及扫描电镜等研究了IM-S在H2S/CO2共存条件下对Q235钢的缓蚀性能,探讨了其在Q235钢表面的吸附行为.结果显示,IM-S具有较好的抗H2S、CO2腐蚀能力,能同时抑制碳钢腐蚀的阴、阳极反应过程,最高缓蚀效率可达92.74%.缓蚀剂在Q235钢表面呈单分子层吸附,属于以化学吸附为主的混合吸附.最后采用量子化学方法对IM-S的缓蚀机理做了进一步分析.