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1.
In‐situ characterization of the early stage of pipeline steel corrosion in bicarbonate solutions by electrochemical atomic force microscopy
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An electrochemical atomic force microscope was used to characterize the early stage of corrosion of an X100 pipeline steel in bicarbonate solutions with varied concentrations by synchronous measurements of electrochemical potential of the steel and its topographic evolution with time. Upon immersion of the steel in 0.01 M NaHCO3 solution, both electrochemical potential and topographic profile are associated with the dissolution of air‐formed oxides present on the steel surface. The potential drops and the surface roughness increases rapidly. When corrosion of the steel occurs, the potential further drops and the surface roughness of the steel increases gradually. As the steel corrosion achieves a steady state, the generation of corrosion products reaches a dynamic equilibrium state. The surface roughness maintain an approximately stable value. In solutions containing increased bicarbonate concentrations, such as 0.1 M and 0.5 M NaHCO3, the steel can be passivated. The formed passive film can eliminate some surface features and improves the surface roughness. The topographic profile of the steel surface in 0.5 M NaHCO3 solution is smoother than that in 0.1 M solution. The surface features within 20 nm become eliminated after 4500 s of immersion in 0.1 M NaHCO3 solution, while larger features within 50 nm in size are eliminated in 0.5 M NaHCO3 solution in the same time period. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
2.
L. E. Tsygankova V. I. Vigdorovich Ya. R. Kim V. I. Kichigin A. V. Boldyrev 《Russian Journal of Applied Chemistry》2005,78(12):1961-1969
The inhibitive power of AMDOR IK-7 formulation, homologous mixture of alkyl ammonium acetates C10–C14 in a specific solvent, and PKU-6 toward corrosion of St. 3 steel in weakly acid media containing 5.8 g l?1 NaCl, H2S, and CO2 was studied. The influence exerted by the inhibitors on the kinetics of partial electrode reactions and on the hydrogenation of steel was examined. Impedance spectra were recorded and analyzed. 相似文献
3.
Do Kyoung Lee Kyung Ju Lee Yong Woo Kim Byoung Ryul Min Jong Hak Kim 《Journal of Polymer Science.Polymer Physics》2007,45(9):1018-1025
Silver polymer electrolytes were prepared by blending silver salt with poly(oxyethylene)9 methacrylate)‐graft‐poly(dimethyl siloxane), POEM‐g‐PDMS, confining silver salts within the continuous ion‐conducting POEM domains of microphase‐separated graft copolymer. AgClO4 polymer electrolytes exhibited their maximum conductivity at high silver concentrations as well as higher ionic conductivities than AgCF3SO3 electrolytes. The difference in conductivities of the two electrolytes was investigated in terms of the differences in the interactions of silver ions with ether oxygen of POEM and, hence, with the anions of salts. Upon the addition of salt in graft copolymer, the increase of Tg in AgClO4 was higher than that in AgCF3SO3 electrolytes. Analysis of an extended configuration entropy model revealed that the interaction of ether oxygen/AgClO4 was stronger than that of ether oxygen/AgCF3SO3 whereas the interaction of Ag+/ClO4? was weaker than that of Ag+/CF3SO3?. These interactions are supported by the anion vibration mode of FT‐Raman spectroscopy. It is thus concluded that the higher ionic conductivity of AgClO4 electrolytes was mostly because of higher concentrations of free ions, resulting from their strong ether oxygen/silver ion and weak silver ion/anion interactions. A small angle X‐ray scattering study also showed that the connectivity of the POEM phase was well developed to form nanophase morphology and the domain periodicities of graft copolymer electrolytes monotonically increased with the increase of silver concentration up to critical concentrations, after which the connectivity was less developed and the domain spacings remained invariant. This is attributed to the fact that silver salts are spatially and selectively incorporated in conducting POEM domains as free ions up to critical concentrations, after which they are distributed in both domains as ion pairs without selectivity. The increase of domain d‐spacing in AgClO4 electrolytes was larger than that in AgCF3SO3, which again results from high concentrations of free ions in the former. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1018–1025, 2007 相似文献
4.
Structure of ZnPO3F · 2,5 H2O, a Novel Inhibitor of Corrosion The crystal structure study of ZnPO3F · 5/2 H2O shows two kinds of Zn environment: octahedral and tetrahedral. The final R index is 0.039 for 1437 independent observed reflections. ZnPO3F · 5/2 H2O is a good corrosion inhibitor for carbon steel in 3% NaCl solutions at a concentration of 10?4 M/l: the inhibitive efficiency estimated by steady-state electrochemical methods is about 96%. 相似文献
5.
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 EHOMO, a lower ELUMO and a lower energy gap than some inhibitors earlier reported as good corrosion inhibitors in the literature. 相似文献
6.
Kristina D. Radosavljević Jelena D. Lović Dušan Ž. Mijin Slobodan D. Petrović Milka B. Jadranin Aleksandar R. Mladenović Milka L. Avramov Ivić 《Chemical Papers》2017,71(7):1217-1224
The electrodegradation of azithromycin was studied by its indirect oxidation using dimensionally stable Ti/RuO2 anode as catalyst in the electrolyte containing methanol, 0.05 M NaHCO3, sodium chloride and deionized water. The optimal conditions for galvanostatic electrodegradation for the azithromycin concentration of 0.472 mg cm?3 were found to be NaCl concentration of 7 mg cm?3 and the applied current of 300 mA. The differential pulse voltammetry using glassy carbon electrode was performed for the first time in the above-mentioned content of electrolyte for the nine concentration of azithromycin (0.075–0.675 mg cm?3) giving the limits of azithromycin detection and of quantification as: LOD 0.044 mg cm?3 and LOQ 0.145 mg cm?3. The calibration curve was constructed enabling the electrolyte analysis during its electrodegradation process. The electrolyte was analyzed by high-performance liquid chromatography and electrospray ionization time-of-flight mass spectrometry. The electrooxidation products were identified and after 180 min there was no azithromycin in the electrolyte while TOC analysis showed that 79% of azithromycin was mineralized. The proposed degradation scheme is presented. 相似文献
7.
J. L. Li S. D. Zhu Z. F. Yin C. T. Qu Y. L. Wei 《Russian Journal of Electrochemistry》2014,50(9):838-845
CO2/H2S corrosion behavior of tubular steel SM 80SS have been investigated utilizing electrochemical measurement technology, weight loss test, scanning electron microscope (SEM) and X-ray diffraction (XRD). The results showed that temperature increased the corrosion rate and changed the corrosion mechanism of tubular steel SM 80SS. Cl? quickened the anodic dissolution and increased the corrosion rate of tubular steel SM 80SS. Furthermore, the addition of Ca2+ and Mg2+ resulted in the corrosion products changing from crystalline FeCO3 to amorphous Fe(Ca,Mg)(CO3)2 and serious corrosion under scale of tubular steel SM 80SS. 相似文献
8.
B.Z. Ginzburg 《Thermochimica Acta》1981,46(3):239-247
The molar heats of dehydration, ΔH¯dehyd., of concentrated sodium chloride and potassium chloride solutions were measured with a differential scanning calorimeter in the scanning and isothermal modes. The overall ΔH¯dehyd. was found to be 44.5 and 44.3 kJ mole?1 H2O for NaCl and KCl solutions respectively. There is an astonishing difference between concentrated NaCl and KCl solutions in the way water is lost. The number of fractions of heat dehydration were 2 for NaCl and 3 for KCl. The excess ΔH¯dehyd. was about 10 kJ mole?1 H2O for fraction II of NaCl, and 17 and 55 kJ mole?1 H2O for fractions II and III, respectively, of KCl. 相似文献
9.
The electrocatalytic reduction of carbon dioxide in aqueous solution using Co [p-N(CH3)3) TPPI under pressure (4~22 kg · cm?2) was carried out on solid-state metal electrodes such as In, Sn, Pb and Pb-Hg. The reduction products were mainly carbon monoxide and a small amounts of formic acid. The effects of the pressure of carbon dioxide, electrolytes, catalyst concentration, electrode materials and potentials on the reduction of carbon dioxide were studied. The optimum voltage for maximum current efficiency of reduction products was at ?1.2 Vvs. SCE for all four kinds of metal electrodes. High current efficiencies (>90%) were obtained with lead and amalgamated lead electrodes in an aqueous solution of NaHCO3 containing 7.4 × 10×5 mol/L of catalyst. 相似文献
10.
Bogdan Tutunaru Adriana Samide Catalin Negrila 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1149-1154
The influence of different ions NO3 ? and SO4 2? on the carbon steel corrosion in ammonium chloride was investigated using mass loss measurements and potentiodynamic polarization. Corrosion products were analyzed using X-ray photoelectron spectroscopy (XPS) and simultaneous thermal and differential scanning calorimetry (TG/DSC). XPS analysis shows that the main product of corrosion is a non-stoichiometric Fe3+ oxyhydroxide, consisting of a mixture of FeO(OH) and FeO(OH) containing inclusions of these anions, species such as Fe3+O(OH,Cl?); Fe3+O(OH,SO4 2?); and Fe3+O(OH,NO3 ?). TG/DSC confirms the decomposition of the rusty products formed by chemical corrosion, compounds like Fe3+ oxyhydroxides, with β-FeOOH as the major phase, crystal structure of which may contain Cl?, NO3 ?, and SO4 2?—e.g., akaganeite [Fe3+O(OH,A)]. 相似文献
11.
The corrosion resistance of AISI 420 stainless steel in 0.1 mol L?1 H2SO4 + 0.1 mol L?1 Na2SO4 solutions at different pH-values and the inhibiting effect of Ce3+ ions was studied using electrochemical polarization methods. The results reveal decreasing of the corrosion rate with an increasing the pH of the solution, which demonstrates the progressive protective character of the inhibitor used. At pH lower than 3.33, the corrosion inhibition was most probably a result of the competitive adsorption of Ce3+ with H+ ions on the cathodic sites of the electrode surface, and it was found to be dependent on the relative concentration of H+/Ce3+. The peroxide generated from the oxygen reduction reaction at pH 3.33 was found to be capable oxidize trivalent cerium (Ce) to the tetravalent state. As obtained hydroxide precipitates act as diffusion barrier hindering the corrosion processes, whereafter a spontaneous passivity occurs on the steel surface at this pH. 相似文献
12.
Hiroki Habazaki Rokuro Nishimura Kenji Okitsu Hiroyuki Inoue Ikuo Kiriyama Fumitaka Kataoka Masatoshi Sakairi Hideaki Takahashi 《Journal of Solid State Electrochemistry》2014,18(2):369-376
The pitting corrosion behavior of high-purity aluminum covered with barrier-type anodic films, which are formed in neutral borate and phosphate electrolytes, has been examined in 0.5 mol dm?3 NaCl solution at an applied potential of ?0.6 V versus Ag/AgCl, which is slightly nobler than the pitting potential of ?0.64 V in the same solution. The pitting current density, i p, increased with time after an incubation time, t i. The double logarithmic plot of i p and polarization time, t, reveal two straight lines, which are separated at the time, τ. The slope becomes larger after τ for the specimens anodized in the phosphate electrolyte, while it becomes smaller for those in the borate electrolyte. Both the t i and τ increase with the thickness of the anodic films, and at the similar film thickness, they are much larger for the anodic films formed in the phosphate electrolyte than for those in the borate electrolyte. The corrosion process can be divided into three stages: the incubation period up to t i, the pit nucleation period before τ, and the pit growth period after τ. We have discussed the different pitting corrosion behavior of the aluminum specimens covered with the anodic films formed in the borate and phosphate electrolytes in terms of ion selectivity of the anodic films. 相似文献
13.
Yong-Jian Qiu John R. Reynolds 《Journal of polymer science. Part A, Polymer chemistry》1992,30(7):1315-1325
The electrochemical quartz crystal microbalance has been employed to investigate the electropolymerization of pyrrole in a variety of aqueous electrolytes. In contrast to the generally accepted cation–radical coupling process for the electropolymerization of pyrrole, an electrochemically initiated chain polymerization, featuring a high polymerization rate and involving little charge transport, was found under specific conditions in the presence of ClO?4, BF?4, and PF?6 electrolytes. The more typical cation-radical coupling mechanism, characterized by a constant polymerization charge to mass deposited ratio, is observed in the presence of Cl?, NO?3, dodecyl sulfate, copper phthalocyanine tetrasulfonate, β-cyclodextrin tetradecasulfate, and poly(styrene sulfonate). Electrochemical characterizations of polypyrrole films prepared in aqueous ClO?4 electrolytes reveal that the polymer formed via chain polymerization exhibits the ability to transport both cations and anions during electrochemical switching between redox states, while the polymer synthesized through cation-radical coupling is only capable of transporting a single ionic species. 相似文献
14.
Weight‐loss tests and electrochemical techniques are used to study the inhibition of BTA and Na2MoO4 either individually or in different combinations for carbon steel in boiling 10.24 mol/L LiBr solution containing 0.07 mol/L LiOH. The result indicates the corrosion of carbon steel is effectively inhibited when BTA or Na2MoO4 is added to the solution individually. The adsorptions of BTA or Na2MoO4 on carbon steel surfaces can be well fitted to a Langmuir adsorption isotherm. The free energy of adsorption of BTA and Na2MoO4 are ?45.07 kJ/mol and ?40.69 kJ/mol, respectively. The corrosion rate is decreased to the minimal value, which is 8.39 μm/y, when 7.28 × 10?4 mol/L Na2MoO4 and 8.39 × 10?4 mol/L BTA are added to a 10.24 mol/L LiBr solution containing 0.07 mol/L LiOH. The inhibition mechanism of the above mixed inhibitors results from the complemental effect of the compact inner layer film composed of Fe‐BTA and the absorbed MoO42? in small quantity of the active site and the outer layer. The passive film of the coordination compound and the adsorbed MoO42? prevent Br? from absorbing and effectively decrease the corrosion of carbon steel. 相似文献
15.
Ye Lin Feng Zeng‐Guo Zhao Yu‐Mei Wu Feng Chen Shi Wang Guo‐Qing 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3650-3665
A novel cyclic ether monomer 3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy‐methyl}‐3′‐methyloxetane (HEMO) was prepared from the reaction of 3‐hydroxymethyl‐3′‐methyloxetane tosylate with triethylene glycol. The corresponding hyperbranched polyether (PHEMO) was synthesized using BF3·Et2O as initiator through cationic ring‐opening polymerization. The evidence from 1H and 13C NMR analyses revealed that the hyperbranched structure is constructed by the competition between two chain propagation mechanisms, i.e. active chain end and activated monomer mechanism. The terminal structure of PHEMO with a cyclic fragment was definitely detected by MALDI‐TOF measurement. A DSC test implied that the resulting polyether has excellent segment motion performance potentially beneficial for the ion transport of polymer electrolytes. Moreover, a TGA assay showed that this hyperbranched polymer possesses high thermostability as compared to its liquid counterpart. The ion conductivity was measured to reach 5.6 × 10?5 S/cm at room temperature and 6.3 × 10?4 S/cm at 80 °C after doped with LiTFSI at a ratio of Li:O = 0.05, presenting the promise to meet the practical requirement of lithium ion batteries for polymer electrolytes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3650–3665, 2006 相似文献
16.
《Electroanalysis》2003,15(13):1129-1133
Electrocatalytic oxidation of thymine at α‐cyclodextrin (α‐CD) incorporated carbon nanotube‐coated electrode (CNT/CE) was thoroughly studied in alkaline media. CNT showed an electrocatalytic effect on the oxidation of thymine, formation of a supramolecular inclusion complex between α‐CD and thymine at CNT/CE further enhanced the sensitivity to thymine. The electrocatalytic behavior was further developed as a sensitive detection scheme for thymine by differential pulse voltammetry. A linear calibration over the concentration range from 2.5×10?5 to 1.8×10?3 mol/L in pH 10.8 NaHCO3‐Na2CO3 buffer solution was obtained with a detection limit of 5×10?6 mol/L. 相似文献
17.
Corrosion resistances of passive films on low‐Cr steel and carbon steel in simulated concrete pore solution
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Ming Liu Xuequn Cheng Gucheng Zhao Xiaogang Li Yue Pan 《Surface and interface analysis : SIA》2016,48(9):981-989
The passive ranges of carbon steel rebar and 3Cr steel rebar in saturated Ca(OH)2‐simulated concrete pore solution with pH 12.6 were determined by means of cyclic voltammetry and potentiodynamic polarization curves. Chronopotentiometry was used to obtain steady‐state conditions for the formation of passive films on rebar samples at different anodic potentials. Electrochemical impedance spectroscopy, Mott–Schottky and X‐ray photoelectron spectrometer curves were employed to compare the formed passive films at different potentials. Additionally, cyclic polarization curves were used to compare the corrosion resistances of formed passive films on the two rebars in saturated Ca(OH)2‐simulated concrete pore solution with different concentration of Cl?. The results show that the passive ranges of the two rebars are all between ?0.15 and +0.6 V, and more stable passive films can be formed on both rebars at the anodic potential of +0.3 V. In the absence of Cl?, the stability and corrosion resistance of the passive film formed on the 3Cr rebar are better than those of CS rebar. The passive film of 3Cr steel has the relatively better pitting corrosion resistance than carbon steel in saturated Ca(OH)2‐simulated concrete pore solution that contains different concentration of Cl?. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
18.
Pedro de Lima Neto Mohamed Atik Luis A. Avaca Michel A. Aegerter 《Journal of Sol-Gel Science and Technology》1994,1(2):177-184
ZrO2 coatings deposited on 316 L stainless steel sheets were synthesized by sol-gel method using Zr(OC3H7)4 as precursor and isopropanol, glacial acetic acid, and water as solvents for application with ultrasounds. Different solutions for dip-coating were prepared with compositions varying between 0.025 and 0.9 mol/dm3 of ZrO2. X-ray diffraction shows that the films densified at 800°C are crystalline with a tetragonal structure. The thickness of the coatings varied from 0.35–0.75 m. The influence of the ZrO2 coatings on the corrosion behavior of stainless steel substrates in aqueous NaCl was studied through potentiodynamic polarization curves at 1 mV/s. The values of the electrochemical parameters allow for an explanation of the role of the films in the increased resistance of steel against corrosion in moderately aggressive environments. 相似文献
19.
Preparation of activated carbon from waste Camellia oleifera shell for supercapacitor application 总被引:3,自引:0,他引:3
Juntao Zhang Liangyu Gong Kang Sun Jianchun Jiang Xiaogang Zhang 《Journal of Solid State Electrochemistry》2012,16(6):2179-2186
The cost-effective activated carbons derived from waste Camellia oleifera shell (COS) by ZnCl2 activation method are investigated as the active electrode material in electric double-layer capacitors (EDLCs) for the first time. The activation temperature and ZnCl2/COS impregnation ratio are two key factors affecting the surface area and pore structure of the prepared activated carbons, which accordingly affect their capacitive performances. Electrochemical investigations indicate that the activated carbon (AC-3-600) obtained at the activation temperature of 600 °C and impregnation ratio of 3 shows the maximum specific capacitance of 374 and 266 F?g?1 in 1 mol L?1 H2SO4 and 6 mol L?1 KOH electrolytes at 0.2 A g?1, respectively. The high capacitance of the AC-3-600 is attributed to its high surface area (1,935 m2 g?1), high total pore volume (1.02 cm3 g?1), and especially the large percentage of micropores (735 m2 g?1). Meanwhile, the activated carbon presents good cycle stability in both acid and alkaline electrolytes during 5,000 cycles at a fair current density of 4 A g?1. So, we had reasons to believe that the activated carbons from waste COS by ZnCl2 activation might be one of the innovative carbon electrode materials for EDLCs application. 相似文献
20.
基于电化学噪声研究缓蚀剂对AA6063铝合金点蚀的影响 总被引:1,自引:0,他引:1
采用电化学噪声(ECN)、电化学阻抗谱(EIS)和极化曲线研究了AA6063 铝合金在3% (w) NaCl 溶液中的亚稳态点蚀萌发和稳态点蚀生长特征, 着重探讨了CeCl3、Na2CrO4、8-羟基喹啉(8-HQ)等三种不同类型缓蚀剂对亚稳态和稳态点蚀的抑制机理. 结果表明: 当铝合金表面阴极相(Al-Si-Fe)周边的Al 基体发生局部溶解后,会导致邻近区域pH值升高(>8.4), 引起Ce(OH)3在蚀点中心区的阴极相表面优先沉积, 从而抑制局部腐蚀的阴极去极化过程. 随着缓蚀剂浓度的提高, 亚稳态噪声峰的平均积分电量(q)随之递减, 但噪声峰的平均寿命几乎没有变化, 表明Ce3+并不能直接加速亚稳态蚀点的修复, 但可降低蚀点内金属Al 的溶解速率. CrO42-不但可加速蚀点修复, 还可降低亚稳态蚀点的形核速率. 8-HQ主要与Al3+、Mg2+等形成不溶性螯合物并沉积在铝合金表面,提高了铝基体的全面抗腐蚀能力, 但并不能显著提高其耐点蚀能力. 相似文献