共查询到20条相似文献,搜索用时 15 毫秒
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E. E. Ebenso U. J. Ekpe S. A. Umoren Ekerete Jackson O. K. Abiola N. C. Oforka 《应用聚合物科学杂志》2006,100(4):2889-2894
The corrosion inhibition of aluminum in H2SO4 in the presence of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) and the effect of addition of halides (KCl, KBr, KI) was studied using the hydrogen evolution technique at 30 and 40°C. Inhibition efficiency (%I) increases with concentration of PVA and PEG—‐but with PEG having higher %I. The %I decrease with increase in temperature from 30 to 40°C in the absence and presence of inhibitor and halides. PVA and PEG were found to obey Freundlish adsorption isotherm. Phenomenon of physical adsorption is proposed from the obtained Ea, ΔGads, and Qads values obtained. The synergism parameters (SI) obtained were found to be greater than unity for both PVA and PEG, which indicates that the enhanced inhibition efficiency caused by the addition of halides is only due to synergism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2889–2894, 2006 相似文献
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The corrosion inhibition of mild steel in 0.1M H2SO4 in presence of starch (polysaccharide) was studied using weight loss and potentiodynamic polarization measurements in the temperature range of 30–60°C. Starch inhibits the corrosion rates of mild steel to a considerable extent; the maximum inhibition efficiency (%IE) being 66.21% at 30oC in presence of starch concentration of 200 ppm. The effect of the addition of very small concentration of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide on the corrosion inhibition behavior of starch was also studied. The IE of starch significantly improved in presence of both the surfactants. The effect of surfactants on the corrosion inhibition behavior of starch appears to be synergistic in nature. Starch alone and in combination with surfactants is found to obey Langmuir adsorption isotherm from the fit of the experimental data of all concentration and temperature studied. Phenomenon of physical adsorption is proposed from the trend of IE with temperature and also the values Ea, ΔGads, and Qads obtained. The results obtained by potentiodynamic polarization measurements are consistent with the results of the weight loss measurement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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针对火电厂循环冷却水水质研究了聚环氧琥珀酸(PESA)的阻垢性能,并同PASP、MA-AA、ATMP等阻垢剂的阻垢效果进行了比较.实验结果表明:PESA阻垢效果优良.比PASP、MA-AA阻垢效果更优,比ATMP阻垢效果稍差.针对凝汽器铜材质(HSn-70A)研究了单一聚环氧琥珀酸的缓蚀性能,开发了与之复配的复合配方,筛选出的最佳复配方案为10mg/L PESA+0.5 mg/L BTA+2mg/L Zn2++10mg/L葡萄糖酸钠,在此条件下铜的腐蚀率仅为0.0005mm/a. 相似文献
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采用失重法考察不同温度下5%氨基磺酸中不同浓度的硫脲对碳钢的缓蚀作用;并对氨基磺酸介质中硫脲在碳钢表面吸附热力学进行了研究。硫脲低浓度时,随浓度增大,缓蚀作用增强;当其浓度达到一定值后,缓蚀作用基本保持不变。实验结果表明,硫脲在碳钢表面发生单分子层吸附,并且满足Langmuir吸附规律。ΔG°<0,吸附过程可以自发进行,并且随着温度的升高ΔG°增大,吸附作用降低。ΔH°<0表明反应是放热过程。ΔS°>0,说明硫脲吸附于表面,随着反应的进行体系更为无序。 相似文献
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M. Poelman I. Recloux N. Cornil N. Blandin L. Deronne Y. LeDisert M.-G. Olivier 《Progress in Organic Coatings》2012
Cathodic electrodeposition is currently used to protect the totality of the world automotive production against corrosion. Although this technology is highly competitive, some aspects, as the coverage of salient edges, could still be improved. Special paints containing flow modifiers have consequently been developed. Salt fog exposure on steel knife blades is the most frequently performed test to characterize the protection afforded by cataphoretic coatings against edge corrosion. In this study, a method based on electrochemical techniques, among which cathodic polarization and electrochemical impedance spectroscopy (EIS), is proposed for the special characterization of edge coverage in a faster and less restrictive way in comparison with salt fog spray. The combination of dc and ac measurements is also employed to accelerate the degradation process and to improve the fitting of EIS spectra. In order to validate these testing methods, different kinds of pretreatments and coatings were selected. The influence on edge corrosion of different parameters as the coating thickness and the amount of flow modifier were determined. 相似文献
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Saviour A. Umoren Moses M. Solomon Ime B. Obot Rami K. Suleiman 《Journal of Adhesion Science and Technology》2018,32(17):1934-1951
The work reports on the study carried out to comparatively assess the corrosion inhibition efficacy of crude ethanolic extracts of date palm leaves and seeds on X60 carbon steel corrosion in 15% HCl solution at 25–60 °C. The corrosion inhibition studies was carried out using weight loss and electrochemical (potentiodynamic polarization and linear polarization resistance) techniques. Preliminary phytochemical screening was performed in order to determine the phytoconstituents present in the crude extracts. The influence of extractive solvents on the corrosion inhibition performance of the extracts was also investigated. It is found that the crude extracts of both date palm leaves and seeds contain saponins, flavonoids, cardiac glycosides and reducing sugars. Tannins is only present in the leaves and absent in the seeds while anthraquinones is absent in both extracts. The crude ethanolic extracts inhibited the corrosion of X60 steel in the aggressive 15% HCl solution with the leaves extract showing superior performance. Inhibition efficiency increased with increase in concentration of the extracts and temperature. Potentiodynamic polarization results reveal that the extracts function as mixed type inhibitors. Corrosion inhibition occurs by virtue of adsorption of components of the extract on the steel surface and was found to follow Langmuir adsorption isotherm model. On the influence of the extractive solvents on the corrosion inhibition performance, the order of inhibition efficiency at 60 °C follows the trend DPLAE (73.6%) > DPLEE (62.5%) > DPSAE (59.9%) > DPSEE (55.9%) with the optimum extract concentration (2000 ppm) studied. 相似文献
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The resistance to pitting corrosion of austenitic stainless steel Cr18Mn12N has been studied in model solutions of sulphuric
acid (0.5 m) containing chloride ions (0.5 m). The cyclic potentiodynamic method has been employed to investigate the effects of chloride ions and agitation rate on the
pitting and repassivation potentials. Electron and optical microscopy, electron diffraction spectroscopy and atomic absorption
spectrometry have been used to detect the surface sites for pit formation and the growth of pit nuclei. The results obtained
with chromium–manganese–nitrogen steel have been compared with those of austenitic Cr18Ni9 stainless steel. A similarity in
pit initiation is established, while steel composition exhibits no significant effect. Cr18Mn12N steel is less prone to repassivation
as compared with Cr18Ni9 steel. 相似文献
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The electrochemical behavior and corrosion of carbon steel in various types of naphthenic acid solutions have been studied by using cyclic voltammetry technique. The data reveal that the anodic excursion spans of carbon steel in naphthenic acid solution are characterized by the occurrence of a well-defined anodic peak (peak A), followed by a passive region. The passivation may be related to the formation and precipitation of oxide film on the electrode surface. The data reveal that increasing naphthenic acid concentration enhances the anodic peak current density (IPA) and shifts its peak potential towards more positive values. The corrosion rate of carbon steel depended critically on the naphthenic acid types. The rate of the corrosion process increased with increasing in molar mass of naphthenic acid, reaching a maximum value in the presence of CHPA acid (C9), and then decreased.
Potentiodynamic polarization measurements indicated that ethoxylated fatty acid derivatives have a strong effect on the corrosion behavior of the carbon steel in naphthenic acid solutions. The inhibition efficiency of these compounds was found to vary with their nature and concentration. The order of effectiveness of the inhibitors was OL(EO)80 > OL(EO)40 > OL(EO)20. The adsorption of ethoxylated fatty acid on the carbon steel surface in naphthenic acid solutions was found to obey Frumkin isotherm and kinetic-thermodynamic model. 相似文献
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Corrosion inhibition property of N-(phenylcarbamothioyl)benzamide (PCB) on mild steel in 1.0 M HCl solution has been investigated using chemical (weight loss method) and electrochemical techniques (potentiodynamic polarization and AC impedance spectroscopy). The inhibition efficiencies obtained from all the methods are in good agreement. The thiourea derivative is found to inhibit both anodic and cathodic corrosion as evaluated by electrochemical studies. The inhibitor is adsorbed on the mild steel surface according to Langmuir adsorption isotherm. The adsorption mechanism of inhibition was supported by spectroscopic (UV-visible, FT-IR, XPS), and surface analysis (SEM-EDS) and adsorption isotherms. The thermodynamic parameter values of free energy of adsorption (ΔGads) reveals that inhibitor was adsorbed on the mild steel surface via both physisorption and chemisorption mechanism. 相似文献
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Saviour A. Umoren 《Journal of Adhesion Science and Technology》2016,30(17):1858-1879
The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the widening utilization of plant extracts for metallic corrosion control and reports on the corrosion inhibition effect of mustard seed extract (MSE) for typical X60 pipeline steel in 2 M HCl and 1 M H2SO4 solutions. Gravimetric and electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization) methods were employed. The effect of immersion time and temperature on the corrosion inhibition effect of the plant extract was also studied. Results obtained show that MSE inhibited the corrosion of steel in both media which was more pronounced in H2SO4 than in HCl environment. Inhibition efficiency increased with increase in the concentration of the extract but decreased with increase in temperature. The potentiodynamic polarization studies revealed that MSE functions as a mixed-type inhibitor. The corrosion inhibition is assumed to occur via adsorption of the components of the extract on the steel surface which was found to obey Langmuir adsorption isotherm model. The morphology of the corroding steel surface in the absence and presence of the MSE was visualized using scanning electron microscopy. 相似文献
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Moses M. Solomon 《Journal of Adhesion Science and Technology》2013,27(21):2311-2333
This article reports the preparation of poly (methacrylic acid)/silver nanoparticles composite (PMAA/AgNPs) by in situ mixing of aqueous solutions of PMAA and 1 mM AgNO3 with natural honey as reducing and stabilizing agent. The prepared PMAA/AgNPs composite was characterized by UV–vis spectroscopy, Fourier transformed infrared, X-ray diffraction and energy dispersive spectroscopy (EDS) while the morphology of the AgNPs in the composite was obtained by transmission electron microscopy (TEM). TEM results revealed that the AgNPs were spherical in shape. The performance of PMAA/AgNPs composite as anticorrosion material for Al in acidic environment was examined by electrochemical, weight loss methods, complemented by surface analysis characterization with scanning electron microscopy (SEM), EDS and water contact angle measurements. Results obtained indicate that PMAA/AgNPs composite is effective corrosion inhibitor for Al in an acid-induced corrosive environment. Inhibition efficiency increased with increase in composite concentration but decreased with rise in temperature. From potentiodynamic polarization results, PMAA/AgNPs composite is found to function as a mixed-type corrosion inhibitor. The adsorption of the composite onto Al surface was found to follow El-Awady et al. adsorption isotherm model. SEM, EDS and water contact angle results confirmed the adsorption of the composite on Al surface. 相似文献