聚环氧琥珀酸对碳钢的缓蚀协同效应的研究

聚环氧琥珀酸(PESA)是一种新型的绿色生物可降解环保型水处理剂.用失重法研究了在上海自来水中聚环氧琥珀酸对碳钢的缓蚀性能以及PESA与PBTCA、锌盐的缓蚀协同效应.研究表明,聚环氧琥珀酸、PBTCA、锌盐在自来水中对碳钢具有良好的缓蚀协同效应.     

高温硫酸体系中碳钢缓蚀剂的研究

在任何温度下,60%以下的硫酸对碳钢的腐蚀速率都随着酸质量分数增大而提高。随着条件,如温度、流速等因素的提高,这种腐蚀还会加剧。针对高温硫酸酸洗环境,研究开发出一种缓蚀剂。通过试验发现,该缓蚀剂在(65±5)℃时,60%以下的硫酸酸洗环境中表现出较好的缓蚀效果,最佳质量分数推荐为1.5%～2.5%。     

碳钢—硝酸体系腐蚀与缓蚀行为研究

采用失重法、容量法和电化学方法研究了碳钢在50g/kg HNO_3中的腐蚀行为,并对Lan-5在碳钢—50g/kg NHO_3体系中的缓蚀行为进行了初步探索研究.实验结果表明:碳钢在50g/kg HNO_3中的阳极腐蚀产物是Fe~(3+),阴极反应主要不是析氢反应.Lan-5是碳钢—50g/kg HNO_3体系的高效缓蚀剂,其缓蚀效率可达到99.9%,缓蚀剂之间具有显著的协同作用.研究结果还发现,碳钢在硝酸—Lan-5介质中有孔蚀倾向,阳极极化加速孔蚀的形成.     

Synergistic effect of halide ions on the corrosion inhibition of aluminum in acidic medium by some polymers

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 E_a, ΔG_ads, and Q_ads values obtained. The synergism parameters (S_I) 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     

Inhibition of mild steel corrosion in acidic medium using starch and surfactants additives

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 30^oC 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 E_a, ΔG_ads, and Q_ads 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     

硫酸介质中各类表面活性剂在锌表面上的吸附及其缓蚀作用

用失重法研究了阴离子表面活性剂十二烷基磺酸钠（ＳＤＳ）,阳离子表面活性剂十二烷基胺（ＡＤＳ）和非离子表面活性剂聚乙二醇辛基苯基醚（ＯＰ）在硫酸介质中对锌的缓蚀作用,发现表面活性剂在锌表面上的吸附是产生缓蚀作用的重要原因,且吸附规律服从Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ方程．最后讨论了表面活性剂的吸附取向．     

双相不锈钢在硫酸介质中的应用探讨

介绍了硫酸的腐蚀特性和双相不锈钢的合金化原理、机械性能、耐腐蚀性能。通过分析比较,双相不锈钢凭借优良的耐腐蚀性能、较高的机械强度及低廉的价格,在烟气脱硫、湿法冶炼、硫酸生产等硫酸介质中具有良好的应用前景,可以替代奥氏体不锈钢甚至镍基合金制作罐、槽和管道等。     

聚环氧琥珀酸及其复配物阻垢缓蚀性能的研究

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.     

硫脲在氨基磺酸溶液中对碳钢的缓蚀作用及其吸附热力学研究

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。     

Electrochemical study of the corrosion behaviour at the edges of electrocoated steel

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.     

Comparative studies on the corrosion inhibition efficacy of ethanolic extracts of date palm leaves and seeds on carbon steel corrosion in 15% HCl solution

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.     

聚天冬氨酸复配物对碳钢、紫铜和不锈钢缓蚀性能研究

以聚天冬氨酸（PASP）、聚丙烯酸（PAA）、水解聚马来酸酐（HPMA）、苯并三氮唑（BTA）为原料,得到一种高效的复合型缓蚀剂配方ρ（PASP）∶ρ（PAA）∶ρ（HPMA）∶ρ（BTA）=2.4∶1.6∶2∶1。采用旋转挂片实验和电化学实验对该缓蚀剂的缓蚀性能进行了评价。结果表明,该缓蚀剂对碳钢、紫铜和不锈钢的缓蚀率分别为84.8%,96.4%,99.2%。动态模拟实验结果显示,该缓蚀剂满足循环冷却水运行要求。     

聚环氧琥珀酸复合药剂阻垢缓蚀性能的中试研究

在一步法合成聚环氧琥珀酸的聚合初期加入有机蒙脱土,成功地将聚环氧琥珀酸颜色变浅,并且合成了聚环氧琥珀酸/有机蒙脱土复合水处理剂(OMMT-PESA)。静态阻垢试验、旋转挂片试验和动态模拟试验结果表明,OMMT-PESA复合药剂的缓蚀、阻垢性能均优于单一的聚环氧琥珀酸,且该复合药剂与杀生剂有较好的相容性。     

Pitting corrosion of Cr–Mn–N steel in sulphuric acid media

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.     

Electrochemical investigations of naphthenic acid corrosion for carbon steel and the inhibitive effect by some ethoxylated fatty acids

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 (I_PA) 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.     

盐酸介质中头孢硫脒对碳钢的缓蚀作用

采用动电位极化曲线和交流阻抗实验,研究了抗生素——头孢硫脒的缓蚀剂在盐酸介质中对碳钢的缓蚀性能和缓蚀作用机理。结果表明,头孢硫脒对碳钢在1.0 mol/L盐酸溶液中具有良好的缓蚀性能,当头孢硫脒浓度为0.4 mmol/L时,缓蚀率达86%以上,为抑制阴极反应为主的混合型缓蚀剂。头孢硫脒在碳钢表面的吸附符合Langmuir等温式,属于单分子层吸附,其吸附行为是以化学吸附为主的物理和化学混合吸附。     

硫酸中Q235钢缓蚀剂的电化学研究

采用塔菲尔极化曲线和电化学阻抗谱(EIS)测量方法,研究了5%(质量分数)硫酸溶液中N,N'-二苯基硫脲(DPH-TU)和十二烷基磺酸钠(SDS)对Q235钢的协同缓蚀效应及其机理.实验表明,添加十二烷基磺酸钠时N,N'-二苯基硫脲的缓蚀效果有促进作用.当N,N'-二苯基硫脲和十二烷基磺酸钠的浓度比为1:1时,其协同缓...     

Adsorption and corrosion inhibition behaviour of N-(phenylcarbamothioyl)benzamide on mild steel in acidic medium

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 (ΔG_ads) reveals that inhibitor was adsorbed on the mild steel surface via both physisorption and chemisorption mechanism.     

Biomaterials for corrosion protection: evaluation of mustard seed extract as eco-friendly corrosion inhibitor for X60 steel in acid media

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.     

Performance assessment of poly (methacrylic acid)/silver nanoparticles composite as corrosion inhibitor for aluminium in acidic environment

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.