Corrosion Inhibition of a Green Scale Inhibitor Polyepoxysuccinic Acid

The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect between PESA and Zn2+ or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2+ and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic structure.

Analysis of inhibition of concrete steel-rebar corrosion by Na_2Cr_2O_7 concentrations:Implications for conflicting reports on inhibitor effectiveness

Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of Na2Cr2O7 on the corrosion of concrete steel-rebar in NaCl and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g(0.0127 mol), 8 g(0.025 4 mol) and 6 g(0.019 1 mol) Na2Cr2O7 exhibited, in that order, high inhibition effectiveness, with respective efficiency, η, of(90.46 1.30)%,(88.41 2.24)% and(84.87 4.74)%, in the NaCl medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g(0.025 4 mol) Na2Cr2O7 concentration having η=(78.44 1.10)%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.

The Use of Sodium Silicate as a Corrosion Inhibitor in a Saline Drilling Fluid: A Nonaggressive Option to the Environment

The function of a corrosion inhibitor in drilling mud compositions is the corrosion protection of the equipment involved in drilling operations. Many compositions involve environmentally several products such as fatty amines of high molecular weight, polyoxylated amines, amides, imidazolines, nitrogen heterocyclic products, etc. The potential advantages of the use of silicates are the effective protection of carbon steel, especially in aerated saline fluids, low costs and non-aggressive behavior to environment. Gravimetric and electrochemical tests were carried out using an aerated solution of 3.5% NaCl and the addition of sodium silicate (Na2SiO3·9H2O) as a corrosion inhibitor at concentrations of 250 to 2000 mg/L. The efficiencies of the corrosion protection of carbon steel using silicate concentrations greater than 1250 mg/L were greater than 92%.

Combating Corrosion in Transmission Pipelines in Marine Environment Using Vernomia Amydalina as Inhibitor

Pipelines are system of pipes designed to transport liquids, gases or solid/ liquid mixtures over long distances. Some are used for domestic, household and sewage purposes. Others are buried underground or submerged in water for transportation of natural oil and gas (O & G) products. In this work, the specimens had to be kept in a workable state and steps were taken to prepare each specimen: all cuts and sheared edges were ground out to prevent them from becoming sites for preferential attack. The finishing of the specimen surface with grit abrasive paper (sand paper) and rinsing of the specimens in distilled water were done. Then degreasing of specimen in acetone and air-dried were carried out. Upon drying, the specimens were immediately weighed to obtain their initial weights. Twelve specimens were used for the test as follows: 6 Aluminum (Al);and 6 mild steel (MS) samples. With a 2 M concentration of Vernomia Amydalina (VA) extract solution, the MS and Al samples were immersed in different plastic containers containing 400 ml of seawater with pH value of 7.25 with no (0%) inhibitor added to it. A 5% (400 ml) of the VA solution was poured into the measuring cylinder for each sample-Al and MS. The specimens were suspended by the strings and completely immersed in the different percentage test media. The same procedure was carried out for each of the different percentages, 10%, 15%, 20%, and 25% and a total of 12 solutions were set up. The experimental procedure used was that seawater of 7.25 pH was obtained from Abonnema water front of Rivers State. At the end of every week (168 hours), the specimens were removed from the corrosive media. Observation and recording of appearance of the specimen noting sites were done. Cleanings of specimen with white handkerchief or tissue paper were carried out and washing of specimen with distilled water, scrubbing of specimen with a soft brush and dipping the specimen into acetone after washing, it was removed to air-dry and weighed. It is observed that optimum inhibition of coupons was obtained between 15% - 25% of VA solution during the first four weeks of testing. At the fifth week the inhibitor was gradually losing its effectiveness. This means that more inhibitor need be added at regular intervals to sustain the effectiveness of the inhibitor.

Study on the Corrosion inhibitor and Fog Suppressor for Chemical Pickling of Iron and Steel

A new type of corrosion inhibitor and fog suppressor composed of Nitrogen-containing alkaloid,water-soluble butadiene lower polymer, and inorganic electrolyte has been investigated by gravimetric and electrochemical method. Effects or this chemicals on pickling rate and hydrogen penetration into iron and steel material in 50～150 g/L HCI or/and H2SO4 solutions at 20～70℃ temperature were examined. The amount of acid fog escaping from the surface of air-liquid was determined by chemical titration. The results indicate that the efficiency of inhibition and suppression depends on film properties by which mean a barrier film on the interface of bare mild steel/solution or an unsolvable liquid membrane as hydrophibic effect.In present work the film-forming mechanism by in situ and chemistry-mechanics effect is also discussed.

Instantly Investigating the Adsorption of Polymeric Corrosion Inhibitors on Magnesium Alloys by Surface Analysis under Ambient Conditions

Surface engineering of magnesium alloys requires adequate strategies, processes and materials permitting corrosion protection. Liquid formulations containing corrosion inhibitors often are to be optimized according to the demands of the respective substrate and following the service conditions during its application. As an interdisciplinary approach, a combination of several techniques for instantly monitoring or elaborately analyzing the surface state of magnesium was accomplished in order to characterize the performance of new adsorbing sustainable amphiphilic polymers which recently were developed to facilitate a multi-metal corrosion protection approach. The application of established techniques like Contact Angle measurements and X-ray Photoelectron Spectroscopy investigations was supplemented by introducing related and yet faster online-capable and larger-scale techniques like Aerosol Wetting Test and Optically Stimulated Electron Emission. Moreover, an inexpensive setup was configured for scaling the inset and the extent of degradation processes which occur at local electrochemical circuits and lead to hydrogen bubble formation. Using these analytical tools, changes of the surface state of emeried AM50 samples were investigated. Even in contact with water, being a moderate corrosive medium, the online techniques facilitated detecting surface degradation of the unprotected magnesium alloy within some seconds. In contrast, following contact with a 1 weight% formulation of a polymeric corrosion inhibitor, surface monitoring indicated a delay of the onset of degradation processes by approximately two orders of magnitude in time. Mainly based on the spectroscopic investigations, the corrosion inhibiting effects of the investigated polymer are attributed to the adsorption of a primary polymer layer with a thickness of a few nanometers which occurs within some seconds. Immersion of magnesium for several hours brings up a protective film with around ten nanometers thickness.

A modified method for evaluation of materials containing volatile corrosion inhibitor

A systematic research on a modified method that was developed to evaluate the effectiveness of volatile corrosion inhibitor(VCI) materials was carried out. The metal specimen in size of 50mm×25mm×2mm was level mounted on the top of a beaker by transparent adhesive tape and the assembly was placed in a constant temperature water bath and kept at approximately 40℃ to accelerate the vaporization of VCI and distilled water, which was placed at the bottom of the beaker at the same time. The experimental results show that the reproducibility of rust appearance and corrosion rate calculated by specimen’s mass loss is perfect. The outstanding characteristic of the rust appearance based on different VCI formula is discovered that is very important in studying the mechanism of VCI and the synergism of chemical reagent. The accelerated ratio is increased greatly as compared with the traditional method and the value is approximately 15 as compared with Shijiazhuang atmospheric environment corrosion test. The modified method is suitable for formula screening test and quick effectiveness evaluation of VCI materials.

Composite corrosion inhibitors for secondary alkaline zinc anodes

The corrosion inhibition property of PEG600 and In（OH）3 as composite corrosion inhibitors for （second-）（ary） alkaline zinc electrodes was studied, and the inhibition efficiency was determined as 81.9%. The research focused on the mechanism by the methods of electrochemical impedance spectroscopy, polarization curves and IR spectroscopy. The results indicate that the corrosion inhibition effectiveness is attributed to the joint inhibition of anodic zinc dissolution and cathodic hydrogen evolution. And the anodic process is depressed to a greater extent than the cathodic process. The synergistic mechanism of the composite inhinbitors proves to be the enhancement of adsorption of PEG600 by In（OH）3. Potentiostatic experiment results and SEM images verify the inhibition of dendritic growth by the composite inhibitors.

Study of the Synergistic Effect Between Corrosion Inhibitors by Using Fractional Free Volume

The fractional free volumes(FFVs)of the adsorption films formed with different ratios of dipropargyl methoxythiourea imidazoline(DPFTAI)and pyridine quaternary ammonium salt(16BD)were calculated by simulation to determine their synergistic corrosion inhibition effect.The results suggest that the composite corrosion inhibitor at the molar ratio between DPFTAI and 16BD of 4:1 gives the best corrosion inhibition effect.This simulation method to predict the synergistic effect between corrosion inhibitors was further validated by mass loss and electrochemical experiments.This finding delivers valuable understandings of inhibition mechanism of corrosion inhibitors.

Three novel dendritic chitosan derivatives for inhibiting acid corrosion of petroleum pipelines

In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic losses and production safety risks. Corrosion inhibitors were widely used in oil industry because of simple operation process and economical. In this study, three environmentally friendly corrosion inhibitors were synthesized based on the natural polysaccharide chitosan. Corrosion inhibition of three dendritic chitosan derivatives (We name them BH, CH and DH) on mild steel in 1 mol/L HCl solution with natural ventilation system was evaluated by weight loss experiment, electrochemical analysis and surface morphology characterization. The experimental results showed that when the three dendritic chitosan derivatives added in the corrosive medium were 500 mg L^(−1), the corrosion inhibition efficiencies were all more than 80%. Based on quantum chemical calculation, inhibition mechanisms of three dendritic chitosan derivatives were investigated according to molecular structures. The results showed that the benzene ring, Schiff base and N atom contained in the molecule were the active centers of electron exchange, which were more likely to form a film on the carbon steel surface, thereby slowing or inhibiting corrosion. The results also predicted the corrosion inhibition effect BH > DH > CH, which was consistent with the experimental conclusion.

Temperature effect on the corrosion and passivation characterization of Ni_(82.3)Cr_7Fe_3Si_(4.5)B_(3.2) alloy in acidic media

The effects of temperature on corrosion and the electrochemical behavior of Ni82.3Cr7Fe3Si4.5B3.2 glassy alloy in HC1,H2SO4,and H3PO4 acids were studied using AC and DC techniques.Impedance data reveal that the susceptibility to localized corrosion increases with increasing temperature.Potentiodynamic polarization curves reveal that the bulk glassy alloy is spontaneously passivated at all the investigated temperature in H2SO4 and H3PO4 solutions.A localized corrosion effect in HCl solution is clearly observed.The apparent activation energies in the regions of Tafel,active,and passive,as well as the enthalpies and entropies of the dissolution process were determined and discussed.The high apparent activation energy（Ea） value for H3PO4 solution in Tafel region is explained by the low aggressivity of PO4^3- ions.

Experimental Investigation of Inhibition Efficiency of Crocin for Chloride-Induced Corrosion of Aluminum Alloys

The use of Crocin, derived from the flowers of Crocus sativus, is investigated as corrosion inhibitor for the AA1050, AA5083, AA5754 and AA6082 aluminum alloys in chloride ions environment. Aluminum and aluminum alloys are subjected to corrosion in the aggressive environment of chlorides, so several green corrosion inhibitors, mostly of plant origin, with minimum impact on health and the environment have been examined. In this study, the inhibition efficiency of 1.25 mM Crocin in a 0.01 M NaCl corrosive solution was assessed via electrochemical corrosion techniques and gravimetric mass loss measurements of the aluminum alloys. The surface of the specimens was examined using Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Stereomicroscopy and Glossiness measurements. Experimental results reveal the protective anticorrosive action of Crocin for all aluminum alloys in the sodium chloride medium.

Synergistic Inhibition Effect of Sodium Silicate and Acrylamide on the Corrosion of Carbon Steel in a High-concentration KCI Solution

The corrosion inhibition performances of sodium silicate（Na2SiO3） and acrylamide（AM） for Q235 carbon steel in a high-concentration KCl solution（25%, mass fraction） were investigated via static mass loss method, elec- trochemical measurements, scanning electron microscopy（SEM）, X-ray photoelectron spectroscopy（XPS） and Auger electron spectroscopy（AES）. AM shows poor inhibition performance, while Na2SiO3 exhibits a better inhibition per- formance. Moreover, the steel gains mass instead of losing mass in the presence of 0.5% Na2SiO3 and 0.5% AM, in- dicating that the corrosion is completely inhibited~ SEM analysis indicates that a compact protective film is formed on the steel surface by the combined use of inhibitors. Our results demonstrate that Na2SiO3 and AM could have a synergistic effect on steel corrosion in high concentrations of KCl. The synergistic inhibition mechanism is further conjectured by the XPS and AES analysis.

Synergistic inhibitive effect of cysteine and iodide ions on corrosion behavior of copper in acidic sulfate solution

The synergistic inhibitive effect of cysteine(Cys)and iodide ions on the corrosion behavior of copper was examined in a 0.5 mol·L^(-1) Na_(2)SO_(4) solution.Potentiodynamic polarization curve revealed that Cys acted as a mixed type inhibitor with a major effect on the cathodic process,consequently decreased the corrosion current density by a great extent and shifted the corrosion potential negatively.The investigated results suggested that iodide ions can enhance the inhibition efficiency of Cys.The inhibition mechanism of Cys and the synergistic effect of the two examined reagents were investigated by fitting experimental impedance data according to a projected equivalent circuit for metal/electrolyte interface.Surface analysis further confirmed that the corrosion inhibition was realized due to the adsorption of the inhibitor molecules at the metal/solution interface.Langmuir adsorption isotherm was proposed to describe inhibition mechanism of Cys on copper surface.Active sites of Cys molecule were used to form inhibitor film on the copper surface.Addition of iodide ion increased its inhibition efficiency by enhancing adsorption of Cys cations through electrostatic interaction with I-pre-adsorbed on Cu surface.

Synergistic effect of seawater's parameters on the corrosion rate of the austenitic stainless steel 304

In this article the corrosion rate of the austenitic stainless steel type 304, under the synergistic effect of environmental factors has been assessed via potentiodynamic polarization scan.Salinity, velocity, pH and temperature are the factors which induce effects on the corrosion rate of the considered metal.Quantitative analysis is applied using the full two-level factorial experimental design method, which results in the contribution value of each parameter in changing the quantity of average corrosion rate in both individual and synergistic cases.Besides this quantitative analysis, qualitative analysis has been used to predict the variation direction.These two analyses show the important role of the synergistic action, which changes the variation direction of corrosion rate and the contribution percentage of each parameter in varying the value of corrosion rate.Applying both these analyses can show the magnitude and quality of each parameter＇s effect, which is remarkably valuable in marine applications.

Photothermal and pH dual-responsive self-healing coating for smart corrosion protection

A novel self-healing coating with photothermal and pH dual-responsive properties has been designed to protect carbon steel against corrosion by loading the stimuli-responsive microcapsules into a shape memory epoxy coating. The sandwich-like microcapsules were based on reduced graphene oxide/mesoporous silica(r GO@MS) assembled with a p H-responsive poly(N,N-dimethylaminoethyl methacrylate)(PDMAEMA) layer, and were loaded with benzotriazole(BTA) inhibitors(abbreviated as rGO@MS-P-BTA). Under near-infrared(NIR) light irradiation, the prominent photothermal effect of rGO could not only elevate the coating temperature to activate the shape memory effect and close the coating scratch, but also facilitate the release of corrosion inhibitors to suppress the corrosion activity. Moreover,the PDMAEMA as a p H-driven “gatekeeper” realized the controlled release of BTA from microcapsules at acid conditions. The surface morphology analysis, electrochemical impedance spectroscopy(EIS), and scanning electrochemical microscopy(SECM) were performed to evaluate the self-healing performance of the composite coatings. The results showed that the combination of NIR light and p H-responsive selfhealing effects endowed the coating with short healing time and prominent healing efficiency.

Analysis of the Effectiveness and Efficiency of the VA Solution on Offshore Pipelines and Ship Materials

The analysis of the effectiveness and efficiency of Vernomia amydalina (VA) solution as an inhibitor on offshore pipeline and Ship materials (Steel) was carried out with the preparation of the specimen and the VA solution. The specimens were kept in a workable state and the VA Solution (inhibitor) prepared from 1200 g of bitter leaf was plucked, weighed and crushed separately. 600 cl of water was added to each of the crushed leaves. The mixture was put in a filter cloth and squeezed with hand to filter out the active concentration ingredients responsible for corrosion inhibition, which produced a 2 M concentration of VA extract solution. After the experiment was carried out the specimen was air-dried and weighed to determine the corrosion rate and weight loss. This was followed by the determination of the inhibitor efficiency at the different hours and at different percentage/concentration of the VA solution on the specimen. Results were obtained for different hours and at different percentage (0%, 5%, 10%, 15%, 20% and 25% inhibitor)/concentration of the VA solution and graphs plotted. It was observed that at the first week of exposure to corrosive medium there was a substantial reduction in weight of coupons but over the next three weeks there was a gradual decline in weight loss and the corrosion rate reduced evenly. It can be said that the percentage of inhibitor to corrosive medium is insufficient. From the graphs plotted, the inhibitor efficiency is considered high when the concentration of the VA solution is high, which implies a right percentage of inhibitor needs to be administered to obtain good efficiency of the solution. Hence as the weeks go by it was clear that the inhibitor was gradually losing its effectiveness. This means that inhibitors need to be added at regular intervals to sustain the effectiveness of the inhibitor. It is also of vital interest to apply the right concentration of inhibitor since CR increases at high concentrations and temperature. This process did not take into consideration moving water.

邻甲苯磺酰胺三元复配缓蚀剂的缓蚀性能研究

为了研制出用量少、效率高的低毒高效缓蚀剂,采用失重法、电化学和扫描电镜(SEM)研究了邻甲苯磺酰胺(OTS)、碘化钾(KI)和十六烷基三甲基溴化铵(CTAB)复配的三元缓蚀剂在0.5 mol·L^(-1)硫酸溶液中的缓蚀作用。通过正交试验得到三元缓蚀剂最优浓度比为OTS∶KI∶CTAB=15∶6∶5,总浓度130 mg·L^(-1)时,缓蚀率可达98.18%。添加三元缓蚀剂后腐蚀过程的活化能增大,说明腐蚀反应更难发生。三元缓蚀剂符合Langmuir吸附等温式,在碳钢表面的吸附为自发的弱化学吸附过程。极化曲线法和电化学阻抗法(EIS)计算的缓蚀率均与失重法一致。极化曲线表明三元缓蚀剂是以抑制阳极反应为主的混合型缓蚀剂。SEM微观相貌可看出添加三元缓蚀剂后,碳钢表面几乎无腐蚀痕迹,说明三元缓蚀剂分子之间具有缓蚀协同作用,形成了致密牢固的保护膜。

二氧化碳缓蚀剂的研究进展

为了有效应对全球气候变暖达到碳中和的目标,碳捕集、利用与封存(CCUS)技术被大力推广和应用。CCUS过程,油气开发和集输过程始终面临着严重的二氧化碳(CO_(2))腐蚀问题。CO_(2)腐蚀会带来严重的经济损失、环境污染和人身安全等问题。相比于采用昂贵的合金材料防腐措施,在普通碳钢基础上添加缓蚀剂是应对CO_(2)腐蚀较为简单、经济的防腐方法之一。总结了近几年不同类型CO_(2)缓蚀剂的研究进展,包括传统的含有N、O、S、P等杂原子的有机缓蚀剂,含有杂环的有机缓蚀剂,具有两亲性的表面活性剂类缓蚀剂,新型无机纳米材料类缓蚀剂(如石墨烯、碳量子点、离子液体和金属配合物等),以及植物提取物、氨基酸、天然油和生物聚合物等天然型绿色环保缓蚀剂。分析了这些不同缓蚀剂的优缺点和适用性,并讨论了这些缓蚀剂的研究现状。同时,总结了缓蚀剂构效关系和协同效应的研究热点及其存在的问题。最后针对这些不同缓蚀剂的特点和研究现状,对未来CO_(2)缓蚀剂的研究方向进行了分析与展望。

某油田污水管道腐蚀现状及防腐蚀措施研究

西部某油田污水管道腐蚀较为严重,采用涂抹防腐涂层的措施效果较差,因此,在分析了污水水质和管道腐蚀现状的基础上,开展了添加缓蚀剂防腐蚀措施研究。结果表明,目标油田污水中Cl-以及成垢离子的含量均较高,并且污水呈弱酸性,其中酸性气体CO_(2)的含量也较高,容易引起污水管道的腐蚀。现场腐蚀监测点中W-1和W-4处的腐蚀速率均在1.5mm·a^(-1)以上,其余两处监测点的腐蚀速率也能达到1.0mm·a^(-1)左右,管道腐蚀现象比较严重。随着实验温度的升高、污水pH值的降低以及污水中CO_(2)含量的增多,腐蚀速率逐渐增大。缓蚀剂HSR-1对污水管道的防腐蚀效果较好,当缓蚀剂HSR-1的加量达到60mg·L^(-1)时,能使污水对管道钢材的腐蚀速率控制在0.076mm·a^(-1)以下,起到了良好的防腐蚀效果。