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.

Polyaspartic acid as a corrosion inhibitor for WE43 magnesium alloy

The inhibition behavior of polyaspartic acid(PASP)as an environment-friendly corrosion inhibitor for WE43 magnesium alloy was investigated in 3.5 wt.%NaCl solution by means for EIS measurement,potentiodynamic polarization curve,and scanning electron microscopy.The results show that PASP can inhibit the corrosion of WE43 magnesium alloy.The maximum inhibition efficiency is achieved when PASP concentration is 400 ppm in this study.

Corrosion inhibition effect of N, N′-bis(2-pyridylmethylidene)-1,2-diiminoethane on AZ91D magnesium alloy in acidic media

The inhibition effect of electrochemical noise, EIS and surface analysis to evaluate N'-bis (2-pyridylmethylidene)- 1,2-diiminoethane (BPIE) Schiff base against AZ91D alloy corrosion in 0.01 mol/L HCl was investigated by different electrochemical methods. Potentiodynamic polarization curves revealed that the BPIE acts as a mixed-type corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) measurements confirmed the corrosion inhibition effect of the BPIE. As the inhibitor concentration increased, the charge transfer resistance increased and the double layer capacitance decreased due to more inhibitor adsorption on the surface. The results obtained by analysis of electrochemical noise (EN) data in time and frequency domains are in good agreement with EIS and polarization results. Moreover, scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) were used to investigate the corrosion inhibition of the BPIE. SEM images showed that the corrosion damage of the alloy surface reduced in the presence of BPIE. The intensity of the XRD peaks corresponding to magnesium-rich α phase increased in the presence of BPIE, indicating lower corrosion of alloy sample. Also, EDX analysis approved the corrosion inhibition performance of the BPIE. The studied Schiff base compound acts by physical adsorption on the alloy surface and its adsorption obeys the Langmuir isotherm.

Benevolent behavior of Kleinia grandiflora leaf extract as a green corrosion inhibitor for mild steel in sulfuric acid solution

The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, UV–visible spectroscopy, and X-ray diffraction analysis. The effect of temperature on the corrosion behavior of mild steel was studied in the range of 308 to 328 K. The inhibition efficiency was observed to increase with increasing concentration of the extract. Polarization curves revealed that the Kleinia grandiflora leaf extract is a mixed inhibitor. Impedance diagrams revealed that an increase of Kleinia grandiflora leaf extract concentration increased the charge transfer resistance and decreased the double-layer capacitance. The adsorption process obeys Langmuir＇s model, with a standard free energy of adsorption（ΔGads） of-18.62 k J/mol. The obtained results indicate that the Kleinia grandiflora leaf extract can serve as an effective inhibitor for the corrosion of mild steel in a sulfuric acid medium.

Efficiency of Chalcone Compounds Inhibitors for Acid Corrosion of Al and Al-3.5Mg Alloy

Corrosion inhibition of Al and Al-3.5Mg alloy by organic compounds, namely chalcones in hydrochloric acid solutions has been investigated by rapid polarization technique and weight loss method. Polarization measurements show that, the inhibitors act cathodically both in case of Al and Al-3.5Mg alloy. It was found from the weight loss measurements that, the inhibition efficiency depends on the substituent in the chalcone compound. The relative inhibitive efficiency of these compounds has been explained on the basis of structure dependent electron donor properties of the inhibitors and the metal inhibitor interaction on the surface. The inhibition efficiency ranges from 16 to 64% for Al and from 30% to 91% for Al-3.5Mg alloy

Evaluation of Propargyl Alcohol as a Corrosion Inhibitor for Duplex Stainless Steel in Hydrochloric Acid

ASTM A182 F51 duplex stainless steel with a 50:50 ratio of austenite to ferrite microstructure is a material used in mechanical engineering.Its uses include the manufacturing of equipment and components subject to acidification or acid stimulation for oil and gas industries.During acid stimulation or acidification,hydrochloric acid(HCl)solution with concentrations ranging from 5%to 28%(by volume)is injected into the limestone(CaCO3)and dolomite(CaCO3·MgCO3)reservoir rock to restore permeability and consequently increase oil well productivity.Therefore,it is important to use a corrosion inhibitor,such as propargyl alcohol,to prevent or inhibit the aggressive attack of HCl on duplex stainless steel.The present study evaluates the corrosion resistance of ASTM A182 F51 stainless steel using gravimetric(mass loss)and electrochemical(polarization)tests.Studies were completed with and without the addition of 500 and 1,000 mg/L propargyl alcohol in HCl solutions with concentrations of 10%and 15%(by volume)at temperatures of 25,40 and 55°C.The good protection by propargyl alcohol of duplex steel immersed in HCl is observed.

Exopolysaccharides from Lactic acid Bacteria as Corrosion Inhibitors

Bacterial EPSs （exopolysaccharides） are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus fermentum Ts are presented and discussed. The Lactobacillus fermentum Ts strain was isolated from types of Bulgarian rye flour. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% fructose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM （scanning electron microscopy） JSM 5510. It could be underlined that 10% sucrose and 10% maltose in the media stimulated the process of protection of corrosion.

Investigation of Aloe lateritia Gel as Corrosion Inhibitor for Mild Steel in 2 M HNO3 and 1 M H2SO4 Media

Corrsion inhibition of Aloe lateritia gel for Mild steel in 2 M HNO3 and 1 M H2SO4 solutions was investigated by potentiodynamic polarization, Scanning electron microscopy (SEM) and Foutier transform infrared (FT-IR). Inhibition efficiency increased with the increase of the concentration of the gel. The optimal concentration of the gel gives maximum inhibition efficiency of 77.4% and 70.3% in 1 M H2SO4 and 2 M HNO3 respectively. Polarization plots shows that, the gel works as a mixed type inhibitor altering both cathodic and anodic reaction. SEM proves the uniform and pitting corrosion at the surface of Mild steel in 1 M H2SO4 and 2 M HNO3 respectively. Using FT-IR potential function groups from pure gel and some stretch shift was observed from corrosion product and some stretch shift from corrosion products was observed.

A Study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as Green Corrosion Inhibitors for Carbon Steel in Sulfuric Acid

A study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as eco-friendly corrosion inhibitors for 1018 carbon steel in 0.5 M H2SO4 has been carried out by using weight loss tests, potentiodynamic polarization curves and electrochemical impedance spectroscopy measuremnts. Results have shown that the three extracts performed as good corrosion inhibitors, but the Eruca vesicaria exhibited the best performance followed by Erythrina americana. The three inhibitors formed a protective, passive film which protected the steel from corrosion. This was because they contain antioxidants present in their molecular structure with heteroatoms such as N, C and O like phenols, amino acids, etc., which react with metal and environment to form the protective film.

Corrosion Inhibition of Carbon Steel in Acidic Mediaby Using Actinidia deliciosa(Kiwifruit)Extract

The corrosion inhibition of 1018 carbon steel in 0.5 M H2SO4 by using Actinidia deliciosa (Kiwifruit) peel extract has been investigated by using potentiodynamic polarization curves and electro-chemical impedance spectroscopy. Two kinds of extracts are investigated, one from the tender, and another one from ripe Actinidia deliciosa. Concentrations include 0, 25, 50, 75, and 100 ppm at room temperature. Results indicate that both kind of extracts acted as good corrosion inhibitors, is more efficient in the ripe extract. Corrosion inhibition efficiency increases with increasing its concentration for ripe extract, whereas for the tender Actinidia deliciosa, the higest inhibitor efficiency is obtained by adding 25 ppm and decresaing with a further increase in its concentration. Both extracts improve the passive film properties by decreasing the passive current density values. It is found that the corrosion inhibition is due to the presence of heteroatoms present in Actinidia deliciosa, mainly quercitine, which is physically adsorbed in the steel following a Frumkin type of adsorption isotherm which forms a protective film.

Corrosion inhibition of α,β-unsaturated carbonyl compounds on steel in acid medium

Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.

Red tetrazolium as an effective inhibitor for the corrosion of cold rolled steel in 7.0 mol·L^(-1) H_2SO_4 solution

The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results show that RTZ acts as an effective inhibitor for the corrosion of CRS in 7.0 mol·L^(-1) H_2SO_4, and the maximum inhibition efficiency is higher than 95% with a RTZ concentration of 2.0 mmol·L^(-1). The adsorption of RTZ on CRS surface follows Langmuir isotherm. RTZ effectively retards both cathodic and anodic reactions, and acts as a mixed-type inhibitor. EIS exhibits two capacitive loops, and their resistances increase drastically in the presence of RTZ. SEM and AFM confirm that the addition of RTZ could significantly retard the corrosion of CRS surface. A series of characterizations like FTIR, RS, XRD and XPS reveal that the corrosion CRS surface is composed of the corrosion products of iron sulfates, iron oxides and iron hydroxide, as well as inhibitor. Theoretical results of quantum chemical calculation and molecular dynamics(MD) indicate that the adsorption center of RTZ+(organic cationic part of RTZ) mainly relies on its tetrazole ring,and the adsorption of RTZ+on Fe(001) surface is in a nearly flat orientation mode.

Experimental and computational chemical studies on the cationic furanylnicotinamidines as novel corrosion inhibitors in aqueous solutions

The corrosion inhibition action of three newly synthesized furanylnicotinamidine derivatives namely: 6-[5-{4(dimethylamino)phenyl}furan-2-yl]nicotinamidine(MA-1256), 6-[5-(4-chlorophenyl)furan-2-yl]nicotinamidine(MA-1266), and 6-[5-{4-(dimethylamino)phenyl}furan-2-yl]nicotinonitrile(MA-1250) on carbon steel(C-steel) was investigated in 1.0 mol·L-1 HCl solution by weight loss(WL), potentiodynamic polarization(PP), electrochemical impedance spectroscopy(EIS), and electrochemical frequency modulation(EFM)techniques. Morphological analysis was performed on the uninhibited and inhibited C-steel using atomic force microscope(AFM) and Infrared Spectroscopy(ATR-IR) methods. The effect of temperature was studied and discussed. Inspection of experimental results revealed that the inhibition efficiency(IE) increases with the incremental addition of inhibitors and with elevating the temperature of the acid media. The adsorption of furanylnicotinamidine derivatives on C-steel follows Temkin’s isotherm. PP studies indicated that the investigated compounds act as mixed-type inhibitors and showed that p-dimethylaminophenyl furanylnicotinamidine derivative(MA-1256) was the most efficient inhibitor among the other studied derivatives with IE reached(95%)at 21 × 10-6 mol·L-1. MA-1266 is highly soluble in aqueous solution and has non-toxicity profile with LC50 N 37 mg·L-1. Thus, MA-1266 can be a promising green corrosion inhibitor candidate with IE N 91% at 21× 10-6 mol·L-1. The experiments were coupled with computational chemical theories such as quantum chemical and molecular dynamic methods. The experimental results were in good agreement with the computational outputs.

Corrosion Inhibition of Mild Steel in Hydrochloric Acid by Tannins Rom Rhizophora Racemosa

Studies on the corrosion behaviour of mild steel electrodes in inhibited hydrochloric acid are described. Conventional weight loss measurements show that a maximum concentration of 140 ppm of tannin from Rhizophora racemosa is required to achieve 72% corrosion inhibition. Similar concentration of tannin: H3PO4 in ratio 1:1 gave 61% inhibition efficiency, whereas efficiency obtained for phosphoric acid as inhibitor in the same environment was 55%. Corrosion rates obtained over six hours of exposure in 1M HCl solution at inhibitor concentrations of 140 ppm are 2 mA/cm2, 2.4 mA/cm2, 2.6 mA/cm2 and 6 mA/cm2 for tannin, tannin/H3PO4 and H3PO4-inhibited and uninhibited specimens respectively. Natural atmospheric exposure studies revealed that specimens treated in H3PO4 resisted corrosion for three weeks, while tannin treated specimens suffered corrosion attack after one week of exposure tests.

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.

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.

Comparison of corrosion resistance of MgAl-LDH and ZnAl-LDH films intercalated with organic anions ASP on AZ31 Mg alloys

The aspartic acid(ASP),an environment-friendly corrosion inhibitor,was explored to intercalate into the ZnAl-layered double hydroxide(ZnAl-LDH)and MgAl-LDH coatings on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and corrosion resistance of the prepared coatings were comparatively investigated.It is found that the uniform and dense layered nanosheet(NS)vertically grows on the substrate,and the MgAl−ASP-LDH films exhibit a three-dimensional(3D)rose-like sheet structure with high ratio of pore coverage.The MgAl−ASP-LDH coating exhibits better corrosion resistance and durability of longtime immersion than ZnAl−ASP-LDH coating.The corrosion current density of two coatings is two or three orders of magnitude lower than that of bare Mg alloy,indicating that ZnAl/MgAl-LDH films intercalated with organic ASP anions can significantly improve the corrosion resistance of Mg alloy.

Electrochemical and Stress Corrosion Cracking Behavior of Alpha-Al Bronze in Sulfide-Polluted Salt Water: Effect of Environmentally-Friendly Additives

The stress corrosion cracking (SCC) behavior of α-Al bronze alloy (Cu7Al) was investigated in 3.5% NaCl solution in the absence and in the presence of different concentrations of Na2S under open circuit potentials using the constant slow strain rate technique. Also, the addition of different concentrations of cysteine (cys), and alanine (ala) to the test solution, as corrosion inhibitors, was studied. Increasing the sulfide ions concentration in polluted salt water resulted in a reduction in the maximum stress (σmax) and an increase in the susceptibility of α-Al bronze towards SCC. The addition of ala and cys to the test electrolyte increased the time to failure by changing the mode of failure from brittle transgranular cracking to ductile failure. Electrochemical tests were performed to assist the interpretation of the SCC data. Electrochemical impedance spectroscopy (EIS) was used to investigate the mechanism of corrosion inhibition. The results support film rupture and anodic dissolution at slip steps as the operating mechanism of the SCC process. Therefore, cys and ala can be considered as potential environmentally-friendly corrosion inhibitors for the SCC of α-Al bronze in 3.5% NaCl solution containing sulfide ions.