Inhibition Efficiency Values Research Articles

Comparative assessment and statistical data of admixed rosemary and castor oil on the corrosion inhibition of high carbon and P4 low carbon mold steels

Admixed rosemary and castor oil extracts (RSCO) were studied for their corrosion inhibition properties on high carbon steel (HCS) and P4 low carbon mold steel (P4S) in 1 M H2SO4 and HCl solution by coupon measurement. Results obtained showed that the admixed oil extract performed effectively on HCS and P4S with mean inhibition efficiency values above 90% for P4S and 80% for HCS in both acid solutions. The inhibition efficiency values of RSCO on P4S and HCS varied only with exposure time in H2SO4 with progressive increase in value compared to the effect of RSCO concentration which was negligible. The corresponding effect of RSCO in HCl solution showed no effect of exposure time and RSCO concentration on its performance on P4S while on HCS the effect of exposure time was observed. The standard deviation values obtained for RSCO inhibition efficiency at all concentrations on P4S and HCS in H2SO4, and HCS in HCl shows the degree of variation from mean values to be significant compared to the values obtained for P4S in HCl solution which were relatively small. The proportion of inhibition efficiency values above 70% inhibition performance are 39%, 44%, 100% and 39% at margin of error of 13%, 13.5%, 0% and 13% for P4S and HCS in H2SO4 and HCl solution. Analysis of variance shows exposure time is the dominant statistically relevant source of variation influencing RSCO inhibition performance in H2SO4 and HCl solutions.

Comparative data on the protection performance of celery, pomegranate and green tea distillates on mild steel in weak H2SO4 solution

The non-toxic properties of plant distillate for application as corrosion inhibitors is an effective alternative to the toxic conventional derivatives currently applied in industries. Data on the corrosion inhibition effect of celery, pomegranate and green tea distillates on mild steel corrosion in 0.5 M H2SO4 from coupon analysis is presented. Results showed the distillates performed poorly at low concentrations from 15% to 45% distillate concentration. At 60% distillate concentration, their inhibition performance was average, but below the values for effective inhibition performance with final inhibition efficiency values of 54.55%, 48.65% and 32.39% for celery, pomegranate and green tea distillates. However, at 75% concentration, the inhibition efficiency values significantly increased to 85.74%, 82.85% and 62.70%. At 90% distillate concentration, the inhibition efficiency outputs of the distillates increased further to 95.83%, 87.08% and 92.37% signifying effective inhibition performance of the distillates. Statistical analysis through ANOVA shows distillate concentration strongly influence the corrosion inhibition performance of the distillates with values above 90% compared to exposure time with values below 7%, which is relatively negligible but statistically relevant. Generally, the results show the distillates are effective at high concentration with respect to distillate concentration.

Solution-Processed Two-Dimensional Metal Oxide Anticorrosion Nanocoating.

Molecularly thin two-dimensional (2D) nanomaterials are attractive building blocks for constructing anticorrosion nanocoatings as an ultimate pursuit in the metal-related industry. However, the nanocoating of prefocused graphene is far from industrial demands due to its high cost, low scalability, and insufficient quality. We propose all requirements to realize rational anticorrosion nanocoating of metal oxide nanosheets. The proof-of-concept study with Ti0.87O2 and Ca2Nb3O10 nanosheets demonstrates that the 10 and 20 nm thick coatings fabricated by a facile layer-by-layer (LbL) self-assembly on stainless steel (SUS) give perfect inhibition efficiency (IE) values of 99.92% and 99.89%, respectively. A driving test with a nanosheet-coated car-baffle demonstrated suitable corrosion resistance and mechanical and thermal robustness for industrial applications. The revealed and controlled thermal oxidation mechanisms are critical toward high-temperature application of the 2D oxide anticorrosion nanocoating. The advantages of nanosheet coating and extensible materials design will open a solid but exciting route to anticorrosion nanotechnology.

Experimental, DFT and MD Assessments of Bark Extract of Tamarix aphylla as Corrosion Inhibitor for Carbon Steel Used in Desalination Plants.

This study aimed to examine the extract of barks of Tamarix aphylla as a corrosion inhibitor. The methodology briefly includes plant sample collection, extraction of the corrosion inhibitor, gravimetric analysis, plotting potentiodynamic polarization plots, electrochemical impedance spectroscopic measurements, optimization of conditions, and preparation of the inhibitor products. The results show that the values of inhibition efficiency (IE%) increased as the concentrations of the inhibitor increased, with a maximum achievable inhibition efficiency of 85.0%. Potentiodynamic polarization (PP) tests revealed that the extract acts as a dual-type inhibitor. The results obtained from electrochemical impedance spectroscopy (EIS) measurements indicate an increase in polarisation resistance, confirming the inhibitive capacity of the tested inhibitor. The adsorption of the inhibitor on the steel surface follows the Langmuir adsorption isotherm model and involves competitive physio-sorption and chemisorption mechanisms. The EIS technique was utilized to investigate the effect of temperature on corrosion inhibition within the 298–328 K temperature range. Results confirm that the inhibition efficiency (IE%) of the inhibitor decreased slightly as the temperature increased. Lastly, the thermodynamic parameters for the inhibitor were calculated.

Aluminum corrosion retardation properties of acetamidophenoxy phthalocyanines: Effect of central metal

Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.

Sustainable betalain pigments as eco-friendly film coating over aluminium surface

Sustainable betalain pigments extracted from beetroots were used as eco-friendly film coating over aluminium surface. The film coating was examined and verified by corrosive 1.0 M HCl solution. Characterization of chemical structure of the betalain pigments was done using spectroscopic attenuated total reflectance Fourier transform infrared (ATR-FTIR) and UV–Vis technique. Scanning electron microscope technique was used to demonstrate the eco-friendly film coating before and after been examined via corrosive 1.0 M HCl solution. Various operating conditions were studied to meet highest inhibition efficiency values such as betalain concentration, operating temperature and turbulent flow, and maximum inhibition efficiency = 98.4% was displayed. Multiple adsorption isotherms like Langmuir, Temkin, and Freundlich were used effectively to determine equilibrium constants and adsorption parameters. Dynamic investigations revealed a decline of rate of corrosion (RC) and rise of activation energy values (Ea) at higher betalain concentrations. Thermodynamic investigations revealed physisorption process, exothermic enthalpy, and low entropic values of betalain on aluminium surface. The noticeable specifications of low cost, abundance and sustainability, environmentally friendly, and high technical feasibility of betalain pigments adapt them to be the futuristic outstanding sustainable film coating for metal surfaces.

Austenitic 316L Stainless Steel; Corrosion and Organic Inhibitor: A Review

Stainless steels are extensively used for both engineering and industrial applications based on their excellent properties which makes them fit for various purposes. During applications, they are usually faced with corrosion attacks which have always been their uttermost challenge. To this reason, this research enumerates the properties of stainless steels, the use of inhibitors for control, existing research on austenitic 316L stainless steel with their inhibitor efficiencies, the environment used, the concentration of the environment used, experimental analysis carried out, and emphasis on the use of organic inhibitor for a sustainable industry. The results of each research showed strong inhibition efficiency values with an optimum efficiency value of 98.86%, which suggests excellent performance of organic inhibitors due to their functional groups and molecular species which promote strong adsorption inhibition mechanism.

Corrosion inhibition behavior of piperidinium based ionic liquids on Q235 steel in hydrochloric acid solution: Experimental, density functional theory and molecular dynamics study

In the present time, there is enormous need for environmentally friendly and effective corrosion inhibitors that can reduce tubular steel corrosion. The present paper explore the adsorption and corrosion inhibition behavior of three ionic liquids (ILs) namely 1-Methyl-1-propylpiperidinium Bromide (IL-1), 1-Butyl-1-methylpiperidinium Bromide (IL-2), and 1-Butyl-1-methylpiperidinium bis(trifluoromethanesulphonyl)imide (IL-3) at Q235 steel/1 M HCl interface using both the experimental and theoretical studies. Weight loss and electrochemical experiments suggests increase in inhibition efficiency values with increasing concentration, and reached to 91.3% (IL-1), 94.7% (IL-2) and 97.4% (IL-3) at only 400 mg/L concentration. However, increase in temperature decreases the inhibition efficiency. The addition of 0.5 mM potassium iodide (KI) enhances the performance of ILs. The adsorption of all three ILs at Q235 steel/electrolyte interface obeyed the Langmuir adsorption isotherm model. PDP study supports the mixed nature with pre-dominantly cathodic adsorption nature of ILs. SEM and AFM analyses supports the adsorption of ILs over the Q235 steel surface. Molecular dynamic (MD) simulations reveals flat adsorption and orientation mode of ILs molecules onto the Q235 steel surface. Quantum chemical, Fukui indices and MD results corroborate with the experimental results.

Mild steel corrosion inhibition by synthesized 7-(Ethylthiobenzimidazolyl) Theophylline

The corrosion inhibition of mild steel by 7-(ethylthiobenzimidazolyl) theophylline (7-ETBT) in 1 M HCl medium was investigated through weight loss and Tafel polarization techniques within a temperature range of 298 to 318 K. The inhibition efficiency depends on the concen­tration of 7-ETBT and reaction system temperature. The maximum inhibition efficiency values of 90.73 and 87.06 %, respectively, were estimated using both weight loss and Tafel polarization techniques at 298 K. The results suggest spontaneous and predominant physical adsorption of 7-ETBT on the metal surface which obeys Langmuir isotherm model. Furthermore, Tafel polarization method revealed that 7-ETBT is a mixed-type inhibitor. Po­tentiodynamic polarization results are in accordance with weight loss data to a good extent.

Study on adsorption mechanism of Metronadiazole activities on Aluminium in 0.5M H2SO4

The inhibition of pure aluminium alloy at a varying concentration of Metronadiazole (MNZ) in 0.5M H2SO4 solution has been studied using electrochemical techniques. The obtained results unveil a decrease in the corrosion rate and high inhibition efficiency values with an increase in the Metronadiazole concentration in the corrosive solution. The samples inhibited exhibits higher polarization resistance value and reduced current densities compared to the uninhibited sample. A mixed inhibition mechanism was proposed for the inhibitive effect of MNZ as shown by the potentiodynamic polarization method. Maximum inhibitory efficiency of 80.53% was recorded for the 12.5 mL MNZ inhibited sample. The obtained results show that MNZ inhibited the pure aluminium corrosion in the sulphuric acid solution by adsorption onto the metal surface fitting the Freundlich adsorption isotherm with a correlation regression coefficient of 0.949.

Ball-type phthalocyanines and reduced graphene oxide nanoparticles as separate and combined corrosion inhibitors of aluminium in HCl

Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for reduced graphene oxide nanosheets (rGONS), tetrakis-[4,4′-((4-(benzo[d]thiazol-2-yl)-1,2-bis(phenoxy)] (diphthalocyaninato gallium (III) chloride) (2) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium(III) chloride) (1). Corrosion inhibition effects of rGONS, 1 and 2 were evaluated alone and in combination in 1.0 M hydrochloric acid solution using electrochemical techniques. The mechanism of aluminum corrosion inhibition revealed predominantly anodic character for rGONS and predominantly cathodic character for 1, 2, and conjugates with rGONS . The polarization technique gave inhibition efficiency values of 96.5% and 96.9% respectively for 1 and 2, which increased in the presence of rGONS to 97.4% and 98.1%, respectively, for the highest concentrations of 1 and 2. Scanning electron microscopy revealed effective metal surface protection by the inhibitors by formation of protective films.

Protection performance of orange oil distillates on low carbon steel in dilute acid electrolytes

Orange essential oil distillate (OOE) was studied for its inhibition performance on low carbon steel in 0.5 M H2SO4 and HCl aqueous electrolyte by electrochemical method and open circuit potential measurement. OOE performance was significantly proportional to it concentration with highest protection efficiency of 76.93% and 94.90% at optimal OOE concentration (10% OOE) in H2SO4 and HCl electrolyte. The performance of OOE at low concentration in H2SO4 was quite poor with inhibition efficiency values below 40%. OOE exhibited greater inhibition action in HCl solution with effective performance beginning at 4% OOE concentration compared to 6% concentration in H2SO4 electrolyte. Corrosion potential deviated basically in the anodic direction signifying the dominant inhibition effect to be through surface coverage of the steel surface. OOE exhibited mixed type corrosion inhibition. Open circuit potential graphs show OOE increases the thermodynamic fluctuation of the carbon steel in H2SO4 solution relative to the plots at 0% OOE, despite effective protection. In HCl, the open circuit potential plots were more electropositive relative to the plots at 0% OOE signifying decreased tendency to corrosion. Optical images of the carbon steel after evaluation with and without OOE significantly contrast each other.

Competitive corrosion inhibition performance of alkyl/acyl substituted 2-(2-hydroxybenzylideneamino)phenol protecting mild steel used in adverse acidic medium: A dual approach analysis using FMOs/molecular dynamics simulation corroborated experimental findings

Competitive corrosion inhibition performances of alkyl and acyl substituted 2-(2-hydroxybenzylideneamino)phenol derivatives as Schiff bases were analysed for protection of mild steels in corrosive 1 molL−1 HCl used in industrial acid-cleansing purposes employing potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The anti-corrosion efficiency of synthesized three different inhibitor molecules, namely, 2-(2-hydroxybenzylideneamino)phenol (Inh-1), 2-((2-hydroxyphenylimino)methyl)-4-methylphenol (Inh-2) and 2-((2-hydroxyphenylimino)methyl)-4-methoxyphenol (Inh-3) were analysed on mild steel sample in the presence of 1 M HCl medium. PDP data reveals that all the three synthesized inhibitor molecules behave as mixed type inhibitor at higher concentration (5 mmol L−1). EIS data reveal that on addition of inhibitor molecules the polarization resistance value increases from 4.76 Ωcm2 to 69.60 Ωcm2, 87.28 Ωcm2 and 115.70 Ωcm2 respectively for Inh-1, Inh-2 and Inh-3 i.e., inhibition efficiency value increases, at 5 mmolL−1 concentration of Inh-1, Inh-2 and Inh-3 reaching a maximum efficiency of 93 %, 94 % and 95 %. The three synthesized inhibitors are liable towards Langmuir adsorption isotherm by spontaneous adsorption of inhibitors on mild steel surface. FESEM, EDX, AFM and contact angle measurement revealed the adsorption and corrosion inhibiting capability of synthesized inhibitors. Acyl substituent enhances corrosion inhibition performance than methyl substituent on 2-(2-hydroxybenzylideneamino)phenol unit. The electronic properties of the synthesized inhibitor molecules were explored using frontiers molecular orbitals (FMOs) analysis. In order to explore the interactions of inhibitors with the metal surface mimicking the real corrosion inhibition phenomenon, the molecular dynamics and Monte Carlo simulation approach were employed. Furthermore, the electron density distribution and radial distribution function have been used to explain the film formation phenomenon in details.

Determining efficiency of inhibition of johar flower ethanol extract (Cassia siamea Lamk.) in the corrosion reaction of A36

The investigation about determining the efficiency of inhibition of johar flower ethanol extract in the corrosion reaction of A36 steel (ASTM)/SS400 (JIS) in 3% NaCl solution has been done. This research aims to determine the immersion time and concentration of johar flower ethanol extract in inhibiting the rate of corrosion on steel plates with the highest value of inhibition efficiency. Making the inhibitor is done by extracting the johar flowers using the maceration method. The extract was mixed into the 3% NaCl corroding media with variations in concentrations of 0, 1000; 2000; 3000 and 4000 ppm, then immersed steel plate samples with a size of 50 × 20 × 3 mm for the variation of immersion time 5; 10; 15 and 20 days. Corrosion testing is carried out using the weight loss method. The test results showed that secondary metabolite compounds in johar flower ethanol extract could function as a corrosion inhibitor by inhibiting the rate of corrosion on the steel plate. The inhibition efficiency for johar flower ethanol extract was found in the concentration of 3000 ppm with immersion time for 15 days, amounting to 33.49%.

An eco-friendly green biopolymer blend for copper corrosion inhibition

Copper is a fascinating metal with wide applications since ancient time. Although Copper is resistant to certain environmental factors and several chemicals, aggressive medium could deteriorate the metal leading to its complete damage. The need for an eco-friendly corrosion inhibitor is much relevant in the present scenario. The inhibition efficiency of gum arabic (GA), sodium alginate (SA) and its blend is investigated using weight loss method, potentiodynamic polarization and electroscopic impedance spectroscopy (EIS) analysis in 1.0 M HCl solution. Higher inhibition efficiency is obtained at room temperature for the blend with 6666 ppm GA and 3333 ppm SA. The values of inhibition efficiency obtained are 88.8%, 80.5% and 86.2% using weight loss, potentiodynamic polarization and EIS analysis, respectively. The investigations are complemented by atomic force microscopy and field emission scanning electron microscopy which helped to analyze the physical adsorption of the biopolymer on the metal surface. The adsorption of the biopolymer on Copper obeyed Langmuir isotherm and inhibition efficiency has an inverse relation with temperature.

Metolazone compound as corrosion inhibitor for API 5L X-52 steel in hydrochloric acid solution

The aim of this research is to evaluate the inhibitive effect of metolazone on API 5L X-52 steel in 2 M HCl solution using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques within a temperature range of 303 to 323 K. Scanning electron microscopy (SEM) was also employed to study the morphology of the corroded coupons in 2 M HCl solution and in the presence of the inhibitor. The efficiency of the inhibition depends on the concentration of metolazone and reaction system temperature. The maximum inhibition efficiency values were 92.7 and 90.7%, respectively, for both EIS and polarization techniques at the temperature of 303 K. The electrochemical impedance spectra (EIS) studies reveal that the process of inhibition is through charge transfer. Potentiodynamic polarization (PDP) studies showed that metolazone is mixed-type inhibitor. The metolazone adsorption characteristics on API 5L X-52 steel surface was found to be spontaneous and obeyed Langmuir adsorption isotherm and the mechanism of adsorption suggest chemisorptions. The inhibition efficiency of metolazone drug obtained by electrochemical methods was in good relationship with each other.
 
 KEY WORDS: Metolazone drug, API 5L X-52 Steel, SEM, Electrochemical, Corrosion inhibition
 
 Bull. Chem. Soc. Ethiop. 2020, 34(2), 407-418
 DOI: https://dx.doi.org/10.4314/bcse.v34i2.16

Comparative electrochemical and spectroscopic analysis of the inhibition effect of molybdates and boiled red onion extract on the corrosion of tin in acidic solution

The corrosion inhibition efficiency (η%) and its passivation mechanisms of tin in 0.2 M malic acid by two different types of potential inhibitors, boiled red onion skin extracts (BROE) and molybdate (MoO4 2−), were examined and compared. The influence of the two inhibitors was evaluated by using the electrochemical polarization and the electrochemical impedance spectroscopy (EIS) methods. The electrode surface coverage was analyzed employing scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The electrochemical polarization curves revealed that increasing inhibitor concentration led to a significant reduction of the tin corrosion rate. The presence of BROE and molybdates produced inhibition efficiency (η%) values of 93 and 87%, respectively. Electrochemical measurements and surface analysis have shown satisfactory agreement, that both inhibitor compounds effectively inhibited tin corrosion in 0.2 M maleic acid by forming protective inhibiting deposits that hindered the active electrochemical corrosion sites on the tin surface. Comprehensive insights into the corrosion inhibition mechanism of these compounds in a 0.2-M maleic acid environment, through the suggested equivalent circuits, are also provided.

Electrochemical behavior of two dyes as corrosion inhibitors for carbon steel in acid medium and studying their biological activities by practical and theoretical aspects

The inhibitive action of azo dye aminophenol derivatives, namely 6-(4-benzenesulfonic acid azo)-3-aminophenol (compound (1)) and 4-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-3-aminophenol (compound (2)) against the corrosion of C-steel in 2 M HCl solution using Tafel polarisation, surface morphology, electrochemical impedance spectroscopy and electrochemical frequency modulation techniques. The inhibition efficiency increased with increasing inhibitor concentrations and decreased with increasing temperature. Tafel polarization curves showed that the corrosion rate was decreased with increasing compounds concentration into HCl solution. Inhibition efficiency values obtained from various methods employed were in reasonable agreement. It was found that the order of % IE of these investigated compounds obey the following order: compound (2) > compound (1). Also, the antimicrobial and antifungal activities of the aminophenol derivatives compounds (1 and 2) and comparing them with the standard antibacterial and antifungal drugs were described. The results showed that the compound (2) is very good antibacterial agents against Bacillus subtilis and Staphylococcus aureus. The compound (2) is more active than the compound (1) and penicillin G against Bacillus subtilis and Staphylococcus aureus. It was found that the compound (2) is more active than penicillin G which is used as the antibacterial standard drug against Enterobacter sp. and Klebsiella pneumoniae. Molecular docking was used to predict the binding between aminophenol derivatives compounds (1 and 2) and the receptors of the crystal structure of Staphylococcus aureus (3q8u) and the crystal structure of Escherichia coli (3t88). The compound (2) showed best interaction with receptor of Staphylococcus aureus (3q8u) than the compound (1).

Assessment of AA5005 aluminum alloy corrosion resistance by Direct Blue 15 inhibitor in sodium chloride medium

The effect of Direct Blue 15 dye (DB-15) on the corrosion of aluminum AA5005 in 3% NaCl solution was studied using gravimetric techniques. The results indicate that the DB-15 acts as an inhibitor in the NaCl environment by adsorption on the metal surface. The inhibition efficiency was found to increase with dye concentration and attained 90.8% at 400 ppm. The effect of temperature on the corrosion behavior of aluminum in 3% NaCl was studied in the range 298 K and 328 K. The inhibition performance was also tested by immersing aluminum in 3% NaCl solution using electrochemical methods; potentiodynamic polarization (PP) curves and electrochemical impedance spectroscopy (EIS). PP measurements showed that DB-15 can be considered as mixed-type inhibitor with predominant anodic action and with inhibition efficiencies that improve with concentration. Electrochemical impedance spectroscopy measurements reveal that the corrosion resistance of oxide film increases with dye inhibitor concentrations. The adsorption of the inhibitor on the AA5005 aluminum alloy surface obeyed the Langmuir adsorption isotherm. The values of inhibition efficiency calculated from weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy are in good agreement.

Theoretical and Experimental Studies of Different Amine Compounds as Corrosion Inhibitors for Aluminum in Hydrochloric Acid

Density Functional Theory investigations using the B3LYP/6-31G* model have been carried out. Several quantum chemical parameters have been computed to interpret the inhibition activity of 2, 4-dinitrophenylhydrazine, o-phenylenediamine, and hydrazine hydrate. The ranking of the quantum chemical calculations classifies 2, 4-Dinitrophenylhydrazine as high efficient inhibitor among the studied molecules. The correspondence of the lowest energy gap (ΔE = 4.27 eV) for the calculated value (88.9%) of the highest inhibition efficiency (%IE) of 2, 4 Dinitrophenylhydrazine. Therefore, in parallel, the experimental inhibition of aluminum corrosion was tested using amine compounds in 1M hydrochloric acid solution by means of gravimetry and gasometry measurements. These compounds have been found to act as effective corrosion inhibitors for aluminum in the acid solution, and the best one was 2, 4-dinitrophenylhydrazine, represent one of the salient agreements between experimental and theoretical measurements. The data are showing that this inhibitor is appropriate for Langmuir adsorption isotherm. SEM micrographs indicate that the surface coverage increases in the presence of 0.5 mM of 2, 4-dinitrophenylhydrazine inhibitor, which in turn results in the formation of the adsorbed compound on the metal surface and the surface is covered by an inhibitor layer that effectively controls the dissolution of aluminum.