Trend Of Inhibition Efficiency Research Articles

Development of a promising nontoxic corrosion inhibitor based on Opuntia dillenii seed oil for iron corrosion in 3Wt% NaCl: Experimental and theoretical approaches

This work concentrates on the application of an eco-friendly and non-toxic formulation based on Opuntia dillenii seed oil (labeled FOD) as a new corrosion inhibitor for iron in 3% NaCl solution. We assessed the potential toxicity of FOD through the oral acute toxicity test. Then, the anticorrosion behavior was conducted at different concentrations, temperatures and immersion times using gravimetric and electrochemical methods. The study exhibited a highest inhibition efficiency of 93% obtained at 750 ppm. The formation of a complex between FOD and metallic surface was confirmed by UV-visible spectroscopy. Surface analysis confirmed the ability of the inhibitor to form a film to protect the metal against electrolyte attack. The theoretical aspect elaborated using molecular dynamics (MD) simulation and density functional theory (DFT) supported all experimental results by illustrating similar trend of inhibition efficiencies and revealed that FOD could serve as an effective inhibitor of iron corrosion in 3% NaCl.

Potential of rare-earth compounds as anticorrosion pigment for protection of aerospace AA2198-T851 alloy

In this study, the anticorrosion potential of carboxylic compounds; Lanthanum 4-hydroxycinnamate La(4OHCin)3, Cerium 4-hydroxycinnamate Ce(4OHCin)3 and Praseodymium 4-hydroxycinnamate Pr(4OHCin)3 for the protection of Al–Cu–Li alloy was investigated in 3.5% NaCl solution using electrochemical tests (EIS and PDP), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The findings achieved show a very good correlation between electrochemical responses and surface morphologies of the exposed alloy, indicating a modification of the surface by precipitation of the inhibitor species, leading to effective protection against corrosion. At optimum concentration 200 ppm, the trend of inhibition efficiency η (%) increases in the order Ce(4OHCin)3 93.35% > Pr(4OHCin)3 85.34% > La(4OHCin)3 82.25%. XPS complemented the findings by detecting and providing information about the oxidation states of the protective species.

Biopolymer sodium alginate based titania and magnetite nanocomposites as natural corrosion inhibitors for mild steel in acidic medium

Green biopolymeric materials and its hybrid nanocomposites, i.e. sodium alginate grafted polymethylmethacrylate based titanium dioxide and iron oxide (SA-g-PMMA/TiO2 and SA-g-PMMA/Fe3O4) have been explored for the prevention of mild steel's corrosion in 15% HCl. It is reflected from the electrochemical impedance data that SA-g-PMMA/TiO2 exhibits maximum inhibition efficiency of 97.28% followed by SA-g-PMMA/Fe3O4 that gives 96.82% efficiency while the unmodified sodium alginate possess merely 84.74% efficiency. The declining trend of inhibition efficiency with rising temperature has been explained through gravimetric studies conducted at 303 K- 333 K. The thermodynamic activation and adsorption parameters revealed the mixed mode of adsorption of inhibitors over mild steel surface which follow Langmuir adsorption isotherm. It has been observed from tafel polarization studies that all studied inhibitors are mixed type in nature. The surface morphological inspection of the mild steel samples was done through FE-SEM and AFM, which revealed the formation of better protective adsorption layer over the exposed metallic surface by the nanocomposites in comparison to sodium alginate alone. In addition to this, the elemental composition of adsorbed film on inhibited mild steel specimens was obtained by XPS technique. Quantum parameters obtained through Density Functional Theory (DFT) further corroborate the experimental outcomes.

Corrosion inhibition of Pichia sp. biofilm against mild steel corrosion in 1 M H2SO4

Pichia sp. was isolated from rotten gooseberry (Phyllanthus emblica) and monitored for corrosion inhibition properties by means of biofilm-forming ability. The corrosion inhibition potential of Pichia sp. was evaluated against mild steel corrosion in 1 M H2SO4 via standard weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PP) techniques. Further, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray (EDX), X-ray photoelectron (XPS) spectroscopy, and atomic force microscopic (AFM) techniques were employed for confirming the biofilm accumulation on the mild steel (MS) surface. The weight loss investigation was carried out at varying temperatures (283 K−303 K), which showed the increasing trend of inhibition efficiency (IE%), and decreasing trend of corrosion rate, along with increasing Pichia sp. isolate’s concentrations. Pichia sp. isolate has shown maximum corrosion inhibition efficiency (>90%) at 283 K with an optimum concentration of 9 × 106 (CFU/mL). However, temperature studies insisted on the physical adsorption of corrosion inhibitor molecules over the metal surface. EIS data revealed enhanced values of charge transfer resistance (Rct), when increasing Pichia sp. isolate concentrations. Potentiodynamic polarization (Tafel curve) investigation revealed that Pichia sp. isolate exhibited mixed-type corrosion inhibition, while predominantly controlling the anodic reaction. The surface analysis data revealed the adherence and anticorrosive nature of Pichia sp. isolate on the MS surface, and a possible corrosion inhibition mechanism has also been discussed.

Theoretical modeling and experimental studies of Terebinth extracts as green corrosion inhibitor for iron in 3% NaCl medium

In this study, essential oils (EOs) obtained from twigs, leaves and fruits of Terebinth (Pistacia terebinthus L.) was characterized by GC/MS analysis. We tested these as green corrosion inhibitors for iron in the neutral chloride medium (3% NaCl), employing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) curves and surface characterizations SEM, EDX, IR spectroscopy were carried out. The theoretical aspect was elaborated using molecular dynamics (MD) simulation and density functional theory (DFT). Analyses of the experimental results showed that the three main components in the EOs from the twigs, fruits and leaves of Terebinth are α-Pinene (32.65–50.58%), Limonene (6.88–15.07%), and α-Terpineol (2.50–5.15%) with quantitative variations. The fruit EO at a concentration of 3000 ppm is characterized by the best anticorrosive protective properties than the leaf and twig EOs. Indeed, the optimum percentage of this EO required to achieve the maximum efficiency was found to be 86.4% at 3000 ppm. The surface investigation strategies (SEM-EDX and IR) further validated that the corrosion barrier happens because of the adsorption of the inhibitors over the iron/3% NaCl interface. Also, the outcomes of the theoretical approach supported all the experimental results by illustrating the similar trend of inhibition efficiencies of various inhibitors and revealed that Terebinth EOs could serve as an effective inhibitor of iron in 3% NaCl.

CORROSION PROTECTION OF MILD STEEL AND ALUMINIUM IN 0.1M AND 1M HCL ACID SOLUTIONS USING PTEROCARPUS OSUN.

The inhibition effect of Pterocarpus osun on the corrosion of mild steel and aluminium in acidic medium was studied using gravimetric techniques. Weight loss measurements were determined on metal coupons in 0.1M and 1M HCl acid within the immersion time of 24-h for 5 consecutive days. Inhibition efficiency was determined by comparing the corrosion rates of mild steel and aluminium in 0.1M and 1M HCl in the presence and absence of additives. The trend of inhibition efficiency was used to propose the mechanism of inhibition. It was found that the plant extract act as inhibitor for acid-induced corrosion of mild steel and aluminium in 0.1M and 1M HCl. Inhibition efficiency of 94.5% and 94.9% were obtained for P. osun for aluminium in 0.1M and 1M HCl and 98.9%and 96.9% for mild steel in 0.1M and 1M HCl respectively. The inhibition efficiency was found to increase with increase in inhibitor concentrations. The adsorption of the inhibitor obeyed Langmuir Adsorption Isotherm. Based on the findings, P. osun stem extract is highly recommended as an alternative to synthetic, toxic chemical inhibitors.

A comprehensive study about anti-corrosion behaviour of pyrazine carbohydrazide: Gravimetric, electrochemical, surface and theoretical study

A relative investigation of various synthesized hydrazone derivatives was examined for their inhibitive impact on mild steel in 1 M HCl medium, using the measurements of weight loss and electrochemical procedures. The different parameters, for example, corrosion rate, inhibition efficiency, and surface coverage were estimated. The weight loss strategy demonstrates the rise in the inhibition efficiency on expanding the amount of inhibitor. The inhibition activity of the compounds was expected to happen by means of adsorption over the steel surface which abides the Langmuir isotherm model. The inhibitors are predicted to be mixed inhibitors i.e. influencing both cathodic hydrogen evolvement and anodic metal dissolution. The surface investigation strategies (SEM-EDX, AFM, and XPS) further validated that the corrosion hindrance happens because of the adsorption of the inhibitors over the metal/solution interface. Also, the outcomes of the theoretical approach supported all the experimental results by illustrating the similar trend of inhibition efficiencies of various hydrazones.

Adsorption and anticorrosion behaviour of mild steel treated with 2-((1H-indol-2-yl)thio)-6-amino-4-phenylpyridine-3,5-dicarbonitriles in a hydrochloric acid solution: Experimental and computational studies

The corrosion inhibition potentials of some derivatives of 2-((1H-indol-2-yl)thio)-6-amino-4-phenylpyridine-3,5-dicarbonitrile (TAPD) namely 2-(1H-indol-2-ylthio)-6-amino-4-(4-nitrophenyl)pyridine-3,5-dicarbonitrile (TAPD-I), 2-((1H-indol-2-yl)thio)-6-amino-4-phenylpyridine-3,5-dicarbonitrile (TAPD-II), and 2-(1H-indol-2-ylthio)-6-amino-4-(4-hydroxyphenyl)pyridine-3,5-dicarbonitrile (TAPD-III) on mild steel in 1 M HCl solution have been investigated using experimental and computational methods. The –OH substituted compound (TAPD-III) showed highest corrosion inhibition efficiency, while the NO2 substituted compound (TAPD-I) exhibited the least efficiency. The inhibition efficiency increased with increase in concentrations of the TAPDs. Weight loss study showed that inhibition efficiencies of the TAPDs obeyed the order: TAPD-III (96.95%) > TAPD-II (93.04%) > TAPD-I (91.30%).Same trend of inhibition efficiencies of TAPDs was observed using experimental and computational techniques. Electrochemical study suggested that TAPDs inhibit corrosion by adsorption on the steel surface and their adsorption behaviour follows the Langmuir adsorption isotherm. The compounds showed mixed-type corrosion inhibition activities. SEM and EDX analyses further confirmed the adsorption of the inhibitor molecules on mild steel surface. Theoretical density functional theory calculations and molecular dynamics simulations gave corroborative results that are in agreement with experimental findings.

Mild Steel Corrosion Mitigation in Sulphuric Acid via Benign Isolated Phytochemicals from <I>Viscum album</I>

We present the evaluation of four Eco-friendly corrosion inhibitors for the corrosion mitigation of mild steel in acid media. The corrosion inhibition of mild steel by ethanol extracts from Viscum album (EEVA) and some of its isolated phytochemical components; phytates extract (PEVA), saponins extract (SEVA), and flavonoids extracts (FEVA) have been studied using gravi-metric and gasometric techniques. The results of the study reveal that these ecofriendly and benign extracts function as good inhibitors for mild steel corrosion in sulphuric acid. Inhibition efficiency of the extracts increases with inhibitor concentration and temperature rise. The trend of inhibition efficiency in lower inhibitor concentration is EEVA > PEVA > SEVA > FEVA and at higher concentration, the order was SEVA > PEVA > EEVA > FEVA. The presence of the plant extracts decreases the corrosion activation energy in the solution which indicates chemical adsorption mechanism. The adsorption of the components of the extracts is consistent with Temkin isotherm. The interaction between the isolated extracts is synergistic at lower inhibitor concentration and antagonistic at higher concentrations. The Kads values for PEVA and SEVA are higher than those of EEVA and FEVA. This implies that PEVA and SEVA are more efficiently adsorbed on the mild steel surface.

Protection of Mild Steel Corrosion in Sulphuric Acid Environment Using Wheat Starch

The corrosion of mild steel in 0.5 M H2SO4acid solution and the inhibition process by wheat starch (WS) was investigated using weight loss and potentiodynamic polarization measurement techniques respectively. Gravimetric results revealed that there is significant reduction in the corrosion rate of mild steel in the presence of inhibited solution compared to blank solution, and also the inhibition efficiency was found to depend on the concentration of the WS. Data on potentiodynamic polarization results confirmed that WS exhibited mixed type inhibition behaviour, though the cathodic effect was more pronounced. The mode of WS adsorption on the corroding metal surface followed Langmuir isotherm model. In addition, the trend of inhibition efficiency with temperature, activation energy and heat of adsorption parameters revealed a strong interaction between the WS constituents and the corroding metal surface, thus indicating that WS lowered the corrosion process by blanketing the mild steel surface through chemical adsorption mechanism. The mechanism of inhibition was discussed in the light of the chemical structure of starch.

Protection of Mild Steel Corrosion in Sulphuric Acid Environment Using Wheat Starch

The corrosion of mild steel in 0.5 M H2SO4acid solution and the inhibition process by wheat starch (WS) was investigated using weight loss and potentiodynamic polarization measurement techniques respectively. Gravimetric results revealed that there is significant reduction in the corrosion rate of mild steel in the presence of inhibited solution compared to blank solution, and also the inhibition efficiency was found to depend on the concentration of the WS. Data on potentiodynamic polarization results confirmed that WS exhibited mixed type inhibition behaviour, though the cathodic effect was more pronounced. The mode of WS adsorption on the corroding metal surface followed Langmuir isotherm model. In addition, the trend of inhibition efficiency with temperature, activation energy and heat of adsorption parameters revealed a strong interaction between the WS constituents and the corroding metal surface, thus indicating that WS lowered the corrosion process by blanketing the mild steel surface through chemical adsorption mechanism. The mechanism of inhibition was discussed in the light of the chemical structure of starch.

Experimental and Theoretical Studies of Inhibitive Behaviour of Millet Starch on the Corrosion of Aluminium in Sulphuric Acid Environment

The corrosion inhibition of aluminium in 2 M H2SO4 by millet starch was investigated using gravimetric technique at 35-65OC and theoretical quantum chemical computations. The results indicate that millet starch functioned as a good inhibitor for acid induced corrosion of aluminium. It was found that increase in inhibition efficiency of the inhibitor was concentration dependent and also addition of potassium iodide increased inhibitive performance of the inhibitor synergistically. Furthermore, the mode of adsorption process of the inhibitor was best modeled using Langmuir adsorption isotherm at all inhibitor concentrations and temperatures studied. The trend of inhibition efficiency with temperature, calculated values of free energy, activation energy and enthalpy of adsorption was used to propose the inhibition mechanism. Theoretical chemical quantum computations were carried out using density functional theory to underscore the relationship existing between the inhibitive performance of millet starch and electronic properties of millet starch. Finally, Molecular dynamic simulations were performed using Forcite quench molecular dynamics to model lowest energy adsorption configurations of the starch molecule on Al surface and to determine the binding energy of adsorption

Experimental and Theoretical Studies of Inhibitive Behaviour of Millet Starch on the Corrosion of Aluminium in Sulphuric Acid Environment

The corrosion inhibition of aluminium in 2 M H2SO4 by millet starch was investigated using gravimetric technique at 35-65OC and theoretical quantum chemical computations. The results indicate that millet starch functioned as a good inhibitor for acid induced corrosion of aluminium. It was found that increase in inhibition efficiency of the inhibitor was concentration dependent and also addition of potassium iodide increased inhibitive performance of the inhibitor synergistically. Furthermore, the mode of adsorption process of the inhibitor was best modeled using Langmuir adsorption isotherm at all inhibitor concentrations and temperatures studied. The trend of inhibition efficiency with temperature, calculated values of free energy, activation energy and enthalpy of adsorption was used to propose the inhibition mechanism. Theoretical chemical quantum computations were carried out using density functional theory to underscore the relationship existing between the inhibitive performance of millet starch and electronic properties of millet starch. Finally, Molecular dynamic simulations were performed using Forcite quench molecular dynamics to model lowest energy adsorption configurations of the starch molecule on Al surface and to determine the binding energy of adsorption

Synergistic inhibition of aluminium corrosion in H2SO4 solution by polypropylene glycol in the presence of iodide ions

Purpose The purpose of this paper is to evaluate the performance of polypropylene glycol (PPG), as a corrosion inhibitor for aluminium corrosion in 0.5 M H2SO4 solution at 303-333 K and the effect of addition of iodide ions on the corrosion inhibition efficacy of PPG. Design/methodology/approach The corrosion inhibition performance of PPG alone and on addition of iodide ions in the acid medium was evaluated using weight loss and electrochemical [electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR) and potentiodynamic polarization (PDP)] methods as well as surface analysis approach at 303-333 K. The morphology of the corroding aluminium surface without and with the additives was visualised using scanning electron microscopy (SEM). The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition and type of adsorption. Findings Results obtained showed that PPG moderately retarded the corrosion of Al in 0.5 M H2SO4 solution. Addition of KI to PPG is found to synergistically improve the inhibitive ability of PPG. From the variation of inhibition efficiency, K_ads, and E_a, with rise in temperature, physisorption mechanism is proposed for the adsorption of PPG and PPG + KI onto the Al surface in 0.5 M H2SO4 solution. Polarisation results showed that PPG and PPG + KI acted as mixed type inhibitor. The adsorption of PPG and PPG + KI, respectively, onto the metal surface followed El-Awady et al. adsorption isotherm model. SEM and water contact angle analysis confirmed the adsorption of PPG and PPG + KI on Al surface. Research limitations/implications The research is limited to aqueous acid environment in aerated condition, and all tests were performed under static conditions. Practical implications The use of PPG as corrosion inhibitor for Al corrosion in acidic medium were reported for the first time. The results suggest that iodide ions could be used to enhance corrosion protection ability of PPG which could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the synergistic effect of iodide ions addition to polymer to control acid-induced corrosion of metal. Originality/value The use of PPG as corrosion inhibitor for Al corrosion in acidic medium were reported for the first time. The results suggest that iodide ions could be used to enhance corrosion protection ability of PPG which could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the synergistic effect of iodide ions addition to polymer to control acid-induced corrosion of metal.

Experimental and Theoretical Studies of Red Apple Fruit Extract as Green Corrosion Inhibitor for Mild Steel in HCl Solution

The corrosion inhibition effect of red apple (Malus domestica) fruit extract for mild steel in hydrochloric acid was investigated by gravimetric and electrochemical methods at 30–60°C. Inhibition efficiency increased with the increase in concentration and temperature. Polarization curves indicate that the extract functions as mixed-type inhibitor. The adsorption of the extract onto mild steel surface followed Langmuir adsorption isotherm model. Chemisorption mechanism is proposed based on the trend of inhibition efficiency with temperature. Quantum chemical calculations and molecular dynamics simulations have been used to provide insights into the mechanism of interaction of the major extract components with mild steel.

Electrochemical Study of Corrosion Inhibition of Mild Steel in Acidic Solution Using Gnetum africana Leaves Extracts

Weight loss and electrochemical (open circuit potential (OCP), linear sweep voltammetry (LSV) and Potentiodynamic polarization (PDP)) techniques were used to assess the effectiveness of Gnetum africana leaves extracts as corrosion inhibitor for mild steel in 1.0 M hydrochloric acid (HCl) solution at 30-45°C. It was found that Gnetum africana leaves extracts retarded the dissolution of mild steel in 1.0 M HCl solution. The inhibition efficiency increased with increase in extract concentration and did reasonably well at increased temperature, which is suggestive of physical and chemical adsorption mechanism. Open circuit potential shows reduction of resistance polarization R p with the addition of the Gnetum africana extract. Potentiodynamic polarization result suggests that Gnetum africana extracts functioned as mixed-type inhibitor. The adsorption of Gnetum africana extracts onto the mild steel surface followed Langmuir and Temkin adsorption isotherm models. The mechanism of physisorption of the extracts onto the mild steel surface is proposed from the trend of inhibition efficiency with temperature which is corroborated by the values of activation parameters obtained from the experimental data.

Humic Acid from Livestock Dung: Ecofriendly Corrosion Inhibitor for 3SR Aluminum Alloy in Alkaline Medium

Humic acids (HAs) extracted from cow, goat, and poultry dung were studied. Extraction was performed by treating the source materials with acid hydrolysis using hydrochloric acid (HCl) before alkaline extraction with sodium hydroxide (NaOH). Yields of 3.33, 2.67, and 1.28% dry weight were obtained from cow, goat, and poultry dung respectively. The extracted humic acids were characterized using Fourier transform-infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopy techniques. The results obtained were in good agreement with commercial HA (Sigma-Aldrich). The humic acid extracted from cow dung was used to evaluate its corrosion inhibition potential for alkaline-induced corrosion of 3SR aluminum alloy using weight loss and electrochemical (potentiodynamic polarization) techniques at 30°–60°C. Results obtained show that the humic acid functions as an excellent corrosion inhibitor for aluminum alloy in 0.1 M NaOH solution. Corrosion inhibition efficiency increased with increase in humic acid concentration but decreased with rise in temperature. Results from potentiodynamic polarization measurements show that the HA behaved mostly as a mixed-type inhibitor. Adsorption of the humic acid was found to obey the Langmuir adsorption isotherm at all concentrations and temperatures studied. The mechanism of physical adsorption has been proposed based on the trend of inhibition efficiency with temperature. The proposed mechanism was also corroborated by kinetic and thermodynamic parameters obtained.

Effect of polyvinylpyrrolidone – polyethylene glycol blends on the corrosion inhibition of aluminium in HCl solution

Purpose– The purpose of this paper is to investigate the effect of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and blended formulations on the corrosion inhibition of aluminium in HCl solutions at 30-60°C and to study the mechanism of action.Design/methodology/approach– The inhibitive effect of the homopolymers and polymer blend was assessed using weight loss and hydrogen evolution methods at 30 and 60°C. The morphology of the corroding aluminium surface without and with the additives was visualized using atomic force microscopy. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition and type of adsorption.Findings– Results obtained show that inhibition efficiency (η%) increases with increase in concentration of the polymers but decreases with increase in temperature. The inhibition efficiency of the homopolymers and their blends decreased with rise in temperature. Inhibition efficiency was found to be synergistically enhanced on blending the two homopolymers with highest inhibition efficiency obtained for (PEG:PVP) blending ratio of 1:3. The phenomenon of physical adsorption is proposed from the trend of inhibition efficiency with temperature.Research limitations/implications– The mechanistic aspect of the corrosion inhibition can be better understood using electrochemical studies such as potentiodynamic polarization and electrochemical impedance spectroscopy.Originality/value– Studies involving the use of polymer blends/mixtures as corrosion inhibitor for metals in corrosive environments are scarce. The results suggest that the mixture could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the use of polymer–polymer mixtures to control acid-induced corrosion of metal.

Inhibition of the corrosion of mild steel in acidic media by use of a new antipyridine derivative

The activity of 4-[5-((4-chlorophenyl)diazenyl)-2-hydroxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazole-3-(2H)-one (CDHBAP) against corrosion of mild steel in 1 M H2SO4 solutions has been investigated by measurement of weight loss and by potentiodynamic polarization and AC impedance studies. The results obtained indicate that CDHBAP is a good inhibitor; its efficiency reaches 99 % at 100 ppm. Polarization studies show that CDHBAP inhibits corrosion of mild steel by means of a mixed-mode mechanism. AC impedance results confirm adsorption of the CDHBAP at the mild steel–acid interface. A decrease in inhibition efficiency is observed with increasing temperature, and activation energies increase in the presence of CDHBAP. Physical adsorption is proposed from the trend of inhibition efficiency and the values of $$ \Delta G_{\text{ads}}^{0} $$ . Formation of a protective layer against acid attack was confirmed by use of FT-IR and UV–visible spectroscopy, X-ray diffraction analysis, and scanning electron microscopy.

Corrosion Inhibition of Q235 Mild Steel in 0.5 M H2SO4 Solution by Phytic Acid and Synergistic Iodide Additives

The inhibition properties of phytic acid (PA) on Q235 mild steel corrosion in 0.5 M H2SO4 was estimated using electrochemical techniques. Polarization results revealed PA to be a mixed-type inhibitor in 0.5 M H2SO4, with a more pronounced cathodic effect, while impedance results indicate adsorption of the PA species on the steel surface. The values of the synergistic factor with KI were higher than unity indicating that both additives act cooperatively to improve inhibition performance. The adsorption of PA followed the Langmuir adsorption isotherm. The mechanism of chemical adsorption is proposed on the basis of the trend of inhibition efficiency with temperature and the calculated values of the activation energy (Ea). Scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy studies revealed the formation of a protective film adsorbed on a mild steel surface. Quantum chemical calculations were used to confirm the ability of phytic acid to adsorb on a steel surface.