Corrosion inhibition of carbon steel in hydrochloric acid solution by fruit peel aqueous extracts

The inhibitive action of the aqueous extracts of fruit peels against corrosion of carbon steel in a 1 M HCl solution was investigated using electrochemical impedance spectroscopy, potentiodynamic polarization curves, weight loss measurements and surface analysis. We analyzed aqueous extracts of mango, orange, passion fruit and cashew peels in different concentrations and found that the extracts act as good corrosion inhibitors for the tested system. The inhibition efficiency increases with increasing extract concentration and decreases with temperature. The adsorption of components of the fruit peel extracts on the surface of the carbon steel follows the Langmuir adsorption isotherm.     

Corrosion inhibition of mild steel in hydrochloric acid solution by Schiff base furoin thiosemicarbazone

A heterocyclic Schiff base furoin thiosemicarbazone was tested for its corrosion inhibition towards mild steel in 1 M HCl solution using weight loss, Tafel polarization and electrochemical impedance spectroscopy techniques. Furoin thiosemicarbazone revealed good corrosion inhibition efficiency even at low concentrations towards mild steel in HCl medium. Comparison of corrosion inhibition efficiency of Schiff base and its parent amine and effect of temperature on inhibition efficiency were also investigated. The adsorption of furoin thiosemicarbazone on mild steel surface obeys Langmuir isotherm.     

Corrosion of carbon steel in concentrated LiNO3 solution at high temperature

The corrosion of carbon steel in concentrated LiNO₃ solution at high temperature was investigated by a weight loss method. Results showed that increasing temperature and pH would increase the corrosion rate, and increasing concentration and adding Li₂CrO₄ would reduce the corrosion rate. The corrosion in LiNO₃ solution was general corrosion and the corrosion products were composed of Fe₃O₄ and Fe₂O₃. A compact passive layer comprising of Cr₂O₃, Fe₃O₄ and Fe₂O₃ was observed with adding Li₂CrO₄, and it could effectively depress the corrosion. The carbon steel corrosion in LiNO₃ solution was much smaller than that in LiBr solution.     

新型噁二唑类缓蚀剂的合成及其缓蚀性能

合成了一种恶二唑类缓蚀剂2,5-（2-十一烷基）-1,3,4恶二唑（简称HOX）,对其进行了表征,并采用静态失重法、动电位极化和电化学阻抗谱（EIS）研究其在HCl介质中对Q235钢的缓蚀作用。研究表明,所合成的恶二唑类化合物是一种性能优异的混合控制型酸性碳钢缓蚀剂,其在碳钢表面的吸附符合Langmuir吸附模型。     

Corrosion inhibition by Justicia gendarussa plant extract in hydrochloric acid solution

Corrosion inhibition effect of Justicia gendarussa extract (JGPE) on mild steel in 1 M HCl medium has been investigated by weight loss and electrochemical techniques. Inhibition efficiency of 93% was achieved with 150 ppm JGPE at 25 °C. The polarization studies showed that JGPE acts as mixed-type inhibitor. The Nyquist plots showed that on increasing JGPE concentration, increases charge transfer resistance and decreases double layer capacitance. JGPE obeys the Langmuir adsorption isotherm. AFM and ESCA confirmed the adsorption of JGPE on mild steel surface. Finally, JGPE inhibition efficiency was discussed in terms of adsorption and protective film formation.     

Corrosion inhibition of austenitic stainless steel by some pyrimidine compounds in hydrochloric acid

The inhibition effect of two pyrimidine derivatives on the corrosion of austenitic stainless steel in 1 M HCl has been studied by Tafel plot, linear polarization, and electrochemical impedance spectroscopy (EIS) at 298 K. Results showed that compounds inhibited steel corrosion in a 1 M HCl solution and inhibition efficiencies increased with the concentration of inhibitor. Polarization curves indicated that all studied pyrimidine derivatives act as mixed type (cathodic/anodic) inhibitors. The adsorption of the inhibitors on the stainless steel surface was found to obey the Langmuir and Dubinin–Radushkevich adsorption isotherm models. Negative values of ΔG_ads in the acidic media ensured the spontaneity of the adsorption process.     

Corrosion inhibition of mild steel in hydrochloric acid by 6‐aminohexanoic acid

The inhibiting behavior of 6‐aminohexanoic acid (C₆H₁₃NO₂) on mild steel corrosion in 1 M HCl as corroding solution at 25 °C was evaluated by weight loss, polarization, and electrochemical impedance spectroscopy (EIS) methods. The weight loss, polarization, and EIS measurements were relatively in good agreement together. Results obtained by the three methods showed that the inhibition efficiency (%IE) increases with increasing the concentration of 6‐aminohexanoic acid up to 6.86 × 10^?05 M (about %IE = 80). It was also found that the adsorptive behavior of the investigated inhibitor on the steel surface followed Langmuir‐type isotherm, the 6‐aminohexanoic acid acted as a mixed type inhibitor and its inhibition mechanism obeys from the chemisorption interaction between 6‐aminohexanoic acid and the mild steel.     

In search of functionality for efficient inhibition of mild steel corrosion both in HCl and H2SO4

Abstract

While the organic ammonium compounds are known to be effective against mild steel corrosion in HCl, these cationic salts are not as effective in sulphuric acid media. A new series of tertiary diallylamines containing C₁₂, C₁₄, C₁₆ and C₁₈ alkyl hydrophobes, N-hexadecylpyrrolidine and their corresponding ammonium salts were found to be among a rare class of inhibitors in arresting mild steel corrosion in HCl as well as in H₂SO₄ media effectively. While all the inhibitor molecules exhibited excellent inhibition efficiencies (%IEs) (～99%) in 1M HCl, ammonium salts containing alkyne moiety at 400 ppm provided 93–97%IE even in 7·7M HCl. The inhibitors (400 ppm) containing diallyl moiety demonstrated the %IEs in the range 80–97% in 0·5M H₂SO₄. The interactions of the π electrons in the diallyl moiety with the low lying vacant d-orbitals of iron help the inhibitor molecules to undergo adsorption and interfere with the anodic dissolution process.     

Inhibitory action of aqueous coffee ground extracts on the corrosion of carbon steel in HCl solution

The effects of aqueous extracts of spent coffee grounds on the corrosion of carbon steel in a 1 mol L⁻¹ HCl were examined. Two methods of extraction were studied: decoction and infusion. The inhibition efficiency of C-steel in 1 mol L⁻¹ HCl increased as the extract concentration and temperature increased. The coffee extracts acted as a mixed-type inhibitor with predominant cathodic effectiveness. In this study, the adsorption process of components of spent coffee grounds extracts obeyed the Langmuir adsorption isotherm. The chlorogenic acids isolated do not seem to explain the corrosion inhibition observed during the use of the coffee extracts.     

A test method for dewpoint corrosion of stainless steels in dilute hydrochloric acid

When acid-containing gases condense on a steel surface a phenomenon called dewpoint corrosion can occur. In this case severe attack can appear and the attack cannot be predicted from traditional immersion test data. Dewpoint corrosion can for instance be found in refinery overhead condensers and in waste incineration plants. An experimental set-up consisting of a closed glass loop has been constructed in which stainless steel samples are exposed to condensing conditions simulating a formed condensate of about 1% HCl. In the loop three stainless steels have been tested. For all three materials higher corrosion rates were found in the loop than obtained in immersion tests but in the same range as can be predicted from service experience.     

Corrosion of carbon steel C1010 in the presence of iron oxidizing bacteria Acidithiobacillus ferrooxidans

In this study, corrosion behaviors of carbon steel C1010 in the presence of an acidophilic, iron-oxidizing bacterial species Acidithiobacillus ferrooxidans were examined. Results showed that A. ferrooxidans cells, with or without attaching to C1010 steel, accelerated its corrosion at a rate of 3–6× those of acidic water, at a pH of 2, without cells. A. ferrooxidans oxidized Fe²⁺ to Fe³⁺ as an energy source and the produced Fe³⁺ rapidly oxidized Fe⁰ to Fe²⁺ was proposed and verified as the reason. In addition, severe pitting corrosion was found on the C1010 steel surface in solutions containing A. ferrooxidans cells.     

Corrosion inhibition of mild steel in hydrochloric acid solution by some double Schiff bases

The inhibition effect of four double Schiff bases on the corrosion of mild steel in 2 M HCl has been studied by polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurements. The inhibitors were adsorbed on the steel surface according to the Langmuir adsorption isotherm model. From the adsorption isotherm, some thermodynamic data for the adsorption process were calculated and discussed. Kinetic parameters activation such as E_a, ΔH∗, ΔS∗ were evaluated from the effect of temperature on corrosion and inhibition processes. Quantum chemical calculations have been performed and several quantum chemical indices were calculated and correlated with the corresponding inhibition efficiencies.     

Aminopyrimidine derivatives as inhibitors for corrosion of 1018 carbon steel in nitric acid solution

The effect of some aminopyrimidine derivatives on the corrosion of 1018 carbon steel in 0.05 M HNO₃ solution was studied using weight loss and polarization techniques. The percentage inhibition efficiency was found to increase with increasing concentration of inhibitor and with decreasing temperature. The addition of KI to aminopyrimidine derivatives enhanced the inhibition efficiency due to synergistic effect. The inhibitors are adsorbed on the steel surface according to Temkin isotherm. Some thermodynamic functions were computed and discussed. It was found that the aminopyrimidine derivatives provide a good protection to steel against pitting corrosion in chloride containing solutions.     

Corrosion inhibition of mild steel in acidic solution by some oxo-triazole derivatives

The oxo-triazole derivative (DTP) was synthesized and its inhibiting action on the corrosion of mild steel in sulphuric acid was investigated by means of weight loss, potentiodynamic polarization, EIS and SEM. The results revealed that DTP was an excellent inhibitor and the inhibition efficiencies obtained from weight loss experiment and electrochemical experiment were in good agreement. Potentiodynamic polarization studies clearly revealed that DTP acted essentially as the mixed-type inhibitor. Thermodynamic and kinetic parameters were obtained from weight loss of the different experimental temperatures, which suggested that at different temperatures (298–333 K) the adsorption of DTP on metal surface obeyed Langmuir adsorption isotherm model.     

Corrosion behaviors of carbon steel in 55% LiBr solution containing PWVA inhibitor

The inhibition performance of PWVA inhibitor on carbon steel was studied in 55% LiBr + 0.07 mol/L LiOH solution. Results indicated that PWVA inhibitor decreased both anodic and cathodic polarization current density and widened the passive potential region of carbon steel in the test solution. It could be classified as mixed inhibitor. PWVA has a strong oxidizability. It could form an intact and compact film which consisted of Fe₂O₃ on carbon steel surface in the test solution. The passive film retarded Br^? which corroded the metal matrix in the test solution. When the concentration of PWVA was 300 mg/L, it showed an excellent inhibition effect. However, when the temperature was higher than 173 °C, the corrosion rate of carbon steel in 55% LiBr + 0.07 mol/L LiOH solution increased rapidly.     

Erosion resistance of CO2 corrosion scales formed on API P110 carbon steel

The erosion resistance of CO₂ corrosion scales formed on carbon steel was investigated in water–sand two-phase flow utilizing weight loss test, scanning electron microscopy, and X-ray diffraction. The effects of CO₂ partial pressure, stirring speed, test time, and grain size on the erosion resistance of the scales were analysed. Results show that several characteristics of CO₂ corrosion scales are key factors affecting erosion resistance. Cubic polynomials are used to fit the erosion rate data, and effectively evaluate the ability of CO₂ corrosion scales to resist erosion. An erosion mechanism, based on fluid dynamics and CO₂ corrosion scales characteristics, is discussed.     

A novel Schiff base-based cationic gemini surfactants: Synthesis and effect on corrosion inhibition of carbon steel in hydrochloric acid solution

The corrosion inhibition characteristics of the synthesized cationic gemini surfactants, namely bis(p-(N,N,N-decyldimethylammonium bromide)benzylidene thiourea (10-S-10), bis(p-(N,N,N-dodecyldimethylammonium bromide)benzylidene thiourea (12-S-12) and bis(p-(N,N,N-tetradecyldimethylammonium bromide)benzylidene thiourea (14-S-14) on the carbon steel corrosion in 1 M hydrochloric acid have been investigated at 25 °C by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiencies obtained from all methods employed are in good agreement with each other. The obtained results show that compound 14-S-14 is the best inhibitor with an efficiency of 97.75% at 5 × 10⁻³ M additive concentration. Generally, the inhibition efficiency increased with increase of the inhibitor concentration. Changes in impedance parameters (charge transfer resistance, R_ct, and double-layer capacitance, C_dl) were indicative of adsorption of 14-S-14 on the metal surface, leading to the formation of a protective film. The potentiodynamic polarization measurements indicated that the inhibitors are of mixed type. The adsorption of the inhibitors on the carbon steel surface in the acid solution was found to obey Langmuir’s adsorption isotherm. The free energy of adsorption processes were calculated and discussed. The surface parameters of each synthesized surfactant were calculated from its surface tension including the critical micelle concentration (CMC), maximum surface excess (Γ_max) and the minimum surface area (A_min). The free energies of micellization (ΔG^o_mic) were calculated. The surface morphology of carbon steel sample was investigated by scanning electron microscopy (SEM).     

Influence of strain Bacillus cereus bacterium on corrosion behaviour of carbon steel in natural sea water

This paper examines the corrosion behaviours of carbon steel immersed in sterile natural sea water with and without strain Bacillus cereus. Electrochemical studies, including Tafel plots and electrochemical impedance spectroscopy (EIS) were performed to evaluate the variation of the corrosion behaviour of carbon steel in medium containing B. cereus as compared to the sterile control samples. The results of Tafel plot measurements showed significant reduction in the corrosion rate in the presence of bacterial biofilm produced by strain B. cereus. The EIS data showed that the charge transfer resistance is greater in a medium containing B. cereus and increases with immersion time.     

Sodium phthalamates as corrosion inhibitors for carbon steel in aqueous hydrochloric acid solution

Three compounds of N-alkyl-sodium phthalamates were synthesized and tested as corrosion inhibitors for carbon steel in 0.5 M aqueous hydrochloric acid. Tests showed that inhibitor efficiencies were related to aliphatic chain length and dependent on concentration. N-1-n-tetradecyl-sodium phthalamate displayed moderate efficiency against uniform corrosion, 42–86% at 25 °C and 25–60% at 40 °C. Tests indicated that compounds behave as mixed type inhibitors where molecular adsorption on steel followed Langmuir isotherm, whereas thermodynamic suggested that a physisorption process occurred. XPS analysis confirmed film formation on surface, where Fe⁺² complexes and Fe⁺² chelates with phthalamates prevented steel from further corrosion.