Enhanced Corrosion Inhibition Research Articles

Corrosion Inhibition of Mild Steel by Cetrimonium trans-4-Hydroxy Cinnamate: Entrapment and Delivery of the Anion Inhibitor through Speciation and Micellar Formation.

Chemical inhibitors are widely used to protect metallic alloys from corrosion in aqueous environments. This Letter investigates the possible synergistic behavior of a quaternary ammonium carboxylate compound toward the development of a new system taking advantage of the surface activity of a known antimicrobial surfactant molecule, hexadecyl trimethylammonium cation, combined with a known organic corrosion inhibitor, the trans-4-hydroxy-cinnamate anion. Short-term potentiodynamic polarization (PP) studies combined with immersion in aqueous chloride solutions demonstrated the high inhibition efficiency of the combination of ions, and NMR pfg-diffusion measurements revealed micellar formation that was concentration- and pH-dependent. The NMR data suggest that speciation changes occur in the solution that correlate with enhanced corrosion inhibition efficiency at higher pH and at concentrations above the CMC of the compound. This new contribution may provide a rational molecular design toward delivering corrosion inhibitors to a metal surface through controlled speciation in solution.

Chitosan nanocomposite coatings with enhanced corrosion inhibition effects for copper

A biopolymer coating on copper was prepared based on chitosan nanocomposite and its corrosion inhibition efficiency was investigated. Inclusion of silica nanoparticles substantially reduces swelling ratio of chitosan coating while enhancing its thermal stability. The corrosion resistance of chitosan-based coatings is improved by introducing 2-mercaptobenzothiazole and silica in the matrix. It is found that upon crosslinking the chitosan coatings, a higher corrosion resistance could be achieved and the highest inhibition efficiency for chitosan nanocomposite coatings is calculated as 85%. The corrosion mechanism is found closely related to mass transition and diffusion process, and also the polarization resistance contributes to the impedance. Calculated impedance using Kramers-Kronig transformation shows good agreement with experimental values, thus validating the impedance measurements. This study exhibits the enhanced efficiency of nanocomposite and potential of chitosan coatings in corrosion prevention for copper.

Enhanced corrosion inhibition of carbon steel in HCl solution by a newly synthesized hydrazone derivative: Mechanism exploration from electrochemical, XPS, and computational studies

The corrosion inhibition properties of a synthesized hydrazone derivative namely, 1-(4-isopropyl phenyl) -2- (2,4-dinitrophenyl) (HYD (iso)) on API 5L-X60 carbon steel (CS) in 1.0 M HCl solution were evaluated by chemical, electrochemical, X-ray photoelectron spectroscopy (XPS) and theoretical studies. The obtained results revealed that the tested compound acted as a good corrosion inhibitor with inhibition efficiency of 96.32% at a concentration of 5 × 10−3 M. The polarization technique indicated that the HYD (iso) belonged to mixed-type inhibitors, preventing simultaneously anodic and cathodic reactions. The binding between the HYD (iso)'s molecule and CS surface follows a Langmuir adsorption type model and its inhibition mechanism is assisted by physical and chemical interactions. Scanning electron microscope (SEM) and contact angle analyses were performed to examine the surface morphology of inhibited and uninhibited samples. Additionally, theoretical studies using Density Functional Theory (DFT) and molecular dynamics (MD) simulation were performed to explore the most reactive sites of the hydrazone molecule and its adsorption mechanism.

Synthesis, characterization and application of glucosyloxyethyl acrylate graft chitosan against pipeline steel corrosion

In this study, glucosyloxyethyl acrylate graft chitosan (GA-CHS) was synthesized by reacting chitosan with glucosyloxyethyl acrylate, previously prepared via catalyzed α-d-glucopyranoside transesterification with excess 2-hydroxyethyl acrylate. This graft GA-CHS copolymer was utilized as a corrosion inhibitor for API 5 L X70 pipeline steel in chloride-enriched (1 M HCl) acid solution. GA-CHS adsorption on the steel surface led to significant inhibition of chloride-induced corrosion compare to unmodified chitosan (CHS). In the presence of GA-CHS, corrosion inhibition increased with its concentration due to the formation of compact protective films; compositional and morphological evidences have been provided. Without this graft copolymer in corrosive electrolytes, the steel coupons corroded due to unrestricted chloride-induced attacks, leading to severe surfaces pits. The linear GA-CHS polysaccharide moiety could have been a contributing factor and the greater edge over unmodified chitosan, regarding enhanced corrosion inhibition as well as its hydroxyl/amino chemical groups in combination with its acrylate functionality.

Corrosion inhibition of 316L-type stainless steel under marine environments using epoxy/waste plastic soot coatings

316L grade stainless steel is widely utilized in industrial applications owing to its exceptional corrosion resistance. However, it is less resistant to aggressive marine environments that contain salt-based seawater. In the present study, we report effective anti-corrosive epoxy polymer coating engineered with carbon soot nanoparticles (derived from waste polyolefin plastics) and coated on a 316L steel substrate via controlled pneumatic fluid atomization technique. Morphological analysis of derived carbon soot nanoparticles revealed an average diameter to be in the range of 41–62 nm. Corrosion inhibition performance of the coatings was studied under aggressive chlorine-based environments via polarization plots, i.e., Tafel plots, and by natural salt spray test for the total duration of 20 days. The scratch test and the solvent resistance rub test revealed adherence to the developed coatings with a 316L steel surface. The developed coatings were found to be uniform, crack-free, and well bonded with the surface of steel substrates. Successive experimental results of the developed coatings indicated enhanced corrosion inhibition properties, which imply its practical applicability for under-water marine applications.

Enhanced corrosion inhibition of aniline derivatives electropolymerized coatings on copper: Preparation, characterization and mechanism modeling

Nanostructured polyaniline (PANi), poly(N-ethylaniline) (PNEA) and their molybdate-doped coatings (PANi-Mo and PNEA-Mo) were electropolymerized on passivated copper surface via voltammetric cycles in oxalic acid solution. The coating structures were featured by morphological observation, attenuated total reflectance infrared spectra (ATR-IR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS); besides, anticorrosive performance of coatings was investigated for copper in 0.5 M H2SO4 solution through electrochemical and topographical measurements. ATR-IR and XRD results documented the occurrence of polymerization over copper surface, while the morphologies implied that the presence of ethyl and molybdate generated the extra increment in coating thickness. Owing to physical barrier of substituent and in-situ dissolving of molybdate, the corrosion of coated specimens was highly suppressed in H2SO4 solution. The protective effect of coatings followed the sequence of PNEA-Mo > PANi-Mo > PNEA > PANi with an inverse trend in porosity index. XPS analyses revealed that repeat units of polymer were in mixed state with predominantly oxidative type, which were inclined to parallelly deposit on copper surface with a strong anchoring strength. Molecular dynamics simulations well supported the configuration and forceful adhesion of polymers on Cu (1 1 1) plane, and indicated the favorable compatibility between polymer and dopant.

Enhanced corrosion inhibition of carbon steel by pyridyl gemini surfactants with different alkyl chains

Three pyridyl gemini surfactants varying in alkyl chain length (DBP: decamethylene bis-pyridinium dibromide; OBP: octamethylene bis-pyridinium dibromide; HBP: hexamethylene bis-pyridinium dibromide.) were applied as corrosion inhibitors for the first time. The inhibition performance of three inhibitors on P110 steel corrosion in HCl solution were studied using gravimetric measurement, electrochemical analysis, scanning electron microscopy (SEM), and quantum chemical calculation. Adsorption of inhibitors onto the steel surface was described well by Langmuir isotherm. All of three compounds were mixed-type inhibitors. The inhibition efficiency of the three inhibitors was in the order: DBP > OBP > HBP, especially as high as efficiency of 91.76% in case of DBP. Increment of the non-polar chain length within the inhibitor contributed to the improvement of corrosion inhibition, which may be due to the stronger hydrophobicity with longer alkyl chain. Results in this study reveal the potential application of non-polar pyridinium gemini surfactants as excellent inhibitors, providing new ideas for synthesizing novel corrosion inhibitor.

Synergistic action of Bacillus subtilis, Escherichia coli and Shewanella putrefaciens along with Pseudomonas putida on inhibiting mild steel against oxygen corrosion.

Microbial biofilm can effectively alter the electrochemical characteristics at metal/solution interface that can either accelerate or decelerate corrosion. The present paper reports about microbiologically induced corrosion inhibition (MICI) using Pseudomonas putida as a dominant bacterium under aerobic condition. Effective corrosion inhibition is achieved by the synergistic metabolic action of P. putida along with Escherichia coli, Bacillus subtilis or Shewanella putrefaciens. The synergistic metabolic actions of these bacteria in biopassivation are analysed with various aspects such as electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM) and confocal laser scanning microscopy (CLSM). Surface topography is quantitatively analysed using optical scanning profilometry (OSP). The binary culture system containing P. putida + E. coli and P. putida + S. putrefaciens achieves an inhibition efficiency of 90% and 85% respectively, despite S. putrefaciens being a corrosion causing bacteria. The P. putida + E. coli system could form a stable biofilm on mild steel surface, with a high corrosion potential (- 329mV vs. Ag/AgCl/KCl sat'd) and a low corrosion rate (1.65 × 10-1mmpy). The presence of B. subtilis in the culture promotes corrosion against normal predictions. In the present case, the metabolic activities of the bacterial system on the mild steel surface cause depletion of oxygen in the medium that leads to suppression of corrosion. In addition, the biofilm could form an effective protective barrier on the metal surface that can suppress diffusion of corrosion products resulting in enhanced corrosion inhibition efficiency.

Durable Hydrophobic Coating Based on Cerium Phosphate Nanorod-Siliconized Epoxy for Corrosion Protection

Here, we present a new eco-friendly cerium phosphate (CP) nanorod system that can be utilized as an anticorrosive pigment to protect steel from corrosive environment. Among the various formulations studied, CP nanorod (10 wt %) loaded epoxy exhibited the best corrosion resistance efficiency. The anticorrosion property of the coating was further improved by the introduction of hydrophobicity through siliconization process. This enhanced the average surface roughness (Ra = 0.4–11 nm) and consequently generated hydrophobic contact angle of 121°. A 3-fold increase of the corrosion resistance of epoxy is attributed to the synergistic effect of the hydrophobic surface and nanorod morphology. The durability of the coating was also studied by an electrochemical method for the duration of two months. The enhanced corrosion inhibition efficiency and durability of the developed coating can be of significant importance for industrial applications.

Improved Corrosion Resistance of Steel in Ethanol Fuel Blend by Titania Nanoparticles and Aganonerion polymorphum Leaf Extract.

A porous and low-density protective film on a steel surface in the corrosive environment can undergo deterioration even in the presence of organic inhibitors due to infiltration of aggressive ions into the pinholes and/or pores. This phenomenon is related to the localized corrosion that takes place even in the presence of an optimal concentration of organic corrosion inhibitors in the given medium. To overcome this issue, we have designed an organic protective film on a steel surface with the help of titania nanoparticles (TNPs) combined with an organic corrosion inhibitor derived from Aganonerion polymorphum leaf extract (APLE), all to be studied in a simulated ethanol fuel blend (SEFB). The TNPs with varied diameters and concentrations have been studied for examining their effect on the inhibition capacity of 1000 ppm APLE on the steel surface in SEFB medium using electrochemical and surface analysis techniques. Enhanced corrosion inhibition of the surficial film was observed in the presence of both the APLE inhibitor and small amounts of TNPs. A direct agreement was observed between the experimental and molecular dynamics theoretical investigations showcasing high binding energy between inhibitor molecules and steel substrates, resulting in a much higher adhesion of the protective film, good thermal stability of the adsorbent film, and electron abundance for the supply of steel substrate of inhibitor species.

Corrosion resistance behavior of PVDF/ZrO2 composite in 3.5% NaCl

Abstract Marine structures come into contact with the seawater. Corrosion occurs on the walls of these structures and can quickly lead from surface damage to aesthetics impairment. The main cause of the corrosiveness are chloride ions which facilitate initiation and propagation of pits. Stainless steels provide a wide range of applications in seawater environments. They are used for the construction of heat exchangers, tanks and capacitors for electrical systems, refrigeration systems for power plants, tidal power, wind turbines localized at sea. Mild steel find its role in almost every product created from metal due to its low cost and easy availability. The polymeric materials are having multiple adsorption sites for bonding with metal surface and provides higher inhibition efficiency than the corresponding monomers. In the present work, the corrosion inhibition of mild steel in 3.5% NaCl by PVDF/ ZrO2 composites were studied. The composite samples were characterized by using XRD, FTIR and SEM. Potentiodynamic polarization and electrochemical impedance spectroscopic techniques were used to explore the enhanced corrosion inhibition of composites. The corrosion inhibition efficiency of PVDZr composites were found to increase with increase in concentration of ZrO2.

Enhanced corrosion inhibition performance of novel modified polyaspartic acid on carbon steel in HCl solution

Novel modified polyaspartic acid with Schiff base structure was synthesized for the first time. Then the corrosion inhibition behavior of polyaspartic acid (PASP) and modified polyaspartic acid (PASP/SB) on carbon steel in 1 M HCl was investigated using gravimetric methods, electrochemical measurements, AFM and SEM. The obtained results indicate PASP/SB as a mixed-type corrosion inhibitor shows the maximum inhibition efficiency of 90.39% at low concentration of 80 ppm, which is much higher than that of PASP. The inhibition performance of PASP/SB is slightly affected by temperature and flow in comparison with PASP. It is found that the inhibition effect of PASP/SB was primarily due to its physical and chemical adsorption on steel surface. Quantum chemical studies confirm the better inhibition and adsorption property of PASP/SB on carbon steel is attributed to the new functional groups on side chain.

Corrosion resistance behavior of PVA/TiO2 composite in 3.5% NaCl

Marine structures come into contact with the seawater. Corrosion occurs on the walls of these structures and can quickly lead from surface damage to aesthetics impairment. The main cause of the corrosiveness are chloride ions which facilitate initiation and propagation of pits. Stainless steels provide a wide range of applications in seawater environments. They are used for the construction of heat exchangers, tanks and capacitors for electrical systems, refrigeration systems for power plants, tidal power, wind turbines localized at sea. Mild steel find its role in almost every product created from metal due to its low cost and easy availability. The polymeric materials are having multiple adsorption sites for bonding with metal surface and provides higher inhibition efficiency than the corresponding monomers. In the present work, the corrosion inhibition of mild steel in 3.5% NaCl by polyvinyl alcohol/TiO2 composites were studied. The composite samples were characterized by using XRD, FTIR and SEM. Potentiodynamic polarization and electrochemical impedance spectroscopic techniques were used to explore the enhanced corrosion inhibition of composites. The corrosion inhibition efficiency of PVTi composites were found to increase with increase in concentration of TiO2.

Enhanced corrosion inhibition effect of chitosan for St37 in 15% H2SO4 environment by silver nanoparticles

The inhibitive performance of chitosan and silver nanoparticles – chitosan (AgNPs-Chi) composite towards St37 steel corrosion in 15% H2SO4 solution was studied using weight loss and electrochemical techniques in addition to surface morphological examination. Results obtained show that chitosan could fairly protect St37 steel surface by 45%. Inhibition efficiency above 94% has been achieved with AgNPs-Chi composite. AgNPs-Chi composite performs better at longer immersion time and elevated temperature. AgNPs-Chi retards both anodic and cathodic redox reactions. The mode of adsorption of AgNPs-Chi onto St37 surface has been described using Langmuir adsorption isotherm. Surface screening results ascertain the adsorption of AgNPs-Chi molecules on St37 surface.

Synthesis, crystal structure, electrochemical and anti-corrosion studies of Schiff base derived from o-toluidine and o-chlorobenzaldehyde

In this report, a Schiff base, E-N-(2-chlorobenzylidiene)-2-methylaniline, has been synthesized and characterized using Elemental analysis, MS, FTIR, and NMR (1H and 13C) spectroscopic techniques. The structure of the compound was determined by single crystal X-ray diffraction studies. The structure showed a disorder, as if ‘inverted’, around a point between the carbon and nitrogen bridge atoms in a 0.68:0.32 ratio. The methyl and chloride swap positions of the opposite phenyl rings, as well as bridging carbon and nitrogen. The solid state molecular geometry has been compared with the theoretical data obtained using density functional theory (DFT). The ELUMO–HOMO, dipole moments, chemical potential, absolute electronegativity and hardness of the compound were studied by DFT. The corrosion inhibition study of the Schiff base was investigated for mild steel in 1 M HCl medium using electrochemical (potentiodynamic polarization and electrochemical impedance spectroscopy) methods. The results showed that the compound exhibited appreciable inhibition efficiency at higher concentration with potentiodynamic polarization studies revealing a mixed-type inhibitor of predominantly anodic type. Scanning electron micrographs (SEM) and EDX studies revealed the film-forming ability of the ligand on the mild steel surface. Some quantum chemical parameters calculated correlate well with the experimental results. Based on the theoretical and experimental results obtained, the enhanced corrosion inhibition efficiency could be ascribed to the presence of the azomethine and the aromatic rings characteristic of the Schiff base.

Enhanced corrosion inhibition behavior of carbon steel in aqueous solution by Phosphoserine-Zn2+ system

The corrosion inhibition effect of carbon steel in aqueous solution was using a synergistic mixture of an environmentally friendly inhibitor system phosphoserine (PS) and Zn2+ using gravimetric studies, potentiodynamic polarization, and electrochemical impedance studies. Potentiodynamic polarization studies showed that the inhibitor system is a mixed type inhibitor. Electrochemical impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the aqueous solution. X-ray photoelectron spectroscopic analysis of the protective film exhibited the presence of the elements viz., iron, phosphorus, nitrogen, oxygen, carbon, and zinc. The chemical shifts in the binding energies of these elements inferred that the surface film is composed of oxides/hydroxides of iron, Zn(OH)2, and [Fe(II)/(III)-Zn(II)-PS] complex. Further, the surface examination techniques viz., FTIR, SEM, and AFM studies confirm the formation of an adsorbed protective film on the carbon steel surface. Based on the results obtained, a suitable mechanism of corrosion inhibition is presented.

Enhanced corrosion inhibition properties of carboxymethyl hydroxypropyl chitosan for mild steel in 1.0 M HCl solution

CHPCS was synthesized and showed better corrosion inhibition than HPCS (corrosion inhibition of 95.3%); its corrosion inhibition mechanism is presented.

Optimization of parameters through Taguchi method for enhanced corrosion inhibition of poly (vinyl alcohol-serine)

Parametric optimization was carried out for the mixture of polyvinyl alcohol (PVA) and l-serine using Taguchi statistical approach. L9 orthogonal array of experiments were designed and the results were analyzed with Qualitek software. Synergistic effect of the mixture was enhanced at the Qualitek predicted optimized conditions. The graft polymer, poly(vinyl alcohol-serine) (PVAS), was synthesized using free radical-initiated reactions of l-serine with PVA in order to achieve effective inhibition. PVAS was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and powder X-ray diffraction analysis. The thermal properties of PVAS were studied by thermogravimetry, differential thermal analysis, and differential scanning calorimetry. The corrosion inhibition property of PVAS on mild steel corrosion was continuously monitored using electrochemical techniques. Temperature effect on the inhibition properties of PVAS was studied using electrochemical and gravimetric measurements. AFM studies confirmed the formation of polymeric film on mild steel surface which inhibits the rate of corrosion. Theoretical calculations using Hyperchem 7.0 proved the better corrosion mitigation properties of PVAS compared to PVA. The experimental results and surface analysis confirmed the effective inhibition process of the graft polymer which was also supported by the theoretical calculations. A good correlation was obtained between the results of the electrochemical measurements, conventional gravimetric measurement, surface analysis, and theoretical calculations. All the studies proved the enhanced corrosion inhibition properties of PVA through grafting of polyserine.

Enhanced corrosion inhibition effect of polypropylene glycol in the presence of iodide ions at mild steel/sulphuric acid interface

The corrosion inhibition effect of polypropylene glycol (PPG) without and with addition of iodide ions at mild steel/0.5M H2SO4 solution interface was investigated using chemical, electrochemical, and surface analysis methods at different temperatures. Results obtained showed that PPG inhibited the corrosion of mild steel in the acid environment. Addition of iodide ions to PPG is found to synergistically enhance the corrosion inhibitive ability of PPG with efficiency in the vicinity of 98.4%. Temperature–inhibition efficiency relationship suggest physisorption of PPG onto mild steel surface and chemisorption when PPG was combined with iodide ions. Potentiodynamic polarization results showed that PPG behaved as mixed type inhibitor but under anodic control when combined with iodide ions. The adsorption of PPG and PPG–iodide ions mixtures onto the metal surface followed Temkin adsorption isotherm model.

Synthesis of polyaspartic acid derivative and evaluation of its corrosion and scale inhibition performance in seawater utilization

A polyaspartic acid derivative (PASP-SEA-ASP) was synthesized from polysuccinimide with 2-aminoethanesulfonic acid and aspartic acid. PASP-SEA-ASP achieved a better corrosion inhibition rate for A3 carbon steel in seawater compared with polyaspartic acid (49% cf. 45% at the dosage of 100mg/L). The development of a composite inhibitor (a mixture of PASP-SEA-ASP, zinc sulfate, 2-hydroxyphosphonoacetic acid (HPAA) and hexadecylldimethyl (2-sulfite) ethyl ammonium on a mass ratio of 15:3:6:1, respectively) led to a significantly enhanced corrosion inhibition effect, achieving an inhibition rate of 97%. The mass ratio of the composite inhibitor could be adjusted to achieve the desired corrosion inhibition rate for seawater with varying characteristics. PASP-SEA-ASP also showed excellent scale inhibition properties for seawater, with a scale inhibition rate of 100% achieved with a dosage of 14mg/L. This study demonstrated the potential of PASP-SEA-ASP to inhibit both corrosion and scale formation in domestic and industrial utilization of seawater such as cooling systems and thermal desalination processes.