The water soluble composite poly(vinylpyrrolidone–methylaniline): A new class of corrosion inhibitors of mild steel in hydrochloric acid media

Novel porphyrin derivatives as corrosion inhibitors for stainless steel 304 in acidic environment: synthesis, electrochemical and quantum calculation studies

A Novel 5,10,15,20-tetra (thiophen-2-yl) porphyrin (P1) and 5,10,15,20-tetrakis (5-Bromothiophen-2-yl) porphyrin (P2) were successfully synthesized, and their chemical structures were proved based on its correct elemental analysis and spectral data (IR and 1H-NMR). These compounds were examined as corrosion inhibitors for stainless steel 304 (SS304) in 2 M HCl utilizing mass reduction (MR) and electrochemical tests at inhibitor concentration (1 × 10-6-21 × 10-6 M). The protection efficiency (IE %) was effectively enhanced with improving the concentration of investigated compounds and reached 92.5%, 88.5% at 21 × 10-6 M for P1 & P2, respectively and decreases with raising the temperature. Langmuir's isotherm was constrained as the best fitted isotherm depicts the physical-chemical adsorption capabilities of P1 & P2 on SS304 surface with change in ΔGoads = 22.5 kJ mol-1. According to the PDP data reported, P1 and P2 work as mixed find inhibitors to suppress both cathodic and anodic processes. Porphyrin derivatives (P1 & P2) are included on the surface of SS304, according to surface morphology techniques SEM/EDX and AFM. Quantum calculations (DFT) and Monte Carlo simulation (MC) showed the impact of the chemical structure of porphyrin derivatives on their IE %.

Computational, Kinetics, and Corrosion Protection Aspects of Electrodeposited Poly(Salicylic Acid) Coatings as a Corrosion Inhibitor for Mild Steel

Poly(salicylic acid) PSA has been electrochemically deposited onto a Pt electrode. The kinetics of the polymerization reaction has been studied. The polymer structure was confirmed and characterized using IR spectroscopy, XRD, SEM, and TGA analysis. The deposited PSA was then collected from the Pt surface and tested as a corrosion inhibitor for a mild steel electrode in an aqueous medium of 1 M sulfuric acid. The corrosion behavior was then evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Corrosion measurements showed that the inhibition efficiency of 20, 50, and 100 ppm of PSA was 33, 57, and 74%, respectively. The inhibition mechanism was proved using adsorption isotherms as well as quantum calculations. The inhibition of the corrosion process was due to the adsorption of PSA on the steel surface, which was found to comply with the Langmuir adsorption isotherm.

Anticorrosive Effect of Halogenated Aniline Enaminoesters on Carbon Steel in HCl

Four enaminoesters derived from halogenated aniline, with potential anticorrosion activity, were synthesized and tested against carbon steel AISI 1020 in acid medium using 1.0 mol L-1 HCl. The synthesis was demonstrated through the reaction of ethyl acetoacetate with four different amines, in the presence of glacial acetic acid and molecular sieve, using ethanol as solvent for 24 h. The evaluation of the anticorrosive activity was performed using the gravimetric technique and electrochemical methods, such as electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarization (PP). Results indicated that the F-EN (Ethyl (2Z)-3-[(4-fluoro-phenyl)-amino]-but-2-enoate) inhibitor had higher corrosion inhibition efficiency, of 98% by mass loss, and 85% by electrochemical techniques. Adsorption obeyed the Langmuir isotherm, thus suggesting that the inhibitors form a monolayer film in metal surface. These results also contributed to the calculations of the physicochemical parameters of $E_{\text{a}}$ , $△{H^{\ne }}_{\text{ads}}$ , and $△{S^{\ne }}_{\text{ads}}$ , which confirmed the corrosion inhibition when compared to the absence of the inhibitors.

Spectroscopic, Electrochemical and Quantum Chemical Studies for Adsorption Action of Polyethylene Oxide on Copper Surface in NaCl Solution

The adsorption action of polyethylene oxide (PEO) on copper surface in 3.5 wt.% NaCl solution was tested using electrochemical frequency modulation (EFM), atomic absorption spectrometry (AAS), UV- visible spectrometry and the morphology of copper surface was investigated by attenuated total reflectance spectroscopy (ATR-FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. Results obtained show that PEO is effective in preventing the corrosion of copper in NaCl solution. The adsorption of PEO onto copper surface was found to follow Langmuir isotherm model. ATR-FTIR, SEM and EDX spectroscopy techniques confirmed the adsorption of protective film of PEO on copper surface. Further, quantum chemical calculations were in agreement with inhibition efficiency (%I) of PEO that were obtained experimentally.

Evaluation of Polyether Copolymer as Green Scale and Corrosion Inhibitor in Seawater

A novel environmentally friendly type of corrosion and scale inhibitor, maleic anhydride-allylpolyethoxy carboxylate copolymer (ML10), was synthesized and characterized by FT-IR and 1H-NMR spectroscopic techniques. The anti-scale property of ML10 in seawater was also studied by static tests for scale and the scale deposits were analyzed by X-ray diffraction (XRD) and SEM, respectively. The results showed that the scale deposits surface morphology and size were changed in the presence of ML10. The performance of the synthesized copolymer as corrosion inhibitor for mild steel corrosion was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. The experimental results indicate that ML10 has a good corrosion inhibition performance and the inhibition efficiency increases with the increase of the ML10 concentration. The adsorption of ML10 obeys Langmuir adsorption isotherm with relatively high value of free energy of adsorption ΔGadsθ. Scanning electron microscopy (SEM) indicated that the corrosion inhibition is due to the formation of a chemisorbed film on the mild steel.

Chitosan oligosaccharide derivatives as green corrosion inhibitors for P110 steel in a carbon-dioxide-saturated chloride solution

Two chitosan oligosaccharide derivatives (PHC and BHC) were synthesized for use as corrosion inhibitors. They were characterized using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The inhibition efficiency of PHC and BHC on P110 steel corrosion in a 3.5 wt.% NaCl CO₂-saturated solution at 80℃ was studied using gravimetric measurement, scanning electron microscopy (SEM), atomic force microscopy (AFM), electrochemical analysis, and quantum chemical calculation. The results indicated that inhibition efficiency increased with increasing concentration of inhibitor. Energy dispersive X-ray (EDX), contact angle, and electrochemical impedance spectroscopy (EIS) measurements showed that the inhibitors had been successfully adsorbed to the surface of the P110 steel. The results of potentiodynamic polarization indicated that both compounds were mixed-type inhibitors.

SECM/SKP and SVET studies on mitigation of N80 steel corrosion by some polymers

Three polymers, namely PAMPS (P1), P(AMPS-co-NVP) (P2) and P(AMPS-co-DMC) (P3), synthesized by common solution polymerization were investigated as corrosion inhibitors for N80 steel in 3.5 wt% NaCl flooded with CO₂.