Two new cobalt(ii) and chromium(iii) complexes were synthesized and characterized by FT-IR, 1HNMR, UV, elemental analysis, TGA, conductivity, XRD, SEM, and magnetic susceptibility measurements. Structural analysis revealed a bi-dentate chelation and octahedral geometry for the synthesized complexes. The optical band gap of the Co(ii)-L and Cr(iii)-L complexes was found to be 3.00 and 3.25 eV, respectively revealing semiconducting properties. The X-ray diffraction patterns showed nano-crystalline particles for the obtained complexes. In addition, the synthesized metal complexes were examined as corrosion inhibitors for mild steel in HCl solution. The electrochemical investigations showed a maximum inhibition efficiency of 96.60% for Co(ii)-L and 95.45% for Cr(iii)-L where both complexes acted as mixed-type inhibitors. Frontier Molecular orbital (FMO) and Natural bond orbital (NBO) computations showed good tendency of the ligand to donate electrons to the metal through nitrogen atoms while the resultant complexes tended to donate electrons to mild steel more effectively through oxygen atoms and phenyl groups. A comparison between experimental and theoretical findings was considered through the discussion.

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Effective corrosion inhibition of mild steel in hydrochloric acid by newly synthesized Schiff base nano Co(ii) and Cr(iii) complexes: spectral, thermal, electrochemical and DFT (FMO, NBO) studies

This study uses nickel nanoparticles coated on the nickel–chromium (Ni–Cr) alloy by the electrodeposition technique to protect the alloy against corrosion. An open-circuit potential and potentiodynamic and linear polarization resistance in a 1 M H2SO4 solution saturated with carbon dioxide were used to study the anticorrosion performance of nanoparticle coatings. When coated with nanomaterials, the corrosion rate of Ni–Cr alloy was lower than when it was bare, and the potential for corrosion increased from −0.433 V for uncoated Ni–Cr alloy to −0.103 V when the electrodes were exposed to saturated calomel. Electrochemical experiments show that nickel-coated Ni–Cr alloy corrosion in sulfuric acid media has high protective characteristics, with an efficiency of 83.69% at 0.165 mA/cm2 current density when pH = 1 is used. As demonstrated by the results of this research, the nickel–chromium alloy can be protected from corrosion in acidic media by a low-acidity bath coating layer. Surface morphologies have shown that coatings at different acidic scales may be able to resist an acid attack because of their excellent adherence to the nickel–chromium alloy surface. Measures for determining and studying the composition of the alloy surface’s protective covering were improved using X-ray diffraction (XRD).

Study of the Corrosion of Nickel–Chromium Alloy in an Acidic Solution Protected by Nickel Nanoparticles

Three novel p-phenylenediamine and benzidine coumarin derivatives were synthetized, namely: 4,4′-((((1,4-phenylenebis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-diyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (PhODB), 4,4′-(((-([1,1′-biphenyl]-4,4′-diylbis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-diyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (BODB) and 4,4′-(((-((3,3′-dimethoxy-[1,1′-biphenyl]-4,4′-diyl)bis(azaneylylidene))bis(ethan-1-yl-1-ylidene))bis(2-oxo-2H-chromene-3,6-iyl))bis(diazene-2,1-diyl))dibenzenesulfonic acid (DODB). Their chemical structures were proved by performing Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance and mass spectrometry analysis. The synthesized p-phenylenediamine and benzidine coumarin derivatives were tested as corrosion inhibitors for mild steel (MS) in 1 M HCl solution using weight loss, electrochemical, morphological, and theoretical studies. The compound 3,3′-dimethoxy benzidine coumarin derivative (DODB) was proved to give the highest efficiency with 94.98% obtained from weight loss measurements. These compounds are mixed inhibitors, as seen by the polarization curves. Impedance diagrams showed that when the concentration of these derivatives rose, the double-layer capacitance fell and the charge transfer resistance increased. Calculated thermodynamic parameters were computed and the mechanism of adsorption was also studied for the synthesized p-phenylenediamine and benzidine coumarin derivatives. The ability of the synthesized derivatives to protect the surface against corrosion was investigated by scanning electron microscope (SEM), UV-visible spectroscopy and energy dispersive X-ray spectroscopy (EDX). Theoretical chemical calculations (DFT) and biological resistivity (SRB) were investigated.

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Corrosion mitigation for steel in acid environment using novel p-phenylenediamine and benzidine coumarin derivatives: synthesis, electrochemical, computational and SRB biological resistivity

Two azo derivatives, 4-((4-hydroxy-3-((4-oxo-2-thioxothiazolidin-5-ylidene)methyl)phenyl) diazinyl) benzenesulfonic acid (TODB) and 4-((3-((4,4-dimethyl-2,6-dioxocyclohexylidene) methyl)-4-hydroxyphenyl)diazinyl) benzenesulfonic acid (DODB) were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) and mass spectral studies. Gravimetric methods, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) techniques and inductive coupled plasma-optical emission spectroscopy were used to verify the above two compounds' ability to operate as mild steel (MS) corrosion inhibitors in 1 M HCl. Tafel data suggest that TODB and DODB have mixed-type characteristics, and EIS findings demonstrate that increasing their concentration not only alters the charge transfer (Rct) of mild steel from 6.88 Ω cm2 to 112.9 Ω cm2 but also changes the capacitance of the adsorbed double layer (Cdl) from 225.36 to 348.36 μF cm-2. At 7.5 × 10-4 M concentration, the azo derivatives showed the highest corrosion inhibition of 94.9% and 93.6%. The inhibitory molecule adsorption on the metal substrate followed the Langmuir isotherm. The thermodynamic activation functions of the dissolution process were also calculated as a function of inhibitor concentration. UV-vis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques were used to confirm the adsorption phenomenon. The quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy (ICPE) measurements, and the anti-bacterial effect of these new derivatives against sulfate-reducing bacteria (SRB) were also investigated. Taken together, the acquired results demonstrate that these compounds can create an appropriate preventing surface and regulate the corrosion rate. 

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Insights into the adsorption and corrosion inhibition properties of newly synthesized diazinyl derivatives for mild steel in hydrochloric acid: synthesis, electrochemical, SRB biological resistivity and quantum chemical calculations

Novel coumarin-buta-1,3-diene conjugated donor–acceptor systems as corrosion inhibitors for mild steel in 1.0 M HCl: Synthesis, electrochemical, computational and SRB biological resistivity

Performance Assessment by Experimental and Theoretical Approaches of Newly Synthetized Benzyl Amide Derivatives as Corrosion Inhibitors for Carbon Steel in 1.0 M Hydrochloric Acid Environment

Abstract The influence of branched N , N ′-bis( p -hydroxybenzoyl) containing propylenediamine (PDA) and triethylenetetramine (TETA) composites for corrosion inhibition of carbon steel in acidic solution (1 M HCl) was investigated using several quantum chemical, electrochemical impedance spectroscopy and potentiodynamic polarization as electrochemical techniques. The investigated molecules were posteriorly characterized by proton nuclear magnetic resonance ( 1 H NMR) and Fourier transform infrared spectroscopy (FTIR) while the surfaces of carbon steel test coupons were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The obtained results revealed that the two amino compounds, N , N ′-bis( p -hydroxybenzoyl) propanediamine ( N , N ′-HBPDA) and N , N ′-bis( p -hydroxybenzoyl) triethylenetetramine ( N , N ′-HBTETA), have significant efficiency toward steel corrosion attack and its inhibition performance was significantly boosted by increasing concentration of di- and tetramine containing inhibitors. The two inhibitors achieved a maximum corrosion inhibition efficiency of 99.1% as indicated from polarization measurements. The isotherm feature of Langmuir adsorption appeared to be proper factor for associating the experimental gains with an applicable mechanism of inhibition process. The free energy ∆G ads was calculated to be − 27.5, 29.1 kJ/mol based on the adsorption isotherm model, indicating physical adsorption on the carbon steel surface. Further, images of the morphological analysis exhibited various features of attack owing to the aggressive medium and the employed concentration of the inhibitor. These synthesized amines supplied many favorable scores in the fabrication of functional mixed-type inhibitors. The computational studies reveal that N , N ′-HBPDA and N , N ′-HBTETA molecules could absorb via several lone pairs and π clouds, confirming their ability to be good corrosion inhibitors. 

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Synthesis, Characterization, Thermodynamic Analysis and Quantum Chemical Approach of Branched N, N′-bis(p-hydroxybenzoyl)-Based Propanediamine and Triethylenetetramine for Carbon Steel Corrosion Inhibition in Hydrochloric Acid Medium

Enas Arafa

Papers

Performance Assessment by Experimental and Theoretical Approaches of Newly Synthetized Benzyl Amide Derivatives as Corrosion Inhibitors for Carbon Steel in 1.0 M Hydrochloric Acid Environment

Synthesis, Characterization, Thermodynamic Analysis and Quantum Chemical Approach of Branched N, N′-bis(p-hydroxybenzoyl)-Based Propanediamine and Triethylenetetramine for Carbon Steel Corrosion Inhibition in Hydrochloric Acid Medium

Alveolar clefts repair using autogenous bone marrow derived mesenchymal stem cells

Eco-Friendly Thermal Insulator from Agricultural Wastes and Chitosan