Durability assessment of LC3-based reinforced concrete under combined chloride-sulfate environment via the EIS technique

The Individual and Combined Effect of Olive Stone Biomass Ash with Coal Fly Ash on the Durability of Water Treatment Tank Concrete Exposed to Ferric Chloride

Results of studying the properties of composite fluoropolymer-containing coatings formed by the cold spray (CS) method on the surface of constructional steel are presented. Different ways of protective coating formation are proposed. The composition of coatings was studied using SEM/EDX analysis. The incorporation of super-dispersed polytetrafluoroethylene (SPTFE) into the coating increases the corrosion resistance of the copper-zinc-based cold-sprayed coating. Analysis of the electrochemical properties obtained using EIS (electrochemical impedance spectroscopy) and PDP (potentiodynamic polarization) indicates that samples treated with SPTFE on a base copper-zinc coating showed lower corrosion current density and higher impedance modulus (jc = 8.5 × 10−7 A cm−2, |Z|f=0.1 Hz = 5.3 × 104 Ω∙cm2) than the specimen with cold-sprayed SPTFE (jc = 6.1 × 10−6 A cm−2, |Z|f=0.1 Hz = 8.1 × 103 Ω∙cm2). The best anticorrosion properties were revealed for the sample with a cold-sprayed base Cu-Zn layer annealed at 500 °C for 1 h, followed by SPTFE friction treatment and re-annealed at 350 °C for 1 h. The corrosion current density jc of such a coating is 25 times lower than that for the base Cu-Zn coating. The antifriction properties and hydrophobicity of the formed layers are described. Obtained results indicate that cold-sprayed polymer-containing coatings effectively improve the corrosion and wear resistivity of the treated material.

/pdf/cold-sprayed-composite-metal-fluoropolymer-coatings-for-2ff92ffp.pdf

Cold-Sprayed Composite Metal-Fluoropolymer Coatings for Alloy Protection against Corrosion and Wear

Although the use and promotion of renewable energies have increased in recent years, it is evident that the use of fossil fuels such as oil and gas continues to be of great importance. Likewise, pipelines are widely recognized as the most reliable and profitable means of transportation for liquid and gaseous hydrocarbons. Nevertheless, due to the nature of hydrocarbons, oil and gas pipelines are continually exposed to deterioration by corrosion and mechanical damage. In this context, this research focuses on the improvement of the surface properties of API 5L grade B pipeline steel by applying a surface hardening process. Samples of an API 5L grade B pipeline steel were exposed to boriding to form a layer of high hardness (from 2.60 GPa for the non-treated material to 14.12 GPa for the samples exposed to 1000 °C for 6 h). The treatment time was set at 2, 4, and 6 h, at temperatures of 850, 900, 950, and 1000 °C. Due to the saw-tooth morphology of the layers and the random nature of the process, it was possible to fit their thicknesses to a probability density function in all the experimental conditions. The crystalline structure of the layers was analyzed by X-ray diffraction and the morphology was observed using SEM and optical microscopy. The layer’s thickness ranged between 26.6 µm to 213.9 µm showing a close relationship with the experimental parameters of time and temperature. Finally, it is studied the changes undergone in the pipeline steel after the thermochemical process, observing an increase in the grain size as a function of the temperature.

https://www.mdpi.com/2079-6412/13/2/298/pdf?version=1674895744

Improving the Surface Properties of an API 5L Grade B Pipeline Steel by Applying the Boriding Process. Part I: Kinetics and Layer Characterization

A prestressed concrete cylinder pipe (PCCP) is created with a complex composition of concrete core, welded steel cylinder, prestressed steel wire, protective mortar and anti-corrosion coating. Due to the economy and complexity of structural prototype tests, the ultimate loading test on PCCP is rarely conducted. In this paper, the three-edge bearing test was carried out on a 3.2 m diameter PCCP with embedded steel cylinder. The strains of concrete core, prestressed steel wire and protective mortar were monitored, and the distribution and width of the concrete cracks were recorded. The test results show that the cracking on the inside concrete at the crown zone occurred before those on the invert zone of the pipe. The prestressed steel wire postponed the tensile stress of out-side concrete at the springing line until subjected to the calculated cracking load (Pc). Due to the moment redistribution caused by the cracking on the inside of the concrete at the crown/invert, the protective mortar at the springing line was cracked at 1.2 Pc and exhibited visible cracking after 1.4 Pc. The prestressed steel wire reached the elastic and strength limit states of 1.4 Pc and 1.6 Pc, respectively. The PCCP designed by the limit state design method can resist the increased external loads after reaching the serviceability limit state. The final failure load of the test pipe is greater than 1.6 Pc, and there is sufficient safety in actual operation. Due to the fact that the damage to the concrete at the crown/invert zone may become a fuse of PCCP failure, the tensile stress of the inside concrete at the crown/invert zone of the PCCP should be accurately verified in the design process.

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Experimental Study on External Loading Performance of Large Diameter Prestressed Concrete Cylinder Pipe

• (E)-3- (5-bromo-2-hydroxystyryl) quinoxalin-2(1H)-one (FR178) and (E)-3-(5-fluoro- -hydroxystyryl) quinoxalin-2(1H)-one (FR179) are a new effective corrosion inhibitors for mild steel in 1.0M HCl. • E)-3- (5-bromo-2-hydroxystyryl) quinoxalin-2(1H)-one (FR178) and (E)-3-(5-fluoro- -hydroxystyryl) quinoxalin-2(1H)-one (FR179) act as mixed-type inhibitors in 1.0M HCl. • The adsorption of (E)-3-(5-bromo-2-hydroxystyryl) quinoxalin-2(1H)-one and (E)-3-(5-fluoro-2 hydroxystyryl) quinoxalin-2(1H)-one are well described by the Langmuir adsorption isotherm. • Surface characteristics analysis by MEB-EDS and DRX provided strong evidence for the existence of inhibition film on mild steel surface. • Quantum chemical parameters were correlated with experimental results. The evaluation of corrosion inhibition of mild steel (M-S) in 1.0 M HCl solution in the absence and the presence of different concentrations of (E)-3-(5-bromo-2-hydroxystyryl)quinoxalin-2(1H)-one (FR178) and (E)-3-(5-fluoro-2-hydroxystyryl)quinoxalin-2(1H)-one (FR179) was studied by electrochemical,and theoretical measurements. These organic inhibitors have proven to be effective corrosion inhibitors for the protection of mild steel.Increasing concentrations of inhibitors contributed to high inhibition efficiencies, which were attributed to the simple blocking action of the anodic and cathodic sites by adsorption of the inhibitors molecules onto the M-S surface. Their inhibition efficiencies can reach about 90.9% and 91.5% when the optimal concentration is 10 -3 M for the two inhibitors FR178 and FR179 respectively.On the other hand, as the temperature rises, the anti-corrosion capability of both FR178 and FR179 diminishes slightly and attains 82% and 84% respectively at the temperature of 328K.Potentiodynamique polarization (PDP) and electrochemical impedance spectroscopy(EIS) demonstrated that both inhibitors examined act as mixed-type inhibitors.Furthermore, X-ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive spectroscopy (SEM/EDS) measurements indicated the formation of a protective layer adsorbed on the mild steel surface. The density functional theory (DFT) and molecular dynamics (MD) simulations were carried out to examine the correlation between molecular and chemical reactivity. The obtained results were found to be consistent with the experimental findings. 

Evaluation of quinoxaline-2(1H)-one,derivatives as corrosion inhibitors for mild steel in 1.0 M acidic media: Electrochemistry, quantum calculations, dynamic simulations ,and surface analysis

Effects of Fly Ash and Simulation of the Natural Hot and Dry Climate of the Moroccan Desert Region on the Durability of Prestressed Concrete Cylinder Pipes

Anticorrosive protection efficiency of novel tetrafunctional epoxy prepolymer, namely 2,3,4,5-tetraglycidyloxy pentanal (TGP), for mild steel in 1 M HCl medium was assessed through potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), contact angle (CA), adsorption isotherm model, temperature effect and thermodynamic parameters. The synthesized TGP was characterized and confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR). The inhibitory efficiencies found at lower concentration of the prepolymer TGP were85% (PDP) and 87.17% (EIS). PDP measurement illustrated that the TGP behaved as a mixed-type inhibitor in the realized solution. SEM and EDS analysis showeda significant decrease in the corrosion of the MS surface in the presence of the inhibitory prepolymer compared with the blank (1 M HCl). Langmuir adsorption isotherm is the most acceptable modelto describe the TGP epoxy prepolymer on the MS area.

/pdf/synthesis-characterization-and-highly-protective-efficiency-1dwr5y8r.pdf

Synthesis Characterization and Highly Protective Efficiency of Tetraglycidyloxy Pentanal Epoxy Prepolymer as a Potential Corrosion Inhibitor for Mild Steel in 1 M HCl Medium

Anticorrosion properties of the epoxy polymer TGETBAU for mild steel in a solution of HCl (1.0M): Experimental and computational approaches

New Xanthene Diones Compounds as a Corrosion Inhibitor of Mild Steel in Acid Medium: Electrochemical, Surface Characterization and Theoretical Insights

R. Lachhab

Papers

Evaluation of quinoxaline-2(1H)-one,derivatives as corrosion inhibitors for mild steel in 1.0 M acidic media: Electrochemistry, quantum calculations, dynamic simulations ,and surface analysis

Effects of Fly Ash and Simulation of the Natural Hot and Dry Climate of the Moroccan Desert Region on the Durability of Prestressed Concrete Cylinder Pipes

Synthesis Characterization and Highly Protective Efficiency of Tetraglycidyloxy Pentanal Epoxy Prepolymer as a Potential Corrosion Inhibitor for Mild Steel in 1 M HCl Medium

Anticorrosion properties of the epoxy polymer TGETBAU for mild steel in a solution of HCl (1.0M): Experimental and computational approaches

New Xanthene Diones Compounds as a Corrosion Inhibitor of Mild Steel in Acid Medium: Electrochemical, Surface Characterization and Theoretical Insights