Influence of 2-(4-chlorophenyl)-2-oxoethyl benzoate on the hydrogen evolution and corrosion inhibition of 18 Ni 250 grade weld aged maraging steel in 1.0 M sulfuric acid medium

Electrochemical corrosion behavior and hydrogen evolution reaction of weld aged maraging steel have been investigated, in 1.0 M sulfuric acid solution containing different concentrations of 2-(4-chlorophenyl)-2-oxoethyl benzoate (CPOB). The data obtained from polarization technique showed that the corrosion current density (i_corr) and the hydrogen evolution rate decrease, indicating a decrease in the corrosion rate of weld aged maraging steel as well as an increase in the inhibition efficiency (η%) with the increase in inhibitor concentration. Changes in impedance parameters were indicative of adsorption of CPOB on the metal surface, leading to the formation of protective film. Both activation (E_a) and thermodynamic parameters (ΔG_ads⁰, ΔH_ads⁰ and ΔS_ads⁰) were calculated and discussed. The adsorption of CPOB on the weld aged maraging steel surface obeyed the Langmuir adsorption isotherm model. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) study confirmed the formation of an adsorbed protective film on the metal surface.     

Chemically modified guar gum and ethyl acrylate composite as a new corrosion inhibitor for reduction in hydrogen evolution and tubular steel corrosion protection in acidic environment

The paper deals with the synthesis of Guar gum and ethyl acrylate (GG-EEA) composite. The synthesized natural polysaccharide composite was used as a corrosion inhibitor to reduce hydrogen evolution and P110 steel corrosion protection in 15% HCl (Hydrochloric acid). The primary corrosion techniques like weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) was used to analyze the corrosion inhibition process. The PDP proposed that GG-EEA composite is a mixed-type corrosion inhibitor and inhibits corrosion by blocking the active sites presenting over the metal surface. The corrosion inhibition performance of GG alone is 77.5%, and that of GG-EEA is 92.3% at 500 mg/L. The adsorption of GG-EEA onto P110 steel is spontaneous and mixed type, i.e., both physical and chemical. The conformation of GG-EEA molecule adsorption was done using a scanning electron microscope (SEM), Energy dispersive x-ray spectroscopy (EDX), Atomic force microscopy (AFM), and X-ray photoelectron spectroscopy studies. Density functional theory (DFT) analysis was done to explore the active sites over the inhibitor in metal-inhibitor interaction. Molecular dynamic simulation (MD) simulations study reveals that GG-EEA has more adsorption capacity than GG alone.     

Inhibition effect of natural polysaccharide composite on hydrogen evolution and P110 steel corrosion in 3.5 wt% NaCl solution saturated with CO2: Combination of experimental and surface analysis

For the analysis of corrosion and hydrogen production inhibition, we have synthesized Guar gum and methylmethacrylate (GG-MMA) composite. The synthesized composite was used as an eco-friendly corrosion inhibitor for P110 steel in 3.5% NaCl solution saturated with carbon dioxide at 50 °C. The primary corrosion techniques like weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) was used to analyze the corrosion inhibition process. EIS study reveals the kinetically controlled corrosion inhibition process. The results of PDP proposed that GG-MMA composite is the cathodic type of inhibitor. The corrosion inhibition performance of GG-MMA alone is 90% at 400 mg/L, and that of formulation with KI (5 mM) + GG-MMA (300 mg/L) is 96.8%. The adsorption of GG-MMA over P110 steel is spontaneous and mixed type i.e., both physical and chemical. The conformation of GG-MMA molecule adsorption was done using a scanning electron microscope (SEM), Contact angle measurement, Atomic force microscopy (AFM), Scanning Electrochemical Microscopy (SECM) and X-ray photoelectron spectroscopy studies.     

Thermal and surface studies on the corrosion inhibition of petroleum pipeline by aqueous extract of Allium cepa skin under acidic condition

In this study, the temperature effect on the inhibitory action of the cheap, eco-friendly and sustainable hot water extract of onion skin (HWEOS) on the corrosion of C-steel petroleum pipeline in 1 M hydrochloric acid solution was investigated using weight loss technique. Generally, the inhibition was found to increase with inhibitor concentration but decreased with the increase in temperature. The presence of protective inhibitor film on metal surface was confirmed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The thermodynamic activation parameters were evaluated, suggesting a physical adsorption, the corrosion process was suggested to be a unimolecular reaction, the enthalpies reflected the endothermic nature of the steel dissolution process. Large and negative values of entropies showed that the activated complex in the rate determining step represented an association rather than a dissociation step. HWEOS adsorbed on the metal surface according to the Langmuir isotherm at all the studied temperatures. The compounds responsible for the inhibitory action of HWEOS were proved to be flavonoids including quercetin and a suggested mechanism of corrosion inhibition was elucidated.     

Ni–P and Ni–Co–P coated aluminum alloy 5251 substrates as metallic bipolar plates for PEM fuel cell applications

This study is aimed to replace graphite bipolar plates in PEM fuel cells with surface modified aluminum alloy. To improve the surface characteristics of aluminum alloy 5251 (AA5251) substrate, Ni–P and Ni–Co–P coatings were deposited using electroless and electroplating deposition techniques [power supply and chronoamperometry]. Surface morphology and chemical composition of prepared coatings have been investigated using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. The corrosion behaviour of Ni–P and Ni–Co–P coated AA5251 was studied in (0.5 M H₂SO₄ + 2 ppm HF) solution by potentiodynamic polarization technique. Lower corrosion current densities and more positive corrosion potentials were gained after coating AA5251 with Ni–P and Ni–Co–P deposits. Much better corrosion resistance was shown by coatings containing cobalt. Potentiostatic tests were carried out at +160 mV (MMS) in air-saturated solution to simulate cathode environment in PEM fuel cells. The current density of Ni–Co–P (1:1)/AA5251 was stabilized at a value lowered by 4 times relative to that at bare AA5251 substrate. Interfacial contact resistance values between coated substrates and carbon paper were measured. Ni–P and Ni–Co–P coatings prepared by electroless method showed ICR values, twice that at ones prepared by electroplating power supply technique.     

Corrosion protection of Sunselect, a spectrally selective solar absorber coating, by (3-mercaptopropyl)trimethoxysilane

The formation of a protective layer from (3-mercaptopropyl)trimethoxysilane (MPTMS) on commercial Sunselect, cermet-based spectrally selective coating (Alanod, DE), was studied by non-electrochemical (infrared reflection–absorption—IR RA, X-ray photoelectron spectroscopy—XPS), electrochemical (cyclic voltammetry (CV) in the presence of a redox probe (Cd⁺²), and potentiodynamic (PD)) techniques. By simple immersion and subsequent dip coating of the Sunselect substrate in the MPTMS sol, the hydrolyzed MPTMS precursor was adsorbed on the substrate, forming a protective layer imparting corrosion stability to Sunselect in a salt spray chamber for at least 20 days, outperforming any other sol–gel coating used so far for the corrosion protection of Sunselect. This was attributed to the penetration of MPTMS into the porous cermet structure through the upper antireflective Sn-oxide layer, as shown from XPS depth profile. Detailed analysis of the hydrolysis and condensation reactions of the MPTMS precursor by ²⁹Si NMR and IR spectroscopic techniques is reported.The most important finding was the observation that the applied MPTMS layer did not affect the spectral selectivity, as inferred from the solar absorptance increase of 1% and thermal emittance increase of not more than 2%.     

Electrodeposited Pt nanorods on a novel flowered-like nanostructured NiCo alloy as an electrocatalyst for methanol oxidation

For the first time, a novel system of Pt nanorods supported on nano flowered-like structure NiCo alloy has been successfully electro-synthesized onto a glassy carbon electrode for the electrocatalytic oxidation of methanol. The electrodeposited system has been characterized using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The electrocatalytic efficiency of the electro-fabricated system of Pt/NiCo/GCE have been confirmed by cyclic voltammetric (CV) and current-time methods. It is discovered that the electrodeposited nano flowered NiCo alloy substrate has a great effect on the electrocatalytic properties of the electrodeposited Pt nanorods. The electrocatalytic efficiency of the new system for methanol oxidation reaction (MOR) is found to be 174 A/g_Pt. The effect of electrodeposition time for NiCo alloy has been studied. Also, the effect of pH, temperature, and concentration for the electrodeposition of Pt catalyst on the electrocatalytic properties of the Pt/NiCo/GCE have been studied for detection the optimum conditions. The mechanism of the electrocatalytic oxidation of methanol has been discussed. Furthermore, the stability and the corrosion resistance test of the Pt/NiCo/GCE system have been investigated by electrochemical impedance spectroscopy (EIS), Tafel plot and current-time methods.     

Inhibition effect of newly synthesized benzoxanthonesderivative on hydrogen evolution and Q235 steelcorrosion in 15% HCl under hydrodynamic condition: Combination of experimental,surface and computational study

The investigation of this study deals with the synthesis using green synthetic approach, characterization and application of benzoxanthones derivative namely 9,9-Dimethyl-12-p-tolyl-8, 9,10, 12-tetrahydrobenzo[a]xanthen-1-one (TBX) for the inhibition of Q235 steel corrosion in 15% HCl under dynamic condition. The results of EIS confirmed towards the increment in R_ct values with rise in concentration. Additionally, results of PDP reveals that TBX is cathodic type inhibitor. The maximum inhibitive excellency of TBX was given at 200 mg/L with the value of 92.3%. The increasing temperature tends to increase in corrosion rate. Langmuir adsorption isotherm provides the excellent fitting. The surface morphology and adsorption of TBX molecules were confirmed using scanning electron microscopy (SEM) and X-photo electron microscopy (XPS). Density functional theory (DFT) and Molecular dynamic simulation (MD) confirmed that corrosion inhibition efficiency ranking obtained for studied molecules is TBXH⁺> TBX.     

New electroplated aluminum bipolar plate for PEM fuel cell

Further improvement in the performance of the polymer electrolyte membrane fuel cells as a power source for automotive applications may be achieved by the use of a new material in the manufacture of the bipolar plate. Several nickel alloys were applied on the aluminum substrate, the use of aluminum as a bipolar plate instead of graphite is to reduce the bipolar plate cost and weight and the ease of machining. The electroplated nickel alloys on aluminum substrate produced a new metallic bipolar plate for PEM fuel cell with a higher efficiency and longer lifetime than the graphite bipolar plate due to its higher electrical conductivity and its lower corrosion rate. Different pretreatment methods were tested; the optimum method for pretreatment consists of dipping the specimen in a 12.5% NaOH for 3 min followed by electroless zinc plating for 2 min, then the specimen is dipped quickly in the electroplating bath after rinsing with distilled water. The produced electroplate was tested with different measurement techniques, chosen based on the requirement for a PEM fuel cell bipolar plate, including X-ray diffraction, EDAX, SEM, corrosion resistance, thickness measurement, microhardness, and electrical conductivity.     

Hydrogen evolution and quantum calculations for potassium sorbate as an efficient green inhibitor for biodegradable magnesium alloy staples used for sleeve gastrectomy surgery

This work-study the hydrogen evolution rate and inhibitive properties of potassium sorbate, as an antimicrobial and food preservative substance, on the corrosion performance of biodegradable AZ91E magnesium alloy utilized as staples in Sleeve Gastrectomy surgery. This substance used for the first time to protect the alloy from the fast surface degradation process when surrounded by simulated peritoneal fluid (SPF) as a corrosive environment in the stomach. Theoretical quantum calculations were utilized to ensure the inhibition effect of potassium sorbate for the tested alloy as a staple. The corrosion resistance was assessed via electrochemical measurements. The degradation and hydrogen evolution rate is found to be significantly reduced with increasing potassium sorbate concentration. The outcomes displayed that the higher concentration of potassium sorbate (10⁻³ M) is the most effective corrosion resistant one with inhibition efficiency reaches 99.6% which is mainly ascribed to the creation of a thin protective film of Mg-sorbate. The results were confirmed with a scanning electron microscope (SEM) images. A cell viability test for the alloy was done using MTT assay which clarifies that the alloy immersed in the higher potassium sorbate concentration have higher cell viability and proliferation.     

Thin foil lithium-aluminium electrode. The effect of thermal treatment on its electrochemical behaviour in nonaqueous media

The effect of the microstructure of aluminium foil electrodes on the electrochemical behaviour of the Li-Al alloy at ambient temperature has been studied by X-ray diffraction, texture goniometric and scanning electron microscopic (SEM) techniques.It was found that thermal annealing of aluminium electrodes close to the theoretical recrystallization temperature of Al reduces the overvoltage of Li alloying and increases the cycling efficiency.It is suggested that the observed uniform, fine-grain microstructure of the β-Li-Al electrode on the annealed substrate reduces the effective current density during cycling.     

Insight of corrosion mitigation performance of SABIC iron in 0.5 M HCl solution by tryptophan and histidine: Experimental and computational approaches

The inhibitory strength of two amino acids namely, tryptophan (Tryp) and histidine (Hist) on the corrosion of SABIC iron (SABIC Fe) in a 0.5 M HCl solution was examined utilizing mass loss (MS), electrochemical (PDP and EIS) and theoretical studies. Density functional theory (DFT) and Monte Carlo (MC) simulation were inspected for Tryp and Hist inhibitors. All the corrosion parameters and theoretical data obtained from these studies confirm the inhibiting impact of the two amino acids. The efficacy of inhibition augment with augmentation the concentration of two amino acids from 100 to 500 ppm and reducing at elevated temperature. The effectiveness of the inhibition depends on the presence of some active centers that accelerate the adsorption process and the molar mass of the inhibitors. The inhibition efficacy of Tryp is greater than that of Hist reaching 92.09% at a concentration of 500 ppm while in the presence of Hist it is 89.37% using PDP measurements. Inhibition was demonstrated by spontaneous adsorption of Hist and Tryp on the surface of SABIC Fe according to the Langmuir adsorption isotherm. PDP curves clarified that the Tryp and Hist compounds acted as mixed type inhibitors. A variety of thermodynamic and kinetics parameters were computed and explained. SEM images demonstrate that the protective layer constructed on the surface of S– Fe in the presence of both amino acids. The results obtained from DFT are in complete agreement with the experimental work. Tryp and Hist compounds are adsorbed horizontally onto the surface of Fe (110).     

Corrosion behavior of TiN-coated stainless steel as bipolar plate for proton exchange membrane fuel cell

Stainless steel is a potential material to be used as the bipolar plate for proton exchange membrane fuel cell (PEFC) because of its suitable physical and mechanical properties. Several coating techniques have been applied to improve its corrosion resistance. But seldom study is focused on the microstructure evolution with corrosion. In the present study, the use of TiN-coated stainless steel as the bipolar plate is evaluated. Two surface coating techniques, pulsed bias arc ion plating (PBAIP) and magnetron sputtering (MS), are adoped to prepare the TiN-coated stainless steel. Their corrosion resistances and electrical conductivities of the coated substrates are evaluated. The performance shows strong dependance on microstructural characteristics. The corrosion of SS304/Ti₂N/TiN prepared by MS mainly occurs on the grain boundary. The corrosion of SS304/TiN prepared by PBAIP mainly takes place from the large particles on the coating. The Ti₂N/TiN multilayer coating provides superb corrosion protective layer for stainless steel. Both the TiN and Ti₂N/TiN coatings provide low contact resistance.     

Improvement of corrosion and electrical conductivity of 316L stainless steel as bipolar plate by TiN nanoparticle implantation using plasma focus

The present work reports the results of TiN-ions implantation into the SS316L samples as bipolar plates by a 4 kJ Mather type Plasma Focus (PF) device operated with nitrogen gas for 10, 20, and 30 shots in order to improve the corrosion resistance and electrical conductivity of samples. The PF can generate short lived (10–100 ns) but high temperature (0.1–2.0 keV) and high density (10¹⁸–10²⁰ cm⁻³) plasma, and the whole process of PF lasts just a few microseconds. X-ray diffraction (XRD) results reveal the formation of a nanocrystalline titanium nitride coating on the surface of substrate. The interfacial contact resistance (ICR) of samples is measured, and the results show that the conductivity of samples increase after coating because of high electrical conductivity of TiN coating. The electrochemical results show that the corrosion resistances are significantly improved when TiN films are deposited into SS316L substrate. The corrosion potential of the TiN coated samples increases compared with that of the bare SSI316L and corrosion currents decrease in TiN implanted samples. Scanning Electron Microscopy (SEM) indicates changes in surface morphology before and after potentiostatic test. The thickness of coated layer which is obtained by cross sectional SEM is about 19 μm.     

Electrochemical characterization of nanostructured Ti–24Nb–4Zr–8Sn alloy in 3.5% NaCl solution

A multifunctional β-type titanium alloy Ti–24Nb–4Zr–8Sn (Ti2448) with high strength and low elastic modulus has advantage of rapid grain refinement by conventional cold processes due to its special highly localized plastic deformation behavior. In the paper, electrochemical behavior of the cold-rolled alloy with nanostructured (NS) grains was studied in 3.5% NaCl solution by potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS) measurement, Lgi-Lgt curve and Mott–Schottky analyses, as well as X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results showed that the NS alloy has better corrosion resistance than the coarse-grained (CG) alloy because the former has more stable and thicker protective passive layer. Such dioxide layer consists of an inner barrier layer and an outer porous layer for both the CG and NS alloy whereas the NS alloy is preponderant in thickness. The passive film is n-type semiconductor and its donor density can be decreased by grain refinement. Therefore, the above positive effect can be explained by the homogeneous and dense passive film formed on the NS Ti2448 alloy due to its high density of grain boundary.     

Corrosion inhibition, hydrogen evolution and antibacterial properties of newly synthesized organic inhibitors on 316L stainless steel alloy in acid medium

Electrochemical corrosion behavior and hydrogen evolution reaction of 316L stainless steel has been investigated, in 0.5 M sulfuric acid solution containing four novel organic inhibitors as derivatives from one family, using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements and surface examination via scanning electron microscope (SEM) technique. The effect of corrosion inhibitors on the hydrogen evolution reaction was related to the chemical composition, concentration and structure of the inhibitor. The inhibition efficiency, for active centers of the four used compounds, was found to increase in the order: -Cl < -Br < -CH₃ < -OCH₃. The corrosion rate and hydrogen evolution using the compound with methoxy group as a novel compound was found to increase with either increasing temperature or decreasing its concentration as observed by polarization technique and confirmed by EIS measurements. The compound with methoxy group (newly synthesized) has very good inhibition efficiency (IE) in 0.5 M sulfuric acid (98.3% for 1.0 mM concentration). EIS results were confirmed by surface examination. Also, antibacterial activity of these organic inhibitors was studied. The results showed that the highest inhibition efficiency was observed for the compound that posses the highest antibacterial activity.     

Effect of carbon black support corrosion on the durability of Pt/C catalyst

The work intends to clarify the effect of carbon black support corrosion on the stability of Pt/C catalyst. The corrosion investigations of carbon blacks with similar structures and characteristics were analyzed by cyclic voltammograms (CV) and X-ray photoelectron spectroscopy (XPS). The results indicate that a higher oxidation degree appears on the Black Pearl 2000 (BP-2000) support, i.e. BP-2000 has a lower corrosion resistance than Vulcan XC-72 (XC-72). The durability investigation of Pt supported on the two carbon blacks was evaluated by a potential cycling test between 0.6 and 1.2 V versus reversible hydrogen electrode (RHE). A higher performance loss was observed on the Pt/BP-2000 gas diffusion electrode (GDE), compared with that of Pt/XC-72. XPS analysis suggests that higher Pt amount loss appeared in the Pt/BP-2000 GDE after durability test. X-ray diffraction (XRD) analysis also shows that Pt/BP-2000 catalyst presents a higher Pt size growth. The higher performance degradation of Pt/BP-2000 is attributed significantly to the less support corrosion resistance of BP-2000.     

Study of different aluminum alloy substrates coated with Ni–Co–P as metallic bipolar plates for PEM fuel cell applications

Pure Al and some of its alloys [Al alloy 6061 (AA6061), Al alloy 3004 (AA3004) and Al alloy 1050 (AA1050)] were coated with Ni–Co–P using electroplating power supply technique. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were applied to study the surface morphology and chemical composition of coated aluminum substrates. Their performance against corrosion was examined using potentiodynamic polarization technique in (0.5 M H₂SO₄ + 2 ppm HF) solution. Corrosion potential values were shifted in the positive direction at all aluminum substrates after their coating with Ni–Co–P. Corrosion current density values at coated pure Al and AA1050 were decreased by ∼18.6 times, compared to those at bare substrates. The stability of coated aluminum alloys was investigated during long-time operation under cathodic environment in PEMFCs using potentiostatic polarization test at +160 mV (MMS) in air-saturated solution. Ni–Co–P/AA3004 substrate showed a high corrosion rate after short time, while coated AA6061 one slowly corroded. Interfacial contact resistance (ICR) values between metallic bipolar plates and gas diffusion layer were measured. Coating AA1050 with Ni–Co–P reduces its ICR value by 13 times. Accordingly, electroplated Ni–Co–P/AA1050 substrate can be chosen as an efficient bipolar plate material in PEMFCs.     

On the electrochemistry of an anode stack for all-solid-state 3D-integrated batteries

This paper will report on the electrochemical and material characterization of a potential planar anode stack for all-solid-state 3D-integrated batteries. The first element of the stack is the silicon substrate. On top of silicon, a Li diffusion barrier layer material is deposited in order to effectively shield the substrate from the battery stack. Several materials are investigated with conventional electrochemical techniques. The best candidates, sputtered and atomic layer deposited (ALD) TiN, are studied in more detail with ex situ X-ray diffraction (XRD) and the reaction mechanism of these materials with Li is discussed. The third element of the stack is the active anode material. Thin films of poly-Si are studied towards their thermodynamic and kinetic properties. Moreover, the growth of SEI layers on top of poly-Si anodes cycled in two liquid electrolytes has been investigated by means of ex situ SEM. Strikingly, when poly-Si is covered with a solid-state electrolyte, prolonged lifetime is found, enabling future 3D-integrated all-solid-state batteries.     

The Ni-deposited carbon felt as substrate for preparation of Pt-modified electrocatalysts: Application for alkaline water electrolysis

A Ni-modified carbon felt (C) electrode (C/Ni) was used as a substrate for preparation of Pt-modified electrode in view of its possible application as electrocatalytic material for the hydrogen evolution activity. The prepared electrode was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV) techniques. The hydrogen evolution activity of the electrode was assessed by cathodic current–potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that the modification of Ni-deposited C by loading low amount of Pt could enhance the hydrogen evolution activity of the electrode.