Alloys In Acid Solutions Research Articles

Corrosion behavior of Ti-based bulk amorphous alloys in acidic solutions

The corrosion behavior of the Ti34.3Zr31.5Cu5Ni5.5Be23.7 bulk amorphous alloy was investigated in different concentrations of the HCl and H2SO4 solutions. Electrochemical testing and scanning electron microscopy analysis indicate that Cl− ions can cause pitting damage in the HCl solution during the polarization process, and the pitting potential decreases with increasing solution concentration. The degree of damage to the corroded surface is positively correlated with the solution concentration. A passive film forms in the H2SO4 solution, indicating good corrosion resistance. X-ray photoelectron spectroscopy shows that the stability of the passivated film decreases with increasing HCl solution concentration. The corrosion rates of the four materials were obtained by an immersion experiment in HCl solution. The results reveal that Ti34.3Zr31.5Cu5Ni5.5Be23.7 bulk amorphous alloy has the best corrosion resistance, with a corrosion rate of 7.22×10−3 mm/a, which is approximately 1/1294 that of 316L stainless steel.

Electrochemical and theoretical investigations of favipiravir drug performance as ecologically benign corrosion inhibitor for aluminum alloy in acid solution

Aluminum–silicon alloys have become a preferred option in the automotive and aerospace industries thanks to their fault-tolerant process ability and reasonable static characteristics at relatively affordable costs. This study aimed to investigate the use of favipiravir (FAV) drug as a biocompatible and eco-friendly inhibitor to protect aluminum alloy (AlSi) surface in an aggressive acid environment (1.0 M HCl). The electrochemical measurements declare that FAV is categorized as an inhibitor of mixed type with a cathodic effect. At 100 ppm, FAV had the highest inhibitory efficiency (96.45%). FAV is associated with lower double-layer capacitance values and more excellent charge-transfer resistance. These results show that AlSi corrosion in 1.0 M HCl is reduced in the presence of FAV. The Langmuir model is well-suited to the FAV adsorption behavior (R2 ≈ 1). Chemisorption is the primary adsorption in this environment. The theoretical calculation studies corrosion inhibitors' molecular structure and behavior. Different quantum chemical properties of the FAV have been calculated, including energy difference (ΔE), softness, global hardness, and energy of back-donation depending on the highest occupied and lowest unoccupied molecular orbitals. In addition, Mulliken and Fukui’s population analysis and the Molecular Electrostatic Potential map represent the electron distribution and the molecule’s active centers. Experimental findings and quantum chemical computations matched, and FAV is recommended as a green corrosion inhibitor.

Corrosion Resistance of Al–Cu–Со, Al–Ni–Со, and Al–Ni–Fe Quasicrystalline Alloys in Acid Solutions

Corrosion Resistance of Al–Cu–Со, Al–Ni–Со, and Al–Ni–Fe Quasicrystalline Alloys in Acid Solutions

Superior corrosion resistance of high-temperature Ir–Ni–Ta–(B) amorphous alloy in sulfuric acid solution

In this work, the corrosion behaviors and underlying mechanisms of high-temperature Ir-based amorphous alloys in an acidic solution were investigated systematically. The Ir-Ni-Ta-B amorphous alloy exhibits a crevice corrosion behavior with a superior corrosion resistance characterized by a low passive current density and a wide passive potential range. It is found that the high-exchange current density of H+ and H2 couple on the metalloid constituent can accelerate the active precipitation of passivation elements, leading to rapid formation of passive film. In sulfuric acid solutions, the formed passive film containing Ir, Ta5+ and Ni3+ oxides significantly increase the corrosion resistance.

Specific Features of the Anodic Behavior of Ti–Nb Alloys in Acid Solutions

Specific Features of the Anodic Behavior of Ti–Nb Alloys in Acid Solutions

Eco-Friendly Roselle (Hibiscus Sabdariffa) Leaf Extract as Naturally Corrosion Inhibitor for Cu-Zn Alloy in 1M HNO3

The eco-friendly compounds especially plant extracts have emerged as green corrosion inhibitors for metals and alloys. The inhibiting impact of Roselle extract on Cu-Zn alloy in 1M HNO3 solution was studied by weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). It was found that Roselle extract acts as a good mixed-type corrosion inhibitor for Cu-Zn alloy in acid solution. The corrosion rate decreases with increasing the extract concentration and increases with raising the temperature. The formation of a protecting film on the Cu-Zn alloy surface with the presence of Roselle extract was confirmed by scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX). The high inhibition efficiency of 94.89 % was recorded for 80% extract solution. There are good agreements between the results from all techniques.

The corrosion behavior and film properties of Al-containing high-entropy alloys in acidic solutions

Aluminum has shown promising application in reducing the high-entropy alloys’ weight and enhancing their mechanical properties. In this work, the impact of solid-solution aluminum on the corrosion behavior and film properties of FeCoCrNiAlx (x = 0.1, 0.3) high-entropy alloy in 0.5 M H2SO4 and 0.5 M HCl solutions was investigated by electrochemical measurement, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The results demonstrate that both of the high-entropy alloys exhibit an equiaxed grain structure with numerous annealing twins. FeCoCrNiAl0.3 alloy still remains the stable FCC substrate without any second phase precipitates. The increasing aluminum content can improve the corrosion resistance of FeCoCrNiAlx by simultaneously increasing Cr oxide content in the passive film and making it thicker in the H2SO4 solution. Nevertheless, the effect is negative in the HCl solution because chloride ions are inclined to combine with the Al-containing metastable ion complexes, which accelerates the dissolution of HEA.

Comparison study on the corrosion behavior of aluminum alloys in different acidic media

Electrochemical study to compare the corrosion resistance of three different aluminum alloys (AA8011, AA4017 and AA1200) in organic acid solutions (nitric and acetic acids) was carried out. Polarization technique was used to determine the corrosion behavior of the alloys in the acid solutions, while potentiometric technique was used to study the passivity of the alloys over time. The surface analysis was carried out on the alloys’ surfaces to know the morphological changes that took place on the surface of the alloys using scanning electron microscopy (SEM). Alloy AA4017 showed the least tendency to pit in acetic acid solution with alloy AA8011 showing the highest susceptibility to pitting in the acidic solutions. All the alloys on the other hand showed high tendencies to pit in nitric acid solution. Considering the rate of corrosion of the alloys in both solutions, alloy AA8011 had corrosion rate of 0.0873 mm/yr., which was the highest in acetic acid solution, while alloy AA1200 had the least corrosion rate of 0.0045 mm/yr. in the solution. Meanwhile, alloy AA4017 exhibited the highest corrosion rate of 0.0552 mm/yr. and alloy AA1200 had the least corrosion rate of 0.0126 mm/yr. in nitric acid solution. These results showed that the AA4017 and AA1200 alloys corroded more in nitric acid solution than in acetic acid solution. Potentiometric test results showed the formation of more stable passive films in nitric acid than in acetic acid solution. The SEM micrographs showed pits formation on the alloys in all the acidic solutions.

Effects of the element La on the corrosion properties of CrMnFeNi high entropy alloys

Abstract The effect of minor inclusion of rare earth element of lanthanum into a well-established high entropy alloy system of CrMnFeNi on their corrosion resistance properties in different media with various concentrations was investigated in this study. The potentiodynamic polarization curves of the CrMnFeNi and CrMnFeNiLa0.1 alloys in acidic solutions exhibit an extensive passive region (ΔE>1100 mV). The Nyquist plot of the La-free CrMnFeNi alloy includes one capacitive loop and one inductive loop and while for the CrMnFeNiLa0.1 alloy only one capacitive loop is present. SEM results show that the morphology of the two alloys is obviously different in different media. XPS data reveals the existence of distinctive content discrepancy of Mn and Ni in passive film between La free and La-containing HEA, strongly implying the considerable impact of La in the passivation process.

Corrosion behaviour of 7075 aluminium alloy in acidic solution.

The objective of this work was to establish the influence of sodium molybdate on the corrosion kinetics of 7075 aluminium alloy in orthophosphoric acid aqueous solution. Corrosion rate was decreased from 75.98 to 3.24 g per m2 per day. The mechanism of corrosion inhibition was studied using scanning electron microscopy, X-ray photoelectron spectroscopy, UV-Vis spectrophotometry and electrochemical impedance spectroscopy. It was revealed that heteropolyoxomolybdate species act as the corrosion inhibitor. They adsorb onto the surface and inhibit an anodic process. Their influence on a cathodic process is much weaker. Phosphomolybdenum blue species do not inhibit corrosion process and their formation is undesirable.

Corrosion Inhibition of Copper-Iron Alloy in Acid Solution Using Cetylpyridinium Bromide as Cationic Surfactant

The corrosion and corrosion inhibition of Cu–Fe (20%) alloy are studied in 0.5 M H2SO4. Copper and iron samples are compared to the Cu–Fe alloy to understand the behavior of the Cu–Fe alloy in the corroding medium. Different techniques such as open circuit potential measurement, Tafel plots and electrochemical impedance spectroscopy (EIS) are used in this study. Dissolution of iron is found to be a controlling step in the corrosion behavior of the Cu-Fe alloy. Scanning electron microscope (SEM) and electron diffraction X-ray spectroscopy (EDX) charts confirm the above conclusion. The aggregation transition concentration (ATC) is determined and its value helps to interpret the CPBr inhibition behavior. Langmuir Adsorption isotherm is found to fit with the experimental data and relatively high negative value of the free energy of adsorption suggests strong adsorbability of the CPBr on the alloy surface.

The Preparation of a Novel Corrosion Inhibitor and Its Corrosion Inhibition Behavior on 2024 Al‐Cu‐Mg Alloy in Acid Solution

AbstractA new corrosion inhibitor was synthesized from chloroacetyl chloride, 1,3‐propanediamine, and dodecyldimethyl tertiary amine. The structure of the synthesized product was characterized using Fourier transform infrared(FTIR). The critical micelle concentration (CMC) was determined from surface tension measurements. The inhibition behavior of the corrosion inhibitor for 2024 Al‐Cu‐Mg alloy was studied using the weight‐loss method and electrochemical measurements in hydrochloric acid solution. Experimental results show: The CMC is 7.767 × 10−4 mol L−1 and IE (C pro = 1 × 10−3 mol L−1) ≈ 87.9%. The adsorption free energy is calculated to be −33.12 kJ mol−1. Therefore, the adsorption mode is more inclined to physical adsorption. When the concentration of the synthesized product is lower than the CMC, it satisfies the Langmuir adsorption model; when the concentration is higher than the CMC, it no longer follows the Langmuir adsorption model.

Study of the hydrogen absorption/diffusion in Pd80Rh20 alloy in acidic solution

Hydrogen absorption/diffusion into Pd80Rh20 alloy (50 μm foil) was studied using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy in 0.1 M H2SO4 at 25 °C in the absence and presence of crystal violet. The double layer capacitance, charge transfer resistance, diffusion coefficient and mass transfer coefficient of hydrogen were determined. The mechanism of hydrogen absorption was discussed. Hydrogen adsorption inhibits the kinetics of hydrogen absorption and, in the presence of crystal violet, it proceeds much faster. At more positive potentials crystal violet is probably desorbed and the kinetics of absorption in the absence and in the presence of crystal violet proceeds with similar rate.

Beneficial Effects of Zn, Al and Ni Addition on the Stability of Some Cu-Ternary Alloys in Acidic Solutions

Copper-based alloys are important materials for many industrial applications but suffer from accelerated corrosion in acidic solutions. In the present work, we investigated the synergistic effects of Al, Ni and Zn as alloying elements on the electrochemical behavior of some Cu-ternary alloys in acidic solution of pH 2. The stability of some Cu-ternary alloys (Cu–10Al–10Zn, Cu–10Al–10Ni and Cu–10Ni–10Zn) in acidic solution (pH 2) was investigated using open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy. The electrochemical behavior of the investigated Cu alloys was dependent on the alloying elements. The results showed that the Cu–10Al–10Zn alloy is more stable than the other two studied alloys. The alloy surface was covered by a barrier layer protecting it from acidic corrosion. The thickness and resistance of the barrier film formed on the Cu–10Al–10Zn alloy increase with the increase in the immersion time. The corrosion process mechanism and the formation of barrier film were explained. The incorporation of Zn ions in the Cu2O barrier film leads to its stabilization, and the stability is enhanced by the presence of Al metal. Based on the analysis presented in the paper, it is concluded that the Cu–10Al–10Zn alloy is highly promising for application in the in acidic environments.

Corrosion Behavior of W-Mo Co-Penetrated Layer Produced by Glow Discharge Plasma Technique in Acid Solution

Abstract To improve the corrosion resistance of Ti6Al4V alloys in acid solution, a W-Mo co-penetrated top layer was prepared by hollow-cathode glow discharge plasma technique below the β phase transition point. The surface morphology, chemical composition and crystal structure of the coatings were determined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray power diffraction (XRD), respectively. Results indicate that a dense co-penetrated layer is produced with maximum thickness of approximately 23 μm. The layer is composed of AlMoTi2 and TixW1-x phases. The static corrosion test is conducted in acid (H2SO4 and HCl, separately) at room temperature (RT) by the electrochemical workstation. The results show that the W-Mo co-penetrated layer could achieve relatively stable corrosion potential in reducing acid and the Icorr of co-penetrated layers occupy merely 1/10 and 1/6 of that of Ti6Al4V substrates. In addition, there is barely any corroded product and crack on the corroded surface of co-penetrated layers, indicating no corroded shedding phenomenon occurs. So the corrosion resistance are obviously improved in the premise of keeping the basic properties of the substrate.

Synthesis of a Novel Gemini Cationic Surfactant and Its Inhibition Behaviour and Mechanism Study on 2024 Al-Cu-Mg Alloy in Acid Solution

Isopropylamine was taken as a raw material to synthesize a new multi-alkyl multiple quaternary-ammonium salts gemini surfactant bis[2-hydroxy-3-(dodecyldimethylammonio)propyl]-isopropylamine dichloride. The structure of the synthetic product was characterized by1H NMR and FTIR. The surface activity was investigated; the inhibition efficiencies and inhibition mechanism of the synthetic product were studied by weight loss method, electrochemical method, microscopic morphology observation, and adsorption model calculation. The results indicate thatcmcof synthetic product was 9.204 ×10-4 mol/L; when the concentrations were lower thancmc, the inhibition efficiencies rose substantially, which was up to 89.3% with the concentration of 9.204 × 10-4 mol/L; when they were higher thancmc, inhibition efficiencies were basically unchanged; polarization tests showed that the synthesis product could restrain both anodic and cathodic reactions; when the concentrations were lower thancmc, the adsorption of the synthetic product conformed to the Langmuir model, which formed monolayer on the 2024 Al-Cu-Mg alloy surface; when they were higher thancmc, it formed bilayer, so the adsorption of the synthetic product did not conform to the Langmuir model anymore.

Inhibition effect of underpotential deposition of metallic cations on aqueous corrosion of metals

Abstract The experimental results reported so far for the inhibition effect of underpotential deposition (UPD) of metallic cations on aqueous corrosion of metals are criticized and discussed based on the prerequisite for UPD. The inhibition effect of Pb2+, Cd2+, Zn2+ or Mn2+ on hydrogen evolution or hydrogen absorption on Armco iron or various steels is classified into three potential regions: bulk deposition, UPD and adsorption of metallic cations without discharging. Moreover, the inhibition effect of Pb2+, Tl+ or Sn2+ on anodic dissolution of pure Fe, Ni or Ni-base alloys in acidic solutions is ascribed to the UPD of these metallic cations. Particularly, in situ X-ray absorption spectroscopy (XAS) for Pb-UPD on Ni has indicated that the electro-deposited Pb species on the Ni surface is metallic to form partly surface alloy and the metallic Pb blocks the active dissolution sites of Ni to inhibit the anodic dissolution. In contrast, in situ XAS for Sn-UPD on Ni has indicated that the electro-deposited Sn species is not only bonded with Ni atoms but also bonded with oxygen atoms and that the anodic dissolution of Ni is inhibited by the oxygenated Sn species on Ni.

Electrochemical and Quantum Chemical Investigations of some Cyanoacetamide Derivatives as Eco-Friendly Corrosion Inhibitors for Aluminum-Silicon Alloy in Acidic Solution

Electrochemical and Quantum Chemical Investigations of some Cyanoacetamide Derivatives as Eco-Friendly Corrosion Inhibitors for Aluminum-Silicon Alloy in Acidic Solution

Organic corrosion inhibitors for aluminium and its alloys in acid solutions: a review

Corrosion inhibition of aluminium in acidic solutions using different organic compounds.

ELECTROCHEMICAL BEHAVIOR OF ELECTRODEPOSITED NANOCRYSTALLINE COBALT-IRON ALLOY COATING IN DIFFERENT PH

The electrochemical behavior of a cobalt-iron (CoFe) alloy electrode in 0.1 M Na2SO4 (sodium sulphate) aqueous solution of different pH was investigated. The presence of a different concentration of dissolved sulphide ions with different pH on the corrosion of electrodeposited cobalt-iron was investigated using the EQCM technique. The corrosion rates of the alloys in acidic solutions are pronouncedly high, compared to those measured in neutral or basic solutions. The presence of sulphide ions accelerates markedly the anodic reaction for all deposits in the basic medium. The dissolution rate was twice two times faster when S2− was added. By employing the EQCM, it was observed that the mass decrease or dissolution rate was significant with an increase in pH concentration.