Papers by Keyword: Corrosion Inhibition

Abstract: The corrosion inhibition on mild steel by eco-friendly paint produced from Mangifera indica leaves extract was carried out using the weight loss and potentiodynamic polarization methods. Central Composite Design (CCD) in Response Surface Methodology (RSM) was used for the design of experiment for the determination of corrosion inhibition efficiency, corrosion rate, and statistical analysis of the experimental results. Corrosion protection paint was formulated, and its efficacy was tested in a hydrochloric acid medium. The surface morphology of the mild steel sample was studied using the scanning electron microscopy (SEM). The corrosion inhibition efficiency of the paint for weight loss and potentiodynamic polarization methods is 83.68 and 99.49 %, respectively. The activation energy for corrosion process with coated mild steel is 26.47 J/mol K, which is higher than the value of 16.89 J/mol K obtained for uncoated mild steel, indicating that the adsorption process is physisorption. The enthalpy change is 23.96 kJ/mol. The positive value indicates that heat is absorbed from the environment. The entropy change is-180 J/mol K, implying that the activation energy complex is the rate determining step representing association rather than dissociation. Langmuir adsorption isotherm was found to be the best fit model. It was concluded from the study that the formulated paint has a high potential for commercialisation and industrial applications.

Abstract: This study investigates the corrosion inhibition of low carbon steel using a synergistic blend of Citrus sinensis extract and 1H-benzotriazole. The inhibition efficiency was evaluated using Density Functional Theory (DFT) with the B3LYP/6-31G(d) basis set and Monte Carlo simulations. Quantum chemical parameters such as EHOMO, ELUMO, ionization potential (IP), and electron transfer (ΔN) were calculated. The results indicate that the mixed inhibitor provides superior corrosion protection compared to individual inhibitors, with adsorption energies of-20511.53 kcal/mol for the combination, significantly higher than-175.09 kcal/mol for Citrus sinensis and-10359.80 kcal/mol for 1H-benzotriazole alone. The combined inhibitor demonstrated enhanced electron donation, reducing the energy gap (ΔE) and improving the stability of adsorption on the steel surface. This suggests that the synergistic interaction of the inhibitors leads to a more efficient, sustainable corrosion protection method, offering an environmentally friendly alternative for steel protection.

Abstract: This research assesses the anticorrosive activity of Musa Paradisiaca (plantain peel extract) on AA6063 aluminum alloy when immersed in a 1M HCl solution. The plantain extract was tested in concentrations of 0.2g, 0.4g, 0.6g, and 0.8g and is considered a natural green corrosion inhibitor. The corrosion studies on AA6063 were carried out by the techniques of potentiodynamic polarization, optical microscopy, SEM/EDS, and XRD analysis. Also, tests were done in the range of 30°C to investigate the inhibition efficiency. It was observed from results that the plantain extract acts as a mixed-type inhibitor and it helps in reducing the corrosion rate by depositing a protective coating on the surface of the alloy. It was found from the Tafel plots that as the concentration of extract was increased, there was a decrease in corrosion current density (j_corr) and an increase in Polarisation Resistance (Rp). The adsorption mechanism agreed with the Langmuir isotherm suggesting that only monolayer adsorption took place. Analysis of the protective film by SEM/EDS and XRD revealed the presence of Fe₂O₃, CaO, Mg, SiO₂, and Zn components. Maximum inhibition efficiency of 82% was recorded at the extract concentration of 0.8g. The study highlights the potential of plantain extract to serve as a viable green inhibitor for aluminium in acidic medium.

Abstract: The widespread corrosion of critical oil and gas infrastructure requires development of innovative and environmentally sustainable solutions. This research considers the repurposing of hitherto un-useful expired drugs to meet this challenge and to do so in ways that also puts stop to the menacing and illegal circulation of expired pharmaceuticals in developing economies. The corrosion inhibitory potential of expired paracetamol was evaluated for mild steel in acidic environment. Electrochemical analysis revealed that the corrosion current decreased from for the mild steel immersed in the blank/uninhibited 0.5M HCl environment to in the case of the sample in the 8g/l environment. The concentration of dissolved ions of iron in the acidic environment also followed this trend supported by the results obtained from the gravimetric analysis. Optical microscopy showed gradual covering of the corroding surface by a layer of inhibitor film with increasing concentration of the additive in the acidic environment. The corrosion inhibition efficiency increased with increasing concentration of the expired drug, reaching a maximum of 73.24% for 8.0 mM of expired paracetamol directly dissolved in the acid. Expired paracetamol acted as a mixed-type inhibitor for mild steel in 0.5M HCl and the corrosion inhibition process was spontaneous. All analyses agreed that expired paracetamol drug is capable of inhibiting corrosion of mild steel in HCl and that the corrosion inhibition is achievable without prior pretreatment. The research is fundamental as it attempts to lay some groundwork for further research towards developing viable and marketable product from this category of materials.

Abstract: Using the weight loss method and scanning electron microscopic examinations, the extract of Andrographis paniculata leaves in various concentrations was examined as a corrosion inhibitor of mild steel in 10% HCl. The weight loss findings demonstrated the effectiveness of plant extract as a corrosion inhibitor at various doses. Studies using scanning electron microscopy confirmed the enhanced surface condition caused by adsorption for corrosion protection.

Abstract: Plant extracts have become an essential renewable resource and eco-friendly for many applications by using corrosion inhibition. In this study, the inhibitive activity of water concentrates of the Acacia nilotica with 0.5M H₂SO₄ stock solution at different concentrations, was studied using the Gravimetric Method. To know the improved impact on the consumption of mild steel, extracts of the plant were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM). SEM confirmed the formation of a protective layer on the surface of mild steel. Different techniques like UV-Visible and weight-loss analysis were studied to detect the organic natural compounds in the extract. Langmuir isotherm was fitted well for this study with a correlation coefficient (R²) of 0.999.

Abstract: The investigation of Corrosion inhibition behavior of synthesized amino acid-based Schiff base inhibitor [(E)-5-nitro-N1-((E)-3-phenylallylidene) benzene-1,2-diamine] was carried out. Its adsorption in two types of (5%) soil solutions was studied at room temperature, using potentiodynamic polarization and gravimetric techniques. The inhibition efficiency obtained at the optimum inhibitor concentration (300ppm), were 23% in acidic and 70% in neutral electrolyte. Results illustrated that the inhibitor worked well in less acidic environment in one of the soil solutions which was relatively acidic than the other. Experimental data of potentiodynamic study also indicated that the inhibitor was more inclined to adsorb on the anodic sites of the carbon steel sample, thus the inhibitor can be categorized as the anodic inhibitor due to suppression of more anodic reaction on the carbon steel sample.

Abstract: α + β titanium alloys especially Ti-6Al-4V alloy have dominated implant industry over the years due to their high corrosion resistance, strength, and flexibility. However, their high modulus (110GPa) compared to the human bone (18-30GPa) results in aseptic loosening of implants. Hydroxyapatite (HA) coating on Ti-6Al-4V alloys has been used to mitigate these demerits, nevertheless, more still need to be done. Hence, the present study aims at developing a natural and economical bioceramic coating on low modulus Ti-13Nb-13Zr alloy substrates using plasma spraying technique for biomedical applications. The bioceramic used was natural HA derived from fish scales (FsHA) and FsHA doped yttria stabilized zirconia at (10-20 wt.%). FsHA/YSZ powders and the coated samples were examined by XRD and SEM/EDX and the surface roughness, microhardness and corrosion resistance of the uncoated substrate and coated samples determined. The XRD pattern showed good crystalline FsHA/YSZ powders for all the compositions while the microstructure of the coatings revealed a fine splat lamellar morphology with partially melted and non-melted FsHA particles along with evenly dispersed Zr particles within the coating matrix for the FsHA/YSZ coatings. The maximum surface roughness (4.215 µm) was found with the FsHA coating while FsHA/YSZ coatings presented the highest hardness values (492.5-536.9 Hv) compared to the FsHA coating (467.8 Hv) and the uncoated substrate (385.9 Hv). Similarly, the corrosion resistance of the Ti-13Nb-13Zr alloy was significantly improved with the deposition of FsHA/YSZ bioceramic coatings.

Abstract: Controlling the corrosion rate of metal materials is one of the key issues in circulating cooling water treatment. In recent years, the treatment of circulating cooling water by microorganisms has become a research hotspot. Compared with the traditional chemical treatment, microbial treatment is an environmentally friendly technology. In this paper, the effects of ammonia nitrogen concentration, microbial dosage and aeration intensity on copper corrosion rate were studied. In order to analyze the experimental data more comprehensively, a full factor experimental design was used to investigate the effects of ammonia nitrogen concentration, microbial dosage and aeration intensity on copper corrosion. The corrosion rate of copper was less than the national standard (< 0.005 mm / a), in which ammonia nitrogen concentration and aeration intensity were significant factors (P < 0.05), and the interaction between ammonia nitrogen concentration and aeration intensity was also significant (P < 0.05), After optimization, the regression rate of the model increased from 85.02% to 92.41%.

Abstract: This research is focused on the synthesis and the ability to inhibit scale and corrosion of poly(acrylic acid-co-acrylamide) (PAA-AM copolymers). A series of polymers were synthesized by free radical polymerization having various weight ratios of acrylic acid (AA) to acrylamide (AM). The structures of the synthesized polymers were characterized by UV-Vis Spectroscopy, FT-IR, and ¹H-NMR. The thermal stability of the polymers was analyzed by a TGA technique. The water solubility of the polymers was examined using a turbidity meter. The scale inhibition performance test was performed by titration of calcium ion with ethylene diamine tetraacetic acid (EDTA) solution. After that, the crystal structure of CaCO₃ scale from the scale inhibition test was examined using a scanning electron microscope. The efficiency of the corrosion inhibitor on low carbon steel AISI 1018 was investigated by a potentiodynamic polarization technique. The result show that PAA-AM copolymers having a 9:1 weight ratio with 45.82% at 100 ppm inhibited scale forming. The corrosion resistance of all inhibitors could be achieved when the concentration of the inhibitor was lower than 100 ppm.