Surface Analysis Research Articles

Reactions of Ru3(CO)12 with 1,5-bis(diphenylphosphino)pentane: Synthesis, characterization, crystal structure, Hirshfeld surface and QTAIM Analysis of Ru3(CO)10(µ-dpppe)

Reactions of Ru3(CO)12 with 1,5-bis(diphenylphosphino)pentane (dpppe) in THF induced by sodium benzophenone ketyl radical anion, resulted in the expected metal cluster [Ru3(CO)11]2(µ-dpppe) (1) and Ru3(CO)10(µ-dpppe) (2) as the main products. Clusters 1 and 2 were characterized by spectroscopic methods, including Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1H and 31P{1H} NMR). The structural features were determined using single crystal X-ray diffraction analysis. In cluster 1 and 2, the (dpppe) links two trinuclear cluster units via phosphine moieties and bridges to Ru–Ru bond, respectively. Both clusters were stabilized by the presence of C–H⸱⸱⸱O interactions and were further analyzed by Hirshfeld surface analysis. The bonding interactions within cluster 2 were studied using the Quantum Theory of Atoms in Molecules (QTAIM). Various local and integral topological properties of the electron density were calculated, along with the source function (SF) calculations and electron localization function (ELF) analysis.

Enhanced photocatalytic oxidation of gaseous acetaldehyde using Fe-grafted ZnO nanocomposites in a continuous flow reactor

The purification of indoor air is a crucial application of photocatalysis, emphasizing the urgent need for more efficient photocatalytic systems. While photocatalytic oxidation of volatile organic compounds (VOCs) has been extensively studied in the liquid phase, effective removal of VOCs in the gaseous state in indoor air remains a significant challenge. This study focuses on the continuous gas-phase oxidation of gaseous acetaldehyde using ZnO and different weight percentage of Fe-grafted ZnO catalysts under light irradiation. The surface analysis using XPS and HR-TEM confirmed the presence of Fe(III) species, and UV-Vis-DRS analysis demonstrated a shift in the absorption edge towards the visible region. Real-time gas FTIR monitoring of acetaldehyde oxidation revealed that the 0.7% Fe(III)-grafted ZnO composite catalyst achieved a higher removal efficiency (74%) compared to bare ZnO and other Fe(III)-grafted ZnO ratios. The enhanced photocatalytic efficiency of acetaldehyde by Fe(III)-grafted ZnO supports indicated direct interfacial charge transfer (IFCT) from ZnO to Fe(III) species. Additionally, the Fe(III) cluster effectively improved the separation of electrons and holes, preventing their recombination and accelerating O₂ activation to generate O₂•⁻ radicals, which lead to high photocatalytic performance. The 0.7% Fe(III)-grafted ZnO also maintained its performance over a prolonged period of 360 min, showing excellent structural stability and durability across multiple cycles. This study highlights the possible synergistic effect of the ZnO and Fe systems, offering a new perspective on the photocatalytic decomposition of gaseous acetaldehyde in indoor environments.

Electrochemical and corrosion behavior of steel rebars in concrete exposed to industrial SO2 and CO2 environment

Investigation into the corrosion mechanism of steel rebars in concrete under the combined influence of SO2 and CO2 is crucial for addressing the corrosion issues in reinforced concrete structures exposed to industrial environments. This study investigated the electrochemical and corrosion behavior of steel rebars in concrete under the combined influence of SO2 and CO2 using electrochemical methods, pH and SO42- concentration tests at the concrete/steel matrix interface, and surface analysis. During the corrosion process, a competitive chemical reaction between SO2 and CO2 occurs. The electrical resistance (Rc) of the concrete cover layer undergoes initial rapid growth, followed by slower increments, and then another period of rapid growth before eventually stabilizing. However, Rc sharply decreases over time, corrosion-induced damage in the concrete cover layer. CO2 diffuses to the vicinity of the rebar before SO2, inducing rebar depassivation. As rust severity increases, significant changes in the rust products are observed, with Fe(III) compounds transforming into Fe(II) compounds, and FeSO4·4H2O and FeSO4·7 H2O are prevalent in the rust products. Furthermore, the formation of ferrous sulfate compounds can lead to local acidification, thereby accelerating the corrosion rate, and hastening the aging and deterioration of the structure, posing a serious threat to the safety of the building structure.

Comprehensive assessment of the corrosion inhibition properties of quinazoline derivatives on mild steel in 1.0 M HCl solution: An electrochemical, surface analysis, and computational study

The efficacy of two compounds, namely 12-(4-chlorophenyl)-3,3-dimethyl-3,4,5,12-tetrahydrobenzo[4,5] imidazo[2,1-b]quinazolin-1(2H)-one (Q-Cl) and 3,3-dimethyl-12-phenyl-3,4,5,12-tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolin-1(2H)-one (Q-H), in inhibiting corrosion on mild steel in 1.0 M hydrochloric acid was evaluated. Surface analytical techniques and electrochemical procedures were employed for examination. The results demonstrated that both Q-Cl and Q-H significantly inhibit corrosion. Specifically, Q-Cl achieved an inhibition efficiency of 85.2 % at a concentration of 10⁻³ M, while Q-H exhibited a higher inhibition efficiency of 91.5 %. Electrochemical investigations suggested that both Q-Cl and Q-H acted as inhibitors of mixed-type corrosion. These chemicals efficiently prevented metal corrosion through adsorption, conforming to Langmuir's adsorption isotherm model. The adsorption mechanism of corrosion inhibition was further supported by surface investigations and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX). Additionally, Density Functional Theory (DFT) and other computational approaches were employed to study the anti-corrosion mechanism of Q-Cl and Q-H. These simulations yielded theoretical results that aligned with the preceding experimental findings.

Imidobis(tetraphenylphosphinato)lanthanoid(III) complexes: Synthesis by oxidative protolysis, and redox transmetallation/protolysis, structural studies and Hirshfeld surface analysis

Redox protolysis of [YbCp2(dme)] (dme = 1,2-dimethoxyethane) by iminotetraphenyldiphosphinate, ({Ph2PO}2NH) LH yields [YbCp{(Ph2PO)2N}2}(MeCN)] 1 and [Yb{(Ph2PO)2N}3] 2 with the last also obtained by oxidative protolysis of Yb(C6F5)2. The complexes [Ln{(Ph2PO)2N}3] ((Ln = Yb 2, Er 3, Gd 4), [Sm{(Ph2PO)2N}3(MeCN)3] 5 and [Nd{(Ph2 PO)2N}3] 6 have all been prepared by redox transmetallation/protolysis reactions between Yb, Er, Gd, Sm or Nd metals, bispentafluorophenylmercury and proligand LH. Complex 1 is formally eight coordinate with an acetonitrile, cyclopentadienyl (Cp) and two chelating O,O′-(Ph2PO)2N ligands, with the MeCN trans to the Cp ring. Complexes 2 and 4·C7H8 are six coordinate monomers with three chelating O,O′ diphosphinate ligands. By contrast 5 is a highly symmetrical nine-coordinate monomer with three acetonitrile and three chelating O,O′-L ligands. The three-dimensional Hirshfeld surface (3D-HS) analysis and the two-dimensional fingerprint plots (2D-FP) were quantified for different intermolecular interactions in complexes 2 and 4.

Torsional vibration suppression of a gear-rotor system using an inerter magnet nonlinear energy sink

The novel inerter magnet nonlinear energy sink (IMNES) utilizes chiral compression-torsion coupling effects to achieve mass augmentation, effectively mitigating torsional vibrations in a gear-rotor system with gear meshing clearance. The positive stiffness generated by the piecewise linear beam combines with the negative stiffness produced by the permanent magnet pair, resulting in the establishment of the IMNES’s nonlinear stiffness. Subsequently, a dynamic model of the IMNES-gear-rotor system is developed. Optimal parameters for the IMNES are determined through analysis of vibrational response surfaces under both transient and steady-state conditions. The numerical calculation of torsional vibration in the IMNES-gear rotor system is conducted across various gear meshing clearances. The results demonstrate that across different gear mesh clearances, the IMNES effectively attenuates torsional vibrations in the gear-rotor system. Under transient excitation, implementation of the IMNES leads to an 87% reduction rate in displacement within the gear-rotor system. In terms of steady-state excitation, simulations show a significant enhancement with a 65% increase in vibration suppression percentage.

Angular Dispersion Analysis of Frequency-Selective Surfaces Based on Wavevector Domain Equivalent Impedance

Angular Dispersion Analysis of Frequency-Selective Surfaces Based on Wavevector Domain Equivalent Impedance

Insights into the inhibitory effects of trichloroisocyanuric acid disinfectant on the phototransformation of polypropylene microplastics

The chemical components in the natural aquatic environment have the potential to be involved in phototransformation of microplastics (MPs). Little information is available regarding the mediation effects of artificially introduced chemicals on MP phototransformation, especially those used in aquaculture water that are vulnerable to human interference. Herein, this study investigated the phototransformation process and mechanism of polypropylene microplastic (PP MPs) in presence of trichloroisocyanuric acid (TCCA) disinfectant with unique properties unlike the conventional inorganic chlorine disinfectants. The results showed that the presence of TCCA inhibited the surface photooxidation of PP MPs. Analysis of PP MP surface and reaction filtrate indicated that the inhibitory effects were likely derived from TCCA derivatives and the weakening in promoting effect of polypropylene microplastic-derived dissolved organic matter (PP-DOM) as photolytic byproducts, with the more important role of free chlorine in initial period and that of other chlorine species (i.e., the adsorbed chloride ions (Cl−), newly formed carbon-chlorine (CCl) bonds, chlorinated cyanurates, and chlorinated products) in middle and later period. The study highlights for the first time the important role of chlorine species derived from TCCA in phototransformation process of co-existed PP MPs and proposes a previously unrecognized phototransformation pathway, which will provide a new understanding and knowledge for the environmental behavior of MPs in aquaculture environment.

Effect of radiofrequency bias power on transmission spectrum of flat-cutoff sensor in inductively coupled plasma

Real-time monitoring of plasma parameters at the wafer plane is important because it significantly affects the processing results, yield enhancement, and device integrity of plasma processing. Various plasma diagnostic sensors, including those embedded in a chamber wall and on-wafer sensors, such as flat-cutoff sensors, have been developed for plasma measurements. However, to measure the plasma density on the wafer surface in real-time when processing plasma with bias power, such as in the semiconductor etching process, one must analyze the transmission spectrum of the flat-cutoff sensor in an environment with bias power applied. In this study, the transmission-spectrum and measured plasma-density characteristics of an electrode-embedded flat-cutoff sensor are analyzed via electromagnetic simulations and experiments under applied bias power. Our findings indicate that the flat-cutoff sensor accurately measures the plasma density, which is equivalent to the input plasma density under low bias power. Conversely, under high bias power, the plasma density measured by the sensor is lower than the input plasma density. Also, a thick-sheath layer is formed owing to the high bias power, which may complicate the measurement of plasma parameters using the flat-cutoff sensor. Plasma diagnostics using a flat-cutoff sensor in thick-sheath environments can be achieved by optimizing the flat-cutoff sensor structure. Our findings can enhance the analysis of plasma parameters on-wafer surfaces in processing environments with bias power applied.

Synergistic synthesis and computational analysis of novel indazole-2-Pyrone hybrids: Toxicity, Hirshfeld surface insights, and antiviral potential against HIV-1 and Coronaviruses

A novel category of hybrids, termed (Z)-6-methyl-3-(1-((1-(prop‑2-yn-1-yl)-1H-indazol-6-yl)amino)ethylidene)-2H-pyran-2,4(3H)‑dione, was synthesized by reductive coupling of N-alkyl-6-nitroindazoles and 2-pyrone using indium or stannous chloride in tetrahydrofuran (THF) with acetic acid. This process yielded (Z)-2H-pyran-2,4(3H)-diones in satisfactory yields. Each synthesized molecule underwent comprehensive characterization through NMR analysis and X-ray diffraction. Additionally, our investigation incorporates quantum chemical modeling via density functional theory (DFT) at the B3LYP/6–311G(d,p) level, along with molecular docking analysis. An analysis of the Hirshfeld molecular surface was undertaken to characterize the type of intermolecular connections. The percentage contributions, shown in the footprint plot, indicate that H…H interactions (33.0 %) are particularly significant in the constitution of the crystal. The favorable pharmacological properties of compounds 5a and 6a, such as good bioavailability, ability to penetrate the blood-brain barrier, and adherence to the Lipinski rule, make them excellent candidates for therapeutic development.

Effects of irradiation on interfacial strength and microstructure of double-layer mullite and alumina coating on SiC

Silicon carbide (SiC) ceramics hold great potential for use in nuclear-reactor components due to characteristics such as high-temperature strength and low activation. Despite their resistance against corrosion in harsh environments, they suffer elevated corrosion rates under particle irradiation. Thin anti-corrosion coatings, such as mullite bond layers and alumina top layers, are essential to enhance the irradiation stability of SiC. The objective of this study was to evaluate the irradiation stability of a double-layer coating developed to enhance the corrosion resistance of SiC in nuclear applications. The coating, which comprised a mullite bond layer and an alumina top layer, was applied to a SiC substrate using laser chemical vapor deposition. Irradiation experiments were conducted at 300°C with 5.1-MeV Si ions up to 10 displacements per atom. To assess the interfacial strength, a novel testing method, called the double-notch shear compression testing method, was developed based on ASTM standards and was implemented using a nanoindenter. This approach enabled precise measurements of the mechanical integrity at the interfaces of the coating under irradiation. The results showed an increase in the interfacial strength at the SiC/mullite and alumina/mullite interfaces with irradiation. Microstructural analysis of the fracture surface through scanning electron microscopy–energy-dispersive X-ray spectroscopy revealed that cracks propagated within the mullite layer, indicating the presence of mullite on the fracture surface. Transmission electron microscopy (TEM) images indicated that a 2-µm-thick transition layer existed at the SiC/mullite interface but not at the alumina/mullite interface. The TEM–electron energy loss spectroscopy suggested that the Al-O bonding structures in the transition layer were changed from tetrahedral (AlO4) to octahedral (AlO6) through irradiation, and this structural transition may directly affect the strength.

Study of Some Physical and Antibacterial Properties of Bio-based (PLA)/(PCL) Blend reinforced with ZrO2 Nanoparticles

The aim of this study was to produce flexible films by combining polylactic acid (PLA) and poly(ε-caprolactone) (PCL), and enhance their strength by reinforcing them with different weight percentages (0.75, 1.5, and 2.25%) of zirconium oxide (ZrO2) nanoparticles (NPs) using a solvent casting process. The physical and antibacterial properties of the films were analysed to determine their suitability for use in food packaging. X-ray diffraction (XRD) patterns of the PLA/PCL films containing 2.25% by weight ZrO2 nanoparticles have a peak at an angle of 2θ = 17.18°, accompanied by smaller peaks. This confirms that these thin films have a semi-crystalline structure and that the molecules in the thin films are well dispersed. Scanning electron microscopy (SEM) analysis of the film surfaces reveals that the pure PLA/PCL films exhibit a smooth surface, while the (PLA/PCL/ZrO2NPs) films have a rough surface. The thermal behaviour of the blends through differential scanning calorimetry (DSC) showed fluctuations due to variations in the reinforcement ratio, resulting in changes in the glass transition and melting temperatures. These oscillations indicate changes in the level of crystallinity. ZnO2 has antibacterial properties that promote growth inhibition, making these films more effective in food packaging.

Development of a new rhodamine 6G based probe and its application as an optical sensor of Cu2+ and Fe3+ ions: A comprehensive experimental and Theoretical studies

A new rhodamine appended probe 3-allyl salicylaldehyde rhodamine hydrazone (RGAL) has been synthesized and thoroughly characterized using various spectroscopic techniques, as well as single crystal XRD. The optical properties of RGAL were investigated in 10 mM HEPES buffer in H2O:CH3CN (2:8, v/v, pH=7.2) in the presence of various cations. RGAL showed selectivity and sensitivity towards Cu2+ during absorption process and “turn on” behavior towards Fe3+ during emission study owing to the opening of a spirolactum ring. The detection limits for Cu2+ and Fe3+ ions using RGAL were determined to be 6.15 ppm and 4.75 ppm, respectively. The binding constant of RGAL with Cu2+ and Fe3+ ions was found to be 1.20 × 104 M−1 and 1.71 × 104 M−1, respectively. Hirshfeld surface and fingerprint analysis of RGAL provides the in-depth analysis of pairwise interaction between two atoms. Furthermore, the topological analysis of RGAL is performed using NCI, AIM, ELF and LOL analysis. The analysis provides information about O78-H79…N71 and C40-H41…O77 hydrogen bonding interactions in themonomer of RGAL whereas various inter- and intra- molecular interactions give strength to the dimer pattern of RGAL.

Crystal structures, NCI-RDG, Hirshfeld surface and energy framework analysis of tetra aryl substitute bispidine and oxaquinuclidine core containing derivatives: A potential COVID-19 drug candidate

Two of the title compounds are crystallized in P21/c and monoclinic face groups. Each crystal unit cell has four molecules. There are two piperidine rings: one in the chair conformation and another one in the boat conformation. The piperidine nitrogen in the boat conformation is joined to the oxygen-containing chair conformation piperidine ring to produce the oxaquinuclidine ring (-N-CH2O-). Furthermore, because of the steric barrier between rings, all aryl groups are oriented in an equatorial position. The crystal network is maintained through several interactions, including C—H⋯O/N/Cl/π. The crystal void and interaction energy studies gave additional evidence of the strength of the crystal packing and intermolecular linkage. Crystal 3b has less cavity than crystal 3c, indicating that it is densely packed. The dispersion energy contribution dominates the stability, according to the analysis of the electrostatic, dispersion, and total energy frameworks. Reduced density gradient (RDG), electron localization function (ELF), and localized orbital locator (LOL) analysis were used to determine the molecular interaction, electron pair density, and maximally localized orbitals overlapping sites, respectively. This approach reveals that oxaquinuclidine ring steric hindrance and the electron densities throughout the molecules. Density function theory (DFT) provides more evidence for the ring's orientation and the molecules' reactivity. A molecular docking investigation of four essential COVID-19 proteins was carried out using these theoretical ideas. This investigation demonstrates that each protein's reactivity varies; certain proteins have more interaction with high electron density molecules (electron-donating substituent), while others have more interaction with low electron density molecules (electron-withdrawing substituent). The ADMET and drug-likeness investigations reveal that methoxy group substituted molecules perfectly correlate with the required pharmacological characteristics. The cytotoxicity of the five compounds was assessed using the HEK293T cell.

Biodegradable active films based on Chlorella biomass and cellulose nanocrystals isolated from hemp stalk fibers

Cellulose nanocrystals (CNC)-reinforced biopolymers have emerged as a widely embraced approach for enhancing the characteristics of biopolymers due to their exceptional properties. Biocomposite (Chl-CNC) films were fabricated by blending Chlorella biomass and varying concentrations of CNCs via a solution casting technique. CNCs were effectively isolated from hemp stalk fibers, as confirmed by structural, surface, thermal, and morphological analysis. The crystallinity of films increased by CNC incorporation, which was confirmed by the XRD. The presence of molecular interactions between CNC and protein-rich Chlorella biomass was illustrated with the FTIR analysis. These interactions enhanced the physicochemical properties of the films. Further, films demonstrated a high level of soil biodegradation in the 42 days, while their total phenolic, chlorophyll, carotenoid contents, and antibacterial activity were unaffected by the incorporation of CNCs. The Chl-CNC films, regardless of CNC addition, indicated antimicrobial activity toward Escherichia coli but not Staphylococcus aureus. These results indicate that developed biobased and biodegradable Chl-CNC films could be highly beneficial in active food packaging applications.

New Hydrazide-Hydrazone Derivatives Containing Coumarin and Indole Moiety: Synthesis, Spectroscopic Characterization and DFT Studies

Two new compounds (3 and 4), coumarin indole derivatives with a hydrazide-hydrazone skeleton, were synthesized, and their spesctroscopic properties, including UV-vis, FTIR, and 1H-13C NMR were investigated experimentally and theoretically. The experimental data and DFT (density functional theory) results of the compounds matched well and showed good agreement. Moreover, the DFT/B3LYP/6-311G++(2d,p) calculations were utilized to perform HOMO and LUMO energy, net atomic charges, MEP surface, and NBO analysis for the optimized geometries of 3 and 4. NBO analysis revealed that the synthesized compounds exhibit high molecular stability because of significant hyperconjugative interactions. The experimental and theoretical band gaps (ΔEg) investigated in some organic solvents with different polarities were determined to be in the range of 2.68-2.75 eV and 3.22-3.25 eV for compound 3, and 2.69-2.77 eV and 3.41-3.47 eV for compound 4, respectively. The compounds demonstrated thermal stabilities with a Td value higher than 300°C.

Caprock sealing integrity and key indicators of CO2 geological storage considering the effect of hydraulic-mechanical coupling - X field in the Bohai Basin, China

Caprock sealing efficiency is an essential guarantee for the long-term safety and stability of CO2 geological storage (CCS). However, the uncertainty in the physical and mechanical properties of deep formations poses challenges to accurately predict the risks of CO2 leakage resulting in CO2 breakthrough or caprock fracture. This study aims to address the issue of imperfect key indicators for caprock sealing by focusing on the CCS project in the Bohai Bay Basin, China. A hydraulic-mechanical (HM) coupling program without considering multiphase flow and the chemical reactions is secondary developed based on the finite element software ABAQUS. Furthermore, a three-dimensional finite element numerical model is established for the analysis of HM coupling, with pore pressure increment (∆PP), Coulomb failure stress (∆CFS) and displacement (U) as evaluation criteria. The Tornado analysis and response surface analysis are employed to analyze the impact of 17 indicators on the caprock sealing, including caprock thickness, burial depth, reservoir and caprock permeability parameters, and mechanical parameters. Subsequently, key performance indicators for caprock sealing are determined. The research results indicate that the reservoir permeability, injection rate, caprock permeability, caprock Young's modulus, caprock internal friction angle, caprock Poisson's ratio, and caprock burial depth are key indicators of caprock sealing capability. The reservoir permeability has a greater impact sensitivity compared to the caprock permeability. Pore pressure and displacement increase with increasing in reservoir permeability. The caprock's resistance to deformation and fracturing increases with increasing in Young's modulus and Poisson's ratio of caprock. This study provides valuable insights for evaluating caprock sealing during CO2 storage in saline aquifers.

Surface Layer Performance of Low-Cost 3D-Printed Sliding Components in Metal-Polymer Friction

Abstract The paper presents the results of contact strength and tribological property tests of spare parts made of a popular resin using a 3D DLP printing technology. Two printer models by the same manufacturer were used in the study. The post-processing technique, which shapes the final functional properties, was diversified. Surface performance properties were compared, i.e. Shore hardness, indentation hardness, Martens hardness, elastic modulus, and parameters related to surface creep and relaxation. Tribo-logical durability in rotary motion and tribological wear in reciprocating linear motion were also evaluated using micro- and nanotribometers. This was followed by surface analyses of the friction track of the analysed materials using microscopic methods: a scanning electron microscope, a WLI interferometric microscope, and an optical microscope. The results were statistically processed and the relationship between the parameters determined in the indentation test was determined.

Performance and biotoxicity of electro-Fenton treatment of bisphenol A: Evaluation of copper recovered from microbial fuel cell cathodes for subsequent catalytic applications

A three-tank microbial fuel cell (MFC) is successfully constructed to achieve electromigration and is used in the electro-Fenton process to treat bisphenol A (BPA). The MFC system exhibits excellent mobility and efficiently aggregates Cu+ to the cathode. Under optimal operating conditions, the MFC achieves a maximum power density of 31.4 mW/m2, which is a 3.4-fold increase over that at 0.5 kΩ. Increasing the external resistance increased the MFC power output (ca 1.5 times) and copper ion migration (ca 4.6 times) while reducing the internal resistance of the system (ca 25.3 %). Surface analysis of the cathode carbon cloth shows a 5.5-fold increase in copper content at 1 kΩ over that at 0.5 kΩ. This also increases the oxygen reduction reaction rate, thereby increasing the H2O2 yield by 1.5 times. The recovered copper cathode at 1 kΩ exhibits the best catalytic degradation of BPA, removing 99.7 % of BPA in 180 min, increasing 1.4 and 1.8 times that obtained at 1.5 and 0.5 kΩ, respectively. The optimal operating conditions significantly increased the abundance of electrochemically active bacteria (Azospirillaceae) (3.2 %−41.7 %), indicating that the optimized MFC is favorable for the rapid acclimatization of electrochemically active bacteria.

Caesalpinia crista seed is used as an eco-friendly inhibitor to prevent the corrosion of aluminium in hydrochloric acid solutions

This investigation delves into the inhibitory impact of Caesalpinia crista (Kanchaki) seed extract (CCE) on the corrosion of aluminium alloy (AA6061) at temperatures varying between 303-333K, employing Potentiodynamic Polarisation (PDP), Electrochemical Impedance Spectroscopy (EIS), and weight loss methodologies. Findings demonstrate that CCE extract effectively safeguards Al against corrosion, with efficacy increasing at higher concentrations. The observed inhibitory action exhibits a mixed-type behavior across all concentrations and temperatures, aligning well with Langmuir isotherm. Notably, the highest level of inhibitory efficiency, reaching 96.87%, is attained at a concentration of 2.0 g/L and a temperature of 303 K for 3 hours. Consistency is observed between the results obtained through EIS and PDP. A plausible mechanism for preventing corrosion in Al alloy is proposed. Surface analysis techniques, such as Atomic Force Microscopy (AFM) and Scanning Electron Microscopy/Energy Dispersive X-ray analysis (SEM/EDX), validate the adsorption of the inhibitor onto Al alloy surfaces. Morphological examinations corroborate electrochemical findings, confirming protection against uniform corrosion in HCl solutions. Additional analyses involve the computation of activation energy and thermodynamic parameters, with a thorough discussion of the results.