Steel Surface Research Articles

Formation and dissolution of porous magnetite layer in contact with lead-bismuth eutectic: Locally equilibrium thermodynamic model

Locally equilibrium thermodynamic model is developed to describe the formation and dissolution of the outer magnetite layer of an oxide film on the steel surface in contact with lead-bismuth eutectic. The model allows to predict the outer layer growth law as a function of dissolved oxygen and iron concentrations, temperature and coolant flow rate. Comparison with experiments allows to explain the phenomenon of magnetite dissolution in two experimentally observed cases: when oxygen concentration in LBE is above the solid magnetite stability line and under the high values of the coolant flow rate, without the consideration of mechanical erosion.

Corrosion inhibition performance and mechanism of triethanolamine-triisopropanolamine rust inhibitor in the simulated concrete pore solution

In this research, aiming to deal with the accelerated corrosion deterioration of steel reinforcement in reinforced concrete in harsh environments, a highly efficient rust inhibitor (triethanolamine (TEA)-triisopropanolamine (TIPA)) (abbreviated as TT), which TEA and TIPA compounded in a ratio 4:6, was proposed. The synergistic rust inhibition effect of TEA and TIPA on steel in the simulated concrete pore solution (SCPS), and its corrosion inhibition performance were investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), dry and wet cycling, and scanning electron microscopy (SEM) measurements. The results showed that TT inhibitor could obviously inhibit the corrosion of steel in the SCPS and could inhibit both cathode and anode. The electrochemical corrosion inhibition performance was the most excellent at the dosage of 1.0 %, and the maximum corrosion inhibition efficiency (η1) reached 95.39 %. After 150 times of dry and wet cycling, the percentage of the corrosion area (S), and corrosion inhibition efficiency (η2) with 1.0 % TT inhibitor were 9.3 % and 84.03 %, respectively, and the mass loss rate (M) decreased by 68.4 %, indicating a better rust inhibition performance. The adsorption of the TT inhibitor conformed to the Langmuir adsorption isotherm and inhibited the corrosion of steel by forming a protective film on steel surface through physicochemical adsorption. This study is of great significance to provide new perspectives and improvement measures to build up the deterioration and extend the service life of reinforced concrete in harsh environments.

Ultrasonic Cavitation Erosion Behavior of GX40CrNiSi25-20 Cast Stainless Steel through Yb-YAG Surface Remelting.

Laser beam remelting is a relatively simple and highly effective technique for the physical modification of surfaces to improve resistance to cavitation erosion. In this study, we investigated the effect of laser remelting on the surface of cast stainless steel with 0.40% C, 25% Cr, 20% Ni, and 1.5% Si on cavitation erosion behavior in tap water. The investigation was conducted using a piezoceramic crystal vibrator apparatus. Base laser beam parameters were carefully selected to result in a defect-free surface (no porosity, material burn, cracks) with hardness capable of generating better resistance to cavitation erosion. The experimental results were compared with those of the reference material. Surface morphology and microstructure evolution after cavitation tests were analyzed using an optical metallographic microscope (OM), scanning electron microscope (SEM), and hardness tests to explore the mechanism of improving surface degradation resistance. The conducted research demonstrated that surfaces modified by laser remelting exhibit a 4.8-5.1 times greater increase in cavitation erosion resistance due to the homogenization of chemical composition and refinement of the microstructure, while maintaining the properties of the base material.

Effect of pH on the controlled release of benzotriazole from halloysite clay nanotubes for corrosion protection of mild steel

Due to the increase in severe consequences of mild steel corrosion, the development of coatings with improvement in corrosion-resistant properties has become very essential. In this work, benzotriazole (BTA) was encapsulated into halloysite nanotubes (HNTs) for inhibiting the corrosion of mild steel surface. The BTA-encapsulated HNT exhibits pH-responsive properties over a wide range of pH. It was found that a large amount of BTA was released at pH 3 (48 %), followed by pH 7 (30 %) and least in the case of pH 10 (20 %). At neutral pH, a rapid release of BTA was observed during initial exposure, reaching a steady-state later, with no significant release further. A salt immersion test was carried out after immersing mild steel (MS) substrates in BTA-HNT nanopowder dispersion in 3.5 wt% NaCl at different pH. SEM images and EDS maps confirmed that corrosion product formation on MS surface at pH 3 was significantly more with corrosion pits along with HNTs throughout the surface. At pH 7 and 10, corrosion pits were observed with very few halloysite nanotubes on the surface. An optimum amount of BTA is required to inhibit corrosion, excessive release may cause more Cl− ions to penetrate, leading to more corrosion. Electrochemical data also reveals the same trend, where the icorr value was maximum for pH 3 (1.09 × 10−5 A/cm2) > pH 7 (4.74 × 10−6 A/cm2) > pH 10 (3.43 × 10−6 A/cm2). Therefore, results suggest that BTA-encapsulated HNT can be efficiently incorporated into the coating matrix for their controlled release to provide corrosion protection under varying neutral and alkaline marine environments.

Two schiff base as corrosion inhibitors for N80 in 1.0 M HCl: Experimental and theoretical studies

Two Schiff base inhibitor were synthesized and the structures of RX-1 and RX-2 were confirmed through infrared (IR) and nuclear magnetic resonance spectroscopy (NMR). The corrosion inhibition properties of the two Schiff base inhibitor on N80 steel in 1.0 M HCl were investigated. The results demonstrate that the corrosion inhibition efficiencies of RX-1 and RX-2 at 200 mg/L were 91.15 %, and 91.09 % by weight loss. The results of Electrochemical impedance spectroscopy (EIS) show that RX-1 and RX-2 form adsorption films on the surface of N80 steel to alleviate the corrosion. Tafel polarization curve (TAFEL) results showed that RX-1 and RX-2 reduced the dissolution of N80 by inhibiting both cathode and anode reactions. Scanning electron microscope (SEM), Energy Dispersive Spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) confirmed the effective adsorption of RX-1 and RX-2 on the surface of N80 steel, thereby preventing direct contact between the corrosive medium and the metal. Density functional theory (DFT) Fukui and molecular dynamics simulation (MD) have proved that there are multiple adsorption sites in 1 M HCl at the molecular level, which can be stably adsorbed on the metal surface. Mean Squared Displacement (MSD) has proved that the protective film formed by RX-1 and RX-2 can slow down the corrosion of N80 steel by hindering the diffusion rate of corrosive ions.

Anti-Corrosion Flocking Surface with Enhanced Wettability and Evaporation.

The corrosion protection of tool steel surfaces is of significant importance for ensuring cutting precision and cost savings. However, conventional surface protection measures usually rely on toxic organic solvents, posing threats to the environment and human health. In this regard, an integrated process of laser texturing and electrostatic flocking is introduced as a green anti-corrosion method on a high-speed steel (HSS) surface. Drawing from the principles of textured surface energy barrier reduction and fiber array capillary water evaporation enhancement, a flocking surface with a synergistic optimization of surface wettability and evaporation performance was achieved. Then, contact corrosion tests using 0.1 mol/L of NaCl droplets were performed. Contact angles representing wettability and change in droplet mass representing evaporation properties were collected. The elements and chemical bonds presented on the corroded surfaces were characterized by X-ray photoelectron spectroscopy (XPS). The results revealed that the flocking surface exhibited the lowest degree of corrosion when compared with smooth and textured surfaces. Corrosion resistance of the flocking surface was achieved through the rapid spread and evaporation of droplets, which reduced the reaction time and mitigated electrochemical corrosion. This innovative flocking surface holds promise as an effective treatment in anti-corrosion strategies for cutting tools.

Synthesis of MnFe2O4 Spinel on Rusted Q235 Steel Surface and Its Corrosion Resistance Properties.

Corrosion of steel is an issue that cannot be ignored in contemporary society. Due to large-scale corrosion, it is urgent to develop a surface treatment process that enhances the corrosion resistance of steel, allowing for application in various scenarios as needed. This study aims to investigate a novel surface treatment process to extend the service life of corroded Q235 steel, reduce its sensitivity to corrosion, and enable its use in multiple environments. This study employs the sol-gel method, using manganese nitrate solutions of varying concentrations to treat the surface of Q235 steel after different electrolysis times. The optimal conditions for precursor preparation were found to be a Mn2+ concentration of 0.1 mol/L and an electrolysis time of 2 h. Electrochemical tests using NaCl solutions of different concentrations revealed a significant reduction in the corrosion current for the composite coating based on Q235 steel treated with this method in NaCl solutions with wt.% = 1, 2, 3, 4, 5. Furthermore, the resistance to corrosion was strongest in the NaCl solution with a concentration of 1 wt.% where the corrosion current decreased from 24.8 µA/cm2 to 6.79 µA/cm2. Additionally, the coating was found to be diffusion-controlled in the early stages of the corrosion process and charge transfer-controlled in the later stages. The MnFe2O4 spinel coating demonstrated the greatest enhancement in corrosion resistance in the wt.% = 1 NaCl solution.

Dual surface-modification by oleic acid and epoxy-based silane coupling agent providing cerium oxide nanoparticles as additive in pentaerythritol oleate with improved high-temperature adsorption performance and tribological properties

An epoxy-based silane coupling agent (KH560) was grafted onto the surface of oleic acid-modified cerium oxide (CeO2-OA) nanoparticles in order to improve the competitive adsorption ability of the anti-wear additives in ester oils and simultaneously hinder the additive desorption owing to thermal disturbance under high-temperature condition. The as-prepared oleic acid-epoxy silane co-modified cerium oxide (CeO2-OA/E) nanoparticles were characterized. The effect of temperature on the adsorption behavior of trityl phosphate (TCP, a commercial high-temperature antifriction agent), CeO2-OA and CeO2-OA/E in PETO was studied using a dissipative quartz microbalance. Their tribological properties as the additives in pentaerythritol oleate (PETO), a polar ester base oil, were evaluated with a four-ball machine and a ball-on-block friction and wear tester; and their tribomechanism was explored with respect to their adsorption behavior on rubbed steel surfaces at elevated temperatures. It was found that the secondary surface-capping of CeO2-OA by the KH560 silane coupling agent resulted in great increases in the surface potential (from 54 mV to 396 mV) and thermal stability as well (the thermal decomposition temperature rose from 185 °C to 254 °C). Among the tesetd lubricant additives, CeO2-OA/E exhibited the highest adsorption mass, because of the highest surface potential the chemisorption ascribed to the epoxy group of the silane coupling agent. Particularly, CeO2-OA/E added in PETO exhibited better friction reduction and anti-wear properties at 150 °C than CeO2-OA and TCP, because CeO2-OA/E added in PETO formed tribofilm composed of CeO2 and SiO2 with excellent thermal stability as well as friction-reduction and antiwear effects through stable chemical adsorption and tribochemical reaction at elevated temperatures.

Protective Effects of Small Molecular Inhibitors on Steel Corrosion: The Generation of a Multi-Electric Layer on Passivation Films

The durability of reinforced concrete structures is significantly influenced by the effectiveness of small molecular inhibitors in preventing the corrosion of steel reinforcements. In a concrete environment, the passive film on steel bars serves as a critical protective component. In this study, a molecular dynamics (MD) simulation is used to study the inhibition mechanism of chloride ions by common corrosion inhibitors (2-Amino-2-thiazoline) in concrete in an excess chloride solution. The results reveal that inhibitors adsorb onto the steel surface primarily through van der Waals forces, with more than 90% of the adsorption occurring vertically. Despite this strong adsorption, inhibitors alone do not form a protective film. In the presence of chloride ions, which frequently penetrate concrete, the coverage rate of inhibitors on the steel surface decreases from 74% to 64%. Nevertheless, inhibitor molecules still provide substantial protection in chloride-rich concrete environments. Further analysis indicates that inhibitor molecules inhibit chloride ions in two ways. Corrosion inhibitor molecules actively desorb from the steel surface to capture chloride ions and prevent them from approaching. Additionally, inhibitors form a multi-electron layer on the steel surface to enhance passive film protection and hinder chloride ion diffusion through Coulombic interactions.

Optimization of defects and high temperature corrosion resistance of laser cladding FeCrAl coatings: Influence of process parameters

To enhance the surface quality and high-temperature corrosion resistance of FeCrAl coatings further, a laser cladding technique was employed to deposit Fe-13Cr-7Al coatings on the surface of 12Cr1MoV heat-resistant steel. The study investigated the influence of laser power, scanning speed, and powder feed rate on the quality and high-temperature corrosion resistance of the Fe-13Cr-7Al coatings. Utilizing 25 orthogonal experiments, coatings were prepared and evaluated through high-temperature corrosion tests to explore the corrosion resistance and mechanisms microstructural analysis of the coatings, including their elemental distribution and corrosion mechanisms, was conducted using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The optimal parameter combinations for laser cladding coatings were discussed. The results indicated that the coating quality was optimal within specific ranges of parameters (laser power 1875–2250 W, scanning speed 33–44 mm/s, powder feed rate 12–18 g/min); deviations outside these ranges led to issues such as incomplete coverage or coating detachment from the substrate. The structure of the laser cladded Fe-13Cr-7Al coatings consisted of columnar grains and α-Fe phase. In high-temperature corrosion testing, the coatings exhibited superior corrosion resistance compared to the substrate, with nearly twice the corrosion resistance variation observed under different process parameters. This study provides a scientific basis for optimizing laser cladding process parameters of Fe-13Cr-7Al coatings, demonstrating that precise control of process parameters significantly enhances the high-temperature corrosion resistance of coatings, thereby opening new possibilities for improving material performance in high-temperature applications.

Synergistic mixture of the Dactyloctenium aegyptium extract and KI as an environment friendly and highly efficient corrosion inhibitor for steel in 0.5 M HCl

To prevent steel from corroding in HCl solution, a cost-effective inhibitor of Dactyloctenium aegyptium and KI is presented. UV–Vis, infrared spectroscopy, and scanning electron microscopy analysis are used to undertake a comprehensive experimental evaluation of the inhibitors and their interactions with the steel. The optimum concentration of the Dactyloctenium aegyptium extract (DAE) with the maximum corrosion protection efficacy is found via electrochemical measurements. The bioactive constituents of the DAE such as Tricin, Vanillic acid, p-hydroxybenzaldehyde, and p-hydroxybenzoic acid conferred a maximum inhibition efficiency of 95.7 % at 800 ppm. The inhibitory activity of its ethanolic extract increased with increasing concentration. Further various adsorption isotherm models including Langmuir, Temkin and Frendluich were used to understand the adsorption of the DAE on the metal surface. The DFT based investigations show that the active constituents of the DAE are highly polarized, soluble in aqueous solution and adsorb on the steel surface efficiently.

Shielding against erosion: Exploring the effectiveness of pre-erosion surface corrosion inhibitors

This study investigates the corrosion inhibition effect and adsorption process of two imidazoline corrosion inhibitors, HEIE and TDEI, on pre-eroded X65 steel surfaces. Analysis of weight loss and electrochemical measurements suggests that the irregular structure of pre-eroded surfaces may impede the uniform adsorption of corrosion inhibitors, resulting in reduced effectiveness pre-erosion. Particularly, at a 30° angle of pre-erosion, corrosion inhibition efficacy is observed to be at its lowest. The corrosion inhibition rates of HEIE and TDEI on X65 steel surfaces are found to be 11.9 % lower under pre-eroded conditions at a 30° angle compared to non-eroded surfaces at the same angle. Molecular dynamics (MD) simulations support these findings, indicating that TDEI exhibits lower energy bandgap values and more negative adsorption energies (Eads) compared to HEIE, aligning with experimental results. Moreover, TDEI demonstrates a smaller diffusion coefficient for corrosive agents than HEIE, suggesting stronger adsorption efficiency and a more pronounced protective effect. Study of the corrosion inhibition effect on pre-eroded surfaces provides new ideas and methods for improving protective measures.

Construction of hard BCC phases FeCrVMnTix wear-resistant high-entropy alloy coatings enhanced by solid solution of Ti elements

To address the complex working conditions encountered by 1Cr13 ferritic/martensitic steel during operation, it is imperative to develop high-entropy alloys (HEAs) protective coatings with enhanced friction resistance. In this work, guided by the valence electron concentration criterion, we constructed a single-phase body-centered cubic (BCC) structure with high hardness. This was achieved through the introduction of titanium (Ti), which has a significantly different atomic radius compared to other elements. FeCrVMnTix (x = 0, 0.5, 1.0, 1.5, and 2.0) coatings were fabricated on 1Cr13 steel surfaces using laser cladding techniques, and the microstructure, mechanical properties, and wear-resistance properties of Ti-doped HEA coatings were investigated. The results reveal that the FeCrVMnTix coatings are comprised of a BCC solid solution. Increasing Ti content refined the dendritic structure of the coatings, enhancing the Vickers hardness from 4.35 GPa to 8.27 GPa and the Young's modulus from 232.6 GPa to 273.2 GPa. Additionally, the wear rate decreased from 3.07 × 10−5 mm3·N−1·m−1 to 4.94 × 10−6 mm3·N−1·m−1. Notably, the FeCrVMnTi2.0 coating demonstrated excellent wear resistance that can be attributed to the solid solution strengthening effect of Ti. These findings underscore the pivotal role of Ti in enhancing the wear resistance of the coatings.

Influence of cooling bed temperature on microstructural, mechanical properties and surface quality of high-strength seismic-resistant rebar

High-strength seismic-resistant rebar is essential in construction engineering, yet balancing its strength, plasticity, seismic resistance, and surface quality poses challenges. This research explores niobium-vanadium-nitrogen composite reinforced steel, examining how cooling bed temperature affects its microstructure, mechanical properties, and surface quality using advanced microscopy techniques. The research reveals that the steel's microstructure primarily consists of ferrite and pearlite. As cooling bed temperatures decrease, both the proportion and colony size of pearlite, along with ferrite size, show a declining trend. Specifically, reducing the cooling bed temperature from 1100 °C to 900 °C results in a decrease in yield strength, tensile strength, and tensile-to-yield strength ratio by 6 MPa, 27 MPa, and 0.03, respectively. Meanwhile, elongation after fracture, total elongation at maximum force, and strength-ductility balance improve by 3.8%, 1.5%, and 1.93%, respectively. At a cooling bed temperature of 1100 °C, significant blistering occurs on the steel surface. Significant blistering at 1100 °C vanishes at 1000 °C and 900 °C, with diminished silicon enrichment in the surface oxide scale. A cooling bed temperature of 1000 °C ± 20 °C is recommended for optimal performance. This study provides a temperature control strategy for the properties of high-strength seismic-resistant rebar rated at 650 MPa and above, contributing valuable insights to the field of advanced construction materials.

Inhibitory Effect of Fennel Fruit Essential Oil and Its Main Component Anethole of Corrosion on Steel Plates in 1 M HCL

Corrosion worldwide causes large losses of metal, which is why various ways are being sought to slow it down. The aim of this study was to investigate the inhibitory effect of fennel fruit essential oil (Foeniculum vulgare Mill.) and its main component anethole. The inhibitory effect of three different concentrations of the fennel essential oil and anethole (1.0 mL/L, 1.5 mL/L, and 2.5 mL/L) in a solution of 1 M HCl at 298 K for 6 h on a sheet of low-carbon steel was investigated. The inhibitory effect was established using gravimetric methods evaluating weight loss, corrosion rate, and inhibition efficiency, as well as electrochemical methods. In gravimetric studies, the inhibition effect of the inhibitors fennel essential oil and isolate anethole at a concentration of 2.0 mL/L was 70.85% and 45.86%, respectively. The anodic polarization curve data at 298 K demonstrate that the anethole and fennel essential oil adsorption on the metal surface creates a barrier that hinders hydrogen ions’ access and prevents them from being reduced on the steel surface’s cathode sites. Fennel essential oil acting as a mixed type-inhibitor can replace synthetic organic substances and could become an alternative to be used as environmental corrosion inhibitors.

Behavior of Retained Austenite and Carbide Phases in AISI 440C Martensitic Stainless Steel under Cavitation

In this work emphasis was given to determine the evolution of the retained austenite phase fraction via X-ray diffractometry technique in the as-hardened AISI 440C martensitic stainless steel surface subjected to cavitation for increasing test times. Scanning electron microscopy results confirmed the preferential carbide phase removal along the prior/parent austenite grain boundaries for the first cavitation test times on the polished sample surface during the incubation period. Results suggest that the strain-induced martensitic transformation of the retained austenite would be assisted by the elastic deformation and intermittent relaxation action of the harder martensitic matrix on the austenite crystals through the interfaces between both phases. In addition, an estimation of the stacking fault energy value on the order of 15 mJ m−2 for the retained austenite phase made it possible to infer that mechanical twinning and strain-induced martensite formation mechanisms could be effectively presented in the studied case. Finally, incubation period, maximum erosion rate, and erosion resistance on the order of 7.0 h, 0.30 mg h−1, and 4.8 h μm−1, respectively, were determined for the as-hardened AISI 440C MSS samples investigated here.

Role of sodium citrate in electrochemical behavior of reinforcing steel exposed to carbonated alkali-activated fly ash contaminated with chloride ions

Alkali-activated fly ash (AAFA) is considered as a promising alternative to ordinary Portland cement (OPC). However, the lack of calcium hydroxide in AAFA leads to an increased susceptibility to carbonation, thereby resulting in a decreased alkalinity of pore solutions in AAFA and significantly impacting the stability of steel passive films. To improve the corrosion resistance of steel in carbonated AAFA environments, sodium citrate was used as an environmentally-friendly corrosion inhibitor with three carboxylate groups. In this context, the corresponding electrochemical behavior of steel exposed to carbonated AAFA solutions with different concentrations of citrate was studied. In spite of the detrimental effect on the initial passivation behavior, sodium citrate was found to effectively improve the corrosion resistance to chloride attack for steel owing to a synergistic inhibition effect of adsorption film and precipitates on the steel surface. In addition, the correlation of citrate concentration and inhibition mechanism in carbonated AAFA solutions was revealed.

Exploring the adsorption of 4,4’-[oxalylbis(imino)]bis(2-hydroxybenzoic acid) layer at steel/biogasoline interface by the combined electrical-optical-simulation approach

Reactions at the steel/biogasoline interface trigger the adsorption of 4,4’-[Oxalylbis(imino)]bis(2-hydroxybenzoic Acid) (ODA) layer on the steel surface, thereby activating a mechanism that inhibited the early reactions. Exploring the conditionally deposited ODA layer requires a combined approach, including electrical, optical, and simulation techniques to track the film development and coating characteristics over time, and with the assistance of atomic force microscopy, quantum chemistry (DFT), and molecular dynamics (MD) simulations to reveal the adsorption mechanism of the ODA layer at steel/biogasoline interface. The four experimental ODA concentrations were conducted, related to the simulated un-coverage, undersaturated-, saturated-, and oversaturated-coverage model of the adsorbate on the adsorbent. The EC-RS data examines surface compositions and their distribution, coating/solution interface, and coating/substrate adhesion by, respectively, Raman spectroscopy (RS), electrochemical impedance spectroscopy (EIS), and current density—potential (I-V) scan. Namely, RS pointed out that an organic layer was established when ODA was added to the simulated biogasoline. EIS results revealed insulator behaviors of the ODA layer at the solid–liquid interface, limiting the charge transfer between the steel substrate and the biogasoline. I-V results showed an increase in surface current density and a decrease in surface polarization resistance of the coating with the rise in ODA concentration. The AFM morphology profile verified the degradation of the sample’s surface when exposed to biogasoline and the minimization of surface damage by ODA addition through adsorption. The simulation findings revealed that the adsorption of ODA on steel preferred physisorption, reaching the most stable state at a specified temperature and ODA concentration. The adsorption mechanism follows the Generalized Langmuir isotherm. The adsorbate (ODA molecules) can produce a transition phase with the steel substrate surface, which modifies the surface thermodynamic characteristics. The combined electro-optical-simulation technique can be applied to investigate various surface phenomena (reactions, catalyzes, adsorption). It especially helps to understand the protective mechanism of inhibitors in different media.

Effect of Crevice Size on Crevice Corrosion of N80 Carbon Steel in CO2-Saturated NaCl-HAc Solution.

The effect of crevice size on the crevice corrosion of N80 carbon steel was investigated by electrochemical measurements and surface analysis in a CO2-saturated NaCl-HAc solution. The N80 carbon steel exhibits a high susceptibility to crevice corrosion in this environment, which can be initiated immediately without an induction period for specimens with crevice sizes of 100 μm, 300 μm, and 500 μm. Typically, crevice solutions become more acidic during crevice corrosion; however, in this study, the crevice solution became alkaline, resulting in galvanic corrosion between the inner and outer steel surfaces and leading to severe crevice corrosion. The pH levels of the crevice solution for specimens with 100 μm and 300 μm crevice sizes are similar, but both are notably higher than that of the specimen with a 500 μm crevice size. As a result, there is no significant difference in the crevice corrosion phenomenon between specimens with 100 μm and 300 μm crevice sizes, but it is more severe than in the specimen with a 500 μm crevice size.

Study on the Scale and Corrosion Inhibition Effect of Curcumin‐Based Novel Polymers

AbstractThe curcumin‐malic acid‐aspartic acid polymer (PCMA) as a new water treatment agent was prepared by solid phase synthesis of curcumin, malic acid and aspartic acid. The static scale inhibition experiments showed that PCMA can inhibit CaCO3 and CaSO4 scale formation by 100.0 % and had excellent scale inhibition effect under various experimental conditions. The mechanism of action of PCMA was obtained by X‐ray diffraction, scanning electron microscope and molecular dynamics simulation. Electrochemical test showed that PCMA is an anodic corrosion inhibitor that achieves 93.1 % corrosion inhibition by forming a protective film on the surface of Q235 carbon steel. Besides, fluorescence spectra proved that PCMA has stable fluorescence intensity.