Multidimensional insights into the corrosion inhibition of 3,3-dithiodipropionic acid on Q235 steel in H2SO4 medium: A combined experimental and in silico investigation

Novel chitosan-oligosaccharide derivatives as fluorescent green corrosion inhibitors for P110 steel

In the exploitation of seawater resources, the transported pipelines are frequently corroded, resulting in economic losses and environmental pollution. The development of corrosion inhibitors is an effective measure to mitigate the corrosion of metals in seawater. In this work, novel chitosan oligosaccharide derivatives (CF) were synthesized as fluorescent eco-friendly corrosion inhibitor by modifying fluorescent monomers. The characterization of CF revealed excellent fluorescence intensity, promising the potential for on-line detection. The inhibition performance of CF on P110 in 3.5 wt% NaCl solution was investigated through experimental evaluation and theoretical analysis. The electrochemical measurements indicated that the corrosion inhibition efficiency was increased from 61.00 % to 91.19 % with the introduction of fluorane. Adsorption isotherm and XPS analysis demonstrated that CF is designed to protect metal by forming the composite film on P110 through physical and chemical adsorption. In addition, theoretical calculations revealed differences in the interaction energies, radial distribution functions and diffusion coefficients of inhibitors on the Fe (110) surface. These theoretical results aligned with the experiments and confirmed the excellent ability of CF in metal corrosion protection from the molecular perspective. This new chitosan derivative provides new possibilities for the development of the green composite inhibitor that allows on-line detection.

Investigation of biodegradable surfactant as a corrosion inhibitor to the cold rolled steel in the membrane separation device process

The membrane process is an effective way to realize resource reutilization. Most membrane devices are made of cold-roll steel (CRS), which is easy to corrode when operating in acid conditions. Herein, the biodegradable surfactant dodecyl dimethyl betaine (BS-12) was used as the inhibitor to protect the CRS in the trichloroacetic acid (TCA) solution. The long-term stability membrane tests showed that adding BS-12 will not harm the membrane performance. The weight loss experiments proved that adding BS-12 with trace amount (10 mg·L-1) endowed the CRS with good inhibition efficiency (95.3 %). The electrochemical tests indicated that the mixed inhibitor- BS-12 works by inhibiting the anode and cathode simultaneously, and the polarization resistance increased to 21 times. The SEM, AFM, and CLSM tests proved that adding BS-12 enabled the CRS surface to remain stable. The FTIR and XPS tests proved that BS-12 adsorbed on the CRS surface via physical and chemical adsorption. The theoretical calculations proved the horizontal adsorption of BS-12 on the CRS surface and the existence of the electron transfer within the BS-12 and CRS. The BS-12 showed great potential in the CRS inhibition of the membrane separation and purification processing.

Corrosion inhibition ability of L-tryptophan and 5-hydroxy-L-tryptophan for mild steel: a combination of experimental and theoretical methods

An investigation into the corrosion inhibition properties of L-tryptophan (TP) and 5-hydroxy-L-tryptophan (5-OH-TP) for mild steel in a 1.0 M HCl acidic medium was conducted using experimental and theoretical methods. Results obtained from polarization curve measurements reveal that TP and 5-OH-TP are effective mixed-type inhibitors, exhibiting the highest inhibition efficiencies of 91.22% and 94.05%, respectively, at a temperature of 293 K and a concentration of 10-2 M. However, their inhibition efficiencies gradually decline with increasing temperature, reaching the lowest values of 70.65% for TP and 73.55% for 5-OH-TP at a concentration of 10-4 M and a temperature of 323 K. The adsorption of TP and 5-OH-TP on the steel surface follows the Langmuir isotherm, suggesting monolayer adsorption. Electrochemical impedance spectroscopy analysis indicates that the adsorbed inhibitors form a protective film, effectively shielding the steel from corrosive agents in the solution. Notably, 5-OH-TP consistently exhibits superior inhibition efficiency compared to TP, attributed to the presence of polar OH groups that facilitate stronger bonding of the inhibitor molecule with the metal surface. Quantum chemical parameters and molecular dynamics simulations further confirm the superior corrosion inhibition ability of 5-OH-TP over TP in acidic environments. In particular, the binding energies of protonated TP at the N3 position and 5-OH-TP at the N4 position are 556.40 and 579.27 kJ mol-1, respectively.

Turning Waste into Treasure: Invasive Plant Ambrosia trifida L Leaves as a High-Efficiency Inhibitor for Steel in Simulated Pickling Solutions

High toxicity is the main reason for the limited application of traditional corrosion inhibitors. Herein, it is critical to find a green, efficient, and long-term stable alternative substitute for the hazardous and conventional corrosion inhibitor. Ambrosia trifida L is widely distributed in fields and riverside wetlands as an invasive plant in China. According to the concept of turning waste into treasure, the extract of Ambrosia trifida L leaves (ATL) has the potential to address this issue due to its natural origin and abundant presence of heterocyclic organics. Therefore, ATL, as a green corrosion inhibitor, is prepared for the first time via a simple water-based extraction method. FT-IR (Fourier transform infrared spectroscopy) and UV-Vis (UV-visible) indicate that ATL extract contains abundant heterocyclic organics with conjugated structures, which exhibit the potential to become a high-efficiency inhibitor. Notably, the active sites of ATL molecules and their interaction with Q235 steel at the molecular/atomic level are revealed via theoretical calculations. The highest Ebinding value observed for the major components in the ATL extract is 259.66 kcal/mol, implying a significant adsorption capacity. The electrochemical results verify that microdose ATL extract can prominently inhibit steel corrosion, and the highest inhibition efficiency (η) is 97.5% (1000 mg/L). Following immersion for 24 h, the η value is enhanced to 99.0%, indicating a reliable and long-term ATL extract protection film is formed on the steel surface in harsh acidic solutions. The results of the weight loss, SEM (scanning electron microscope), and LSCM (laser scanning confocal microscopy) are consistent with the above conclusions. Finally, this study anticipates providing theoretical support for developing novel green plant extract inhibitors and aiding in their application in industrial pickling environments.

Halogen-Free Functional Quaternary Ammonium-Based Ionic Liquid as an Ecofriendly Corrosion Inhibitor for Q235 Steel in Acids

A halogen-free quaternary ammonium-based ionic liquid functionalized with benzotriazole, BTA-16-BTA, was synthesized. Its anticorrosion effects on Q235 steel were evaluated in two different acids (6 M HCl or 1 M H3PO4) by weight loss and electrochemical tests. BTA-16-BTA shows the best performance at 30 °C with the highest inhibition efficiencies of 98.84% in 6 M HCl and 96.40% in 1 M H3PO4. The adsorption behavior of BTA-16-BTA molecules on Q235 steel in HCl solution obeys the Langmuir isotherm with an adsorption energy of about -40 kJ·mol-1, which implies chemisorption. Quantum chemistry calculation indicates that the chemical adsorption originated from the injection of π-electrons from inhibitor molecules into empty 3d orbitals of Fe atoms. The tight adsorption of inhibitor molecules and associated dehydration of the steel surface promoted the corrosion inhibition in HCl solutions. In H3PO4 solutions, passivation by phosphate anions and adsorption of inhibitor molecules contributed synergistically to the excellent anticorrosion performance.

Regulating the Anode Corrosion by a Tryptophan Derivative for Alkaline Al-Air Batteries

Screening a green corrosion inhibitor that can prevent Al anode corrosion and enhance the battery performance is highly significant for developing next-generation Al-air batteries. This work explores the non-toxic, environmentally safe, and nitrogen-rich amino acid derivative, N(α)-Boc-l-tryptophan (BCTO), as a green corrosion inhibitor for Al anodes. Our results confirm that BCTO has an excellent corrosion inhibition effect for the Al-5052 alloy in 4 M NaOH solution. An optimum inhibitor addition (2 mM) has increased the Al-air battery performance; the corrosion inhibition efficiency was 68.2%, and the anode utilization efficiency reached 92.0%. The capacity and energy density values increased from 990.10 mA h g^-1 and 1317.23 W h kg^-1 of the uninhibited system to 2739.70 mA h g^-1 and 3723.53 W h kg^-1 for the 2 mM BCTO added system. The adsorption behavior of BCTO on the Al-5052 surface was further explored by theoretical calculations. This work paves the way for constructing durable Al-air batteries through an electrolyte regulation strategy.

Benzethonium chloride as a tungsten corrosion inhibitor in neutral and alkaline media for the post-chemical mechanical planarization application

The cleaning solution for the post-chemical mechanical planarization (post-CMP) process of tungsten in neutral-alkaline media requires corrosion inhibitors as an additive, especially for advanced devices where the device node size shrinks below 10 nm. In the present study, the corrosion inhibition performance of benzethonium chloride (BTC) is evaluated in neutral-alkaline conditions. The electrochemical impedance spectroscopy (EIS) analysis showed ∼ 90 % of corrosion inhibition efficiency with an optimum concentration of 0.01 wt% BTC at both pH 7 and 11. Langmuir adsorption isotherm, frontier molecular orbital theory, molecular simulation, contact angle, precipitation study, and X-ray photoelectron spectroscopy analysis were performed to identify the inhibition mechanism of the BTC molecule on the W surface. Based on the proposed mechanism, the electrostatic attraction between the positively charged N atom in the BTC molecule and the negatively charged W surface initiates the adsorption of the molecule. The high dipole moment and large molecular size enhance the physical adsorption of the molecule to the surface. In addition to this, the adsorption isotherm analysis shows that possible chemical interaction with a moderate value of Gibbs free energy change of adsorption exists between the W and BTC molecule. The excellent corrosion inhibition efficiency of BTC on W is confirmed by the frontier molecular orbital theory and molecular dynamic simulation analysis.

Chitosan derivatives as promising green corrosion inhibitors for carbon steel in acidic environment: Inhibition performance and interfacial adsorption mechanism

Among the biodegradable polysaccharide, chitosan is widely present in the cell membranes of bacteria and algae and in the cell walls of higher plants. As a promising biopolymer, chitosan has great potential as eco-friendly corrosion inhibitor. Herein, two synthetic chitosan derivatives (N-phenylthiourea chitosan (CS-PT), N-phenyl-O-benzylthiourea chitosan (CS-PT-Bn)) were investigated as high-efficient acidic corrosion inhibitors to deal with the corrosion issue of carbon steel. The anti-corrosion property of the chitosan derivatives was explored by electrochemical tests, surface characterization and theoretical calculations. The experimental results indicate that both CS-PT and CS-PT-Bn present high-efficient inhibition performance with the inhibition efficiency of 98.4% and 98.5% at the concentration of 100 mg/L, respectively. Their adsorption mechanism at steel/solution interface is revealed by quantum chemical calculations, molecular dynamics (MD) and GFN-xTB calculations. It is found that CS-PT and CS-PT-Bn adsorb at the steel/solution interface by forming Fe-N and Fe-S bonds. Compared to CS-PT molecule, the introduction of benzyl group endows CS-PT-Bn molecule with stronger electrostatic effect and hydrophobicity, which favors the interfacial adsorption of CS-PT-Bn molecule on carbon steel surface.

Theoretical and electrochemical evaluation of tetra-cationic surfactant as corrosion inhibitor for carbon steel in 1 M HCl

Recently, scientist study the role of surfactants for carbon steel corrosion protection. In the present study, newly tetra-cationic surfactant (CS4: 1,N1'-(ethane-1,2-diyl) bis (N1, N2-didodecyl-N2-(2- (((E)-3-hydroxy-4-methoxy-benzylidene)amino)ethyl)ethane-1,2-diaminium) chloride) based on Schiff-base compound(5,5'-((1E,17E)-2,5,8,11,14,17-hexaazaoctadeca-1,17-diene-1,18-diyl)bis(2-methoxyphenol) was synthesised, purified and characterized using FTIR and ¹HNMR spectroscopy. The synthesized Tetra-cationic surfactant (CS4) was evaluated as anti-corrosion for carbon steel (CS-metal) in aggressive 1 M HCl using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques (PDP). CS4 compound had a good surface-active property by reducing the surface tension as a result to the hydrophobic chains role. The prepared CS4 behaved as hybrid inhibitor (mixed-type) by blocking the anodic and cathodic sites. CS4 exhibited good inhibition efficiency reached 95.69%. The surface morphology of CS-metal was studied using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS)confirming the anti-corrosive effect of CS4 compound returned into the adsorption process of CS4 molecules over CS-metal which obeyed Langmuir adsorption isotherm. The inhibitive effect of CS4 was supported by theoretical quantum chemical studies using the density functional theory (DFT), Monte Carlo (MC) and Molecular Dynamic (MD) simulation.

Date Palm Seed Extract for Mild Steel Corrosion Prevention in HCl Medium

The inhibition effects of the date palm seed extract corrosion of mild steel in 0.5 M HCl at different concentrations are investigated by potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy (EIS) and weight loss tests. Additionally, this study provides a fundamental understanding of aromatic adsorption on iron (Fe) surfaces. Furthermore, the surface morphology and the extracts are performed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The maximum inhibition efficiency of 95, 96, and 91% were realised at 1400 mg/L for PDP, EIS, and weight loss, respectively. The inhibitive action of the DPS extract against mild steel corrosion in an acid solution has been supported by SEM analysis. The FTIR showed that the extract contained hydroxyl (−OH) and methoxyl (−OCH3) functional groups. The DFT depicted the adsorption sites at the oxygen (O) and carbon (C) atoms as deduced from the Fukui functions, Mulliken atomic charge, and the highest occupied molecular orbital-lowest occupied molecular orbital (HOMO-LUMO) analysis. The DPS preferred to form chemical bonds by donating electrons to the Fe surface. The coordinate bonds between the O and C atoms and the metal surface resulted in a high inhibition efficiency value. In conclusion, date palm seed extract is an effective inhibitor to protect mild steel from corrosion in an acidic medium.

Metals and metal oxides polymer frameworks as advanced anticorrosive materials: design, performance, and future direction

Metals (Ms) and metal oxides (MOs) possess a strong tendency to coordinate and combine with organic polymers to form respective metal–polymer frameworks (MPFs) and metal oxide polymer frameworks (MOPFs). MPFs and MOPFs can be regarded as composites of organic polymers. MPFs and MOPFs are widely used for industrial and biological applications including as anticorrosive materials in the aqueous phase as well as in the coating conditions. The presence of the Ms and MOs in the polymer coatings improves the corrosion inhibition potential of MPFs and MOPFs by improving their self-healing properties. The Ms and MOs fill the micropores and cracks through which corrosive species such as water, oxygen, and corrosive ions and salts can diffuse and destroy the coating structures. Therefore, the Ms and MOs enhance the durability as well as the effectiveness of the polymer coatings. The present review article is intended to describe the corrosion inhibition potential of some MPFs and MOPFs of some most frequently utilized transition metal elements such as Ti, Si, Zn, Ce, Ag, and Au. The mechanism of corrosion inhibition of MPFs and MOPFs is also described in the presence and absence of metal and metal oxides.

Experimental and Theoretical Studies toward Superior Anti-corrosive Nanocomposite Coatings of Aminosilane Wrapped Layer-by-Layer Graphene Oxide@MXene/Waterborne Epoxy

Herein, layer-by-layer MXene/graphene oxide nanosheets wrapped with 3-aminopropyltriethoxy silane (abbreviated as F-GO@MXene) are proposed as an anti-corrosion promoter for waterborne epoxies. The GO@MXene nanohybrid is synthesized by a solvothermal reaction to produce a multi-layered 2D structure without defects. Then, the GO@MXene is modified by silane wrapping under a reflux reaction, in order to achieve chemical stability and to create active sites on the nanohybrid surface for reaction with the polymer matrix of the coating. The organic coating modified with 0.1 wt % F-GO@MXene has revealed superior corrosion protection efficiency than the organic coatings modified with either F-GO or F-MXene nanosheets. The impedance modulus at low frequency for the pure epoxy, epoxy/F-MXene, epoxy/F-GO, and epoxy/F-GO@MXene coatings is 4.17 × 10⁵, 5.5 × 10⁸, 4.46 × 10⁸, and 1.14 × 10¹⁰ Ω·cm² after 30 days of immersion in the corrosive media, respectively. The remarkable anti-corrosion property is assigned to the intense effect of the nanohybrid on the barrier performance, surface roughness, and adhesion strength of the epoxy coating. The complemental analysis based on first-principles density functional theory reveals that the adhesion strength related to the silane functional groups in its complexes follows the order F-GO@MXene > F-MXene > F-GO. The enhanced stabilization predicted on the GO@MXene nanohybrid ultimately stems from the combined role of the electrostatic and van der Waals forces, suggesting an increase in the penetration path of the corrosive media.

First-Principles Calculations to Investigate the Oxidation Mechanism of Pristine MoS2 and Ti-Doped MoS2

Generally, MoS2 is easily oxidized when exposed to oxygen, and the antioxidation mechanism of MoS2 is still a challenge. Thus, more efforts were made to greatly improve its antioxidation performance. It was reported that the Ti atom doped with MoS2 was treated as the effective method to enhance its antioxidation performance; however, the detailed antioxidation mechanism was not well understood. Superior to experimental methods, the first-principles method could provide deep insight into the atomic information and serve as a useful tool to gain an understanding of the antioxidation mechanisms of the doped MoS2; thus, the antioxidation behavior of the Ti-doped MoS2 was investigated in detail using first-principles calculations. However, an opposing conclusion was obtained from the calculated results compared to the previous experimental results; that is, the incorporation of the Ti atom was not helpful for improving the antioxidation performance of MoS2. The strange phenomenon was well probed and discussed in detail, and understanding the oxidation mechanism of the Ti-doped MoS2 would be helpful for expanding its applications in the ambient atmosphere.

Electrochemical, Isotherm, and Material Strength Studies of Cucumeropsis mannii Shell Extract on A515 Grade 70 Carbon Steel in NaCl Solution

In this study, corrosion inhibition efficiency of Cucumeropsis mannii shell extract (CMSE) was tested on A515 Grade 70 carbon steel in 1.0 M NaCl solution. Potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and weight loss (WL) measurements were used to investigate the inhibition efficiency. Scanning electron microscopy, Fourier transform infrared spectroscopy, atomic adsorption spectroscopy, and energy dispersive spectroscopy were used to characterize the carbon steel and extract. PDP and EIS measurements revealed maximum inhibition efficiency of 91.2% and 92.2%, respectively. Tafel plot confirmed inhibitor to be a mixed type. A monolayer adsorption of CMSE molecules occurred spontaneously by physisorption. Polarization resistance increased with increasing inhibitor concentration. WL measurement revealed decrease in corrosion rate with increasing concentration of corrosion inhibitor. Maximum Young modulus and hardness of 202.4 GPa and 112.3 BHN, respectively, were recorded for the carbon steel at a minimum corrosion rate and load. Pitting and uniform corrosion were formed on the carbon steel in the absence of CMSE. CMSE contains –OH, –OCH3, and –C-NH3 as active functional groups. In conclusion, Cucumeropsis mannii shell extract acted excellently as corrosion inhibitor for A515 Grade 70 carbon steel in 1.0 M NaCl.

Thiourea derivatives acting as functional monomers of As(Ш) molecular imprinted polymers: A theoretical and experimental study on binding mechanisms

Thiourea derivatives are expected to be potential monomers of As(Ш) molecular imprinted polymers (MIPs) which are used to specifically recognize As(Ш). However, the specific recognition and binding mechanisms between template and monomers are unclear, which limits the practical applications of MIPs in As(Ш)detection. In this work, density functional theory (DFT) calculations, molecular dynamics (MD) simulations and experimental methods were jointly applied to explore the binding interactions between H₃AsO₃ and thiourea derivatives and environmental factors influences, aiming to find out the best monomer and optimal preparation conditions for H₃AsO₃ MIPs. Among five monomer candidates, (2, 6-difluorophenyl) thiourea (FT) was calculated to be the most potential one, while allyl thiourea (AT) was the second choice. Configurations of the most stable binding complexes were found out. The optimal solvent was found to be toluene and the bindings were more favorable at pH 7.5 in aqueous solution. Besides, EGDMA was proved as the best cross-linker with the optimal ratio of template: monomer: cross-linker= 2:3:20. Moreover, the binding interactions were identified to be hydrogen bonds, and the non-covalent nature was revealed. These findings provide references for efficient design and preparation of good-performance H₃AsO₃ MIPs, which can be used to detect and remove As(Ш) from environment.

In Silico Approaches for Some Sulfa Drugs as Eco-Friendly Corrosion Inhibitors of Iron in Aqueous Medium

This paper addresses the prediction of the adsorption behavior as well as the inhibition capacity of non-toxic sulfonamide-based molecules, also called sulfa drugs, on the surface of mild steel. The study of the electronic structure was investigated through quantum chemical calculations using the density functional theory method (DFT) and the direct interaction of inhibitors with the iron (Fe) metal surface was predicted using the multiple probability Monte Carlo simulations (MC). Then, the examination of the solubility and the environmental toxicity was confirmed using a chemical database modeling environment website. It was shown that the presence of substituents containing heteroatoms able to release electrons consequently increased the electron density in the lowest unoccupied and highest occupied molecular orbitals (LUMO and HOMO), which allowed a good interaction between the inhibitors and the steel surface. The high values of EHOMO imply an ability to donate electrons while the low values of ELUMO are related to the ability to accept electrons thus allowing good adsorption of the inhibitor molecules on the steel surface. Molecular dynamics simulations revealed that all sulfonamide molecules adsorb flat on the metal surface conforming to the highly protective Fe (1 1 0) surface. The results obtained from the quantum chemistry and molecular dynamics studies are consistent and reveal that the order of effectiveness of the sulfonamide compounds is P7 > P5 > P6 > P1 > P2 > P3 > P4.

Long-Term Corrosion Behavior of Strong and Ductile High Mn-Low Cr Steel in Acidic Aqueous Environments

To expand the industrial applicability of strong and ductile high Mn-Low Cr steel, a deeper understanding and mechanistic interpretation of long-term corrosion behavior under harsher environmental conditions are needed. From this perspective, the long-term corrosion behaviors of 24Mn3Cr steel under acidic aqueous conditions were examined through a comparison with conventional ferritic steels using the electrochemical measurements (linear polarization resistance and impedance), and immersion test followed by the metallographic observation of corrosion morphologies. In contrast to conventional ferritic steels, 24Mn3Cr steel, which had the lowest corrosion resistance at the early immersion stages (i.e., the highest corrosion current density (i_corr) and lowest polarization resistance (R_p)), showed a gradual increase in corrosion resistance with prolonged immersion. Owing to the slow formation kinetics of (Fe,Cr)-enriched oxide scale, a longer incubation time for ensuring a comparatively higher corrosion resistance is required. On the other hand, conventional ferritic steels had an oxide scale with less densification and a lower elemental enrichment level that did not provide an effective anti-corrosion function. From the results, this study can provide significant insight into the industrial applicability of the high Mn-low Cr steel by providing the mechanistic interpretation of corrosion behaviors in acidic aqueous environments.

Theoretical, chemical, and electrochemical studies of Equisetum arvense extract as an impactful inhibitor of steel corrosion in 2 M HCl electrolyte

A new type of Equisetum arvense aerial part (EAAP) extract was ready to be tested as a corrosion inhibitor for steel-based parts in Multi-stage flash (MSF) segments while the segments were being acid cleaned. The EAAP extract was identified using Fourier-transform infrared (FTIR) and High-performance liquid chromatography (HPLC). When compared to the specimen exposed to blank solution, EAAP extract molecules covered about 97% of the carbon steel surface in 2 M HCl solution, and the corrosion rate was reduced to 0.58 ± 0.02 μg cm^-2 h^-1 at 300 mg l^-1. EAAP extract tends to have a blended impact on both anodic and cathodic sites on the surface of carbon steel. The thermodynamic activation factors are substantially higher in the presence of extract solution than in the absent of extract, demonstrating that the carbon steel surface would corrode slowly in the presence of EAAP extract. Theoretical models were used to validate the adsorption of EAAP extract on steel surfaces.

Insight into the anti-corrosion performance of two food flavors as eco-friendly and ultra-high performance inhibitors for copper in sulfuric acid medium

2,5-dihydroxy-1,4-dithiane (DDD) and 2,5-dimethy- [1.4] dithiane-2,5-diol (DTDD) two food flavors as environmentally-friendly inhibitors for Cu in 0.5 mol/L H₂SO₄ media were researched via theoretical calculation and experimental ways. Electrochemical measurement data showed that DDD and DTDD can exhibit high level anti-corrosion feature. The anti-corrosion efficiency of DDD and DTDD were as high as 99.6% and 98.9%, respectively. The atomic force microscope (AFM) and scanning electron microscope (SEM) tests showed that the Cu specimens were immersed in the H₂SO₄ with 5 mM DDD and DTDD for 30 h at the 298 K, and the Cu specimen surface was still smooth. Besides, the adsorption of DDD and DTDD at the interface of Cu/solution was comply with Langmuir adsorption. Theoretical calculation data showed that DDD exhibit more ascendant anti-corrosion feature than DTDD.