Tafel Curves Research Articles

Efficient hydrogen production via overall water splitting using CuO/ZnO decorated reduced graphene oxide as bifunctional electrocatalyst

Conjunction of ‘n’ and ‘p’-type materials have gained considerable attention for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) as potential substitutions to noble metal based nanomaterials. Current work has been designed to synthesize mixed-phase nanocomposite (NC) based on copper (CuO) and zinc oxide (ZnO) nanowires (NWs) and reduced graphene oxide (rGO). A facile chemical reduction method was used for the preparation of NWs, rGO were prepared using modified Hummer's method and lastly CuO/ZnO NWs were grafted on rGO to fabricate NC (CuO/ZnO@rGO) by wet-chemical approach. Characterization techniques were employed to confirm the formation as well as different morphological features of NC. Noticeable D and G bands in Raman spectrum confirmed the formation of NC and EDAX confirmed the presence of C, O, Zn and Cu. XRD analysis has confirmed hexagonal wurtzite structure of NC with a crystallite size of 10.1392 nm. Synthesized material was then investigated for OER and HER in an alkaline medium. As electrocatalyst, NC exhibited overpotential (OP) of 1.678 V to accomplish 10 mA/cm−2 current density (J) in OER and −358 mV (10 mA/cm−2) for HER respectively. Tafel curves of CuO/ZnO@rGO in OER (42 mV dec−1) and HER (270 mV dec−1) were found similar enough to others studies. Proliferated electrochemical activities are responsible for such a lower OP and Tafel slope values that may be due to electronic couplings of copper and zinc, or the homogenous distribution of both the metal oxides which gives polydispersity in their structure as confirmed by SEM images. Promising results of the current study indicated high-performance of synthesized electrocatalyst. Further studies can be designed to evaluate the efficiency of different combinations of noble/non-noble metals or metal oxides with rGO as potential candidate for electrochemical reactions.

Improved bioactivity and corrosion resistance of NbO containing plasma electrolytic oxidation coating on ZM21 Mg alloy

ABSTRACT The present study reports the effect of niobium oxide (NbO) phase on the microstructure, corrosion, and bioactivity of coating on ZM21 Mg alloy by plasma electrolytic oxidation (PEO) process. NbO containing coatings are obtained by adding Potassium Niobate (KNbO3) along with the base electrolyte system, while the base electrolyte system consisted of sodium phosphate (Na3PO4⋅12 H2O) and potassium hydroxide (KOH). X-Ray Diffraction (XRD) was used for phase analysis, and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) was employed to extract the microstructural features. Tafel curves were generated to study the corrosion behaviour, and bioactivity test was conducted in the simulated body fluid (SBF) for 14 days to study the bioactivity. XRD results revealed that the PEO coatings consisted of MgO phase, whereas the sample coated in the electrolyte containing KNbO3 showed NbO phase in addition to MgO phase. NbO containing coating showed higher corrosion resistance and excellent bioactivity.

Effects of rare earth oxides on wear resistance and corrosion resistance of 316L/TiC composite coating by laser cladding

In this paper, 316L/TiC composite coatings with different kinds of REOs (Y2O3, La2O3, CeO2, PrO2, Nd2O3) at identical contents (2%) were prepared on S355 marine steel using the laser cladding technology. The surface morphology, phase composition, microhardness, coefficient of friction curve (COF), Tafel curve and electrochemical impedance spectroscopy (EIS) impedance of the test specimens were studied with such instruments as scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffractometer, Vickers microhardness tester, friction and wear tester, and multi-channel electrochemical workstation. The results show that the coating with REO added owns increased thickness and is uniform and dense without such defects as crack, and hole. The microstructure evolution mechanism of the coating from the bottom up is as follows: Cellular crystal, planar crystal → columnar crystal → equiaxed crystal. The phase composition of the coating with REO added remains unchanged, and is still Ni–Cr–Fe austenite phase and TiC phase. Further comparison shows that the coating with Nd2O3 added owns improved hardness, with a mean hardness of 3 times that of the substrate, and has a COF decreasing to 0.69, with wear loss becoming small. The coating with Nd2O3 added has the largest Ecorr, the smallest Icorr, large Z value and phase angle, the greatest Rct, and an nct value of 1, indicating that the coating has dense passivation film and small corrosion tendency, with low corrosion rate. Therefore, this study provides reference experimental and theoretical bases for application of 316L/TiC composite coating with Nd2O3 added at 2% in surface strengthening and repair of steel for marine engineering equipment.

Synthesis and Characterization of Superhydrophobic Epoxy Resin Coating with SiO2@CuO/HDTMS for Enhanced Self-Cleaning, Photocatalytic, and Corrosion-Resistant Properties.

The exceptional corrosion resistance and combined physical and chemical self-cleaning capabilities of superhydrophobic photocatalytic coatings have sparked significant interest among researchers. In this paper, we propose an economical and eco-friendly superhydrophobic epoxy resin coating that incorporates SiO2@CuO/HDTMS nanoparticles modified with Hexadecyltrimethoxysilane (HDTMS). The application of superhydrophobic coatings effectively reduces the contact area between the metal surface and corrosive media, leading to a decreased corrosion rate. Additionally, the incorporation of nanomaterials, exemplified by SiO2@CuO core-shell nanoparticles, improves the adhesion and durability of the coatings on aluminum alloy substrates. Experimental data from Tafel curve analysis and electrochemical impedance spectroscopy (EIS) confirm the superior corrosion resistance of the superhydrophobic modified aluminum alloy surface compared to untreated surfaces. Estimations indicate a significant reduction in corrosion rate after superhydrophobic treatment. Furthermore, an optical absorption spectra analysis of the core-shell nanoparticles demonstrates their suitability for photocatalytic applications, showcasing their potential contribution to enhancing the overall performance of the coated surfaces. This research underscores the promising approach of combining superhydrophobic properties with photocatalytic capabilities to develop advanced surface modification techniques for enhanced corrosion resistance and functional properties in diverse industrial settings.

The Possibility of Using Barley Grains Extract as an Acidic Corrosion Inhibitor for Carbon Steel

تمت دراسة تأثير مستخلصات بذور الشعير على تآكل الفولاذ الكربوني في 1M حمض كلور الماء للتحقق من إمكانية استخدام كمثبط أخضر في عملية التنظيف وإزالة الترسبات الحمضية للمبادلات الحرارية، عند درجات حرارة مختلفة. أُجريت عمليات الاستخلاص باستخدام الايثانول والماء %50 حجماً، وبطريقتي النقع والأمواج فوق الصوتية. تمت دراسة آلية تأثير المثبط الذي أعطى أفضل كفاءة تثبيط، من خلال دراسة الامتزاز والتآكل بالطرق الكهروكيميائية (مخططات تافل، ومطيافية المقاومة الكهروكيميائية) والحسابات الترمودينامكية. أظهرت نتائج الدراسة عدم وجود تأثير لطريقة الاستخراج على سلوك التثبيط ، حيث أظهر التثبيط كدالة للتركيز زيادة معنوية في كفاءة التثبيط حتى التركيز 400 جزء في المليون ، ثم ظهرت مستقلة عنها في كلتا الطريقتين. ، ومع ذلك كانت درجة الحماية أعلى لمستخلص طريقة النقع عند التركيز 800ppm 87.01%) مقارنة بـ 80.56% لمستخلص الأمواج فوق الصوتية). أشارت دراسة آلية التثبيط لهذا المستخلص إلى إمكانية الامتزاز الكيميائي للمستخلص وإعادة لترتيب الشحنات في الطبقة المزدوجة الكهربائية . أبدت فعالية التثبيط ارتفاعاً مع درجة الحرارة.

Electrochemical analysis of the corrosion resistance of annealed steel with nickel coating in marine environment simulations: chronoamperometric and voltametric study

This study conducts a comprehensive investigation into the corrosion resistance of annealed steel wire, commonly used in marine construction, emphasizing its importance for the material's durability and functionality in such applications. An innovative approach was implemented by applying a Nickel (II) Chloride Hexahydrate coating through electrodeposition. This process was meticulously adjusted, varying critical parameters such as exposure time and electrical potential. To mimic marine corrosive conditions, a Sodium Chloride solution was used, allowing for a detailed comparative analysis between coated and uncoated samples. The evaluation was based on rigorous quantitative measurements of the wire's surface state and corrosion potential, using TAFEL curves for precise interpretation. The findings empirically demonstrated that the coating significantly enhances corrosion resistance, markedly outperforming untreated steel. These results reinforce the proposition of nickel electrodeposition as an effective and viable strategy for corrosion protection in marine industrial applications.

The Corrosion Resistance of Concrete-Filled Steel Tubes with the Assembly Unit of Na2MoO4 and Benzotriazole

Steel pipes are commonly used to strengthen the concrete’s load-bearing capacity. However, they are prone to corrosion in salt erosion environments. In this study, the influence of Na2MoO4 and benzotriazole on concrete-filled steel tubes’ corrosion performance is investigated. The steel pipes’ mass loss rates (MRs), ultrasonic velocity, electrical resistance, and the AC impedance spectrum and Tafel curves of concrete-filled steel tubes were used to characterize the degree of corrosion in the steel pipes. Scanning electron microscopy–energy-dispersive spectrometry and X-ray diffraction were used for studying the composition of steel pipe rust. The research results revealed that the NaCl freeze–thaw cycles (F-C) and NaCl dry–wet alternation (D-A) actions had a reducing effect on the mass and ultrasonic velocity of the concrete-filled steel tubes. After 300 NaCl F-C and 30 NaCl D-A, the MRs were 0%~0.00470% and 0%~0.00666%. The corresponding ultrasonic velocities were 0%~21.1% and 0%~23.6%. When a rust inhibitor was added, the results were the opposite. The MRs decreased by 0%~80.3% and 0%~81.6% with the added Na2MoO4 and benzotriazole. Meanwhile, the corresponding ultrasonic velocities were 0%~8.1% and 0%~8.3%. The steel tubes were corroded after 300 NaCl F-C and 30 NaCl D-A. The addition of rust inhibitors improved the corrosion resistance of the concrete-filled steel tubes by increasing the electrical resistance before NaCl erosion. The corrosion area rate decreased by using the rust inhibitors. The corrosion resistance effect of benzotriazole was higher than that of Na2MoO4. The concrete-filled steel tube with an assembly unit comprising 5 kg/m3 of Na2MoO4 and 15 kg/m3 of benzotriazole had the best corrosion resistance under the erosion induced by NaCl F-C and D-A. Rust inhibitors reduced the content of iron-containing crystals and iron elements. The specimens with 5 kg/m3 Na2MoO4 and 15 kg/m3 benzotriazole had the lowest concentration of iron-containing crystals and iron elements.

Growth mechanism and corrosion resistance of layered double hydroxide film on magnesium alloy without external addition of magnesium and aluminum salts

This study first reports in-situ growth of layered double hydroxide (LDH) coatings on magnesium alloy surface without external adding magnesium (Mg2+) and aluminum (Al3+) salts with the aid of a chelating agent at ambient pressure and relatively low temperature (≤ 95 °C). The morphology, composition, and structure of the deposits on the magnesium alloy surface were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), etc. Combined with open-circuit potential (OCP)-time curves, the mechanism of growth and formation process of the LDH film was proposed. The process was divided into four stages, i.e., dissolution of the Mg substrate, formation of Mg(OH)2, nucleation of LDH by transformation of Mg(OH)2 phase, and growth of LDH phase. The corrosion resistance of the LDH coating before and after treatment with vanadate and tungstate was evaluated through electrochemical impedance spectroscopy (EIS), Tafel curves, and immersion measurements. Compared to bare magnesium alloy and pristine and vanadate-treated LDH, the LDH coating modified with tungstate exhibited the most effective corrosion protection for magnesium alloy AZ31, without obvious signs of corrosion after exposure to a 3.5 wt% NaCl solution for seven days.

Justicia brandegeeana as a green corrosion inhibitor for carbon steel in sulfuric acid

ABSTRACT The anti-corrosive effect of the extract in ethanol of Justicia brandegeeana (Acanthaceae) against carbon steel AISI 1020 in sulfuric acid medium 1 mol L−1 was investigated. In addition to the effect of seasonality, several techniques were used to investigate the anti-corrosive activity, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), linear polarization resistance (LPR), and weight loss. The chelating effect was analyzed by UV-Vis spectrophotometry and the surface was analyzed by scanning electron microscopy (SEM). The results showed that the inhibition efficiency is dependent on the concentration of the extract, reaching its maximum at 1500 ppm and despite having good thermal stability (82.41% inhibition at 70°C), it decreases with increasing temperature, indicating a physisorption behavior. The extract obeyed the Langmuir isotherm and the Tafel curves characterized it as a mixed inhibitor, with a tendency to cathodic region. It also presented a 52% chelating effect against Fe+2 ions, and the SEM analysis indicated a protection with the presence of plant extract, thus minimizing surface roughness. These results indicated the J. brangeeana ethanol extract as a green anti-corrosive agent.

Efficient Counter Electrode of MoS2‐GO/PEDOT:PSS for Platinum‐free, High Performance Dye Sensitized Solar Cells

AbstractThe aim of this work is to fabricate the efficient platinum‐free counter electrodes for the development of advanced and high performance dye sensitized solar cells. MoS2‐GO/ PEDOT:PSS counter electrode has served as low‐cost, simple preparation and high efficient counter electrode for a DSSC. The Cyclic‐Voltammetry, electrochemical impedance spectroscopy and Tafel curve analysis indicate that the MoS2‐GO/PEDOT:PSS counter electrode possesses low charge transfer resistance on the electrolyte–electrode interface, high electrocatalytic activity and fast reaction kinetics for the reduction of tri‐iodide to iodide at the counter electrode. The DSSCs made with MoS2‐GO/PEDOT:PSS counter electrode achieve high power conversion efficiency of 7.73 % under standard light illumination of 100 mW/cm2, is higher than the platinum based counter electrode DSSC (5.53 %). The results witnessed the developed counter electrode is efficient and potential for platinum‐free dye sensitized solar cell applications.

Soybean and Glycine as Potential Corrosion Inhibitors for Steel in Hydrochloric Acid: Electrochemical and Morphological Studies

The potential of soybean and glycine as organic corrosion inhibitors for steel in acid solution was examined through weight loss tests and potentiodynamic polarization. Both soybean and glycine were characterized via FTIR and UV-visible. The result shows that the soybean and glycine contain isoflavone and nitrogen bonds respectively as a beneficial element in inhibiting the corrosion of steel. Corrosion tests were performed with and without the presence of soybean and glycine for 3 days of immersion in the acidic medium. Corrosion inhibition efficiency measured via electrochemical test found that both soybean and glycine give an excellent corrosion inhibition efficiency at 1.5 g/L in 0.5 M HCl up to 96% and 94% respectively. Tafel analysis reveals both inhibitors perform mixed types inhibitors which predominantly anodic inhibition. Pseudo-passivation was observed in the Tafel curve indicating the capabilities of both inhibitors to passivate the corrosion at anodic potential. Observation of the steel samples through an optical microscope shows that the corrosion of the steel surface was inhibited in the addition of soybean and glycine in HCl. The roughness of the steel surface affected by the combination of uniform and pitting corrosion was also reduced. In overall, soybean and glycine exhibit excellent anticorrosive properties due to the presence of significant chemical structures and active functional groups. Analysis of the inhibition mechanism through isotherm showed that soybean and glycine followed Langmuir isotherm, indicating the adsorption type for both inhibitors is chemisorption. The results obtained from this study could be a good reference in diversifying the study of amino acids as metal corrosion inhibitors to benefit metal-based industries.

Study on the photogenerted cathodic protection of Ti-P-V-O coating photoelectrode prepared by microarc oxidation method for 304 stainless steel

Photocathodic protection is a promotion strategy for the corrosion protection of metallic materials, and the selection of photocathodic materials is a critical factor in improving the performance of photocathodic protection of metallic materials. Herein, a Ti-P-V-O composite semiconductor photoelectrode with an adjustable porous structure was prepared by the micro-arc oxidation (MAO) method using titanium alloy (TC4) as the matrix and ammonium metavanadate (NH4VO3) as the additive. The photogenerated open circuit potential, instantaneous photocurrent density response value, electrochemical impedance spectroscopy, and Tafel curve of as-prepared Ti-P-V-O photo-electrodes were measured after coupling with 304SS to clarify the cathodic protection effect for 304 stainless steel (304SS). It is found that the as-prepared Ti-P-V-O coating photoelectrode has a more negative open circuit potential, a more significant photocurrent density response, more effective interface carrier transport ability, lower resistance, lower compounding efficiency of photogenerated electron/hole pairs, and more negative conduction band level, as compared with that of TiO2 coatings. Moreover, the optimized Ti-P-V-O photoelectrode (Ti-P-V-O&300 V) exhibited the maximum negative shift of the corrosion potential (410 mV vs. SCE) for coupling with 304 stainless steel. This work presents a new strategy for constructing an efficient coating photo-electrode for photocathodic protection of metallic materials.

Exploring the effectiveness of two triazole derivatives as copper corrosion inhibitors in NaCl solution: A combined approach of quantitative chemistry and dynamic molecular simulations

The present study investigates the effectiveness of a novel inhibitor, 2‑hydroxy-5-((4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)methyl) benzaldehyde (STR), in preventing copper from corrosion in a 3.5 wt.% NaCl solution. A comparative study of the inhibition efficiency between our newly synthesized water-soluble triazole STR, and the commercially available Benzotriazole (BTA) was evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests. The results revealed a substantial reduction in the rate of copper oxidation with increasing inhibitor concentrations. At 10−3 M, STR and BTA demonstrated inhibition efficiencies of 92.73% and 97.62% respectively. Analysis of the Tafel curves showed that the inhibitors used exhibited mixed type behavior. Langmuir isotherms showed that the STR and BTA molecules are adsorbed on copper surface, following the chemical adsorption process. Theoretical calculations based on density functional theory (DFT) method and molecular dynamic (MDS) simulations, provided valuable insights into the efficacy and mode of action of STR and BTA as copper corrosion inhibitors in a 3.5 wt.% NaCl solution.

Anisotropic adsorption of xanthate species on molybdenite faces and edges and its implication on the flotation of molybdenite fines

Utilizing xanthate in bulk flotation of Cu-Mo sulfide ores is inevitable, but the implication of xanthate on the flotation of molybdenite fines is barely understood. In this study, the influence of sodium butyl xanthate (SIBX) on the flotation of molybdenite fines and the interaction mechanism was comprehensively investigated by micro-flotation tests, contact angle, adsorption capacity, electrochemical tests, atomic force microscopy (AFM), Fourier Transform Infrared Spectrometer (FTIR), X-ray Photoelectron Spectroscopy (XPS) and density functional theory (DFT) calculations. Micro-flotation tests indicated that SIBX significantly enhanced the flotation of molybdenite fines across a wide pH range. Contact angle, adsorption capacity, Tafel curves, AFM, FTIR and XPS results suggested both xanthate and dixanthogen species adsorbed on molybdenite surfaces, thus improving the hydrophobicity of both edges and faces. Rest potential measurements clarified dixanthogen species dominated on faces while xanthate ions prevailed on edges. DFT calculations elucidated dixanthogen physically adsorbed (−66.06 kJ/mol) on faces while xanthate chemisorbed (−235.62 kJ/mol) on edges via the hybridization of two S atoms within SIBX with two Mo atoms to form highly covalent bonds. This work first clearly unveiled the anisotropic adsorption mechanism of SIBX species on faces and edges, significantly improving the flotation efficiency of molybdenite fines.

Analyzing the preparation, oxidation-related behavior, and electrochemical properties of three-dimensional hierarchical porous WC/C composites

In this study, we prepared biomass porous WC/C composites with a three-dimensional porous structure, and investigated their pore structure, oxidation-related behavior, and electrochemical properties. The results showed that a higher reaction temperature was conducive to the formation of WC on the carbon template. The porous WC/C composites retained the porous structure of the biomass carbon material, and had a large specific surface area (364.19 m2⋅g−1). The overpotential and slope of the Tafel curve of the WC/C composites were lower by 281 mV and 197 mV·dec−1, respectively, than those of the carbon template, while they exhibited a significant increase in electrocatalytic activity. The activation energy of the oxidation reaction of the composites (68.95 kJ⋅mol−1) was higher than that of the carbon template (42.19 kJ⋅mol−1), and their resistance to oxidation improved.

Microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings on the Cu substrate surface by plasma spray method

In this study, the microstructure, wear and corrosion properties of Cu–SiC/WCCo composite coatings produced on Cu substrates by plasma spray method were investigated. In order to achieve this aim, SiC and WCCo powders were added to copper at different rates such as 5 %, 10 % and 20 % by weight. In order to determine the microstructure properties and phase distribution of the produced coatings, optical microscope, SEM-EDS and XRD analysis were investigated. The reciprocating wear method was used in order to determine the wear properties and the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods was used to determine the corrosion properties. The electrical conductivities of the coating layers were performed according to the eddy current principle. XRD analysis results showed that in both coating types, ceramic particles decomposed in the plasma flame and as a result, binary and ternary metallographic phases were formed. There were significant increases in hardness by adding ceramic particles to Cu, especially with 20 % WCCo additive, the hardness obtained was 82 % higher than the Cu substrate. When the wear properties were examined, both abrasive/adhesive wear types were observed in the copper substrate and coating layers. In all samples, material loss increased as the load increased. Both EIS measurements and Tafel curve results showed that the Cu-5% WCCo coating had the best corrosion resistance among the coatings. When the electrical conductivity results of all samples were compared, the electrical conductivity decreased with increasing rate of carbide in the coating.

Electrochemical sensor for sensitive detection of an anticancer drug Capecitabine by modified carbon paste electrode with tetrahydrodipyrazolo pyridine derivative and Cu-MCM-41 nanoparticles

In this work, the electrochemical performance of the modified carbon paste electrode with tetrahydrodipyrazolo pyridine derivative as an organic modifier, and Cu-MCM-41 nanoparticles have been investigated to determine Capecitabine (CAP), an anticancer drug. CAP has been used for treating some cancers such as rectal, stomach, breast, pancreatic, and colon cancer. It works by inhibiting cancer cells growth. Herein, an organic modifier was prepared using a green biocatalyst in a biomimetic synthesis, a simple method was used for synthesis of Cu-MCM-41 nanoparticles. The electrochemical parameters such as the transfer coefficient and the number of electrons and protons involved in the redox reaction of the modifier were calculated using cyclic voltammetry (CV). Also, an electrocatalytic reaction was observed for CAP oxidation on the modified electrode surface as a result of a reduction in the CAP species oxidation overvoltage. To measure the CAP species by the modified electrode, some optimizations were performed. The Tafel curve was used to determine the transfer coefficient between the CAP and modifier, which was determined as 0.9. The chronoamperometric experiment was also investigated to obtain the numerical value of the CAP diffusion coefficient (D = 7.67 × 10–6 cm2 s−1). The calibration curve was drawn by the differential pulse voltammetry technique (DPV), and linear ranges of 2.0–80.0 µM and 80.0–800.0 µM, and the detection limit (LOD = 0.144 µM) were obtained. To evaluate the efficiency of the proposed sensor for CAP determination, measurement was done on a real blood serum sample. The proposed sensor displayed good selectivity, repeatability, and stability.

Influence of Si contents on the microstructure and corrosion resistance of the Zn−Al−Mg−Si alloys

Hot dip galvanized products are widely used in various aspects of production and life due to their excellent corrosion resistance. Some studies have added a fourth trace alloying element to the zinc aluminum magnesium coating to form a quaternary alloy for better performance. This article prepared two different types of Zn−Al−Mg alloy ingots with trace amounts of Si added by induction melting, consisting of Zn1Al1Mg0.01Si and Zn1Al1Mg0.05Si, and solidified them in a heating furnace with argon gas protection atmosphere. The precipitation process of Zn1Al1Mg(0.01,0.05)Si alloy components under non equilibrium and equilibrium solidification conditions was calculated. The initial crystalline phase of the alloy and the initial solidification temperature were predicted through phase diagram calculations. The microstructure and phase types of the alloy were analyzed using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FE-SEM). The electrochemical Tafel curves of Zn1Al1Mg(0.01,0.05)Si with different Si contents showed that the Zn1Al1Mg0.05Si has the highest corrosion potential and Zn1Al1Mg0.01Si has the lowest corrosion current which means the 1Al1Mg0.01Si alloy possesses the highest corrosion resistance. The Nyqust curves and bode curves also showed that the practical impedance of 1Al1Mg0.01Si alloy is higher than that of 1Al1Mg0.05Si. Moreover, electron probe X-ray micro-analyzer(EPMA) reveals the distribution of Si elements in the Zn1Al1Mg(0.01,0.05)Si. At present, there is little research on the microstructure and properties of quaternary alloys containing silicon. Therefore, studying the influence of silicon content on the microstructure and properties of alloys is of great significance.

Research on the Anti-corrosion Performance of Corrosion Inhibitor under Salt Freeze-Thaw Cycles

In this study, a multifunctional corrosion inhibitor (referred to as CI) was incorporated into C30 concrete. The effect of CI on the free chloride content, Tafel curves of reinforcement, and quality loss rate (QLR) were investigated under salt freeze-thaw cycles (SFTCs). Additionally, the scanning electron microscope (SEM) was employed to examine the corrosion of the reinforcement surface. The results indicated that CI was beneficial in reducing the internal free chloride content within the concrete. It could also form an adsorption film on the reinforcement surface, effectively lowering the corrosion rate and minimizing QLR, and providing excellent protection for the steel reinforcement.

The novel preparation of waterborne acrylic polyurethane-silica organic-inorganic interpenetrating network coatings

In this paper, a waterborne acrylic polyurethane-silica organic-inorganic interpenetrating network (IPN-WAPU-nSiO2) coating was prepared using filling hydroxyethylation modified nano-silica with 10 nm diameter (HEM-nSiO2) into waterborne acrylic polyurethane paint. Fourier transform infrared spectroscopy (FT-IR) confirms that HEM-nSiO2 can react with isocyanate to form amino ester bonds, which enhances the compatibility with acrylic polyurethane matrix and the microstructural morphology demonstrates that nano sized silicon are completely integrated into the IPN-WAPU-nSiO2 coating, which forms a significant difference from the composite waterborne acrylic polyurethane-silica (c-WAPU/nSiO2) coating prepared from filling 10 nm diameter of silica. The resulting IPN-WAPU-HEM-nSiO2 coating filling 0.1 wt% of HEM-nSiO2 has outstanding wear resistance, toughness and excellent resistance to salt spray for over 360 h with 15 μm thickness. Tafel curve and electrochemical impedance spectroscopy (EIS) reveal the outstanding corrosion protection: the |Z|0.01Hz of IPN-WAPU-HEM-nSiO2 (3wt‰) coating remains 4.61 × 109 Ω·cm2 after soaking in 3.5 wt% NaCl solution in 60 °C for 60 days, which is caused by the very dense coating with unique organic-inorganic IPN structure.