Corrosion Resistance Of Metals Research Articles

Literature Review−Effect of Additives and Post-Treatments on Corrosion Resistance and Mechanical Properties of Plasma Electrolytic Oxidation Products in Magnesium and Titanium

<p class="Abstract">Plasma Electrolytic Oxidation (PEO) is a method of converting metal surfaces into an oxide layer with the help of plasma to improve the surface mechanical properties and corrosion resistance of metals. A PEO layer of about 10-50 μm is obtained quickly from 1 second-10 minutes at a voltage range of 150-500 V with AC or DC mode. Characteristics of the outer layer of PEO have pores and cracks, while the inner layer is relatively denser. Cracks and pores reduce the corrosion resistance and mechanical properties of the coating. In this study, a literature search was carried out on the effect of adding additives and post-treatment on the characteristics of PEO coatings grown on magnesium (Mg) and titanium (Ti) metals for biomedical applications. Mg and Ti metals have opposite chemical properties; Mg is a reactive metal, while Ti is an inert metal. Comparing the behavior of the PEO process and the coating produced by the two different metals is absorbing and necessary to understand the fundamentals of the PEO process. The results of a literature search show that the addition of additives increases the growth rate of the coating so that the coating is thicker and more wear resistant. The hardness of the coating also increases due to the additive particles trapped in the oxide layer filling the micro pores so that the surface becomes denser and more homogeneous. Therefore, corrosion resistance also increases, as indicated by a decrease in corrosion current as measured by the polarization test and an increase in the impedance modulus as measured by the electrochemical impedance test (EIS). The post-alkali treatment allows for increased surface bioactivity, as indicated by the rise in the Ca/P ratio after immersion in a physiological solution.</p>

Corrosion-Resistant Polymer Composite Tubes with Enhanced Thermal Conductivity for Heat Exchangers

The heat transfer surfaces of heat exchangers are usually made of metals which may suffer from severe corrosion. When corrosive fluids are present, highly corrosion-resistant metals, graphite or ceramics are used, resulting in high costs. This study presents measured data on the thermophysical and mechanical properties of recently developed corrosion-resistant polymer composite tubes for use in heat exchangers. Extruded polymer composite tubes based on polypropylene or polyphenylene sulfide filled with graphite flakes were investigated. The anisotropic thermal conductivities of the polymer composite tubes were measured at various temperatures. The through-wall thermal conductivity of the tubes made of polypropylene filled with 50 vol.% graphite is increased by a factor of 30 compared to pure polypropylene, resulting in a thermal conductivity of 6.5 W/(m K) at 25 °C. The tubes composed of polyphenylene sulfide filled with 50 vol.% graphite have a through-wall thermal conductivity of 4.5 W/(m K) at 25 °C. The mechanical properties of the polymer composites were measured using tensile and flexural tests at different temperatures. The composite materials are more rigid and keep their mechanical properties up to a higher temperature level compared to the unfilled polymers. Surface roughness measurements show the very smooth and sealed surface of the composite tubes. The results contribute to establishing the viability of using polymer composites for heat exchanger applications with corrosive fluids.

A curcumin quantum dot blended polyacrylonitrile electrospun nanofiber coating on 316 L SS for improved corrosion resistance in the marine environment.

Corrosion of 316 L SS is a significant global concern and recently polymeric nanofibers have been gaining attention for their potential in enhancing the corrosion resistance of metals. In this work, an electrospinning technique was deployed for the deposition of a curcumin quantum dot (CMQD) blended polyacrylonitrile (PAN) nanofibrous anticorrosive coating on 316 L SS. The optimized PAN-CMQD coated samples obtained from the weight loss studies were examined to assess their corrosion inhibition characteristics in 3.5 wt% NaCl electrolyte as the corrosion environment using potentiodynamic polarization and electrochemical impedance spectroscopy. The PAN-CMQD coated samples showed two-order reduction in I corr compared to the uncoated 316 L SS. The results of the long-term analysis for 30 days revealed no significant changes in I corr and E corr values and no pit formation for PAN-CMQD coated samples, proving the longevity of the coating. Thus, this work will serve as a cost-effective futuristic strategy for the large-scale development of anticorrosive nanofibrous coatings for enhancing the corrosion resistance behavior of metals and alloys in various industrial sectors.

Study on superhydrophobicity and corrosion resistance of the micro-nano structure prepared by femtosecond laser

The wettability as well as the corrosion resistance of metal is closely related to the surface microstructure. A surface structure with micro protrusion and nano ripple was designed and constructed on 316L stainless steel by femtosecond pulse laser. Superhydrophobic surfaces with a great contact angle over 150° were obtained by surface modifications of heat treatment or fluorination treatment. The corrosion resistance of the superhydrophobic micro-nano structured surfaces was studied through electrochemical testing. The result of polarization curve revealed that the superhydrophobic micro-nano structured surfaces possessed a higher corrosion potential, signifying the susceptibility to corrosion was reduced. Besides, the results of impedance indicated that the superhydrophobic micro-nano structured surfaces exhibited greater total resistance when compared to the original surface, demonstrating the corrosion resistance was enhanced. According to the results, the superhydrophobic surface, characterized by its micro-nanostructure, facilitates the formation of a protective gas film. Additionally, the intricate micro-nano rough structure, in conjunction with the gas film, effectively shields the underlying surface from infiltrative processes, thereby mitigating the potential exacerbation of corrosion phenomena.

Achieving Highly Durable Intermetallic PtMn3N Electrocatalyst via the Strong Metal‐N Bonds toward Oxygen Reduction Reaction

AbstractPt‐based intermetallic compounds have been considered promising electrocatalysts in the practical applications of fuel cells; however, the development of Pt‐based catalysts that meet performance targets of high activity, maximized stability, and low cost remains a huge challenge. Herein, an atomically ordered and low‐Pt intermetallic nitride (PtMn3N) catalyst are synthesized consisting of a strained Pt shell and PtMn3N core on carbon support via the KCl‐matrix protection strategy. The PtMn3N catalyst represents a high mass activity of 0.70 A mgPt−1 at 0.9 V and a specific activity degradation of 4.2% after 5000 potential cycles for the oxygen reduction reaction (ORR) in rotating disk electrode (RDE) testing, which substantially outperformed commercial Pt/C (0.25 A mgPt−1 and 17.4%). Density functional theory calculations reveal that the introduction of Mn elements to the Pt lattice is beneficial to produce appropriate compressive strain to weaken the binding energy of oxygen species and the introduction of N elements to promote the strong metal‐N interactions is conducive to alleviating the dissolution of metal atoms, allowing for displaying the prominent durability. This work provides an effective strategy of N‐doped Pt‐based intermetallic compounds to enhance the corrosion resistance of 3d transition metals and to enhance the ORR performance.

Experimental study on rotary inter-module connections with corrosion-resistant metal materials: Under axial tension

Modular construction is an innovative construction technology that has attracted considerable attention for its pronounced advantages in reducing reliance on on-site labor, speeding up construction, enhancing productivity, and ensuring superior quality. To extend the applicability of modular construction to structures in corrosive environments, such as ocean floating structures for exploring renewable energy, a rotary inter-module connection employing corrosion-resistant metal materials was proposed herein. Six full-scale inter-module connection specimens made of grade S30408 austenitic stainless steel, grade S220503 duplex stainless steel, and grade A96061-T6 aluminum alloy were tested under axial tension. The load-displacement relationships of each specimen were recorded to enable a thorough analysis of the strength, stiffness, and ductility of the tested specimens. As compared to the conventional carbon steel counterparts, the stainless steel specimens showed superior load-bearing capacity with improved ductility, while the aluminum alloy specimens experienced brittle fracture at the bolt shank-bottom plate junction with reduced load-bearing capacity. Three typical failure modes were identified in the experimental study, namely, plastification of the connector and lower corner fitting, plastification of the connector and both corner fittings, and fracture of the bolt. The load-strain relationships of each specimen were also discussed to analyze the load transfer mechanism and structural behavior of the connection. In addition, the applicability and accuracy of the simplified calculation methods based on beam bending theory and Navier solution for rectangular thin plates, respectively, were discussed based on the test results.

Influence of Reinforcing nano-Al<sub>2</sub>O<sub>3</sub> Particles on Microstructure and Hardness Properties of HVOF Sprayed 80Ni20Cr Coatings

80Ni20Cr coatings produced by high-velocity oxygen fuel (HVOF) thermal spray technique are novel and widely used to improve the corrosion and wear resistance of metal and steel components in many applications, especially in coal-fired power plants. The present study investigated the effects of nano-Al2O3 at 0.5 wt.% on the microstructure of HVOF-sprayed 80Ni20Cr coating deposited on AISI 304L steels corresponding to its coating hardness. The coating was successfully sprayed with a thickness of 150 – 180 µm. The microstructure and phase formed by the coating were analyzed by a field emission electron microscope (FE-SEM) and an X-ray diffractometer (XRD). Synchrotron X-ray fluorescence spectroscopy (SRXRF) was used to confirm the Cr solid solution in the Ni-based coating. The presence of the nano-Al2O3 phase in the 80Ni20Cr coating was characterized by electron backscattered diffraction (EBSD). The nano-Al2O3 particles were homogenously distributed in the coating layers. The incorporation of nano-Al2O3 into 80Ni20Cr enhanced coating characteristics by decreasing surface roughness by 23% and increasing coating hardness by around 4%.

Laser-zoned treatment of magnesium surfaces with predictable degradation applications

Magnesium metal is a promising material for medical applications due to its biocompatibility and similar modulus of elasticity to human bone. However, its complex corrosion process must be addressed before it can be used clinically to match post-implantation tissue repair. This study aims to regulate material degradation by utilizing laser surface treatment. The surface of pure magnesium was modified using nanosecond and femtosecond laser methods to create various micro-nanostructures, such as chain, streak, column, and groove structures. Surface roughness and wettability tests revealed that the groove structures had higher roughness values. All structures exhibited hydrophilicity, but the femtosecond laser-generated structures were more hydrophilic. Electrochemical tests and immersion experiments demonstrated that femtosecond laser modification significantly improved the corrosion resistance of magnesium metal compared to polished samples. Cytotoxicity experiments showed that the laser-treated magnesium was not cytotoxic. Based on the results, we constructed various structures on the magnesium rods in different regions. As a result, the rods exhibited multi-stage biodegradation behavior in simulated body fluids (SBF). This study presents a novel approach to controlling the degradation sequence of medical metals.

Electrochemical corrosion study of CH-xTiO2 (x=Ag, Mg, Sr, and Zn) coated Ti–6Al–4V alloy for dental implant

Ti–6Al–4V is a widely used material for dental and orthopedic implants due to its biocompatibility and excellent mechanical properties. However, it is susceptible to corrosion when exposed to the human body and oral environment. To alleviate this issue and for enhancing and improving its application in dentistry, we applied a protective coating to the alloy surface. Thin films of CH-xTiO2 (x = Ag, Mg, Sr, and Zn) composites were deposited on titanium alloy substrates using the sol-gel dip coating technique. It is an environmentally friendly technique known for enhancing metal corrosion resistance. The surface roughness and morphology of coated and uncoated substrates were analyzed using profilometry, SEM, and AFM. The results revealed that the coating effectively protects the alloy surface. Corrosion protection in artificial saliva was evaluated through potentiodynamic polarization (Tafel), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) studies. The results indicate that the CH-xTiO2 coating significantly improves the corrosion resistance of titanium alloy surfaces in artificial saliva, enhancing the durability and performance of dental implants in challenging oral environments and thus increasing patient satisfaction.

DIELECTRIC BARRIER DISCHARGE BASED PLASMA DEVICE FOR COLD STERILIZATION IN WATER WITH ADDITIONAL ULTRASONIC CAVITATION

A prototype of plasma sterilizer based on dielectric barrier discharge (DBD) with additional ultrasonic cavitation for cold sterilization has been developed. It provides sterilization of reusable small dental instruments, and components made from corrosion-resistant metals and alloys (stainless steel, titanium, etc.), as well as surgical instruments, implants, small drills, plastic sundries, ozone resistant medical rubbers (silicone, etc.), polymers, epoxy resins and glass. The sterilizer is well suited for dentistry and can be used in medical, sanatorium, outpatient and other medical institutions, as well as in military field surgery. The volume of the sterilization bath is 2.5 l. The ozone concentration at the output of the ozone generator is 35…52 mg/l, the ozone concentration in the sterilizer chamber is 6.5…8 mg/l, depending on the water temperature and its volume in the bath. The dependence of the increase of ozone concentration in water on time at different oxygen flow rates is monitored.

(Invited) Nitrogen-Doped High-Entropy Alloy as Efficient and Stable Electrocatalyst

The development of Pt-based catalysts for use in fuel cells that meet performance targets of high activity, maximized stability, and low cost remains a huge challenge. The high-entropy alloy (HEA) is one of the most promising candidates for electrocatalysts, owing to their unique properties involving the high entropy effect, lattice distortion effect, sluggish diffusion effect, and “cocktail” effect.1 Alternatively, nitrogen (N)-doping effects have been well documented and demonstrated in our previous studies, which further fine-tune the adsorption energetics of intermediates and improve the corrosion resistance by the pinning effect of metal-nitrogen bonds.2-3 Combining the HEA and N-doping strategies, the tailored lattice and interstice atomic sites lead to the formation of chemically stable multiple metal-nitrogen (M-N) bonds and the generation of the possible synergistic effect on promoting ORR performance. Herein, we report a N-doped high-entropy alloy (HEA) electrocatalyst that consists of a Pt-rich shell and a N-doped PtCoFeNiCu core on a carbon support (denoted as N-Pt/HEA/C). The N-Pt/HEA/C catalyst showed high mass activity of 1.34 A mgPt -1 at 0.9 V for the oxygen reduction reaction (ORR), which substantially outperformed commercial Pt/C and most of the other binary/ternary Pt-based catalysts. The N-Pt/HEA/C catalyst also demonstrated excellent stability in both rotating disk electrode (RDE) and membrane electrode assembly (MEA) testing. Using operando X-ray absorption spectroscopy (XAS) measurements and theoretical calculations, we revealed that the enhanced ORR activity of N-Pt/HEA/C originated from the optimized adsorption energy of intermediates, consequent of the tailored electronic structure formed upon the N-doping. Furthermore, we showed that the multiple metal-nitrogen bonds formed synergistically improved the corrosion resistance of the 3d transition metals and enhanced the ORR durability.References Yao, Y.; Dong, Q.; Brozena, A.; Luo, J.; Miao, J.; Chi, M.; Wang, C.; Kevrekidis, I. G.; Ren, Z. J.; Greeley, J.; Wang, G.; Anapolsky, A.; Hu, L., High-entropy nanoparticles: Synthesis-structure-property relationships and data-driven discovery. Science 2022, 376 (6589), eabn3103.Zhao, X.; Xi, C.; Zhang, R.; Song, L.; Wang, C.; Spendelow, J. S.; Frenkel, A. I.; Yang, J.; Xin, H. L.; Sasaki, K., High-Performance Nitrogen-Doped Intermetallic PtNi Catalyst for the Oxygen Reduction Reaction. ACS Catalysis 2020, 10 (18), 10637-10645.Zhao, X.; Cheng, H.; Song, L.; Han, L.; Zhang, R.; Kwon, G.; Ma, L.; Ehrlich, S. N.; Frenkel, A. I.; Yang, J.; Sasaki, K.; Xin, H. L., Rhombohedral Ordered Intermetallic Nanocatalyst Boosts the Oxygen Reduction Reaction. ACS Catalysis 2020, 11 (1), 184-192.

Effect of shot peening on surface characteristics and high-temperature corrosion behaviour of super 13Cr martensitic stainless steel

Super 13Cr, as an economy stainless steel (SS) for oil country tubular goods, needs stable corrosion resistance in high-pressure and high-temperature (HPHT) downhole medium. Severe plastic deformation (SPD) are the surface modification technology to improve mechanical properties, fatigue behavior and corrosion resistance of metals, and shot peening (SP) has been the most widely used SPD process. However, there are quite limited studies about the microsutructure evolution, residual stress, and high-temperature corrosion behavior of SP-treated martensitic SS. In this study, super 13Cr martensitic SS was treated by SP with various air pressures and nozzle speeds. The surface characteristics and high-temperature corrosion behaviour in 3.17 mol/L K2HPO4 solution were investigated through finite element model analysis, characterization of residual stress and microstructure, as well as electrochemical and stress corrosion cracking (SCC) tests at 160 °C and 10 MPa. The results showed that SP-treated super 13Cr could generate high-level compressive residual stress and SPD microstucture, including nano-sized equiaxed grains, gradient lamellar structure and fragmented carbides. Increasing air pressure contributed to achieve uniform nanocrystalline, but tended to generate high dislocation density and surface defects. The improving effect of SP treatment at low air pressure of 0.15 MPa on passivation ability was limited, and high air pressure adversely impacted corrosion resistance. SP-treated specimens showed high SCC susceptibility, due to the introduction of more surface defects, high angle grain boundaries, and dislocations.

Dual-metal-based (Mo, Ni) MOFs nanoplates for enhanced corrosion resistance and frictional resistance of epoxy resin on magnesium alloy surfaces

Magnesium alloys face severe corrosion issues due to their high electrochemical activity. In recent years, polymer coatings containing metal-organic frameworks (MOFs) have shown great potential in improving the corrosion resistance of metals. In this study, nickel salts and molybdate were used as metal sources, and 4,4′-bipyridine was used as the organic ligand. For the first time, a nickel and molybdenum-based metal-organic framework (Mo-Ni-MOF) was synthesized via hydrothermal method. Mo-Ni-MOFs were then incorporated as nanofillers into epoxy resin and coated on AK61M magnesium alloy to enhance its long-term corrosion resistance. Characterization tests including FT-IR, FE-SEM, EDX, XRD and XPS confirmed the successful reaction between metal ions and organic ligands, indicating successful coordination. TEM analysis revealed that the MOFs consisted of nanosheets with diameters ranging from 20 to 100 nm. BET analysis demonstrated the porous structure of the synthesized nanoparticles, with a high specific surface area ranging from 6 to 44 m2.g−1 and an average pore size ranging from 9 to 32 nm. Salt spray tests demonstrated that MOFs synthesized under different conditions exhibited superior long-term corrosion resistance compared to pure epoxy coatings in artificial scratch coating performance. Electrochemical impedance spectroscopy (EIS) testing revealed a three-order-of-magnitude enhancement in |Z| at 0.01 Hz for the most effective MOF compared to pure epoxy resin. Tafel tests showed a significant decrease in corrosion current, with reductions of 2–3 orders of magnitude. Friction tests revealed a decrease in the coefficient of friction after the addition of MOFs, with reductions ranging from 0.1 to 0.4, indicating improved durability of the coating against friction.

Strain-dependent work function of metal surfaces: Insights from first-principles investigation

Establishing a fundamental understanding of the relationship between electronic work function (WF) and applied strain is crucial for the development flexible electrodes of and enhancement of metal corrosion resistance. The underlying mechanisms of this relationship have remained unknown, largely due to inconsistencies from previous studies caused by different strain states and the complex impact of anisotropic surface effects. In this study, we employ first-principles methods to investigate the work functions of strained metal surfaces. Our research findings suggest that lateral strain states significantly affect the WF, while strain perpendicular to the surface has minimal influence. Through subjecting the metal surface to linear elastic deformation, we establish a canonical relationship between the work function and strain. Further comparison of work functions under biaxial strain indicates that surfaces with high atom packing density exhibit greater susceptibility to strain. The mechanism behind the strain-dependent WF is attributed to the interplay of bulk electronic structure and surface dipole effects, which. These effects are influenced by volume changes and the redistributedion of charge density. To this end, we propose an effective strain-induced approach for engineering the WF of metal electrode is proposeds, with potential applications in other various materials.

Influence of Grain Size and Film Formation Potential on the Diffusivity of Point Defects in the Passive Film of Pure Aluminum in NaCl Solution

The influence of grain size on the corrosion behavior of pure aluminum and the defect density and diffusion coefficient of surface passive films were investigated using electron backscatter diffraction (EBSD) and electrochemical testing techniques, based on the point defect model (PDM). Samples with three different grain sizes (23 ± 11, 134 ± 52, and 462 ± 203 μm) were obtained by annealing at different temperatures and times. The polarization curves and electrochemical impedance spectroscopy results for the pure aluminum in the 3.5% NaCl solution showed that with decreasing grain size, the corrosion current (icorr) decreased monotonously, giving rise to a noble corrosion potential and a large polarization resistance. The Motte–Schottky results showed that the passive films that formed on pure aluminum with fine grains of 23 ± 11 μm had a low density (3.82 × 1020 cm−3) of point defects, such as oxygen vacancies and/or metal interstitials, and a small diffusion coefficient (1.94 × 10−17 cm2/s). The influence of grain size on corrosion resistance was discussed. This work demonstrated that grain refinement could be an effective approach to achieving high corrosion resistance of passive metals.

Study on the disinfection effect of chlorine dioxide disinfectant (ClO2) on dental unit waterlines and its in vitro safety evaluation

BackgroundEnsuring the safety of dental unit waterlines (DUWLs) has become a pivotal issue in dental care practices, focusing on the health implications for both patients and healthcare providers. The inherent structure and usage conditions of DUWLs contribute to the risk of biofilm formation and bacterial growth, highlighting the need for effective disinfection solutions.The quest for a disinfection method that is both safe for clinical use and effective against pathogens such as Staphylococcus aureus and Escherichia coli in DUWLs underscores the urgency of this research.MaterialsChlorine dioxide disinfectants at concentrations of 5, 20, and 80 mg/L were used to treat biofilms of S. aureus and E. coli cultured in DUWLs. The disinfection effectiveness was assessed through bacterial counts and culturing. Simultaneously, human skin fibroblast cells were treated with the disinfectant to observe changes in cell morphology and cytotoxicity. Additionally, the study included corrosion tests on various metals (carbon steel, brass, stainless steel, aluminum, etc.).ResultsExperimental results showed that chlorine dioxide disinfectants at concentrations of 20 mg/L and 80 mg/L significantly reduced the bacterial count of S. aureus and E. coli, indicating effective disinfection. In terms of cytotoxicity, higher concentrations were more harmful to cellular safety, but even at 80 mg/L, the cytotoxicity of chlorine dioxide remained within controllable limits. Corrosion tests revealed that chlorine dioxide disinfectants had a certain corrosive effect on carbon steel and brass, and the degree of corrosion increased with the concentration of the disinfectant.ConclusionAfter thorough research, we recommend using chlorine dioxide disinfectant at a concentration of 20 mg/L for significantly reducing bacterial biofilms in dental unit waterlines (DUWLs). This concentration also ensures satisfactory cell safety and metal corrosion resistance.

SYNTHESIS OF COPOLYMERS FOR PROTECTIVE COATINGS

Copolymers were obtained in this work and the methodology for their synthesis was worked out. Various fillers were selected for the polymer coating. Resulting copolymers have good adhesion required for composite protective coatings. An experiment was conducted to determine the corrosion resistance of metals coated with copolymers when exposed to aggressive environments, as well as to determine the hardness and thickness of the polymer coatings obtained. It was found that the polymer coating filled with bronze powder, despite the small thickness of 43.4 μm, hasthe best adhesion and corrosion properties, as well as having the highest hardness values of 80.5 HB. Such physical and mechanical properties of polymer coatings allow them to be used as protective coatings for metal products working under the influence of aggressive media.

Mechanical properties of FDM 3D printed component using self-made PLA-titanium filament: hardness perspective

3D printing, also known as additive layer manufacturing, is a technique that creates three-dimensional objects or any shape from a digital model. It works by building objects layer-by-layer, similar to how a laser printer operates. Fused Deposition Modeling (FDM) is a widely used technique in 3D printing because it is easy to use, cost-effective in production, and environmentally friendly. This study focuses on a self-made filament made of a PLA-titanium mixture. PLA is a biodegradable thermoplastic polymer sourced from plants, whereas titanium is a strong, lightweight, and corrosion-resistant metal. To measure the hardness of different materials, there are several methods available. In this study, the Shore D hardness test, specifically designed for polymer materials, was used. Data were collected using the Taguchi method, specifically L4 (23), and the data were analysedusingAnalysis of Variance (ANOVA). The variations in print parameters examined in this study include nozzle temperature (230°C and 240°C), layer height (0.2 mm and 0.3 mm), and print speed (30 mm/s and 40 mm/s). The aim of this study was to determine whether there were any changes in the hardness of the specimens. The ANOVA results revealed that the most influential parameter was print speed, with a contribution value of 56.01%. The results demonstrated that the printing parameters affected the hardness of the printed specimens. The highest hardness level of 56.3 Shore D was obtained with a nozzle temperature of 240°C, a layer height of 0.3 mm, and a print speed of 30 mm/s. The application of this study was demonstrated through the creation of dentures made from PLA-titanium.

Cell membrane-inspired self-assembly corrosion resistant liquid metal composite coating with photothermal/electrothermal anti-icing/de-icing performance

Liquid metals have been expected to be promising photothermal/electrothermal anti-icing materials for their excellent electrical and thermal conductivity. However, inescapable oxidation and corrosion limit the life and efficiency of liquid metal materials. Inspired by the self-assembly of phospholipid molecules in cell membranes, self-assembly corrosion resistant liquid metal composite coating is designed to protect liquid metal from icing and corrosion hazards. Based on self-assembly of fluor‑silicon molecules mimicking phospholipid molecules and micro-nano surface morphology, the coating has water contact angle of 150.8°and icing delay time of 497 s, which is 4.21 times that of unmodified liquid metal. Under the combined action of 80.5 °C photothermal effect and superhydrophobicity, the de-icing efficiency of the coating is 2.04 times that of the unmodified liquid metal. The photothermal de-icing efficiency remains 99.3 % after two months of acid corrosion and 94.4 % after two months of alkali corrosion. In addition, the thermal network of the coating leads to thermal conductivity of 3.66 W/mK and flame retardancy with UL94 at V0 rating. The coating is made into an electrothermal device with 52.5 °C heating temperature and rapidly de-icing property. The cell membrane-inspired self-assembly liquid metal composite coating provides a secure solution for long-term photothermal/electrothermal anti-icing/de-icing in exposed environment.

ВЛИЯНИЕ УСЛОВИЙ ХРАНЕНИЯ АВТОБУСОВ В КРЫТЫХ ОТАПЛИВАЕМЫХ СТОЯНКАХ НА ИНТЕНСИВНОСТЬ КОРРОЗИОННОГО ИЗНАШИВАНИЯ КУЗОВОВ

The efficiency of the rolling stock of road transport is determined by both the efficiency of organizing transport work and the cost of ensuring the operability of vehicles. One of the current problems with the operation of buses is the corrosive destruction of their bearing structure, which leads to both a reduction in the operating time of vehicles and an increase in the operating costs associated with the overhaul of bodies. During the work, it was revealed that the main reasons for the intensive corrosion destruction of bus bodies are insufficient corrosion resistance of metals that are used in the manufacture of the body frame. The main places of occurrence of body corrosion foci are: wheel arches; rear and lower parts of the bus, which are more affected by adverse road conditions; upper and lower parts of window openings in case of seal leakage. Studies were conducted on the temperature and relative humidity of the indoor heated bus parking area in winter. Based on the results of the study, dependencies were obtained: air temperature in the indoor parking room from ambient temperature, relative air humidity in the indoor parking room from relative ambient air humidity, relative air humidity in the indoor parking room and ambient temperature. The nature of air exchange between the parking room and the environment has been established. According to the results of the study, factors contributing to the intensive corrosive destruction of bus bodies were established.