Salt Spray Test Research Articles

Effects of Si Addition on Interfacial Microstructure and Corrosion Resistance of Hot-Dip Zn–Al–Mg–Si Alloy-Coated Steel

Alloy coatings protect steel from corrosion in various applications. We investigated the effects of Si addition on the microstructure, electrochemical behavior, and corrosion resistance of steel sheets coated with a hot-dip Zn–Mg–Al–Si alloy using a batch-type galvanization process. Microstructural analysis revealed that the Zn–Al–Mg alloy coating layer contained a significant amount of Fe that diffused from the substrate, leading to delamination due to the formation of brittle Fe–Zn intermetallic compounds. However, the introduction of Si resulted in the formation of a stable Fe2Al3Si inhibition layer at the substrate–coating interface; this layer prevented interdiffusion of Fe as well as enhanced the coating adhesion. Additionally, the formation of acicular Mg2Si phases on the coating surface improved the surface roughness. As the Si content increased, the corrosion resistance of the coating improved. Specifically, the Zn–Al–Mg coating layer with 0.5 wt.% Si exhibited excellent anti-corrosion performance, without red rust formation on its surface even after 2600 h, during a salt spray test.

Characterization and performance of organic-inorganic composite zinc phosphate with nano-sheet structure synthesized by a composite reaction of sol-gel with silane modification

Organic-inorganic composite zinc phosphate pigment with nano sheet structure (KH560-SZP, sheet zinc phosphate with γ-(2,3-epoxypropoxy) propytrimethoxysilane) was prepared by a simple composite reaction of silane modification method and solation-gelation method. Then the characteristics of KH560-SZP pigment, interfacial compatibility of KH560-SZP pigment/resin and corrosion inhibition of KH560-SZP coating with defect were studied through Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), Thermal Gravimetric Analysis (TG), sedimentation experiment, Inductively Coupled Plasma (ICP-OES), electrochemical test, and salt spray test. Result showed that the prepared KH560-SZP pigment had a nanosheet structure with thickness of 25–40 nm, and there were 2.11 % of organic resin functional groups in the pigment, which made the pigment well dispersed in the resin. The dissolution rate of PO43− in the KH560-SZP extracting was faster, and its concentration reached saturation just 2 h (the SZP needed 4 h). Hence, the KH560-SZP coating showed effectively prolong the diffusion path of electrolyte in the scratch-free coating and inhibit the corrosion reaction at the scratch areas.

Effect of iron powder on zinc reactivity and anticorrosion performance of zinc-rich epoxy coatings

This study investigated the impact of iron powder on zinc reactivity and anticorrosion performance of zinc-rich epoxy (ZRE) coatings. Incorporating iron powder into ZRE coatings enhanced their overall anticorrosion performance, as evidenced by improved cathodic protection and reduced rust creep in salt spray tests. Furthermore, salt spray and EIS tests on cracked ZRE coatings demonstrated the enhanced sacrificial cathodic protection and physical barrier property with the inclusion of iron powder, attributed to the promoted sacrificial oxidation of zinc particles at damaged areas. The enhanced zinc dissolution in the presence of iron powder was also observed in immersion tests and potentiodynamic polarization tests on compressed Zn and ZnFe pellets.

Formation of Li-Al LDH conversion layer on AA2024 alloy for corrosion protection

AA2024 aluminium alloy is widely used in the aerospace industry. However, it is known to be highly susceptible to localised corrosion, which is related to its complex microstructure, mainly the presence of numerous Cu-rich intermetallic particles. One of the effective solutions to increase their corrosion resistance relies on the formation of layered double hydroxide (LDH) based conversion coatings (CC). This investigation aims to understand how the conditions of in situ Li-Al LDH-CO32-/OH– CC growth affect their further protective ability. For that purpose, concentration of reactants (0.05–0.15 M Li2CO3), pH of the electrolyte (10–12), temperature (30–50 °C) and treatment time (15 min-30 h) were systematically varied. Additionally to that, NH4OH was applied as a chelating agent for the synthesis of Li-Al LDH-CO32-/OH– as well as for the pH control. The obtained protective coatings were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), glow discharge optical emission spectroscopy (GDOES), Raman spectroscopy, salt spray test (SST) and electrochemical impedance spectroscopy (EIS). Among all varied parameters, involvement of chelating agent was found to be the most efficient for the formation of a coating with the highest level of corrosion protection. This is attributed to the formation of soluble complexes between NH4OH and Cu, resulting in dissolution of the intermetallics. It also prevents further redeposition of Cu species and consequently, the formation of new highly active Cu cathodes on the AA2024 alloy surface.

Corrosion Behavior of 10 ppi TAD3D/5A05Al Composite in a Chloride Environment.

This study utilizes desalted and denitrated treated aluminum dross (TAD) as a raw material, along with kaolin and 10 ppi (pores per inch) polyurethane foam as a template. The slurry is converted into an aluminum dross green body with a three-dimensional network structure using the impregnation method. A three-dimensional network aluminum dross ceramic framework (TAD3D) is created at a sintering temperature of 1350 °C. The liquid 5A05 aluminum alloy at a temperature of 950 °C infiltrates into the voids of TAD3D through pressureless infiltration, resulting in TAD3D/5A05Al composite material with an interpenetrating phase composite (IPC) structure. The corrosion behavior of TAD3D/5A05 composite material in sodium chloride solution was examined using the salt spray test (NSS) method. The study shows that the pores of the TAD3D framework, produced by sintering aluminum dross as raw material, are approximately 10 ppi. The bonding between TAD3D and 5A05Al interfaces is dense, with strong interfacial adhesion. The NSS corrosion time ranged from 24 h to 360 h, during which the composite material underwent pitting corrosion, crevice corrosion and self-healing processes. Results from Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) indicate that, as corrosion progresses, the Ecorr of TAD3D/5A05Al decreases from -0.718 V to -0.786 V, and Icorr decreases from 0.398 μA·cm-2 to 0.141 μA·cm-2. A dense oxide film forms on the surface of the composite material, increasing the anodic Tafel slope and decreasing the cathodic Tafel slope, thus slowing down the rates of cathodic and anodic reactions. Factors such as lower interface corrosion resistance or a relatively weak passivation film at the interface do not significantly diminish the corrosion resistance of TAD3D and 5A05Al. The corrosion resistance of the composite material initially decreases and then increases.

Amino-Modified Graphene Oxide from Kish Graphite for Enhancing Corrosion Resistance of Waterborne Epoxy Coatings.

Waterborne epoxy (WEP) coatings with enhanced corrosion resistance were prepared using graphene oxide (GO) that was obtained from kish graphite, and amino-functionalized graphene oxide (AGO) was modified by 2-aminomalonamide. The structural characteristics of the GO and AGO were analyzed using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). And the anti-corrosive performance of waterborne epoxy-cased composite coatings with different addition amounts of AGO was investigated using electrochemical measurements, pull-off adhesion tests, and salt spray tests. The results indicate that AGO15/WEP with 0.15 wt.% of AGO has the best anti-corrosive performance, and the lowest frequency impedance modulus increased from 1.03 × 108 to 1.63 × 1010 ohm·cm-2 compared to that of WEP. Furthermore, AGO15/WEP also demonstrates the minimal corrosion products or bubbles in the salt spray test for 200 h, affirming its exceptional long-term corrosion protection capability.

Effectiveness of Thymol Blue and Phenolphthalein in Sol-Gel Coatings for Sensing and Inhibiting Corrosion on Mild Steel.

Development of smart coatings incorporated with corrosion indicators that can warn of corrosion through signaling the alteration of pH or metal-ion concentration at the corrosion site, and simultaneously mitigate further corrosion, stands out as a highly efficient and economical approach to address corrosion issues. In this context, the present work provides a comprehensive comparison on the effectiveness of thymol blue (TB) and phenolphthalein (PhPh) in both sensing and inhibiting corrosion on mild steel. While most of the works primarily focused on independently investigating the corrosion indication behavior of different active agents, our study intends to offer valuable insights through the comparative analysis of TB and PhPh in making well-informed decisions when selecting the most effective indicator for a given set of application scenarios. Initially, TB and PhPh were dissolved in a 3.5% NaCl solution, and their ability to indicate and inhibit corrosion on mild steel was verified through a drop test and an electrochemical study, respectively. An electrochemical study and a salt spray test were carried out to evaluate the corrosion sensing and inhibiting capabilities of the coating produced on a mild steel substrate by integrating TB and PhPh in the sol-gel matrix. The synergistic effect of TB and PhPh in sensing and inhibiting corrosion was also studied by combining TB and PhPh in the sol-gel matrix. It was found that TB-based coatings showed approximately 8 times better inhibiting performance (in terms of charge transfer resistance) when compared to PhPh-based coatings, while the PhPh-based coating was around 16 times more sensitive (with respect to concentration and time) in indicating corrosion when compared to TB-based coatings on a mild steel substrate. Nevertheless, the combination of TB and PhPh in a 1:3 ratio incorporated into the sol-gel coating exhibited increased sensitivity in detecting corrosion and showed improved corrosion inhibition on mild steel.

Protective and Flame-Retardant Bifunctional Epoxy-Based Nanocomposite Coating by Intercomponent Synergy between Modified CaAl-LDH and rGO.

Extensive utilization in various settings poses extra requirements of coatings beyond just anticorrosion properties. Herein, 8-hydroxyquinoline (8-HQ) intercalated CaAl-based layered double hydroxide (CaAl-8HQ-LDH) was loaded on reduced GO (rGO) through a one-pot hydrothermal reaction, which was employed as the nanofiller endowing the epoxy (EP/CaAl-8HQ LDH@rGO) with excellent flame-retardancy while ensuring efficient protection for mild steel. Results of electrochemical impedance spectroscopy (EIS) demonstrated the durability of the EP/CaAl-8HQ LDH@rGO-coated specimen, with the impedance at the lowest frequency (|Z|0.01Hz) maintained as 1.84 × 1010 Ω cm2 after 120 days of immersion in a 3.5 wt % NaCl solution. Even for the scratched EP/CaAl-8HQ LDH@rGO system, only a slight decline in |Z|0.01Hz was observed during 180 h of exposure to the NaCl solution, indicating a self-healing feature supported by salt spray tests. UL-94 burning tests revealed the V-0 rating for EP/CaAl-8HQ LDH@rGO with improved thermostability. Strong physical barrier from two-dimensional rGO and the release of 8-HQ from LDH interlayers accounted for the anticorrosive and self-healing properties. However, O2-concentration dilution and charring-layer promotion governed the flame-retardant behavior of the nanocomposite coating. The intercomponent synergy of nanofillers achieved in this work may provide a useful reference for designing multifunctional coatings.

Construction of wear resistant superhydrophobic structure without degrading the surface mechanical properties of alloy layer

The vulnerability of superhydrophobic surface structures frequently leads to a loss of their superhydrophobicity under friction, significantly restricting their broad-scale applicability. The preparation of alloy layers emerges as an effective strategy to enhance the mechanical properties of metal surfaces. The construction of superhydrophobic structures without loss of mechanical properties of alloy layer is expected to lead to the preparation of superhydrophobic surface with excellent wear resistance. In this study, a superhydrophobic surface with excellent hardness and wear resistance was successfully prepared by a two-step process of electrospark deposition and anodization. The superhydrophobic surface maintained superhydrophobicity under long distance friction. Firstly, alloy layer with micron bulges and excellent mechanical properties was constructed on the metal surface by electrospark deposition, which was then slightly anodized to create hierarchical micro-nano bulges rather favourable to superhydrophobicity, and anodization did not degrade mechanical properties of the surface. The surface is provided with excellent superhydrophobicity after modification with fluorosilane. SEM, 3D profilometer and roughness tester were adopted to explore microscopic morphology of the sample surfaces. XPS and FTIR were used to explore chemical components of the sample surfaces. The element distribution of the sample surfaces was analysed through EDS, and wettability of the sample surfaces was explored through the contact angle test. The hardness test and wear test were applied to explore mechanical properties of the sample surfaces. It was proved through linear friction, droplet impact, hammering and knife scratch that the superhydrophobic surface could maintain good superhydrophobicity under multiple forms of mechanical destruction, while the neutral salt spray test, electrochemical tests and acid and alkali soaking test proved the excellent property of corrosion resistance of the superhydrophobic surface. In addition, the prepared superhydrophobic surface also features an excellent self-cleaning property.

Exploring the electrochemical and mechanical properties of lithium-ion batteries in salt spray environments

With the pressing need to expedite the transition toward a greener marine industry, energy-efficient and eco-friendly lithium-ion batteries (LIBs) are increasingly favored. However, compared to land applications, marine environments pose unique challenges to the utilization of LIBs, thereby necessitating targeted safety measures. In this study, prismatic LIBs (PLIBs) are subjected to standard salt spray tests to emulate marine environments, and the resultant morphological changes and external voltage response of the batteries under the corrosion behavior are analyzed. Subsequently, the impacts of the salt spray environment on the electrochemical performance of PLIBs are assessed through a range of characterization techniques including scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and charge-discharge test. Finally, quasi-static ball indentation tests are carried out on the corroded batteries to study the behaviors under mechanical abusive loading scenarios. Results reveal that the most prominent effect of the salt spray environment on the batteries is the occurrence of swelling, attributable to the imperfect sealing of the battery tabs. This study represents an innovative exploration of the viability of LIBs in the marine environments, providing fundamental theoretical guidance for early detection of battery corrosion and collision risks, as well as facilitating protective design considerations.

A g‐C3N4/PANI S‐scheme heterojunction with face‐to‐face structure to improve the anticorrosion property on Q235 steel and enhanced mechanism study

AbstractIn photocatalytic anticorrosion perspective, the migration rate of excited electrons from surface layers to substrate steels restricted the performance of g‐C3N4 due to the high resistance between interface of g‐C3N4 layers and adhesive layers. Herein, an S‐scheme g‐C3N4/polyaniline (PANI) heterojunction with face‐to‐face structure was established by a secondary calcining method. The as‐prepared heterojunctions were applied to protect Q235 carbon steel, and the results showed that the anticorrosion performance of S‐scheme g‐C3N4/PANI heterojunction is much higher than that of g‐C3N4 and PANI coating layers according to salt spray test. Photocurrent intensity indicated that the optimum amounts of g‐C3N4 and PANI were 0.06 and 0.09 mL/cm2, which are benefit for the transport of excited electrons due to the optimum thickness of coating layers. Furthermore, the S‐scheme g‐C3N4/PANI heterojunction can promote the separation rate of charge carriers and suppress the recombination rate at the same time, which are inferred from photocurrent intensity, electrochemical impedance spectra, super‐depth‐of‐field microscope, and photoluminescence investigation. In the last, the enhanced anticorrosion performance of S‐scheme g‐C3N4/PANI heterojunction with face‐to‐face structure was deduced according to mentioned characterization.

Effect of cerium nitrate concentration on corrosion protection of hybrid organic/inorganic Si/Zr sol-gel coating applied on hot-dip galvanized steel

This present work investigates the corrosion performance of hybrid organic/inorganic Si/Zr sol-gel doped with various cerium nitrate concentrations applied on hot-dip galvanized steel. The Si/Zr sol-gel solution was prepared from tetraethyl orthosilicate (TEOS), 3-(trimethoxysilyl)propyl methacrylate (MAPTMS), and zirconium(IV) propoxide (ZTP). The effect of the addition of cerium nitrate was evaluated by electrochemical impedance spectroscopy (EIS) versus immersion in 0.1 M NaCl solution and salt spray test. The results indicated that cerium nitrate contents affected the protective behavior of sol-gel coating in long term. Additionally, the sol-gel doped with 650 ppm Ce (III) presented the optimal corrosion protection of the sol-gel coating formed on hot-dip galvanized steel substrate.

Novel multifunctional nanocomposites containing graphitic carbon nitride/silanized Nb2O5 nanofillers for the protection of steel surfaces in the automobile industry

The inorganic nanofiller niobium pentoxide (Nb2O5) was altered with [3-(2-aminoethylamino)propyl]trimethoxysilane (AEPS) and the resulting AEPS/Nb2O5 was encased with graphitic carbon nitride (GCN) in pure epoxy resin (EP). The protection performance of mild steel coated with epoxy in the presence of various concentrations of GCN encapsulated in silanized Nb2O5 was investigated using electrochemical techniques in a marine environment. A limiting oxygen index (LOI) test showed that GCN/AEPS-Nb2O5 considerably enhanced the flame retardancy properties of the epoxy coating. The PHRR and THR values for EP-GCN/AEPS-Nb2O5 significantly decreased by 81 % and 69 %, respectively, compared to those of pure EP, showing that the material is more flame-retardant. The results of salt spray tests showed that the addition of GCN/AEPS-Nb2O5 enhanced corrosion protection and reduced water absorption. Even after 960 h of exposure to seawater, epoxy-GCN/AEPS-Nb2O5 exhibited increased coating resistance of 8.99E9 Ω.cm2, according to the EIS measurements. According to SECM research, coated steel made of the EP-GCN/AEPS-Nb2O5 nanocomposite has the lowest degree of ferrous ion dissipation (1.0 I/nA). According to the FE-SEM/EDX results, the decomposition products of silanized GCN were enhanced, generating a sturdy inert nanolayered coating. To prevent ions from penetrating the specimen, EP-GCN/AEPS-Nb2O5 crystallizes into a strong, inert coating, has greater adhesive strength, and can endure prolonged immersion without losing its integrity. Therefore, the EP-GCN/AEPS-Nb2O5 nanocomposite could act as a viable coating component in the automobile industry.

Comparative Study of Anti-Corrosion Properties of Different Types of Press-Hardened Steels.

Hot stamping (or press hardening) is a new technology that is widely used in the production of advanced high-strength steel parts for automotive applications. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), and accelerated corrosion tests (the neutral salt spray test and periodic immersion test) were conducted on press-hardened samples produced from uncoated (cold-rolled and cold strip production (CSP) hot-rolled) and Al-Si-coated press-hardened steels to elucidate their distinct anti-corrosion mechanisms. The cross-sectional micromorphology and element distribution of three types of press-hardened steels after a neutral salt spray test were observed using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). The corrosion resistance of Al-Si-coated press-hardened steel was found to be significantly diminished following the hot stamping process due to the presence of microcracks and elevated iron content in the coating subsequent to austenitizing heat treatment. On the other hand, the corrosion resistance of uncoated press-hardened sheets produced from cold-rolled and CSP hot-rolled press-hardened steel was found to be proximal due to their nearly identical composition and microstructure (fully martensite) after the hot stamping process. Considering the high efficiency and energy-saving properties of hot-rolled press-hardened steel, it holds the potential to replace cold-rolled and even aluminum-silicon-coated press-hardened steel in automobile manufacturing.

Influence of corrosion on ultra-low cycle fatigue performance of steel butt-welded joints with various welding methods

Preferential corrosion of welded joints in steel structures has been observed in a wide range of scenarios and should receive enough attention. The current work focuses on the corrosion and ultra-low cycle fatigue (ULCF) behavior of low-alloy steel weld joints. Firstly, 1600 h neutral salt spray (NSS) tests were conducted on welded joints made by different welding methods, and then topography scanning of corrosion pits was carried out. It was found that the welded region is more susceptible to corrosion. Dynamic polarization curves of the welded joints were measured, and the results show that the self-corrosion potential of the welded region is lower than that of the base metal (BM) region, while the corrosion current density is higher than that of the BM region. Subsequently, cyclic tests were carried out on the corroded weld joints. The results show that corrosion can cause a maximum reduction of 11.79% in yield load and 20.87% in ultimate load of the welded joints. Corrosion has slight influence on the energy dissipation capacity of welded joints, but the maximum reductions in ULCF life could reach 77.31% due to corrosion. Fractography analysis further shows that secondary cracks, map cracks, and intergranular brittle fracture, apart from more common fatigue fracture, ductile fracture, and quasi-cleavage fracture, appear on the fracture surfaces. Supplementary numerical simulation was conducted to enable a better understanding of the failure processes. In the simulation, a geometric modeling method using topography scanning data of corrosion surface was proposed. By using the proposed modeling approach, together with Chaboche cyclic plasticity constitutive model and cyclic void growth model (CVGM) for capturing fracture behavior, the predicted results show an acceptable agreement with the experimental ones.

Magnesium Alloy Composite Water‐Repellent Surface with Durable Corrosion Resistance and Self‐Cleaning Behavior

Magnesium (Mg) alloys have poor corrosion resistance, higher requirements for corrosion resistance of the coating, and the changes in the environment in the actual application are complicated and diverse. Therefore, it is urgent to develop bio‐inspired water‐repellent surfaces (WRSs) with long‐lasting corrosion resistance and multiple excellent properties for Mg alloys. In this study, a composite water‐repellent surface (CWRS) with long‐lasting corrosion resistance and self‐cleaning behavior is prepared by combining laser processing, hydrothermal treatment, and immersion method on the Mg alloy surface. The effect of ambient temperature changes on the wettability and corrosion resistance of the CWRS is investigated. The experimental results showed that a uniform and dense CWRS with a film thickness of 36 μm could be prepared on the Mg alloy surface at an ambient temperature of 180 °C, demonstrating excellent corrosion resistance and self‐cleaning behavior. In addition, in the harsh salt spray test, it is found that even if the superhydrophobicity of the CWRS was lost, the surface still has good corrosion resistance. Multifunctional CWRSs have become a research hotspot, and it is of great significance to promote the application of Mg alloys in actual working conditions.

Study of the role of aluminium and corrosion mechanism in galvalume coating in the marine atmospheric environment

PurposeThis study aims to investigate the role of aluminium (Al) in marine environment and the corrosion mechanism of galvalume coatings by conducting accelerated experiments and data analysis.Design/methodology/approachSamples were subjected to accelerated corrosion for 136 days via salt spray tests to simulate the natural conditions of marine environment and consequently accelerate the experiments. Subsequently, the samples were examined using various test methods, such as EDS, scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS), and the obtained data were analysed.FindingsGalvalume coatings comprised interdigitated zinc (Zn)-rich and dendritic Al-rich phases. Corrosion was observed to begin with a Zn-rich phase. The primary components of the corrosion product film were Al2O3 and Zn5(OH)8Cl2·H2O. It was confirmed that the role of Al was to form a dense protective film, thereby successfully blocking the entry of corrosive media and protecting the iron substrate.Originality/valueThis study provides a clearer understanding of the corrosion mechanism and kinetics of galvalume coatings in a simulated marine environment. In addition, the role of Al, which is rarely mentioned in the literature, was investigated.

Epoxy coating reinforced with graphene-PANI nanocomposites for enhancement of corrosion-resistance performance of mild steel in saline water

Protective coatings enriched with different types of chemical additives, functional fillers, and nanostructured materials are gaining immense interest to minimize corrosion. The present work demonstrates the synthesis of chemically functionalized reduced graphene oxide (rmGO) and emeraldine salt form of polyaniline (PANI-ES)-based rmGO-PANI-ES nanocomposites as protective functional fillers for epoxy coating to inhibit mild steel corrosion. The oxidative polymerization of aniline into PANI-ES is initiated on nitrogen-rich active sites of rmGO, and it propagates along the basal plane of rmGO, eventually enwrapped the graphene sheets by interfacially grown PANI-ES. The synthesis of rmGO-PANI-ES nanocomposites and their chemical, morphological, crystalline, and structural characteristics are examined by the FTIR, 13C NMR, XPS, XRD, Raman, SEM, and HRTEM analyses. The multiple interactions between the highly polar nitrogen-rich rmGO-PANI-ES nanocomposites and the epoxy matrix strengthened the coating and increased the hardness and elastic modulus. The corrosion inhibition performance of epoxy coating enriched with the rmGO-PANI-ES nanocomposites is probed by electrochemical impedance spectroscopic (EIS) and salt spray tests using an accelerated corrosive environment (3.5 wt% NaCl). The rmGO-PANI-ES-15 nanocomposite having 0.15 wt% rGO in epoxy coating showed superior corrosion inhibition performance. The total electrochemical impedance of epoxy coating (8.7 ×103 Ω.cm2) increased to 4.7 ×1015 Ω.cm2 after incorporating 1 wt% rmGO-PANI-ES-15 nanocomposite. The enhancement of electrochemical impedance by ∼12 orders of magnitude demonstrates the effectiveness of the rmGO-PANI-ES nanocomposites for corrosion mitigation in a harsh corrosive environment. The high surface area and remarkable structural barrier of the 2D chemically functionalized graphene furnished excellent protective coverage. The PANI-ES of rmGO-PANI-ES nanocomposites formed a passive layer of fully reduced leucoemeraldine base of PANI (PANI-LEB) on the coating-mild steel interface by accepting the electrons, generated during the anodic oxidation of iron. These events collectively increase the impedance by multifolds and inhibit steel corrosion. The present findings revealed that graphene-enriched conductive polymeric nanocomposites-based coatings can be promising solution to mitigate corrosion of metal-based installations in a marine environment.

Unraveling the interfacial structure of TA2 titanium-A36 steel composite plate and its corrosion behavior in marine environment

In this study, the microstructure and corrosion behavior of the interface of a titanium-steel composite plate were analyzed and compared with that of cladding material and steel substrate. The results showed that the interface exhibited a complex laminar structure. The mass losses after the salt spray test indicated an accelerated corrosion effect at the composite interface, and the effect diminished with the extension of corrosion time. A significant accelerated corrosion crack was observed at the interface after the corrosion test. Furthermore, the multiple corrosion mechanism was elaborated in combination with electrochemical activity test in different regions of the composite interface.

Дослідження методів випробування лакофарбового покриття на стійкість до корозії

This scientific work is aimed at researching the testing methods of paint coatings used for protecting the metal parts of automobiles in order to determine their resistance to corrosion processes. Paint coatings are used to protect the metal surfaces of automobiles from corrosion in various climatic conditions and under the influence of aggressive factors such as atmospheric conditions, chemical substances on the road, polluted air, and other corrosive environments, making their quality and effectiveness of great significance.
 Different methods of testing paint and varnish coatings are considered, such as neutral salt spray test, acetic acid salt spray test (with and without copper acceleration), and cyclic corrosion testing. Attention is also given to parameters such as test duration, temperature regimes, and chemical aggressiveness of the environment to establish the effectiveness of these methods. The analysis of the tests allows determining which methods best meet the requirements for assessing the corrosion resistance of paint coatings. The work also investigates the impact of various factors, such as the type of paint coating, surface preparation, and operating conditions, on the test results. It was determined that the proper selection of test methods and adequate assessment of their effectiveness help in improving the corrosion resistance of the paint coating in various operating conditions.
 The work has important practical applications in the automotive industry by enhancing the quality of protection for automotive coatings against corrosion and extending their service life in various operating conditions. The obtained results will help improve the quality and durability of paint coatings, metal structures, and other products against corrosion by choosing the optimal method for testing paint coatings. This scientific work has practical significance for engineers and manufacturers involved in the development and application of corrosion-resistant coatings.