Rust Formation Research Articles

Effect of P Addition on the Corrosion Resistance of Steels before and after Rust Formation

Effect of P Addition on the Corrosion Resistance of Steels before and after Rust Formation

Investigation of Corrosion Behavior of Cenosphere reinforced Iron Based Composite Coatings

In the present study cenopshere was reinforced with FeCrNiC (Metco 42C) as matrix material and prepared four different feedstock powders such as FeCrNiC+0%Cenosphere, FeCrNiC+5%Cenosphere, FeCrNiC+10%Cenosphere and FeCrNiC+15%Cenosphere were coated by plasma spray technique on T22 substrate. Evaluation of the substrate and coatings potential under salt spray test was performed. Dense fog of 5% NaCl salt water was used to create a corrosive atmosphere within the chamber. The salt water's pH was kept constant at 6.5-7. The materials that underwent corrosion were examined using X-ray diffraction (XRD), and scanning electron microscopy (SEM). The FeCrNiC+15%Cenosphere and FeCrNiC+10%Cenosphere coatings exhibited reduced weight loss during a 168-hour corrosion test compared to the FeCrNiC+5%Cenosphere, FeCrNiC coatings, and substrate. The excellent chemical stability and corrosion resistance of Cr23C6, SiO2, NiO, and Cr2O particles contribute to gradually avoid the formation of red rust on Fe-based coated samples with exposure approaches to 52 and 130 hours.

Fabrication of a Hydrophilic Al2O3/AlN EP Coating with Self‐Cleaning and High‐Efficiency Anti‐Corrosion Properties

AbstractCurrently, with the gradual development of anticorrosive coatings, the pursuit of simple preparation methods and the improvement of anticorrosive coatings’ properties have become the major research trends. This study successfully prepared a hydrophilic super anticorrosive coating through a simple mixing method. The coating has a contact Angle of 67.8° and a rolling Angle greater than 20°. This coating can withstand 180 days of salt spray test with no bubble or rust formation when placed on a Q 235 substrate in a 3.5 wt % NaCl solution, demonstrating the excellent corrosion resistance of the AO0.4AN0.6EP coating. Furthermore, after being immersed in a 3.5 wt % NaCl solution for 3 days, the AO0.4AN0.6EP coating exhibited the largest impedance diameter (2.07×108 Ω⋅cm2), almost three times larger than other coatings, and possessed the highest Bode modulus value, one order of magnitude higher than other coatings. After immersion in a 3.5 wt % NaCl solution for 7 days, the AO0.4AN0.6EP coating had the largest Ecorr and the smallest icorr, indicating its superior corrosion resistance. In addition to corrosion resistance, the AO0.4AN0.6EP coating showed no signs of cracking, discoloration, or decomposition after being exposed to ultraviolet aging lights for 30 days, demonstrating its excellent UV resistance. Moreover, neither dry soil particles nor muddy water could adhere to the coating surface, proving its good self‐cleaning ability. Therefore, this coating holds promising applications in the field of super corrosion‐resistant coatings.

The structural assessment for concrete structure on the onset of cracking with respect to steel corrosion

The present study concerns structural behaviour of a marine bridge in terms of cracking exposed to a seawater environment under the risk of chloride-induced corrosion with the axial loading. In the modelling process, the corrosion propagation was expressed into the rust formation on the steel surface, while the axial load was given 5–30 % to the compressive strength of concrete. The interfacial gap between steel and concrete was taken 10 µm, imposing the buffering capacity against a build-up of the rust at the steel-concrete interface. As a result, it was found that the tensile damage produced the cracking on the surface of concrete with a minimal corrosion of steel, which was further developed into the inner concrete depth with increasing corrosion formation. Also, an increase in the axial load resulted in an increase in the surface cracking at a given rust formation. At the steel-concrete interface, the cracking was much affected by the compressive deformation arising from a build-up of rust, as being limited in the vicinity in the interfacial zone, presumably due to the limited rust formation. A combination of steel corrosion and axial loading imposes the accelerated cracking of concrete structure then to rapidly deteriorate its serviceability.

Bond performance of reinforcing bars in fly ash-based engineered geopolymer composites under uniform and nonuniform corrosion conditions

While concrete is the most popular building material in the world, corrosion of the steel reinforcement in reinforced concrete (RC) structures poses ongoing durability issues. In this study, the effects of alkali activator modulus, concentration, and different corrosion periods are rigorously investigated utilizing accelerated electrochemical corrosion techniques under both uniform and nonuniform corrosion conditions. Bond stress and bond stress deterioration are evaluated to provide a thorough examination of corrosion-induced fracture formation through pull-out experiments. X-CT 3D imaging is also used to understand the spread of rust in both corrosion scenarios. Results show that mixes with lower alkali activator modulus and higher alkali activator concentration might result in better bond stress preservation and higher ultimate bond stress under corrosion. High bond stress, however, usually corresponds to a more brittle failure when subjected to pull-out force. Nonuniform corrosion treatment can result in differential rust formation and a quicker bond breakdown between steel bars and engineered geopolymer composites (EGCs) than uniform corrosion. Furthermore, under corrosion, EGCs with high alkali activator modulus tend to form more penetrating cracks with limited width and depth. Both narrow and deep penetrating fractures can arise from EGCs with low alkali activator concentration.

Grafted sepiolite as smart nanocontainer for Daphne Gnidium plant extract: PH-dependent controlled release and effective green anti-corrosion coating

This study focuses on advancing the development of environmentally sustainable and efficient active anti-corrosion coatings for metal substrates in various engineering applications. A novel smart anti-corrosive container was developed using fibrous sepiolite clay (Sep). Sep was first subjected to grafting with 3-Aminopropyl-diethoxy-methylsilane (APDEMS). Subsequently, the grafted-Sep (Sep-G) was used to load a Daphne Gnidium plant extract (DGE) as a natural corrosion inhibitor. The modification process of Sep was carefully monitored and characterized through Zeta potential, scanning electron microscopy, X-ray diffraction, UV/visible spectroscopy, and Fourier transform infrared spectroscopy. The results highlighted the successful clay modification with a silane loading of 7.68 % and a DGE adsorbed amount of approximately 58 mg/g. The DGE release behavior of the elaborated nanocomposite (Sep-G@DGE) was studied at different pH values and showed distinct pH-dependent release profiles. The rates were in the following order: acidic > alkaline > neutral. Electrochemical properties of Sep-G@DGE were investigated on a bare mild steel electrode in 0.1 M NaCl solution, demonstrating a corrosion inhibition efficiency of 90 % for a 24-hour immersion time at a concentration of 1 g/L. Moreover, the beforehand prepared nanocontainer, Sep-G@DGE, was incorporated into an alkyd resin to formulate a smart anti-corrosion coating. This coating exhibited enhanced anti-corrosion properties and sustained inhibitory effects over time compared to that of a pure alkyd coating. The coating's efficiency is attributable to the high dispersion of the layered clay mineral structure, which allowed an on-demand release of the DGE inhibitor. In addition, the presence of free APDEMS NH3+ group leads to the formation of electrostatic interactions with the adsorbed chloride ions on the metal surface, acting thus as a barrier against corrosive agents and inhibit rust formation in paint cracks.

Effectiveness of Grouting and GFRP Reinforcement for Repairing Spalled Reinforced Concrete Beams

Corrosion of steel reinforcement from chloride exposure can compromise the strength of reinforced concrete structures. Rust formation expands, applying pressure on concrete, resulting in cracks and spalling. Prompt repair is crucial for severe cases of spalling. This research assessed the efficacy of repair strategies for reinforced concrete beams post-spalling, including grouting and different techniques involving Glass Fiber Reinforced Polymer (GFRP) reinforcement. The research examined four variations of reinforced concrete beams, each sized at 150 mm × 200 mm × 3300 mm. Results showed that the standard beam (BK) had an average maximum load capacity of 29.74 kN. In contrast, the grouted beam (BGR) demonstrated a reduced maximum load of 14.39 kN, along with decreased steel and concrete strain compared to BK. This suggests that the grouting repair did not fully restore the beam's flexural capacity after spalling. Incorporating GFRP strips (BGRS) led to a marginal increase in the beam's maximum load, albeit remaining below BK, with lower steel and concrete strain than BK. However, the steel and concrete approached their yield points, indicating enhanced flexural performance. The full-wrap GFRP beam (BGRSF) experienced an 8.08% increase in maximum load compared to BK, with concrete strain surpassing BK, suggesting an enhancement in flexural stiffness. Doi: 10.28991/CEJ-2024-010-07-05 Full Text: PDF

Mitigation of Steel Corrosion Threshold Utilizing Plant-Based Green Corrosion Inhibitors through Electrochemical Techniques

Corrosion of steel reinforcement is a major cause of deterioration in reinforced concrete structures. The corrosion process is influenced by the concrete-steel interface, with the alkaline concrete pore solution initially providing passivation. However, ingress of aggressive substances like chlorides can disrupt the passive layer, initiating active pitting corrosion above a threshold level often taken as 0.4% chloride by cement weight. Once the chloride threshold is exceeded, corrosion propagation depends on oxygen and moisture availability. The resulting rust formation causes expansive cracking and spalling of the concrete cover. Corrosion damage can be mitigated through use of inhibitors like calcium nitrite though high dosages impair concrete strength. Recently, plant-based organic compounds have shown promise as green corrosion inhibitors. The corrosion behavior of steel in concrete can be evaluated through impressed accelerated corrosion testing along with electrochemical techniques like half-cell potential mapping and resistivity measurements. These allow assessment of the probability of corrosion and corrosion rate. Techniques like linear polarization resistance and electrochemical impedance spectroscopy can also quantify instantaneous corrosion rate. Proper structural condition assessment and repair using both conventional and green inhibitors is crucial to control steel corrosion, maintain service life and ensure safety. Further research is needed on green corrosion mitigation methods and advanced non-destructive testing techniques.

In-situ groundwater remediation of contaminant mixture of As(III), Cr(VI), and sulfanilamide via electrochemical degradation/transformation using pyrite

Electrochemical advanced oxidation processes (EAOPs) are effective in removing persistent contaminants from groundwater. However, their practical applicability depends significantly on various site-specific characteristics. Therefore, the primary objective of this investigation was to study the feasibility of EAOPs and pyrite, which is a sulfide mineral, to effectively remove the mixture of arsenic (As (III)), chromium (Cr (VI)), and sulfanilamide in groundwater. We conducted a comparison of three systems: (1) EAOP alone, (2) pyrite alone, and (3) a combined EAOP and pyrite system. In EAOP alone, sulfanilamide was effectively oxidized (80%), while the electrochemical transformation of As(III)/Cr(VI) into As(V)/Cr(III) was limited. In just the pyrite system, As(III), Cr(VI), and sulfanilamide were adsorbed onto the surface of pyrite (60%, 20%, and 18%). Neither the EAOP nor the pyrite system alone could effectively treat the contaminants mixture. Nonetheless, the combined system completely removed As(III), Cr(VI), and sulfanilamide by the synergistic reaction. This could be attributed to the formation of green rust, a natural adsorbent mineral produced as a reaction of dissolved iron, generated via electrochemical pyrite oxidation, with the groundwater electrolyte (e.g., CO3 or SO4). This system harmonized the combined approach of EAOP and pyrite to effectively eliminate both organic and inorganic contaminants. Environmental implicationA paper proposed electrochemical oxidation (EO) with pyrite to remove both organic and inorganic contaminants from groundwater. The removal performance of the combined system was evaluated, and the synergistic mechanism was revealed. The combination of EO and pyrite with synergistic removal effectively removed the mixture of both contaminants. This could be attributed by the formation of green-rust by electrochemical activation for pyrite. Compared to the single system of EO and pyrite alone, the combined system with EO and pyrite improved removal performance. Results suggested that the combined system could be used for green groundwater remediation.

Self‐healing characteristics of superabsorbent polymers in epoxy coating for corrosion inhibition of carbon steels

AbstractThis study evaluated the self‐healing characteristics of superabsorbent polymers (SAP) in epoxy polyamide paint systems applied using brush application. The SAP underwent preliminary characterization to determine its primary properties and was then incorporated into the epoxy primer at different percentages. The epoxy‐SAP coating systems then underwent various tests to evaluate their self‐healing capability. Excellent adhesion is obtained with the coating system composed of initial epoxy primer, epoxy‐SAP layer, final epoxy primer, and an epoxy enamel topcoat. Electrochemical impedance spectroscopy (EIS) reveals that the addition of SAP increased the charge transfer resistance and pore resistance and decreased the double layer capacitance of the coating system in a span of 5 h, confirming the self‐healing of the coating. Maximum corrosion protection for 5 h is obtained between 15 to 20 wt% SAP. Lastly, it is determined through long‐term immersion tests that the addition of SAP in the coating significantly decreases the rust formation; however, the coating starts to peel off due to the swelling of SAP after 2–3 days.

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.

Capacity assessment of uncorroded and corroded dapped‐end beams by NLFE and strut‐and‐tie based methods

AbstractThe verification of dapped‐end beams degraded by corrosion is a problem, especially for existing bridges in service. This paper proposes a nonlinear finite element (NLFE) modeling procedure and a simple strut‐and‐tie based procedure for predicting the response of dapped‐end beams subjected to chloride corrosion. Firstly, the finite element modeling strategy, based on the adoption of multilayer shell elements and the PARC_CL 2.1 crack model is described. Then, the degradation effects on concrete, rebars, and steel‐to‐concrete interaction are defined as a function of the propagation period of corrosion. In particular, the effects of corrosion on the reinforcement are modeled by applying a reduction of tensile strength that considers for both the reduction of cross‐section and the ultimate strain caused by pitting. Concrete splitting cracking due to volume expansion during rust formation is modeled by reducing the mechanical properties of concrete. Corrosion effects in steel‐to‐concrete interaction are modeled by applying a bond strength decay to the spring elements connecting corroded rebars—modeled with truss elements—and concrete multilayer shell elements. The proposed finite element procedure is used to study two scenarios based on different spatial distributions of corrosion‐prone areas. Subsequently, a simplified analytical approach based on the strut‐and‐corroded tie method—called S&CT method—is proposed and compared with the finite element outcomes. Finally, the validations of the two proposed methods are presented with respect to a corroded dapped‐end beam, showing that corrosion of rebars affects the resistance mechanisms of the dapped‐end beam, by reducing both resistance and ductility. The proposed simplified analytical S&CT method provides conservative and safe results compared to the numerical NLFE model and to experimental data.

Unveiling the future of steel corrosion inhibition: a revolutionary sustainable odyssey with a special emphasis on N+-containing ionic liquids through cutting-edge innovations

Graphical abstract illustrates how ionic liquids protect metal surface from corrosion, highlights the factors affecting efficacy and associated chemical reactions with and without ionic liquids, highlighting their role in preventing rust formation.

Corrosion Behavior of Fe-P Binary Alloys in Low-pH Solution

Phosphorus is well known as an element which is difficult to be completely removed from steels and affects workability, welding property, and corrosion resistance. In atmospheric corrosion of steels, phosphorus improves the corrosion resistance by the formation of compact and high-density rust. In contrast, phosphorus increases the corrosion rate of steels in hydrochloric acid, but the precise reason is still unclear.In this research, the effect of phosphorus on corrosion behavior of Fe-P binary alloys was investigated by electrochemical measurements and immersion test in a low-pH solution, and corrosion morphology was examined by scanning electron microscopy.

Effect of Different Passivation Treatments on Alkali Zn-Ni Coatings: Corrosion Resistance and Adhesion Performance of Geomet 321 and ML Black Coatings

This study aims to improve the corrosion properties of (AISI 1040) materials used in the automotive industry. For this purpose, two different coating techniques were applied to the same surface. As part of the research, different passivation processes (transparent, blue, yellow, and black) were applied to alkaline Zn-Ni coatings. Geomet 321 and Geomet ML Black coatings were deposited on the passivation layer to form a double-layer coating. In order to investigate the adhesion and corrosion effects of these coatings, a dry adhesion test, a water test, a humidity test, and a salt spray test were carried out, and cross-cut adhesion tests were carried out after each corrosion test. After all these tests, rust formation was analysed by visual analysis, and atomic weight percentages and coating thicknesses were examined by X-ray. The transparent passivation after the Zn-Ni coating fully satisfied both adhesion and corrosion protection requirements for 321 and ML Black coatings. No red rust formation was observed on the coating samples after the test; only partial white rust formation was observed, and no peeling of the coating layer was detected in the adhesion tests. As a result, the optimum result of the passivation processes used for Geomet 321+ML Black coatings applied after the Zn-Ni + passivation process was obtained with transparent passivated Zn-Ni coatings. Even after 1200 hours, no red rust was observed in passivated Zn-Ni coating+ Geomet 321+ Geomet ML Black.

Exploring the influence of Cu addition on the microstructure and substance transformation in corrosion product layer of X80 steel

The influence of Cu addition on the microstructure evolution and substance transformation in corrosion product layer was explored through comprehensive microscopic characterization and immersion test. The Cu lowers the Ar3 and Ms temperatures of X80 steel, facilitating the Granular Bainite formation while impeding the development of Polygonal Ferrite. Furthermore, the Cu facilitates the development of stable corrosion products, leading to an increased proportion of these substances in corrosion product layer and a reduction in their dissolution and detachment during rust formation. And the formed oxide (CuO) not only enhances the stability of the corrosion product layer but also provides nucleation sites for CuFeO2 production. CuFeO2 carries a negative charge, which enhances the Cl− blocking ability of the corrosion product layer. The inclusion of these substances in corrosion product layer enhances its resistance to corrosive media. The corrosion product layer offers the best protection for the steel when the Cu addition is 1.5 wt%.

Corrosion Resistance Enhancement of Reinforced Concrete in Marine Environment by Partial Replacement of Black Rice Husk Ash

In this work, the black rice husk ash (BRHA), a pozzolanic material, was used as a partial replacement in concrete with the weight percentages of 0%, 10%, 20%, 30%, 40% and 50% for enhancing the corrosion resistivity in the marine environment. The compressive strength, corrosion by accelerated corrosion test by impressed voltage (ACTIV), and chloride (Cl−) penetration of concrete specimens were investigated after 28 days of curing. For corrosion and chloride penetration analyses, the 20% of BRHA replacement specimen was the most effective concrete specimen because the deformation was not observed within 19 days of the test. The cement specimens with lower BRHA percentages were cracked due to the development of stress by the rust formation. For higher BRHA percentages, the protective Fe2O3 was dissolved due to the acidic environment caused by higher chloride accumulation in the cement specimens. The steel rebar was then aggressively attacked by the chloride and it was finally broken. Therefore, the optimization of the BRHA percentage is needed to minimize corrosion. However, the longer curing time of 20% BRHA replacement specimen is required for increasing the compressive strength because its compressive strength is slightly lower than the standard.

Study of rust layer evolution in Q345 weathering steel utilizing electric resistance probes

In this study, a corrosion-monitoring sensor was used to investigate the evolution mechanism of rust formation on Q345 weathering steel. The results indicate that rust layer formation proceeded through alternating thickening and conversion (no thickening) stages. Specifically, the transformation of Fe2+ to γ-FeOOH increased the thickness of the rust layer in the thickening stages. After each thickening stage, conversion occurred: the composition of the rust layer changed, which entailed an increase in the α-FeOOH content. In the stage of conversion, no thickening occurred and this process was the controlling step of weathering steel rust stabilization.

Causes of Leaks in the Main Engine Cooling Jacket MT. Mulia Karsa 2

Between the cylinder wall and the cylinder block is the cylinder block is an intermediary cooling device called the primary cooling jacket of the main engine system. Here, the cooling fluid is able to draw heat away from the cylinder wall and continue its circulation. Due to an issue with the jacket cooling of the primary engine system, ship operations had to be suspended for maintenance, prompting the current investigation. The study aims to pinpoint the reasons behind jacket cooling leakage in the main engine room and suggest viable countermeasures. Observation, interviews, and reviews of relevant literature are just a few methods used to gather information. The study took a descriptive, qualitative approach, using tools like SHEL and the fishbone diagram to analyze data. According to the results of this research, a lack of attention to the planning and maintenance system for the main engine, o-ring deterioration in the jacket cooling main engine system, corrosion of the cooling jacket, rust formation in the tank, suboptimal water preheating temperature, and a lack of maintenance all contribute to leaks in the main engine cooling system. Several variables contribute to the main engine's less-than-ideal cooling efficiency. The jacket cooling system damage system's o-ring or a leak in the jacket cooling system are two examples of these problems with the primary engine system. In addition, the primary engine cooler's cooling water jacket is subpar, and its circulation is subpar. In addition, the exhaust gas temperature from the main engine is inconsistent, and rising temperatures have not yet resulted in the engine's shutoff. The primary engine system performs maintenance at the specified intervals specified in the handbook to handle problems with jacket cooling leaks. O-ring and cooling jacket replacement, chemical dosing, water pH testing, and routine temperature checks are all part of the maintenance process.

Roles of grain refinement in the rust formation and corrosion resistance of weathering steels

Weathering steels with different grain sizes (20.0 µm, 3.8 µm, and 0.6 µm) were prepared through a combination of cold-rolling and heat-treatment processes. Their corrosion behaviors were investigated using wet/dry cyclic corrosion tests in 3.5 wt% NaCl solution. The results indicate that grain refinement has a positive effect on the rust layer formation. It accelerates the formation of a more stable, compact, and protective rust layer, along with enhanced enrichment of alloying elements (Cr, Ni, and Cu) as oxide compounds within the rust layer. Moreover, grain refinement shows promise in inhibiting non-uniform corrosion and the formation of "deep-and-narrow" corrosion pits.