Improved Corrosion Resistance Research Articles

Empowered corrosion-resistant products through HCP crystal network: a topological assistance

Human computer interaction (HCI) aims to enhance product effectiveness and efficiency by empowering users. This research examines corrosion resistance in alloys, a concern due to technological advancements. Metals and alloys are susceptible to degradation, leading to functionality loss, structural collapse, and environmental contamination. Improving corrosion resistance is crucial for product efficiency. In this paper, HCI identifies requirements that emphasize taking an existing hexagonal closely packed (HCP) network, investigating the network for requirements in the form of vertices and edges, mapping different vertices and edges of the network graph with topological invariants, solving the network graph by invariants, and providing results for modeling and design of advanced networks and architectures. The HCI also ensures and investigates the optimization of results produced under the specifications. The study examines network graph results for irregularities, providing guidelines for engineers and manufacturers to create advanced alloy architectures with characteristics through mathematical and graphical methods.

Improvement of Corrosion and Wear Resistance of Mg-Li Alloy by Binary- and Ternary-Layered Double Hydroxide/Steam Coating Composite Coatings

Improvement of Corrosion and Wear Resistance of Mg-Li Alloy by Binary- and Ternary-Layered Double Hydroxide/Steam Coating Composite Coatings

Hybrid Zinc Coatings with Improved Corrosion Resistance Based on Chitosan Oligosaccharides

Hybrid Zinc Coatings with Improved Corrosion Resistance Based on Chitosan Oligosaccharides

Design and Development of Ti–Zr–Nb–Ta–Ag High Entropy Alloy for Bioimplant Applications

A new non‐equiatomic 35Ti–35Zr–20Nb–5Ta–5Ag at% high entropy alloy (HEA) is designed by combining the HEA concept with the properties required for bioimplants. Mechanical alloying is used to synthesize the HEA, which is then compacted at 550 and 700 MPa and sintered at 1300 °C. The phases, microstructure, and mechanical properties are investigated, and in vitro corrosion properties are studied in a simulated body fluid. After 20 h of mechanical alloying, a single body‐centered cubic (BCC) phase with a nanocrystalline size of 3.6 nm was formed. After sintering, the microstructure is composed of dual‐phase BCC structures: the major BCC 1 phase, the grain boundary BCC 2 phase, and the ultra‐fine equiaxed phase. The results of the micro‐indentation test indicate that the elastic modulus of the HEA is 84.4 ± 8.7 and 113.2 ± 13.36 GPa, and its Vickers microhardness is 3.47 ± 0.1 and 5.35 ± 0.2 GPa when it was compacted at 550 and 700 MPa respectively. The corrosion resistance tests reveal that HEA compacted at 700 MPa has higher corrosion resistance than commercial Ti6Al4V alloy. The developed Ti–Zr–Nb–Ta–Ag HEA has improved corrosion resistance and a lower elastic modulus, making it a potential candidate for bioimplant applications.

Microstructure, Hardness, Wear Resistance, and Corrosion Resistance of As-Cast and Laser-Deposited FeCoNiCrAl0.8Cu0.5Si0.5 High Entropy Alloy

FeCoNiCrAl0.8Cu0.5Si0.5 high-entropy alloys were fabricated using vacuum induction melting and laser deposition processes, followed by a comparison of the structural and mechanical properties of two distinct sample types. The as-cast FeCoNiCrAl0.8Cu0.5Si0.5 alloy is comprised of BCC1, BCC2, and Cr3Si phases, while the laser-deposited alloy primarily features BCC1 and BCC2 phases. Microstructural analysis revealed that the as-cast alloy exhibits a dendritic morphology with secondary dendritic arms and densely packed grains, and the laser-deposited alloy displays a dendritic structure without the formation of granular interdendritic regions. For mechanical properties, the as-cast FeCoNiCrAl0.8Cu0.5Si0.5 alloy demonstrated higher hardness than the as-deposited alloy, with values of 586 HV0.2 and 557 HV0.2, respectively. The wear rate for the as-cast alloy was observed at 3.5 × 10−7 mm3/Nm, with abrasive wear being the primary wear mechanism. Conversely, the as-deposited alloy had a wear rate of 9.0 × 10−7 mm3/Nm, characterized by adhesive wear. The cast alloy exhibited an icorr of 4.062 μA·cm−2, with pitting as the form of corrosion. The laser-deposited alloy showed an icorr of 3.621 μA·cm−2, with both pitting and intergranular corrosion observed. The laser-deposited alloy demonstrated improved corrosion resistance. The investigation of their microstructure and mechanical properties demonstrates the application potential of FeCoNiCrAl0.8Cu0.5Si0.5 alloys in scenarios requiring high hardness and enhanced wear resistance.

Improvement of corrosion resistance and electrical conductivity of a Cr–C coated heat-assisted forming stainless steel bipolar plate for proton exchange membrane fuel cell

Heat-assisted forming is gaining increasing attention for its potential in improving the formability and quality of metallic bipolar plate (BPP) of proton exchange membrane fuel cell (PEMFC). However, the effects of heat-assisted forming and the subsequent coating process on corrosion resistance and electrical conductivity of stainless steel BPP still remain unclear. This work proposes a way to improve simultaneously the corrosion resistance and electrical conductivity of heat-assisted forming stainless steel BPP by depositing a Cr–C coating directly on its surface without removing the oxide layer using the magnetron sputtering method. Potentiodynamic tests indicate that self-corrosion current density and corrosion current density at 1.0 V (vs. Ag/AgCl) of the Cr–C coated heat-assisted forming SS316L BPP prepared under 900 °C for 10 min are 0.021–0.040 μA cm−2 and 77.54 μA cm−2, respectively, both of which are smaller than those of coated SS316L BPP formed under room temperature. In addition, the contact resistance is close to that of the gold-plated copper plate under the same pressure. The corrosion resistant intermediate oxide layer and conductive network formed between Cr–C coating and metal substrate through defects of oxide layer may be the main reason for improvement of its corrosion resistance and electrical conductivity, respectively.

Effects of Niobium Addition on the Mechanical Properties and Corrosion Resistance of Microalloyed Steels: A Review

Steel structures are prone to corrosion, a chemical reaction between steel and the atmosphere that gradually weakens the material. Over time, this reaction can significantly reduce the structural integrity and lifespan of steel elements. Without intervention, corrosion can cause structures to fail, leading to financial, environmental, and potential human losses. Enhancing steel’s corrosion resistance is crucial, and one method involves adding niobium (Nb). Niobium microalloyed steels are known for their increased strength, and some research indicates that Nb may also improve corrosion resistance by making the grain structure of the steel finer. However, the complete potential of Nb in corrosion prevention remains underexplored, with significant research gaps across various scales, from microstructural impacts on durability to macroscopic effects on mechanical properties. The research community has utilized numerous experimental approaches to test corrosion resistance under different conditions, but there is a lack of comprehensive studies that aggregate and analyze these findings. This paper seeks to fill that void by reviewing the impact of Nb on the strength and corrosion resistance of structural steels, examining how steel beams’ ultimate capacity degrades over time and identifying key areas where further research is needed to understand Nb’s role in mitigating corrosion.

A comprehensive literature mining and machine learning to decipher and predict effects of concrete materials on concrete corrosion of sewer pipe

ABSTRACT The concrete composition of different pipelines varies greatly, and a comprehensive analysis of the impact of concrete design on pipeline corrosion is required. Developed an integrated model based on Scikit-Optimize, XGBoost and SHAP to analyze concrete’s carbonation and sulfuric acid resistance from five aspects: binder type, supplementary cementitious material (SCM’s), aggregate, admixture and w/b. Choose Scikit-Optimize for parameter optimization. As an explanation model, the SHAP model can perform analysis well and explain the analysis basis of the XGBoost training model. The established model can accurately predict the corrosion effect (R2 >0.987) without overfitting. Binder should be maintained at 380 to 400 (kg/m3). Water/binder and coarse aggregate/binder are the two main factors that influence the binder, and they should be maintained at a ratio of around 0.4 to 0.6 and 2.5, respectively. Fly ash (FA) should be SCM’s used as at a range of 300 to 350 (kg/m3) to improve corrosion resistance.

Corrosion behavior of Q420qNH plate and welded joint in deicing salt medium by cyclic immersion + infrared drying

ABSTRACT The corrosion behavior of Q420qNH steel plate and welded joint in deicing salt medium is investigated by cyclic immersion + infrared drying accelerated corrosion experiments. The results show that the corrosion products are mainly Fe2O3 and FeOCl under the influence of Cl- concentration differential corrosion microcells in the immersion corrosion anoxic stage, and the corrosion products are mainly β-FeOOH, γ-FeOOH, and Fe3O4 under the influence of oxygen concentration differential corrosion microcells catalyzed in the infrared drying stage. Throughout the corrosion process, the corrosion weight gain and average corrosion rate of the welded sample is always lower than that of the plate sample. The Iα-FeooH/Iβ-FeooH + FeOCl peak intensity ratio of the welded sample is always higher than that of the plate sample and the heat- affected zone sample. The corrosion types of the three samples are inhomogeneous total corrosion + pitting, and the depth of the pits in the plate is much larger than that in the weld and the heat-affected zone. In the late stage of corrosion, the self-corrosion current density is: plate > heat-affected zone > weld, and the resistance of the rust layer of the weld and heat-affected zone samples is 1.66 times and 1.31 times of that of the plate sample, respectively. This is because the microstructure of the weld and heat-affected zone are composed of a large number of fine acicular ferrite and lath-shaped bainite generated inside the original austenite grains, and the small angle grain boundary is not conducive to the initiation and expansion of pitting corrosion. In addition, the higher content of Cu, Cr, Ni and other elements in the weld can refine the rust layer products and effectively impede the intrusion of Cl-, contributing to the improvement of corrosion resistance. As the combined effect of Cl- and immersion anoxic environment inhibits the formation of α-FeOOH and promotes the formation of the large number of loose and unstable β-FeOOH and soluble FeOCl, the weathering steel is not well protected by the rust layer during cyclic immersion corrosion in deicing salt medium.

Recent Advances in the Deposition of Aluminide Coatings on Nickel-Based Superalloys: A Synthetic Review (2019–2023)

Thermal barrier coatings (TBCs) are widely used to improve the oxidation resistance and high-temperature performance of nickel-based superalloys operating in aggressive environments. Among the TBCs, aluminide coatings (ACs) are commonly utilized to protect the structural parts of jet engines against high-temperature oxidation and corrosion. They can be deposited by different techniques, including pack cementation (PC), slurry aluminizing or chemical vapor deposition (CVD). Although the mentioned deposition techniques have been known for years, the constant developments in materials sciences and processing stimulates progress in terms of ACs. Therefore, this review paper aims to summarize recent advances in the AC field that have been reported between 2019 and 2023. The review focuses on recent advances involving improved corrosion resistance in salty environments as well as against high temperatures ranging between 1000 °C and 1200 °C under both continuous isothermal high-temperature exposure for up to 1000 h and cyclic oxidation resulting from AC application. Additionally, the beneficial effects of enhanced mechanical properties, including hardness, fatigue performance and wear, are discussed.

Development of potentiostatically deposited cerium conversion coating for Mg alloys

AbstractIn this work, cerium conversion coating (CeCC) was deposited on AZ91D Mg alloy using potentiostatic polarization method combined with phosphate pore‐sealing treatment. Initially, the optimum deposition parameters to obtain a crack‐free surface were found. The characterization of coating revealed the presence of a nodular morphology of cerium oxide deposits. Next, the electrochemical behavior of the coated surface was assessed using potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5 wt% NaCl solution. Based on electrochemical characterization, the coating exhibited a fivefold increase in the charge transfer resistance and a corresponding 76% reduction in corrosion rate, when compared to the bare surface. Furthermore, the conversion coating exhibited improved corrosion resistance when evaluated using the immersion test. Therefore, these findings demonstrate the feasibility of the potentiostatic method for creating nearly crack‐free CeCC on Mg alloys, unlike conventional conversion coatings. Moreover, this approach holds great potential for effectively mitigating the corrosion issues in Mg alloys.

Effect of Boron Content in LiOH Solutions on the Corrosion Behavior of Zr-Sn-Nb Alloy.

In pressurized water reactors, LiOH may be concentrated in some areas, leading to the accelerated corrosion of fuel claddings. Injecting boric acid into primary coolants can mitigate the accelerated corrosion effect of LiOH on Zircaloys, but the effects of boron content on the corrosion behavior of the Zr-Sn-Nb alloy are still unknown. This work focused on the corrosion and hydrogen absorption behavior at 360 °C/18.6 MPa in 100 mg/kg LiOH solutions with 0 mg/kg, 50 mg/kg, and 200 mg/kg boron contents for up to 510 days, aiming to study the effect of boron content on corrosion resistance in LiOH solutions. Corrosion kinetics, microstructures of oxide films, hydrogen absorption concentrations and hydride morphology were obtained after the test. The results show that injecting boron in LiOH solutions can significantly reduce the corrosion weight gain, hydrogen concentration, and hydrogen length of Zr-Sn-Nb alloys, that is, improving corrosion resistance effectively. During the oxidation of the Zr-Sn-Nb alloy, B3+ and Li+ incorporate in oxide films. The incorporation of Li+ may lead to the generation of oxygen vacancies, which can carry oxygen from the solutions to O/M interface, accelerating corrosion. The incorporation of B3+ in oxide films will slow down the oxidation of Zr-Sn-Nb alloys by reducing the oxygen vacancies caused by Li+ aggregation.

Corrosion behaviour of SiC particulate reinforced AZ31 magnesium matrix composite in 3.5 % NaCl with and without heat treatment

Magnesium is a lightweight structural material widely utilised in automotive applications. To enhance its mechanical properties, ceramic particulate reinforcement can be incorporated, particularly for wear resistance and high-temperature applications. However, the addition of ceramic particles to magnesium can compromise its corrosion resistance due to microgalvanic cell formation at the interfaces between the Mg matrix and the second phase. This reduces the chemical protection provided by the passive film. In this study, the corrosion properties of AZ31 and AZ31-5SiC samples were investigated, with a focus on the effect of heat treatment. Detailed microstructural and electrochemical analyses revealed that the AZ31 cast sample forms an effective passive film, resulting in improved corrosion resistance. However, the addition of SiC particles to AZ31 increased the corrosion rate, with corrosion mechanisms evolving over time. To mitigate these effects, a heat treatment process was employed to dissolve β-Mg17Al12 eutectic and Al8Mn5 intermetallic phases. The heat-treated AZ31 with SiC exhibited an improvement in corrosion resistance. These findings highlight the potential for heat treatment to enhance their corrosion resistance, thereby broadening their application prospects.

Improving the Corrosion Resistance of Micro-Arc Oxidization Film on AZ91D Mg Alloy through Silanization

The presence of inherent micro-pores and micro-cracks in the micro-arc oxidation (MAO) film of Mg alloys is a key factor contributing to substrate corrosion. A composite film layer with high corrosion resistance was achieved through silanizing the micro-arc oxidation film. The corrosion performance of the MAO films treated with various silane coupling agents was assessed through morphological characterization and electrochemical tests. SEM graphs depicted that the silane film can effectively seal the defects existing in micro-arc oxidation film, and electrochemical tests indicated the significant corrosion resistance improvement of MAO film after silanization treatment.

Development and Application of Intelligent Coating Technology: A Review

Coating technology, as a part of surface engineering, has shown remarkable potential in future industrial applications. With the continuous development and improvement of coating technology, coatings have gradually become an indispensable part of industrial manufacturing, possessing various excellent properties and characteristics, such as superhydrophobicity and self-cleaning, enhanced biological antibacterial properties, and improved corrosion resistance. Intelligent coatings are not only rigid barriers between substrates and the environment but also coatings designed to respond to the environment and improve coating life or achieve certain special functions through this response. Biomimetics is a discipline that studies the structure, function, and behavior of living organisms and applies them to engineering design. Combining bionics with intelligent coating materials can not only improve the performance and functionality of intelligent coatings but also create more intelligent coating materials. This paper includes advanced superhydrophobic intelligent coatings, anticorrosion intelligent coatings, biological antibacterial intelligent coatings, and other intelligent coatings with specific functions. We also provide a detailed overview of the preparation methods and technologies of various representative intelligent coatings, as well as their properties and applications, which will offer some valuable references for the development direction of future intelligent coatings.

Effect of alloy 625 buffer layer on corrosion resistance of nickel base hardfacing

Nickel base hardfacing alloys serve to mitigate corrosion losses at elevated temperatures. Efficacy of Nickel base hardfacing alloys can be compromised when applied onto Fe base substrates due to iron dilution in hardfacing. The degree of Fe dilution can be reduced by using advanced deposition methods and optimized deposition parameters. Gas Tungsten Arc Welding (GTAW) method is commonly employed for its cost-effectiveness and versatility, but it tends to induce higher Fe dilution due to increased heat input. This study aims to reduce the degree of Fe dilution and enhance corrosion resistance by introducing a nickel base buffer layer (alloy 625) between the nickel base hardfacing alloy and AISI 316L stainless steel substrate. For comparative purposes, Ni base hardfacing alloy was deposited on the substrate without any buffer layer. Hardfacing depositions were prepared using manual GTAW process. Process parameters namely, deposition current, voltage, travelling speed, pre-heating temperature, and cooling method were kept constant. Samples underwent aging at 1123 K for 4 h, followed by microstructural examination via optical and scanning electron microscopes. Iron (Fe) dilution quantification was performed using energy dispersive spectroscopy (EDS). The EDS analysis showed that the use of buffer layer between the hardfaced deposit and the substrate decreased the degree of Fe dilution in the hardfaced deposit. X-Ray diffraction (XRD) analysis was performed to identify various phases formed in the hardfaced deposit. Potentiodynamic polarization test was performed to assess the corrosion resistance of hardfaced deposit in 3.5 wt% NaCl solution. Results show significant improvement in corrosion resistance of hardfacings deposited sample with buffer layer as compared to those without buffer layer. Aging treatment further enhanced corrosion resistance. The corrosion resistance data is correlated with the microstructure and phases formed in various samples.

Effect of SiC addition on laser-based CoNi binary alloy coatings on Ti-6Al-4V alloy

AbstractThis research explores the impact of variations in laser scanning speed and the incorporation levels of SiC-Ni-Co powders on Ti-6Al-4V alloy using laser surface cladding technique. Key parameters, including a consistent laser power of 700 W, a 4 mm beam spot size, a powder feed rate of 1.0 g/min, and a gas flow rate of 3 L/min, along with fixed powder compositions, were maintained. The laser scanning speeds were adjusted to 0.4 m/min, 0.8 m/min, and 1.2 m/min. Microstructural analyses were carried out using scanning electron microscopy (SEM) while Vickers microhardness was employed to assess coating hardness, and corrosion properties were evaluated using a linear potentiodynamic polarization technique. Following the corrosion attack, the protective oxides formed were identified through SEM and X-ray diffractometer (XRD). The results revealed a strong metallurgical relationship between the clad layer and the substrate, demonstrating the effectiveness of the laser-clad technique. Particularly, the highest laser scan speed exhibited the most significant improvements in hardness and corrosion resistance. The coatings displayed an average hardness value of 1269.20 HV0.1, a notable fourfold increase compared to the substrate's value of 334 HV0.1. Concerning corrosion, a clear correlation emerged between scan speed and polarization resistance, confirming that higher scan speeds could lead to enhanced polarization resistance.

Investigation of the influence of nano-CrN concentration on the performance of Ni-W coatings in X80 pipeline steel

A novel nano Ni-W-CrN composite coating was developed for X80 pipeline steel to enhance its structural properties and corrosion resistance. The study explored the effects of varying CrN nanoparticle concentrations (0, 5, 10, 15, 20 g/L) in the deposition solution using techniques such as SEM, EDS, and XRD for analysis and an electrochemical workstation for corrosion testing. The optimal CrN concentration was identified at 10 g/L, resulting in a coating with peak hardness (811HV), low friction coefficient (0.16), minimal wear rate (1.18×10−4 mm3·(N·m)−1), and improved corrosion resistance. This coating significantly outperforms Ni-W alloy coatings in hardness, wear resistance, and elastic recovery, offering a promising approach for enhancing the performance of X80 pipeline steel surfaces.

Laser remelting of high-velocity arc-sprayed Fe-based amorphous coating for improving corrosion resistance in 3.5 % NaCl solution with varying Na2S concentrations

In this study, high-velocity arc-spraying (HVAS) was employed to produce Fe-based amorphous coatings, and subsequent to that, laser remelting (LR) technology was applied on the as-sprayed coatings (ASC) to prepare laser remelted coatings (LRC). The corrosion resistance of both coatings was tested in 3.5 wt% NaCl solutions containing varying Na2S concentrations (0, 20, 50, 100, and 200 ppm) to accurately simulate the corrosion environment of offshore components. The corrosion behavior was investigated using electrochemical workstation, scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. The experimental results revealed that LR resulted in the elimination of defects in Fe-based amorphous coatings, a substantial reduction in porosity, the disappearance of the laminar structure, and the achievement of a homogeneous composition. The corrosion tendency of ASC and LRC both exhibited a pattern of initially decreasing, then increasing and finally decreasing with increasing sulfide concentration. This was attributed to the deposition of corrosion products on the surface and the dissolution of the corrosion products. When the sulfide concentration exceeded 50 ppm, the corrosion current density of both coatings slowly and was lower than that at 20 ppm, indicating that both coatings possessed strong corrosion resistance at higher sulfide concentrations. Highly polarized anions in solution (e.g. HS−, S2−) occupied vacancies in the passivation film, destabilizing the coating's passivation film and consequently diminishing its corrosion resistance. From the electrochemical analysis, it was evident that LRC exhibited greater corrosion resistance than ASC at all sulfide-containing solution concentrations, which was attributed to its smoother surface, denser structure and more stable passivation film.

Surface modified molybdenum disulfide nanosheets for corrosion resistance improvement on polyurethane coatings

Abstract Organic–inorganic hybrid coating has been applied on metallic corrosion protection effectively. Molybdenum disulfide (MoS2) nanosheets with graphene-like two-dimensional lamellar structure were an anticorrosion inorganic additive, rendering the organic coating better corrosion resistant. However, the aggregation and poor solubility are still current issues that should be addressed. Functionalization MoS2 nanosheets with surface modified by polydopamine (PDA) and silane coupling agent (KH560) were prepared in polyurethane (PU) composite coatings to obtain dense and intact multilayer network structure coatings for corrosion protection. KH560-PDA-MoS2/PU coating with crosslinked polymer network structure has a high impedance modulus, large contact angle, and strong hydrophobicity. The coating meets the national technical standards for salt spray testing and nitric acid (HNO3) titration testing, demonstrating excellent corrosion resistance.