Corrosion Resistance Research Articles

A Study on Microstructural Evolution and Corrosion Behavior of Ti36-Al16-V16-Fe16-Cr16 High-Entropy Alloy Fabricated via Spark Plasma Sintering Technology

AbstractThis study focused on the synthesis of Ti36-Al16-V16-Fe16-Cr16 high-entropy alloys (HEAs) through spark plasma sintering to ascertain their corrosion resistance performance. Varied sintering temperatures, ranging from 700 to 1100 °C were employed to discern their impact on the alloy's characteristics. The fabricated HEAs underwent characterization using scanning electron microscopy and X-ray diffraction. A potentiodynamic polarization measurement was employed to compare the electrochemical properties of HEAs sintered at different temperatures in sulfuric and chloride aggressive media. The study outcomes indicate that the HEA sintered at 1000 °C exhibited superior corrosion resistance compared to other HEAs at other temperatures. This study contributes valuable insights into the nuanced relationship between sintering temperature, microstructure, and corrosion resistance of Ti36-Al16-V16-Fe16-Cr16 HEAs.

Biocompatibility and corrosion resistance of drug coatings with different polymers for magnesium alloy cardiovascular stents

Recently, advances in enhancing corrosion properties through various techniques, and the clinical application of biodegradable cardiovascular stents made from magnesium (Mg) alloys face challenges to corrosion resistance, blood compatibility, and biocompatibility. Drug-eluting stents (DES) offer a solution to enhance the corrosion resistance of Mg alloys while simultaneously reducing the occurrence of restenosis. In this study, WE43 Mg alloy was pretreated using electropolishing technology, and different polymers (PEG and PLLA) were used as drug-polymer coatings for the Mg alloy. At the same time, PTX, an anticoagulant, was incorporated to achieve drug coating of different polymers on WE43 Mg alloy. The corrosion resistance of different polymer-drug coatings was assessed using a plasma solution. Furthermore, in vitro and in vivo tests were used to evaluate the blood biocompatibility of these coatings. The results indicated the PTX-PEG-coated WE43 Mg alloy exhibited the highest corrosion resistance and the most stable drug release profile among the tested coatings. Its hemolysis rate of 0.6 % was within the clinical requirements (<5 %). The incorporation of PEG prevents non-specific protein adsorption and nanoparticle aggregation, enhancing the surface hemocompatibility of WE43 Mg alloy. Therefore, the PTX-PEG coating shows promising potential for application in the development of drug-coated Mg alloy.

Biomimetic hydrogel coatings for improving the corrosion resistance, hemocompatibility, and endothelial cell growth of the magnesium alloy

The fast biodegradation and poor biocompatibility of Mg alloys in physiological environments are still the main problems restricting their application in cardiovascular stents. In this study, the hydrogel coatings (SBMA-AAM) with different proportions of methacryloyl ethyl sulfobetaine (SBMA) and acrylamide (AAM) were built on the surface of AZ31B magnesium alloy through ultraviolet (UV) polymerization. The corrosion degradation behavior, hemocompatibility, and endothelial cell (EC) growth performance of the samples were studied in detail. The findings revealed that the uniform and dense SBMA-AAM coatings could significantly enhance the corrosion resistance. In addition, the hydrogel coatings showed excellent hydrophilicity, which increased the albumin adsorption while inhibiting the fibrinogen adsorption, and thus reduced the platelet adhesion and activation and hemolysis rate, accordingly significantly enhancing their anticoagulant performance. Furthermore, SBMA-AAM hydrogel coating promoted the EC adhesion and proliferation and the vascular endothelial growth factor (VEGF) and nitric oxide (NO) secretion of ECs, which is conducive to promoting endothelialization. When the concentration ratio of SBMA and AAM was 1: 2, the modified magnesium alloy showed the best corrosion resistance and biocompatibility. Therefore, the SBMA-AAM hydrogel coating could effectively regulate the corrosion degradation performance and biocompatibility of Mg alloys, laying a foundation for the application of Mg alloys in cardiovascular stents.

Preparation of robust superhydrophobic stainless steel mesh for Oil-Water separation through Mn-Assisted control of one-step electrodeposited Zn growth

Removing oil spills from water presents a significant challenge in environmental remediation. Among various separation materials available, superhydrophobic materials have emerged as promising solutions, notable for their efficiency, cost-effectiveness, and eco-friendliness. The precise control of micro/nanostructure synthesis plays an essential role in creating superhydrophobic surfaces. Herein, the present study demonstrates controlled growth of well-defined hexagonal platelet-like micro/nanostructures of zinc crystals. This is achieved through deliberate manipulation of the electrodeposition crystal growth process, a facet frequently disregarded in previous studies. Notably, the present work, based on the distinctive properties of the Zn hexagonal close-packed structure (hcp), focuses on the effects of incorporating Mn and deposition parameters on the performance of Zn coatings. These findings offer valuable insights into selectively constructing Zn crystal planes for future electrodeposition endeavors. The resulting zinc/manganese stearate (SZM) coating on stainless steel mesh (SSM) shows remarkable water contact angles, reaching an impressive 163.1 ± 2.4°, in accordance with the Cassie-Baxter theory. This feature facilitates highly efficient oil–water separation. Coupled with size sieving of SSM, SZM coatings exhibit an oil–water separation efficiency of up to 99.86 % and a flux as high as 55.58 kL/m2h. Furthermore, the SZM coating exhibits long-lasting superhydrophobicity and exceptional corrosion resistance, even when subjected to challenging conditions such as high temperatures up to 200℃, pressure reaching 7 kg/cm2, or exposure to chemical and mechanical stresses. These enduring properties make SZM coatings suitable for constructing gravity-based and continuous oil–water separation systems, establishing them as a practical solution for diverse oil–water separation applications.

Influence of ultrasonic power modulation on the optimisation of aluminium alloy micro-arc oxidation coating properties

Conventional micro-arc oxidation (MAO) technology, due to the randomness and transient nature of arc discharge, produces coatings with numerous defects, poor abrasion resistance, and inadequate ability to effectively block the intrusion of corrosive media. In this paper, ultrasonic-assisted technology was used to study the effect of different ultrasonic power regulation on the performance optimization of MAO coating on 6061 aluminum alloy. The coating microstructure and elemental composition were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometer, and its hardness, wear resistance, corrosion resistance and other properties were tested. The results show that the prepared coating has the characteristics of high hardness, good wear resistance and excellent corrosion resistance under the assistance of ultrasonic power of 50 W. This is mainly attributed to the cavitation effect, mechanical effect and thermal effect generated by the corresponding ultrasonic power, which effectively enhances the surface quality, performance and service life of the coating. This study provides valuable insights into the interaction between ultrasound power and the resulting MAO coatings, and has important implications for optimizing ultrasound-assisted processes and improving coating properties.

Sustainable Fire Protection: Reducing Carbon Footprint with Advanced Coating Technologies

Metallum Fire-Resistant paint, denoted as MFR henceforth, represents a cutting-edge insulating material with dual functionality as a fireproof solution, presenting substantial advantages in the realm of construction applications. This exposition derives its primary insights from the scholarly contributions documented in publications. The focal point of these investigations includes the assessment of fire hazards associated with polyethylene materials in building structures and the enhancement of mortars in high-temperature environments in tunnels. The purpose of this study is to evaluate the effectiveness of a modified cork-based coating (MFR) compared to traditional coatings in terms of corrosion protection, fire resistance, and thermal insulation properties in construction applications. This evaluation focuses on quantifying the efficacy of MFR by examining key properties, such as adhesion, the reduced thickness required for fire protection, thermal conductivity reduction, and corrosion resistance under extreme environmental conditions. MFR is highly effective in fire prevention for buildings and tunnels, withstanding temperatures over 1000 °C while maintaining structural integrity. A unique aspect of MFR is its use of cork shavings, a typically underutilized byproduct from wine-bottle-stopper production. This innovative not only amplifies MFR’s fire-resistant attributes, but also introduces sustainability and judicious resource utilization into its manufacturing processes.

Corrosion behavior and strengthening mechanism of Ni-Cu alloy coating on NdFeB magnets

In this paper, the pulse-reverse current electroplating technique was utilized to deposit nickel–copper (Ni-Cu) alloy coatings on the surface of neodymium magnets (NdFeB). Compared with the nickel (Ni) coating, the corrosion resistance of the nickel–copper alloy coating has been significantly improved. Additionally, the results show that alloying can effectively prolong the incubation period of pitting nucleation and improve the self-healing ability of coating. The structure and microstructure of the coating show that the surface of the nickel–copper coating is flat and the grains preferentially grow along the (111) close-packed surface, which also makes the coating to have higher densification and significantly reduces the number of self-corrosion sites and corrosion tendency of the coating. The lower binding energy copper(I) oxide (Cu2O) produced by nickel–copper coatings at the initial corrosion stage can reduce the formation of metal cation holes and prolong the incubation period of pitting corrosion. After pitting formation, the corrosion products copper(I) oxide and dicopper chloride trihydroxide (Cu2(OH)3Cl) of copper (Cu) in the pitting hole have a certain hindrance to corrosion and are conducive to promoting passive reconstruction, which is an important reason for higher self-healing ability and higher corrosion resistance of the nickel–copper alloy coating.

Durable and Hydrophobic Self-Healing Coating with Rapid Thermal Activation and Prolonged Corrosion Resistance

Durable and Hydrophobic Self-Healing Coating with Rapid Thermal Activation and Prolonged Corrosion Resistance

Fatigue Analysis of Composite Leaf Springs - A Review

The purpose of this paper is to provide a review of work that has been carried out in analyzing composite leaf springs. Leaf springs made of fibre reinforced composites exhibit much more advantages when compared with steel leaf springs. Most importantly, polymer composites increase the performances of vehicles by decreasing the weight of the leaf spring and also by providing corrosion resistance. This paper summarizes the fatigue analysis of composite leaf springs by considering the results obtained by some of the research works.

INFLUENCE OF GAS ENVIRONMENT OF SPRAYING ON THE PROPERTIES OF GAS-THERMAL METALLIZED COATINGS

This article is devoted to the study of the influence of the technological parameters of spraying, in particular the gaseous medium, on the physical and mechanical properties and corrosion resistance of gas-thermal metallization coatings. To protect the housings of submersible electric motors (PAD) in oil and gas wells, the method of electric arc metallization (EDM) has become widespread, due to the high level of physical and mechanical properties of the resulting gas-thermal metallization coating, high productivity and cost-effectiveness of the process, as well as the mobility of equipment. Despite the effectiveness of this method of protection, it does not exclude the occurrence of corrosion processes in the metal of the PAD body. In this regard, research aimed at increasing the operational life of the metallization coating is relevant and promising.The article considers the theoretical aspects of the influence of the technological parameters of the spraying process on the properties of the metallization coating. The effect of the sputtering gas medium on the physical and mechanical properties and corrosion resistance of metallization coatings has been experimentally investigated. Comparative tests and studies of gas-thermal metallization chromium-nickel coatings applied by the EDM method in an air environment and in an argon environment have been carried out. The main trends and features of the formation of metallization chromium-nickel coatings applied by the EDM method and the effect of the application mode, in particular the technological gas spraying medium on the microstructure studied on metallographic grinds using a scanning electron microscope with an attachment for energy dispersion analysis; microhardness determined by the Vickers method are determined; The wear resistance is determined by abrasive wear during friction against non-rigidly fixed abrasive particles and the corrosion resistance of the resulting coatings, determined by autoclave tests during exposure in a simulated environment containing corrosive components.The study of the influence of certain technological parameters of spraying of gas-thermal metallization coatings, including the gas medium, on the properties of the coatings obtained is a fairly promising task aimed at increasing the operational life of the metallization coating, which in the future will reduce the cases of premature failure of oilfield equipment.

Enhanced electrochemical corrosion resistance of 316L stainless steel manufactured by ultrasonic rolling assisted laser directed energy deposition

Enhanced electrochemical corrosion resistance of 316L stainless steel manufactured by ultrasonic rolling assisted laser directed energy deposition

Effect of Mo and Sn co-regulation on low alloy steel corrosion in tropical marine atmosphere

The influence of co-regulating Mo and Sn on the corrosion resistance of low alloy steel in tropical marine atmospheric was investigated. The combined addition of Mo and Sn has been found to significantly improve the corrosion resistance of low alloy steel, augmenting the protective capabilities of the rust layer. This combined addition promotes the formation of protective compounds like α-FeOOH and FeCr2O4 within the alloy rust layer. Furthermore, it facilitates the conversion of Cr, Ni and Cu into corrosion-resistant oxides such as Cr2O3, NiFe2O4 and CuO, thereby enhancing the density of the rust layer. Additionally, as corrosion progresses over time, higher levels of Sn addition lead to increased Sn content within the inner rust layer, consequently bolstering the protective qualities of the rust layer. This comprehensive understanding sheds light on the synergistic effects of Mo and Sn in fortifying the corrosion resistance of low alloy steel, offering insights for the development of advanced corrosion-resistant materials in marine environments.

Engineering Corrosion Resistance in Magnesium Alloys for Biomedical Applications: A Synergy of Zn/Ca Atomic Ratio and Texture-Based Approach

Magnesium (Mg) and Magnesium-Zinc-Calcium alloys present a compelling option for biodegradable implant materials. Utilizing Vacuum Induction Casting, Mg–2.5Zn-xCa (with x = 0.3, 0.5, 0.9, 1.15 wt%) alloys were fabricated and subjected to hot-rolling for thermo-mechanical processing. The hot-rolled Mg–2.5Zn-0.3Ca alloy exhibits the lowest corrosion rate along with the highest basal texture. Increasing the Zn/Ca atomic ratio intensifies the basal texture and enhances corrosion resistance. Elevated Zn concentration improves corrosion resistance via Ca2Mg6Zn3 phase formation, while increased Ca content diminishes corrosion resistance due to the Mg2Ca phase. Advancement of this alloy is poised to extend Mg alloy use in innovative biomedical bone implants.

Effects of Fe addition on the mechanical and corrosive properties of biomedical Co-Cr-W-Ni alloys for balloon-expandable stents

Co-20Cr-15W-10Ni (mass%, CCWN) alloy is extensively used as a platform material for balloon-expandable stents. In this study, the mechanical properties of CCWN alloy are improved following the addition of Fe, and the effects of Fe addition on the mechanical and corrosive properties of the alloy are investigated. As-cast specimens were fabricated by adding pure Fe to a commercially available CCWN alloy (base alloy) such that the resulting alloys contained 4, 6, and 8 mass% Fe. The as-cast specimens were subjected to homogenization heat treatment at 1523 K for 7.2 ks and then hot-forged at 1473 K (as-forged specimens). The as-forged specimens were cold-rolled at a reduction rate of 30% and heat-treated at 1473 K for 300 s (recrystallized specimens). The matrix of the recrystallized base- and Fe-containing alloys consisted of a single γ (face-centered cubic)-phase. The Fe-added alloys revealed precipitates composed of the η-phase (M6X-M12X-type phase, M: metallic element, X: C and/or N). The average grain size of the recrystallized base and Fe-added alloy specimens was approximately 34 μm and the amount of added Fe had no significant effect on the static recrystallization behavior of the resulting alloys. Alloys containing 6 mass% or more Fe showed improvements in strength and ductility compared with the base alloy. When the Fe-added alloys were compared, their strength decreased whereas their ductility increased when the added Fe increased. Because Fe acts as a γ-phase-stabilizing element for Co, Fe addition increases the stacking fault energy of the base alloy, resulting in the formation of the ε (hexagonal close-packed)-phase owing to the suppression of strain-induced martensitic transformation (SIMT), and improvements in ductility. No deterioration in corrosion resistance was observed following the addition of up to 8 mass% Fe to the base alloy. Based on these results, the addition of Fe to CCWN alloy may be considered an effective method to improve its mechanical properties, especially ductility, without impairing its corrosion resistance. The results of this study will be useful for the future development of Ni-free Co-Cr alloys for next-generation, small-diameter stents.

Influence of the Dispersion of Carbon Nanotubes on the Electrical Conductivity, Adhesion Strength, and Corrosion Resistance of Waterborne Polyurethane Composites

Due to the presence of many flammable substances in the working environments of the petrochemical industry, anticorrosive conductive coatings need to be used on metal equipment to avoid safety accidents like fires. However, existing conductive solvent-based coatings are volatile when exposed to flammable and toxic organic solvents. Thus, in this work, a series of eco-friendly anticorrosive waterborne polyurethane (WPU) composites with multi-walled carbon nanotubes (MWCNTs) were prepared via a low-cost and practical process; the dispersion of MWCNTs was revealed when present in different amounts, and the mechanism behind the conduction of WPU composites was determined. We concluded that low amounts of MWCNTs were well dispersed, generating a conductive network, and the WPU composite was not entirely covered by the MWCNT particles, so the electrical conductivity in certain parts of the coating was good. When the content of MWCNTs was excessive, some stretched MWCNTs dispersed to the top of the composite and many MWCNTs agglomerated at the bottom. Additionally, when the content of MWCNTs was increased, the electrical conductivity, corrosion resistance, and adhesion strength of the WPU composite decreased. Our results could provide a theoretical foundation for the preparation of anticorrosive conductive waterborne composites for protecting equipment in the petrochemical industry.

The Influence of Surface Nanocrystallization of TA2 Titanium Alloy on Its Corrosion Resistance

In this study, the surface nano treatment of TA2 titanium alloy was realized by means of surface mechanical wear treatment. The microstructure and electrochemical properties of the nanocrystalline layer were investigated by SEM, TEM, Electrochemical Impedance Spectroscopy, and Potentiodynamic Polarization, while the nucleation mechanism of the passivation film was discussed. The results indicate that the original coarse grains on the sample’s surface are transformed into randomly oriented nanocrystals by surface mechanical attrition treatment (SMAT). The corrosion current density of the surface nanocrystallized TA2 titanium alloy (9.2 nA·cm−2) experienced a reduction of two orders of magnitude compared to untreated TA2 titanium alloy (134.5 nA·cm−2) in 3.5 wt.% NaCl solution. The SMAT methods accelerates nucleation mechanism transitioning to continuous nucleation.

Strengthening of RC Beam with GFRP Composites in Shear N. B. Bhopale

The rehabilitation, repair and strengthening of existing reinforced concrete (RC) structures is essential due to factors such as aging, steel reinforcement corrosion, construction/design defects, increased service loads demand, seismic events, and advancements in design guidelines. Fiber-reinforced polymers (FRP) are now being recognized as a promising material for the rehabilitation of such structures, through strengthening or repairing. In buildings and bridges, RC sections are commonly found in the form of beams and girders. Shear failure of RC beams is particularly due to its sudden occurrence without warning. Therefore, the utilization of externally bonded (EB) FRP composites for shear strengthening of RC beams has gathered popularity as a structural enhancement technique, primarily due to advantages of FRP composites, such as high strength-to- weight ratio and exceptional corrosion resistance. In addition, FRP repair systems give a cost-saving choice to traditional repair methods and materials. A study was performed to analyse the shear characteristics of RC beams enhanced with continuous glass fiber-reinforced polymer (GFRP) sheets. Reinforced concrete beams externally bonded GFRP sheets subjected to failure using a symmetrical two-point concentrated static loading system. The experimental data obtained included load, deflection, and failure modes of each beam, along with the effect of the number of GFRP layers on the beams The failures observed in strengthened beams typically commence with the debonding of the FRP sheets, followed by brittle shear failure. The shear capacities of these beams were higher than that of the control beam.

Predicting shear strength of fiber-reinforced concrete beams reinforced with longitudinal FRP bars with machine learning techniques

ABSTRACT This study investigates the shear strength prediction of Fibre-Reinforced Concrete (FRC) beams reinforced with Fibre-Reinforced Polymer (FRP) bars and without stirrups through the application of Machine Learning (ML) techniques. The utilisation of FRP bars, particularly Glass Fibre-Reinforced Polymer (GFRP) and Basalt Fibre-Reinforced Polymer (BFRP) bars, has emerged as a promising alternative to traditional steel reinforcement due to their superior mechanical properties and corrosion resistance. Moreover, the incorporation of macro- and micro-discrete fibres into concrete compositions enhances both shear and flexural behaviour while reducing crack propagation induced by tensile stresses. The primary objective of this research is to develop accurate predictive models for the shear capacity of FRP-reinforced concrete beams, considering various influential parameters. Six different ML techniques, namely Multiple Linear Regression (MLR), Gaussian Process Regression (GPR), k-Nearest Neighbors (KNN), Support Vector Machines (SVMs), Artificial Neural Networks (ANNs) and Random Forest Regression (RFR), are employed to analyse the complex interactions between input variables, such as fibre type, bar diameter, concrete compressive strength, beam dimensions and the resulting shear strength. By leveraging these computational approaches, we aim to overcome the limitations of conventional analytical methods and provide robust predictions for structural design and optimisation.

Controlled Compositions in Zn–Ni Coatings by Anode Material Selection for Replacing Cadmium

Cadmium-based coatings have long been used to protect high-strength steel in aerospace, but due to cadmium’s toxic and carcinogenic nature, its use is increasingly restricted. Zinc–nickel coatings, containing 10–14 wt% Ni, offer superior corrosion resistance compared to pure zinc, making them a promising alternative. However, Zn–Ni coatings are prone to cracking, which can compromise their protection. This study investigates how different anode materials influence crack formation and coating properties during electrodeposition. Zinc and nickel anodes produced coatings with consistent thicknesses of 13–15 µm, while 1020 steel and stainless steel resulted in thicker coatings of up to 33 µm. Notably, coatings deposited with nickel anodes demonstrated strong adhesion and consistent interface quality. Zinc anodes achieved a high Ni content of about 13.5 wt%, whereas 1020 steel and stainless steel produced lower Ni content, around 7 wt%. Additionally, zinc and nickel anodes led to fewer defects and minimal porosity, in contrast to the higher porosity observed with 1020 steel and stainless steel anodes. Furthermore, zinc anodes maintained stable voltages (~0.5 V), contributing to more uniform coatings. In terms of corrosion resistance, zinc anodes exhibited a lower corrosion rate of 0.44 mm/year compared to 1.54 mm/year for nickel anodes. This study highlights the importance of anode selection in reducing cracking and optimizing Zn–Ni coatings, presenting them as a safer and more effective alternative to cadmium-based coatings.

Fabrication and Properties of Superhydrophobic Colored Stainless Steel Surface for Decoration and Anti-Corrosion

A colored superhydrophobic surface on a stainless steel substrate was achieved by means of high temperature oxidation combined with subsequent spraying modification by superhydrophobic nano-silica film. Comprehensive characterizations of the surface were performed in terms of color, morphology, composition, wettability, and corrosion resistance by optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), contact angle, potentiodynamic polarization, and electrochemical impedance spectroscopy measurement. At 400 °C, the surface was pale yellow, gradually turning yellow and then red as the temperature increased. At 700 °C and 800 °C, the surface colors were blue and dark brown, respectively. The samples with oxide films demonstrated lower contact angles, specifically 80.5° ± 2.5 at 400 °C, 79.1° ± 2.8 at 500 °C, and 75.6° ± 3.4 at 600 °C. The polarization resistance measured on the oxidized film formed at 600 °C exceeded 7.93 × 104 Ω·cm2. After spraying the treatment, these colorful surfaces exhibited superhydrophobicity, they were self-cleaning, and they satisfied anti-corrosion properties. The treatment performs as an excellent barrier and exhibits a high corrosion resistance of 4.68 × 106 Ω·cm2. The successful preparation of superhydrophobic colored surfaces offers the possibility of providing stainless steel with both decoration value and self-cleaning function simultaneously by our proposed chromium-free fabrication process.