Remarkable Corrosion Resistance Research Articles

Synthesis of O,F Co-Modified g-C3N4 for Photocatalytic H2 Evolution Activity Improvement and Corrosion Protection

Herein, we report the rational synthesis of porous g-C3N4 co-modified with oxygen (O) and fluorine (F) for the first time. Incorporating colloidal SiO2 during thermal polymerization introduces lattice oxygen, forming C–O bonds, while post-treatment with NH4·HF2 establishes C–F bonds. The dual incorporation of O and F elements extends visible light absorption and effectively promotes the separation and transport of photoexcited charge carriers. Consequently, the co-modified g-C3N4 (O,F-g-C3N4) achieves a 13.2-fold increase in H2 evolution rate compared to pristine g-C3N4. This synthesized O,F-g-C3N4 is then dispersed in waterborne polyurethane (WPU) to create an anti-corrosive coating for Q235 carbon steel substrates. Water resistance, mechanical property, and electrochemical characterization analyses reveal that the O,F-g-C3N4/WPU composite coating exhibits remarkable corrosion resistance with a high protection efficiency of 90.23%. This work offers a straightforward approach for developing highly efficient g-C3N4-based photocatalysts and corrosion-resistant coatings.

Towards remarkable corrosion protection by synergizing PANI with plasma-electrolyzed inorganic layer

Notwithstanding the increasing interest in the enhancement of the corrosion properties of active metallic materials, the role of organic corrosion barrier remains insufficiently understood with respect to the formation of structural microdefects in the inorganic layer and the decrease in the corrosion rate. The present work proposed the mechanism by which an organic polymer would improve the barrier properties of the defective TiO2 coating as an inorganic layer and thereby, improve corrosion protection. This protection mechanism enhances the hydrophobicity of the TiO2 surface because of the notable homogeneity of the organic polymer polyaniline (PANI). The adsorption of PANI on the surface of the TiO2 coating was verified using SEM and EDAX. The electrochemical performance was enhanced remarkably because of the integral synergy between TiO2 and PANI in the composite, which could be controlled by adjusting the number of deposition cycles. In addition, the novel protection mechanism of this hybrid layer was based on the counter anions stored within PANI. These were released as active corrosion inhibitors upon the onset of a severe chemical attack on the TiO2 layer or metal substrate. Thus, these composites reduced the diffusion of metal ions and prevented the penetration of corrosive ions, thereby yielding a remarkable corrosion resistance.

A significant improvement in corrosion resistance and biocompatibility in ZrNbTiCrCu high-entropy films induced by the precipitation of Cu

Utilizing nanotechnology and composites to create a protective film on titanium alloy is an effective means of achieving the desired high performance. Self-assembly of nanocomposite structures offers a promising route to forming high entropy alloy films (HEAFs), but controlled preparation remains challenging. This work used magnetron sputtering through adjusting preparation parameters to prepare ZrNbTiCrCu HEAFs, achieving a significant improvement in corrosion resistance and biocompatibility induced by the precipitation of Cu. According to the electrochemical corrosion test, without obvious corrosion pits on the surface of S2 after corrosion, a passivation film composed of bimetallic oxide CuCrO2 formed on the film surface, indicating that ZrNbTiCrCu HEAFs have remarkable corrosion resistance performance. In the cytocompatibility experiment, the cell viability of HEAFs reached over 95 % due to the precipitation of Cu, suggesting their excellent biocompatibility. In addition, ZrNbTiCrCu HEAFs exhibit outstanding antibacterial ability, especially when the sputtering current is 0.6 A, and the in vitro antibacterial rate of the sample against Escherichia coli is close to 99 %.

Corrosion-oriented self-healing coating based on ZnMg MOF for efficient corrosion protection of aluminum alloy via in-situ LDH film formation

A corrosion-oriented self-healing coating system relying on metal–organic framework (MOF) based nanofiller is designed for aluminum alloy protection. The nanofiller is comprise of ZnMg MOF nanoparticle as a framework, salicylaldoxime corrosion inhibitors inside the MOF, and a polydopamine layer on the MOF surface. The Al3+ ions generated from the aluminum alloy substrate at the damaged coating area can etch the nanofiller, causing the collapse of the nanofiller and releasing the corrosion inhibitors to suppress the corrosion process in time. Subsequently, Zn2+ and Mg2+ ions from the nanofiller co-precipitate with Al3+ to form a dense AlZnMg layered double hydroxide (LDH) film, which provides further protection performance at the exposed alloy surface. Electrochemical impedance spectroscopy results demonstrate that the intact MOF@S/P coating exhibits a remarkable corrosion resistance property. For the damaged coating, the self-healing performance originated from the formation of LDH layer and the release of corrosion inhibitors gradually took effect, with the |Z|0.01Hz value increasing 2.27 times within 14 days. Moreover, under near-infrared irradiation, the photothermal effect of polydopamine will accelerate the release of corrosion inhibitor, the formation of LDH film, as well as the shape memory effect of coating defect for an efficient recovery of the corrosion resistance property. This novel coating system enables a corrosion-driven and location-specific repair with in-situ deposition of both an inhibitor film and an LDH film. As the first work to fully utilize and consume nanofillers on demand, this approach prevents inadequate use of healing agents, addressing a significant challenge in corrosion-driven self-healing coatings. The self-healing mechanism ensures target-oriented corrosion protection that makes the most efficient use of the healing substances.

Improving the interfacial bonding strength of a silane anticorrosion film on copper surfaces using small-molecule corrosion inhibitors

The weak binding ability of silane to copper surfaces restricts its use in copper anticorrosion. In this study, the P–OH groups in etidronic acid (HEDP) were utilized to establish chemical bonds with copper and to react with 3-mercaptopropyltrimethoxysilane (PropS-SH), serving as a bridging mechanism to enhance the anchoring of silane onto copper surfaces. Moreover, the presence of HEDP promoted the condensation of silane, leading to the formation of a denser and thicker film with outstanding corrosion resistance. SEM results indicated that the thickness of the PropS-SH/HEDP film was about 125 nm, and defects at the copper–film interface were repaired. Electrochemical tests demonstrated that the PropS-SH/HEDP film exhibited remarkable corrosion resistance, achieving an anticorrosion efficiency of 99.95 %. Immersion testing showed that the PropS-SH/HEDP film was capable of withstanding immersion in a 3.5 wt% NaCl solution for 10 days, displaying a durability 5 times greater than that of the standalone silane film.

Exploring the Potential of High Entropy Alloys: A Comprehensive Review on Microstructure, Properties and Applications: Part I

Over the past few years, there has been a notable surge in research interest surrounding high entropy alloys (HEAs) owing to their exceptional properties. Unlike conventional alloys, HEAs consist of five or more principal elements, which offer endless possibilities for developing new alloy systems. HEAs exhibit a high concentration of mixing elements, resulting in high disorderliness of the atomic structure within the material, known as high entropy. This unique nature provides HEAs with desirable properties, including excellent mechanical and physical properties at elevated temperatures, making them ideal for high-temperature applications like cryogenic engines and gas turbines. Moreover, HEAs have shown remarkable corrosion resistance, positioning them as viable options for applications in demanding environments such as marine settings, oil and gas pipelines and chemical processing plants. This comprehensive review paper analyses recent studies on various HEAs. Part I introduces HEAs and describes their synthesis, microstructure, hardness and strength properties.

Additive manufacturing nickel-aluminum bronze alloy via wire-fed electron beam directed energy deposition: Enhanced mechanical properties and corrosion resistance compared to as-cast counterpart

In the present work, a wall-structured nickel-aluminum bronze (NAB) alloy was fabricated via electron beam directed energy deposition (EB-DED) additive manufacturing with a single-pass multi-layer deposition strategy. A comprehensive comparative analysis of microstructure, mechanical properties, and corrosion resistance was conducted against a conventionally cast NAB alloy. The inherent rapid solidification and cyclic thermal processing of the EB-DED technique profoundly influenced the microstructural evolution of the NAB alloy. The as-deposited NAB alloy exhibited a fine-grained microstructure, devoid of the martensitic β′ phase, accompanied by the spheroidization of partial κIII precipitates, and a homogeneous distribution of alloying elements. These distinctive microstructural attributes synergistically enhanced the strength, hardness, and toughness of the NAB alloy, conferring superior mechanical properties compared to its cast counterpart. Furthermore, the as-deposited alloy demonstrated remarkable corrosion resistance in a 3.5 wt% NaCl solution, significantly outperforming the cast alloy. The underlying mechanisms governing the structure-property relationships were elucidated. This comprehensive investigation provided insights into the unique characteristics and potential applications of EB-DED fabricated NAB alloys, positioning them as promising candidates for high-performance components subjected to severe mechanical and corrosive service conditions.

Designing a Microstructure of NiCo-LDH@CNTs@Carbon Foam for Efficient Electromagnetic Wave Absorption and Excellent Environmental Tolerance.

The constantly evolving environment imposes increasingly stringent demands on the mechanical qualities of materials employed for absorbing electromagnetic waves (EMWs). Therefore, there is an urgent need for advanced materials capable of efficiently absorbing EMWs and withstanding harsh electromagnetic conditions. In this study, the electrodeposition method was effectively used to synthesize nickel-cobalt layered double hydroxides (NiCo-LDHs) in a controlled manner on a composite structure of carbon nanotubes and carbon foam, creating an exquisite construction. The manipulation of the electrodeposition time facilitated the regulation of the density of the layered structure within the composite material, thereby significantly enhancing its polarization relaxation performance. Increased defect sites and interface polarization enhance impedance matching and the attenuation constant, resulting in greatly improved absorption performance. The optimized sample demonstrated exceptional wave-absorbing performance in comparative experimental analysis, attaining a maximum reflection loss of -58.18 dB. It also has an effective absorption bandwidth of 5.36 GHz at a wavelength of 2.28 mm. The exceptional isolation effect of LDH, coupled with the outstanding insulation ability of the porous carbon skeleton, confers remarkable corrosion resistance and thermal insulation performance on the composite material. Hence, this discovery offers novel insights into designing environmentally tolerant absorbent materials.

Helmet-Roled Molecules Carrying Double Metronidazole Frameworks and Phenyl Ring for Strengthening Adsorption and Anticorrosion on Mild Steel.

This study prepared new helmet-roled molecules (HMs) carrying metronidazole frameworks and a phenyl ring for strengthening adsorption and anticorrosion on mild steel. The adsorption of the HMs on the copper surface was understood by material simulation computation. Furthermore, the surface analysis experiments suggest that the studied molecules could be adsorbed to a mild steel surface through the chemical coordination bonding. The remarkable corrosion resistance of the HMs for mild steel in HCl was surveyed by potentiodynamic polarization and electrochemical impedance spectroscopy at 298 K. The HMs including two metronidazole skeletons displayed the stronger corrosion inhibition effect on mild steel than the HM1 bearing one single metronidazole part (the corrosion inhibition efficiency, HM3, 98.03%, HM2, 95.14%, HM1, 88.72%). The results presented in this study provided an efficient strategy to develop new clinical medicine-based corrosion inhibitors for metal in acid medium through molecular preconstruction.

R32-Al5W: A new stable high-temperature alloy

Due to the high melting point, exceptional mechanical properties, and remarkable corrosion resistance exhibited by Al5W, researchers have conducted extensive research on the structural characteristics of Al5W. To identify the lowest energy structures and find new structures, a combination of particle swarm optimization and first-principles calculations was employed to identify energy-favorable Al5W structures under ambient pressure. The experimental P63 phase and the previously predicted R3¯c phase were identified. Notably, a new R32-Al5W phase was proposed. A comparative analysis on the structural stability, elastic, thermodynamic, and electronic properties of these three Al5W phases were conducted. The results indicate that R32-Al5W exhibits favorable thermodynamic stability, with a predicted bulk modulus close to that of R3¯c-Al5W. All the three Al5W phases demonstrate brittle behavior. The P63-Al5W phase displays larger shear anisotropy in the (010) and (001) planes, while the R32-Al5W phase shows greater shear anisotropy on the (100) plane compared to other two phases. Furthermore, employing Clarke’s and Cahill’s models, the minimum thermal conductivity of Al5W phases was predicted, revealing a magnitude order of P63 >R3¯c > R32. Our calculated melting points also conform to this trend.

Coupled multiple heterogeneous interfaces lychee-like FeSiAl@C@SiO2@BTA for self-healing corrosion protection and enhanced microwave absorption

Corrosion-resistant ferromagnetic absorbers (FMAs) with self-healing properties are crucial for enhancing their durability under harsh conditions. Herein, we fabricated lychee-like FeSiAl (FSA)@C@SiO2@1H-Benzotriazol (BTA) coupled with multiple heterogeneous interfaces by coating FSA with a C@SiO2@BTA layer using sol-gel, thermal reduction, and molecular encapsulation techniques. The FSA@C@SiO2@BTA showed superior microwave absorption (MA) performance than FSA, with a widest absorption bandwidth of 10.44 GHz at 1.98 mm and a maximum reflection loss of −57.81 dB at 2.98 mm. The enhanced MA performance was due to the better impedance matching and the synergistic effects of interfacial and dipole polarization induced by the C@SiO2@BTA layer. Moreover, the FSA@C@SiO2@BTA exhibited a remarkable corrosion resistance, with a corrosion rate of 3.28 × 10−10 m/s, which was two orders of magnitude lower than that of FSA, and a corrosion protection efficiency of 99.0 %. The epoxy resin coating containing FSA@C@SiO2@BTA also demonstrated a self-healing ability within 5 min after being damaged mechanically. This study presents a novel model that integrates MA, corrosion resistance, and self-healing, heralding new avenues for developing corrosion-resistant FMAs in marine applications.

Electrochemical responses and surface degradation analyses alumina and feldspar dental materials in acidic environments: A comprehensive in vitro study

This in vitro study examines the electrochemical responses and surface degradation of alumina and feldspar dental ceramic materials in acidic environments using cyclic polarization and electrochemical impedance spectroscopy (EIS). Alumina and feldspar demonstrate balanced responses in both Fusayama Artificial Saliva and acidic solutions, indicating effective passivation. SEM/EDX analyses after 168-h immersion reveal significant elemental variations, suggesting complex surface phenomena and chemical reactions leading to oxide layer formation. Alumina exhibits increased Si, O, Al, Na, K, and C counts, while feldspar shows increased Si, O, Al, Na with reduced C and Ca levels, indicating complex reactions. Immersion induces notable elemental composition modifications, with alumina showing remarkable corrosion resistance and feldspar undergoing selective dissolution. This study provides insights into the electrochemical and surface degradation of these materials, emphasizing long-term stability and the need for continuous monitoring of protective layer dynamics in future research on corrosion-resistant dental biomaterials.

Surface modification of mild steel to circumvent challenges in chemical vapour deposition of graphene coating for durable corrosion resistance

Graphene possesses unique combination of characteristics (i.e., inertness, impermeability and toughness) to qualify as ideal coating material for corrosion resistance, and graphene coatings on nickel and copper have been shown to provide excellent and durable corrosion resistances. However, growing graphene directly on mild steel by chemical vapour deposition (CVD), is prohibitively challenging due to high solubility of carbon in mild steel at high temperatures. The non-trivial challenge was circumvented through surface modification of steel by electroplating with Cu and Ni, accounting for the critical consideration, i.e., the inter-diffusivity of iron in nickel or copper. However, the key finding was that the undesirably high thicknesses of the electroplated Cu and Ni layers were detrimental, and optimization of their thicknesses was essential for successful deposition of the required quality graphene. The optimised thicknesses were derived on the basis of the fundamental diffusion calculations. The uniform multi-layered graphene coating on the suitably modified mild steel surface provided remarkable corrosion resistance in an aqueous chloride solution, and electrochemically validation of the corrosion durability for extended exposure (>1000 h) was characterised.

Development of an epoxy resin-based anticorrosive coating enhanced by monolayer amino-modified graphene oxide

Epoxy resin (EP) serves as a prevalent material for anti-corrosion coatings, yet its corrosion resistance demands further refinement. In this work, monolayer amino-modified graphene oxide with an average height of 0.930 nm and 1.023 nm was synthesized using urea and melamine, named NGO and MGO, respectively. When incorporated into EP coatings, the NGO and MGO exhibit outstanding protective properties. The impact of different concentrations of NGO and MGO on the corrosion resistance of EP coated Q235 samples were meticulously examined. Through electrochemical measurements and salt spray tests, it was determined that the coatings containing 0.1 wt% NGO or 0.3 wt% MGO exhibited remarkable corrosion resistance. Furthermore, we conducted a comparative analysis of the corrosion resistance between the NGO and MGO composite EP coatings. Following immersion in a 3.5 wt% NaCl solution for 240 h, the impedance modulus at low frequencies (|Z|0.01 Hz) of the MGO composite coating was approximately two orders of magnitude greater than that of the NGO composite coating. Even following an extended immersion period of 480 h, the |Z|0.01 Hz for MGO-EP continued to maintain an advantage of one order of magnitude.

Study on the structure, growth pattern and corrosion behavior of CoCrFeNiAl high entropy alloy coatings - base on hollow cathode effect

The surface of TC18 titanium alloy was coated with a CoCrFeNiAl HEA coating using double-glow plasma surface metallurgy. The structure, phase, and growth mode of the coating were investigated, along with its electrochemical corrosion behavior. The prepared HEA coating, under the influence of the hollow cathode effect and non-equilibrium diffusion, exhibits a composite structure consisting of a deposited layer and an interdiffused layer. It demonstrates robust metallurgical bonding with the substrate, and it exhibits a hardness of 12.66 GPa and an elastic modulus of 158.52 GPa, along with exceptional hardness and high elastic modulus. The primary phase of the coating consists of an FCC solid solution, with a minor presence of Ni3Al and Al8Cr5 phases. TEM results demonstrate that hollow cathode enhanced sputtering effectively refines the grain structure on the substrate surface. The high entropy alloy coating, characterized by a significant abundance of nanocrystalline and amorphous structures, is obtained under the bombardment of high-energy particles. Gradually increasing from the interface to the deposited layer, there is an augmentation in the content of nanocrystals. The transition from the substrate to the sedimentary layer comprises three distinct regions: a surface fine crystal region, a nanocrystalline structure region, and a nanocrystalline and amorphous precipitated phase-rich region. In 3.5 wt% NaCl solution, the electrochemical corrosion rate of the coating is 1.36 × 10−1 μm·year−1, which is about ten times lower than that of the substrate. Moreover, pre-soaking forms a stable oxide film on the coating's surface, effectively preventing corrosion and demonstrating its remarkable corrosion resistance.

Mechanical and electrochemical properties of (MoNbTaTiZr)1-xNx high-entropy nitride coatings

High-entropy materials possess high hardness and strong wear resistance, yet the key bottleneck for their practical applications is the poor corrosion resistance in harsh environments. In this work, the high-entropy nitride (HEN) coatings of (MoNbTaTiZr)1-xNx (x = 0–0.47) were fabricated using a hybrid direct current magnetron sputtering technique. The research focus was dedicated to the effect of nitrogen content on the microstructure, mechanical and electrochemical properties. The results showed that the as-deposited coatings exhibited a typical body-centered cubic (BCC) structure without nitrogen, while the amorphous matrix with face-centered cubic (FCC) nanocrystalline grain was observed at x = 0.17. Further increasing x in the range of 0.35–0.47 caused the appearance of polycrystalline FCC phase in structure. Compared with the MoNbTaTiZr metallic coating, the coating containing nitrogen favored the high hardness around 13.7–32.4 GPa, accompanied by excellent tolerance both against elastic and plastic deformation. Furthermore, such N-containing coatings yielded a low corrosion current density of about 10−8–10−7 A/cm2 and high electrochemical impedance of 106 Ω cm2 in 3.5 wt.% NaCl solution, indicating the superior corrosion resistance. The reason for the enhanced electrochemical behavior could be ascribed to the spontaneous formation of protective passive layers over the coating surface, which consisted of the dominated multi-elemental oxides in chemical stability. Particularly, noted that the (MoNbTaTiZr)0.83N0.17 coating displayed the highest hardness of 32.4 ± 2.6 GPa and H/E ratio at 0.09, together with remarkable corrosion resistance, proposing the strongest capability for harsh-environmental applications required both good anti-wear and anti-corrosion performance.

Combinatorial investigation on corrosion resistance of Ir-Ni-Ta alloys

Metallic glasses are often considered to exhibit remarkable corrosion resistance. However, the respective roles of chemical composition and amorphous structure remain unclear. In this work, we take Ir-Ni-Ta alloy system as a model system and utilize combinatorial fabrication and high-throughput characterizations to reveal the correlations between alloy composition and corrosion current density and corrosion potential. The results indicate strong correlations of corrosion current density with metal-metal bond strength and metal-oxygen bond strength, suggesting that the corrosion of the Ir-Ni-Ta metallic glasses is primarily controlled by chemical composition. However, an amorphous structure can facilitate the formation of denser passive film, and thus superimpose a positive influence on alloys that inherently exhibit corrosion resistance. Our findings would help the designing metallic glasses of superior corrosion resistance.

Heat-Localized and Salt-Resistant 3D Hierarchical Porous Ceramic Platform for Efficient Solar-Driven Interfacial Evaporation.

Solar-driven interfacial evaporation (SDIE) is a highly promising approach to achieve sustainable desalination and tackle the global freshwater crisis. Despite advancements in this field, achieving balanced thermal localization and salt resistance remains a challenge. Herein, the study presents a 3D hierarchical porous ceramic platform for SDIE applications. The utilized alumina foam ceramics (AFCs) exhibit remarkable corrosion resistance and chemical stability, ensuring a prolonged operational lifespan in seawater or brines. The millimeter-scale air-filled pores in AFCs prevent thermal losses through conduction with bulk water, resulting in heat-localized interfaces. The hydrophilic nature of macroporous AFC skeletons facilitates rapid water replenishment on the evaporating surface for effective salt-resistant desalination. Benefiting from its self-radiation adsorption and side-assisted evaporation capabilities, the AFC-based evaporators exhibit high indoor evaporation rates of 2.99 and 3.54kg m-2 h-1 under one-sided and three-sided illumination under 1.0 sun, respectively. The AFC-based evaporator maintains a high evaporation rate of ≈2.77kg m-2 h-1 throughout the 21-day long-term test. Furthermore, it achieves a daily water productivity of ≈10.44kg m-2 in outdoor operations. This work demonstrates the potential of 3D hierarchical porous ceramics in addressing the trade-off between heat localization and salt resistance, and contributes to the development of durable solar steam generators.

Effects of spraying power on Fe-based amorphous coatings

To avoid the corrosion damage caused by cavitation and sediment erosion on the turbine blades, Fe-based amorphous coatings were deposited on steel of hydraulic turbine blades using plasma spraying with various spraying power. The effects of spraying power on the microstructure, electrochemical corrosion and wear resistance were systematically studied. Results show that the coatings have remarkable corrosion resistance and wear resistance compared with the substrate. Porosity is the most critical factor influencing the corrosion resistance of coatings. The anti-corrosion performance increases and the wear rate decreases as the spraying power increases. The coatings prepared at 25 kW has excellent corrosion resistance and wear resistance, with a corrosion rate of 0.011 mm·a−1, and a wear rate of only 5.91 mm3·N−1·m−1.

Generation of array of square microcavity on quartz by ultrasonic micromachining process utilizing developed micro tool

Quartz possesses distinct characteristics such as exceptional hardness, high brittleness, non-conductivity, remarkable corrosion resistance, efficient transmission within specific wavelengths, strong electrical insulation properties, and the ability to withstand high temperatures and thermal shocks. These extraordinary attributes have led to its component in a wide range of applications, including the fabrication of microelectronic chips, biochips, biological channels, microfluidics, optical lenses, beam-splitting lenses, etc. Ultrasonic micromachining (USMM) is a highly promising technique within the realm of micromachining to create micro features on quartz surfaces. In the present research, array of square micro tools has been designed and developed by the wire-electrical discharge machining (EDM) process. By utilizing the developed array of square micro tools, microcavity arrays have been generated by the USMM process. The influences of process parameters on material removal rate (MRR), width deviation (WD), angular deviation, and taper of square microcavities have been investigated in the present research work. The higher MRR is obtained as 1.427 mm3/min at higher abrasive slurry concentration and lower WD of micro cavities is obtained as 37 µm and lower taper angle is 1.109° at 5% abrasive slurry concentration. The lower value of angular deviation is obtained as 0.836° at a lower power rating during the generation of an array of square microcavity on quartz by the USMM process. By employing array of micro tools, the accuracy of micro features can be improved, and also productivity can be increased.