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The tantalum oxide film was fabricated using an anodization process in a 0.5M H 2 SO 4 electrolyte. The evolution and corrosion resistance mechanism of anodized film on the Ta surface has been investigated by experiments and theoretical calculations. The results indicate that the sample with an anodic oxidation voltage of 20V and an anodic oxidation time of 60 min (Ta 20-60) exhibits the thickest oxidation film, measuring 360.00 nm and comprising an outer porous layer and an inner dense layer. Ta 20-60 demonstrates the highest E corr value of 0.009 V and the lowest I corr value of 0.879 μA cm−2, with a minimal density of point defects at 1.24 × 1019 cm−3, which imparts superior corrosion resistance. The calculation result shows that the growth rate of Ta anodic oxidation film is controlled by the diffusion and migration of vacancy defects. The O atom passes through one bridge site from the tetrahedral gap to another tetrahedral gap (Path 1) on the complete (110) surface has a low diffusion barrier of 0.470 eV and the shortest diffusion path of 2.04 Å, which is the most favorable path for the diffusion of O atoms. This paper offers a fresh perspective on the corrosion resistance of tantalum while furnishing guidance for improving Ta oxide film performance. [ABSTRACT FROM AUTHOR]

This study investigated the failure behavior and mechanism of conductive and corrosion-resistant film on magnesium alloy under "double 85" test conditions. The surface morphology, microstructure, and composition of ITO composite conversion film (ITO film) at different damp-heat test times were analyzed using X-ray photoelectron spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, and the corrosion resistance was investigated using an electrochemical workstation in contact with a 3.5 wt.% NaCl solution. The electrical contact resistance (ECR) was measured using the four-wire Kelvin detection technique, and the bandgap was determined using an ultraviolet diffuse reflectance spectrometer. The results demonstrated that the ECR of the ITO film increased from 10−1 Ω in−2 to 106 Ω in−2, and the bandgap increased from 2.363 to 2.777 eV after the damp-heat test. In addition, the impedance arc radius of the film decreased to approximately one-fifth of its original value, and the impedance modulus value decreased to less than 104. These findings indicated that exposure to a damp-heat environment resulted in an increase in the electrochemically active points within the film participating in the electrochemical reactions and expansion of the electrochemical reaction area. This exacerbated the corrosion of the magnesium substrate because it resulted in the destruction of the film, leading to an increase in the number of pores and defects, which heightened the exposure of the substrate to corrosive media. Furthermore, Cl− ions could easily penetrate through cracks in the film, which promoted charge transfer processes and accelerated the electrochemical corrosion reactions. In summary, these factors collectively resulted in the failure of the film's conductivity and corrosion resistance. [ABSTRACT FROM AUTHOR]

The present study investigates the formation mechanism of black spot defects on the surface of industrial continuously hot-dip galvanized Zn-2Al-1.5Mg coatings. Electrochemical experiments and neutral salt spray tests are conducted to study the corrosion resistance of the black spot defects and their influence on the corrosion mechanism of the coatings. The results show that the enrichment of Mg elements within the coating is the fundamental cause of the formation of this defect. The enrichment of Mg elements leads to a reduction in the size of primary Zn, an increase in the proportion of eutectic structures and the MgZn2 within the defective coatings. Consequently, the defective coatings exhibit the higher surface hardness and, after skin pass rolling, display the different reflective properties compared to surrounding coatings. The black spots feature is attributed to the formation of oxide film containing MgO. The electrochemical test results indicate that black spot defect exhibits enhanced corrosion resistance due to the lower Volta potential difference (VPD) between each phase on its surface. Moreover, the fine and dispersed cathodes not only avoid the occurrence of extremely pH sites, but also facilitate the formation of uniform distributed corrosion products with high protective ability. In the 600-h neutral salt spray experiments, Zn-2Al-1.5Mg coatings with black spot defects exhibit enhanced corrosion resistance, which is attributed to the Mg enrichment delaying the decomposition of highly protective corrosion products. [ABSTRACT FROM AUTHOR]

A high‐entropy rare‐earth disilicate (Er0.25Y0.25Ho0.25Yb0.25)2Si2O7 (hereinafter referred to as (EYHY)2Si2O7) ceramic was synthesized by a heat treatment process combined with spark plasma sintering. According to the experimental results, (EYHY)2Si2O7 presents good phase stability and low thermal conductivity ([1.48–2.35] W∙m−1∙K−1) from room temperature to 1200°C. Its coefficient of thermal expansion is (3.89–5.32) × 10−6 K−1 from 200 to 1400°C, similar to SiC‐based materials ([4.5–5.5] × 10−6 K−1). Due to the multiple doping effects, (EYHY)2Si2O7 exhibits outstanding corrosion resistance performance in water‐vapor corrosion tests. Its weight loss is 1.79 mg/cm2 after corrosion at 1600°C for 30 h in the presence of 50% H2O‐50% O2, which is lower than the corresponding four single components Re2Si2O7 (Er2Si2O7, Y2Si2O7, Ho2Si2O7, and Yb2Si2O7) under the same conditions. Therefore, high‐entropy (EYHY)2Si2O7 ceramics are regarded as potential environmental barrier coatings materials for SiC ceramic matrix composites. [ABSTRACT FROM AUTHOR]

Nickel-aluminum (Ni–Al) composite coatings containing nickel nanoscale twins have been prepared by co-electrodeposition on copper substrate. Effects of Al particles on microstructure, chemical composition, friction properties, and corrosion resistance of Ni–Al coatings were investigated. It presents an even and compact structure with granular surface that Al are evenly dispersed in pyramidal-like nickel lattice. Adding Al could alter crystal orientation, refine grains and promote strengthening effects induced by nanoscale twinning. It can enhance anti-corrosion properties and decrease the coefficient of friction (COF). The minimum COF was obtained at 10 g L−1 Al. The larger amounts and even dispersion of Al, the better corrosion resistance and the smaller COF. Increasing Al from 20 to 40 g L−1, incorporated Al in top surface rose from 20.86 to 30.13 wt%, which was larger than in cross section from 13.93 to 18.86 wt%. As the incorporated depth increased, the particle color changed from grey to dark. Nano-twins were generated around enveloped Al particles. The roughness increased as Al rose from 10 to 40 g L−1. The average roughness (R a) was of 191–231 nm. Ni–Al-5g and Ni–Al-80g have excellent anti-corrosion features, owning the maximum R ct of 1437.2 and 1565.1 kΩ cm2, respectively, associated with the amount and distribution of Al particles, preferred orientation, grain sizes, and twinned structure. The enhanced corrosion resistance might be due to the generation of uniform, compact aluminum oxide layer by doping Al in nickel. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) ceramic membranes are highly sought-after for their exceptional properties including high temperature resistance, corrosion resistance, good hydrophilicity, high flux, and high mechanical strength. However, achieving stable regulation of high solid content SiC slurries for membrane preparation remains a significant challenge. This study presents a novel approach to stabilize the dispersion of high solid content SiC slurries by controlling parameters such as solid content, pH, ball milling time and spray coating parameters. Furthermore, the impact of different milling durations on SiC particle size and membrane performance is systematically investigated, establishing, for the first time, a direct correlation between milling time and particle size. The investigations reveal that prolonged ball milling, specifically 18 h, results in a notable reduction in membrane pore size by approximately 40 %, accompanied by a remarkable enhancement in retention performance, as evidenced by a substantial increase in the average retention rate for 500 nm fluorescent microspheres from 54.61 % to 98.89 %. This study not only offers a practical method for the stable preparation of ceramic slurries, but also provide important reference for membrane morphology control and pore size regulation. These insights hold significant promise for advancing SiC membrane technology in applications such as wastewater treatment and resource recovery. [ABSTRACT FROM AUTHOR]

ABSTRACT This study developed a green and efficient surface protection method for Cu–Ni alloys. A zinc dibenzyl dithiocarbamate film was prepared on the surface of electrodeposited Cu–Ni alloys using the self‐assembly method to improve the material's corrosion resistance in seawater. The influence of zinc dibenzyl dithiocarbamate concentration and self‐assembly time on the corrosion resistance of the self‐assembled films was investigated through electrochemical testing. The findings revealed that at a zinc dibenzyl dithiocarbamate concentration of 10 mmol/L and a self‐assembly time of 20 min, the self‐assembled film exhibited the most robust corrosion resistance, achieving a maximum corrosion inhibition efficiency of 97.70%. The self‐assembly and adsorption mechanism of zinc dibenzyl dithiocarbamate were explored using molecular dynamics simulations and adsorption isotherms. The protective effect of self‐assembled films was visually observed through salt spray testing. Zinc dibenzyl dithiocarbamate self‐assembled film technology has high application prospects in the field of marine anti‐corrosion. [ABSTRACT FROM AUTHOR]

The utilization of Ag electrodes in inverted perovskite solar cells (PSCs) is prevalent; however, their inherent reactivity and corrosive characteristics toward perovskite materials often lead to significant stability concerns. Here, 1‐ethyl‐3‐methyl‐1h‐imidazolium 2‐mercaptobenzothiazole (EM) ionic liquid is designed and introduce it into the bathocuproine (BCP) barrier layer to mitigate the potential chemical corrosion of the Ag electrode by the perovskite layer. EM forms multiple interaction modes through the coordination of two types of bonds, C─N, C═N, and C─S, and chelation with Ag, resulting in the formation of a dense chemical anti‐corrosion layer on the Ag surface. By raising the Ag electrode's corrosion potential and decreasing its corrosion current, the occurrence of chemical reactions and corrosion of the Ag electrode by the perovskite layer is effectively suppressed. Additionally, the ionized EM optimizes the band structure and conductivity of BCP and enhances the electron transfer capability at the electron transport layer/Ag interface. The BCP:EM‐based inverted PSCs exhibit an efficiency of 25.11% and excellent stability. Under continuous operation at 45 °C and one sun illumination, the encapsulated device maintains 85.6% of its initial efficiency after 1000 h at the maximum power point. [ABSTRACT FROM AUTHOR]

Compared with machine staining, traditional manual staining faces various problems, such as a low preparation success rate, low efficiency, and harm to the human body due to corrosive gases. Therefore, a stainer that is of low cost, has strong corrosion resistance, and is suitable for small-batch preparation should be developed. In this study, by choosing a rotary scheme as the structural basis, a reusable container cover and a master-slave manipulator cooperation scheme are developed, which greatly improve the space utilization rate. Through material selection and structural design, in the designed stainer, effective protection against strong acids with high volatility and permeability is realized, thereby eliminating the corrosion issue. Using the designed splitting-running algorithm for the dyeing procedure, simultaneous multistaining is realized, which significantly improves the staining efficiency. Compared with large-sized stainers, the cost of the proposed stainer is very low, which will help popularize early screening for cervical cancer in low- and middle-income countries. [ABSTRACT FROM AUTHOR]

LiCoO2 has become the most widely used cathode material in lithium‐ion batteries because of its high capacity and excellent stability. The high‐temperature solid‐state method is commonly used for the preparation of LiCoO2. However, this method will produce highly penetrating Li2O, which causes spall or fracture of the insulating refractory materials in the kiln. In this study, the corrosion resistance of bubble alumina, mullite, and calcium hexaaluminate (CA6) insulating refractories to LiCoO2 has been thoroughly investigated. Combining the laboratory‐scale interfacial reaction experiments with post‐experimental life cycle analysis of industrial insulating refractories, the interaction between the insulating refractory materials and LiCoO2 after calcination at 900°C for 5 h and the corrosion behavior of LiCoO2 on different insulating refractory materials following heat treatment at 900°C for 5 h every time and repeated seven times are investigated. The corrosion mechanisms are concluded by analyzing the physicochemical composition and macro‐ and micromorphology of the three insulating refractory materials before and after corrosion. The results can provide a basis for the use of insulating refractories in the development of lithium batteries. [ABSTRACT FROM AUTHOR]

FRP profile‐concrete hybrid beam, composed of a FRP profile beam, a concrete slab made of normal concrete (NC) or ultra‐high‐performance‐concrete (UHPC), and shear connectors, shows significant potential for employment in large‐span bridges due to its excellent corrosion resistance, lightweight, and easy construction. The structural behavior of such hybrid beam was simulated using a three‐dimensional non‐linear finite element model (FEM) in Abaqus. The Hashin failure model and concrete damage plastic (CDP) model were employed to characterize the progressive failure of FRP, NC, and UHPC, respectively. The FEM considered partial shear connection by utilizing shear load‐slip model and the orthotropic behavior of the FRP profile. The proposed FEM was validated through comparisons with experimental data in terms of load‐midspan deflection curve, load‐end slip curve, and failure modes. A parametric study was subsequently conducted to identify the effects of various factors, including concrete strength, bolt spacing, concrete slab width, concrete slab height, FRP flange and web thickness, and shear span. Based on the results yielded from FEM analysis, the accuracy of the calculation method in Chinese standard (GB‐50608) for predicting the loading capacity of hybrid beams was evaluated and found too conservative. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to investigate the corrosion resistance of Fe‐36Ni Invar alloys with varying Mg contents in a 3.5 wt% sodium chloride solution. The electrochemical results reveal that the incorporation of Mg amplified the corrosion behavior of Fe‐36Ni Invar alloy. The inclusion compositions undergo a transformation with the increase of Mg content, evolving from MnO–MnS in 0 Mg alloy to MnO–MnS–MgO in 0.0015 Mg alloy, and ultimately to MnS–MgO–MgS in 0.0030 Mg alloy. During the corrosion process, the small‐sized MnS–MgO–MgS inclusions exhibit greater stability compared to the MnO–MnS inclusions, rendering them less susceptible to attack and dissolution. Adding Mg diminishes the size and number density of inclusions, which effectively decreases the susceptibility to pitting initiation. The introduction of Mg refines the microstructure and elevates the fraction of twin boundaries, which also is responsible for the enhancement of corrosion resistance. [ABSTRACT FROM AUTHOR]

This study investigated the corrosion behaviour of dissimilar steel-to-aluminium laser-welded conduction, and keyhole mode (partial- and full-penetration) lap joints through electrochemical techniques and advanced microstructural characterisation. The corrosion resistance of the weld was found to be higher than the base materials, primarily due to the presence of cathodic FexAly (η-Fe2Al5, θ-Fe4Al13, β-FeAl) intermetallic compounds (IMCs) with high corrosion potential. The different micro and macro-galvanic corrosion mechanisms were found at various interfaces around the weld, resulting in localised pitting corrosion. The keyhole mode welding showed improved corrosion resistance, primarily attributed to the type, size, and distribution of IMCs. [ABSTRACT FROM AUTHOR]

ABSTRACT The advancement of smart coatings for bioimplants has yielded a combination of biocompatibility and corrosion resistance. 316L stainless steel (316LSS) is a commonly used commercial implant, but it has limitations in biocompatibility and durability, which hinders the widespread utilization of 316LSS alloys. In this study, the 316LSS alloy is coated with a mixture of zirconium dioxide (ZrO2), prepared using the sol–gel method, and graphitic carbon nitride (g‐C3N4), synthesized by thermal polymerization. XRD and Raman analyses confirmed the crystal structure and purity of the synthesized samples. The corrosion resistance property was assessed using OCP, POL, and PEIS. The findings demonstrate that the ZrO2/g‐C3N4‐coated 316LSS shows significantly enhanced corrosion resistance and biocompatibility in a simulated body fluid. The in vitro bioactivity test reveals that the ZrO2/g‐C3N4 coating leads to the formation of an apatite layer over the surface of 316LSS. The elemental composition of the HAP deposition was confirmed by Raman analysis. The results suggested that the ZrO2/g‐C3N4–coated 316LSS substrate is a promising material for use in biomedical applications. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, we explore the corrosion resistance of AA2198‐T8 alloy in friction stir‐welded zones, focusing on microstructure changes and resulting corrosion susceptibility. Macrogalvanic coupling effects are observed in weldment under corrosive conditions, particularly in the welding joint (WJ), heat‐affected zones, and base metal (BM). Severe localized corrosion is prevalent in anodic zones, revealing intricate trenching patterns around micrometric particles in cathodic domains. Investigating isolated zones exposes SLC across all welding‐affected regions and BM, underscoring the involvement of microgalvanic cells in corrosion. The novel utilization of a syringe cell as an electrochemical tool proves to be instrumental in delineating the electrochemical characteristics of welding testing zones. Notably, stir zone within WJ emerges as the region depicting the lowest corrosion resistance, a critical finding substantiated by localized electrochemical impedance spectroscopy. These insights into the interplay of electrochemical phenomena and microstructural attributes have implications for advancing corrosion mitigation strategies and alloy engineering in materials science. [ABSTRACT FROM AUTHOR]

This work presents a systematic investigation of the corrosion behavior of two materials, 316 stainless steel (316), and Ti6Al4V alloy (Ti6Al4V), in simulated seawater (3.5wt.% NaCl solution). This includes electrochemical tests, immersion experiments, scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) analyses. The polarization curves demonstrate that passivation occurs in both alloys. The lower self-corrosion and passivation current densities of Ti6Al4V indicate that its corrosion resistance is superior to that of 316. However, the impedance spectrum of the 316 shows a larger capacitive arc radius, which is indicative of the presence of a more robust passivation film on its surface. The results of the immersion experiments demonstrate that 316 exhibits a high-corrosion rate under static conditions, which can be attributed to the instability of the passivation film and environmental factors. However, under dynamic conditions, the corrosion rate is lower due to the effect of scouring. In contrast, Ti6Al4V demonstrated superior corrosion resistance in a variety of environmental conditions. In the context of simulated seawater, both 316 and Ti6Al4V exhibited varying degrees of corrosion behavior. Consequently, when selecting corrosion-resistant materials, it is imperative to select suitable materials according to the specific use environment and requirements. [ABSTRACT FROM AUTHOR]

Nanocomposite coatings have garnered significant attention for their potential applications in various fields, including dentistry. These coatings consist of a base matrix, typically a polymer, ceramic, or metal, embedded with nanoparticles that confer enhanced properties do not present in the bulk material. By incorporating nanoparticles into a suitable matrix, these coatings exhibit superior properties including bioactivity, wear resistance, corrosion resistance, antibacterial activity, and drug release capabilities. This review specifically covers the application of nanocomposites as (1) bioactive/osteoconductive coatings, (2) antibacterial/antimicrobial nanocomposite coatings, (3) tribological/corrosion protection nanocomposite coatings, and (4) drug delivery nanocomposite coatings. [ABSTRACT FROM AUTHOR]

The carbon-based metal-free catalyst was prepared by the hydrothermal method. The boron functionalized carbon dots modified g-C3N4 (BCDs/g-C3N4) photoelectrode showed excellent photoelectrocatalysis performance. Due to boron doping, the agglomeration of the complex is effectively inhibited, the specific surface area is increased and the number of active sites is increased. In addition, the boron atoms in BCDs interact closely with the nitrogen atoms of g-C3N4, which accelerates the electron transfer rate between the carbon dots and g-C3N4. Compared with g-C3N4, the photocurrent intensity of BCDs/g-C3N4 increases by 2.26 times. Finally, the photoelectrocatalytic (PEC) degradation efficiency of phenol by BCDs/g-C3N4 reached about 100% within 180 min. The BCDs/g-C3N4 photoelectrode has good acid and alkali corrosion resistance, universal applicability and cyclic stability. [ABSTRACT FROM AUTHOR]

The regained interest in using the externally applied magnetic field (MF) to engineer properties in the solid state has opened a new lane and expanded the existing paradigm to control the microstructure and improve the performance of materials. One area to explore is the enhancement in corrosion resistance of an intricately shaped component for structural applications. This work evaluated the corrosion resistance of paramagnetic Ti alloy, Ti–6Al–4V, treated in a static MF of 2 T. To investigate the magnetically induced microstructural evolution in terms of α-phase fraction and dislocation density and its effect on corrosion behavior, the material was studied in three conditions: as-received (hot rolled) plate, 5% cold-rolled, and 5% cold-rolled + annealed. Experiments involved performing corrosion tests and evaluating phases and dislocation density via X-ray diffraction and electron microscopy. A decrease in dislocation density was observed for magnetic exposure of 2 T for all conditions, with a drastic decrease of ~ 38.5% for the cold-rolled sample. An evident improvement in corrosion resistance of magnetically treated paramagnetic alloy as a result of the negative magneto-plasticity effect paves new pathways for tailoring the properties. [ABSTRACT FROM AUTHOR]

ABSTRACT In order to improve the comprehensive properties of TC4 titanium alloy, micro‐arc oxidation (MAO) coating is prepared on the surface of a TC4 substrate in a basic electrolyte with varying concentrations of Sr(OH)2. The surface morphology, phase composition, element distribution, and corrosion resistance of MAO coatings are analyzed by scanning electron microscopy, X‐ray diffraction, an energy‐dispersive spectrometer, the electrochemical test, and the erosion–corrosion test. The results show that the voltage of the MAO process increases and then decreases; the surface morphology and density of the coatings are greatly improved after doping Sr(OH)2. When the concentration of Sr(OH)2 is 0.6 g L−1, the thickness, hardness, and adhesion strength of the coating reach the maximum values of 37.04 μm, 836.2 HV, and 21.8 N, respectively. At this time, the wear resistance and corrosion resistance are the best, and the friction coefficient and the corrosion rate are the lowest: 0.3352 and 1.04 × 10−10 mm a−1, respectively. [ABSTRACT FROM AUTHOR]

The addition of Ca and Sb in Cr‐bearing steel presents improved corrosion resistance during the field exposure test in a marine atmosphere environment. Through local hydrolysis reactions, Ca and Sb can form CaO, Sb2O3, and Sb2O5 to prevent the intrusion Cl− into the corrosion product film, which improves the protectiveness of the corrosion product film and reduces the corrosion rate. The formation of CaCl2 decreases the relative content of β‐FeOOH and makes the corrosion product film more stable. Due to the inhibition of Sb on the local acidification of corrosion product film, Ca and Cr are able to bond with more hydroxide for generating the corresponding oxides and improving the corrosion resistance of Cr‐bearing steel. [ABSTRACT FROM AUTHOR]

The performance of the anode varies from the impurity ions in the copper electrowinning process. This work focused on the variation of the electrochemical behavior of the Pb-0.06%Ca-1.2%Sn anode as the Fe ions (Fe3+ and/or Fe2+) existed in the electrolyte by electrochemical characterization. Copper electrodeposition experiments were conducted under a current density of 300 A/m2, with the Fe ion concentration in the electrolyte controlled within the range of 0 to 20 g/L and the Cu ion concentration maintained at 45 g/L at a temperature of 45 °C. The variation in the corrosion resistance, catalytic activity, and structural composition of the anode film layer was analyzed in-depth according to the presence of Fe ions. The results show that the structure of PbO2 on the surface of the film was changed as Fe ions doped into the anode film, and the oxygen evolution activity of the anode was also improved. However, the corrosion resistance decreased with increasing Fe3+ concentration. Furthermore, the addition of 2 g/L Fe2+ in the electrolyte containing 2 g/L Fe3+ led to an elevation in the corrosion resistance of the anode to some extent and further increased the oxygen evolution activity. [ABSTRACT FROM AUTHOR]

Mitigating the adverse effects of corrosion failure and low-temperature icing on aluminum (Al) alloy materials poses significant research challenges. The facile fabrication of bioinspired superhydrophobic materials offers a promising solution to the issues of corrosion and icing. In this study, we utilized laboratory-collected candle soot (CS), hydrophobic fumed SiO2, and epoxy resin (EP) to create a HF-SiO2@CS@EP superhydrophobic coating on Al alloy surfaces using a spray-coating technique. Various characterization techniques, including contact angle meter, high-speed camera, FE-SEM, EDS, FTIR, and XPS, were employed to investigate surface wettability, morphologies, and chemical compositions. Moreover, a 3.5 wt.% NaCl solution was used as a corrosive medium to evaluate the corrosion resistance of the uncoated and coated samples. The results show that the capacitive arc radius, charge transfer resistance, and low-frequency modulus of the coated Al alloy significantly increased, while the corrosion potential (Ecorr) shifted positively and the corrosion current (Icorr) decreased by two orders of magnitude, indicating improved corrosion resistance. Additionally, an investigation of ice formation on the coated Al alloy at −10 °C revealed that the freezing time was 4.75 times longer and the ice adhesion strength was one-fifth of the uncoated Al alloy substrate, demonstrating superior delayed icing and reduced ice adhesion strength performance. [ABSTRACT FROM AUTHOR]

This study investigates the impact of strontium (Sr) additions on the corrosion resistance of an LM6 (A413) aluminium alloy. By incorporating varying concentrations of Sr (0.01 wt.% and 0.05 wt.%), the morphological and corrosion behaviours of the alloy were analysed under different corrosive environments, including sulphuric acid, sodium hydroxide, and sodium chloride solutions. The results demonstrate that Sr modifications significantly enhance the alloy's corrosion resistance, with the most substantial improvement observed at 0.05 wt.% Sr. The analysis revealed that the weight loss of the alloy in sulphuric acid decreased by 2.5% with 0.05 wt.% Sr after 10 days of immersion, due to the formation of a stable passive oxide layer. In sodium hydroxide, however, the weight loss was reduced by 5% with 0.05 wt.% Sr after 10 days, indicating aggressive uniform corrosion. In the 3.5% sodium chloride solution, the corrosion rates remain relatively low, and the 0.05 wt.% Sr alloy showed a decrease in corrosion product formation over time, suggesting enhanced resistance. Detailed surface analyses, including 3D profiling and morphology assessments, revealed that Sr additions refine the eutectic silicon phase, transforming it from a coarse to a more desirable fibrous or lamellar structure, thus improving the alloy's overall performance. The innovative findings underscore the potential of Sr as an effective microstructural modifier for enhancing the durability and longevity of Al-Si alloys in corrosive environments. [ABSTRACT FROM AUTHOR]

In this study, we optimized the traditional composition of AISI 8630 steel and evaluated its corrosion resistance through a series of tests. We conducted corrosion tests in a 3.5% NaCl solution and performed a 720 h fixed-load tensile test in accordance with the NACE TM-0177-2016 standard to assess sulfide stress corrosion cracking (SSCC). To analyze the corrosion products and the structure of the corrosion film, we employed X-ray diffraction and transmission electron microscopy. The corrosion rate, characteristics of the corrosion products, structure of the corrosion film, and corrosion resistance mechanism of the material were investigated. The results indicate that the optimized AISI 8630 material demonstrates excellent corrosion resistance. After 720 h of exposure, the primary corrosion products were identified as chromium oxide, copper sulfide, iron oxide, and iron–nickel sulfide. The corrosion film exhibited a three-layer structure: the innermost layer with a thickness of 200–300 nm contained higher concentrations of alloying elements and formed a dense, cohesive rust layer that hindered the diffusion of oxygen and chloride ions, thus enhancing corrosion resistance. The middle layer was thicker and less rich in alloying elements, while the outer layer, approximately 300–400 nm thick, was relatively loose. [ABSTRACT FROM AUTHOR]

Difficult-to-cut titanium matrix composites (TiB+TiC)/Ti6Al4V have extensive application prospects in the fields of biomedical and aerospace metal microcomponents due to their excellent mechanical properties. Jet electrochemical micromilling (JEMM) technology is an ideal method for machining microstructures that leverages the principle of electrochemical anodic dissolution. However, the matrix Ti6Al4V is susceptible to passivation during electrochemical milling, and the inclusion of high-strength TiB whiskers and TiC particles as reinforcing phases further increases the machining difficulty of (TiB+TiC)/Ti6Al4V. In this study, a novel approach using NaCl+NaNO3 mixed electrolyte for the JEMM of (TiB+TiC)/Ti6Al4V was adopted. Electrochemical behaviors were measured in NaCl and NaCl+NaNO3 electrolytes. In the mixed electrolyte, a higher transpassive potential was required to break down the passive film, which led to better corrosion resistance of (TiB+TiC)/Ti6Al4V, and the exposed reinforcing phases on the dissolved surface were significantly reduced. The results of the JEMM machining indicate that, compared to NaCl electrolyte, using mixed electrolyte effectively mitigates stray corrosion at the edges of micro-grooves and markedly improves the uniformity of both groove depth and width dimensions. Additionally, the surface quality was noticeably improved, with a reduction in Ra from 2.84 μm to 1.03 μm and in Rq from 3.41 μm to 1.40 μm. [ABSTRACT FROM AUTHOR]

Water-cooled wall tubes are susceptible to high-temperature corrosion during service. Applying high-performance coatings via laser cladding on the tube surfaces can significantly enhance corrosion resistance and extend the service life of the tubes, providing substantial economic advantages. This paper prepared Y2O3/IN625 composite coating by means of high-speed laser cladding. Furthermore, the effects of Y2O3 addition on the microstructure evolution, hardness, as well as the high-temperature corrosion behaviors have been systematically investigated. The results show that Y2O3 addition can effectively refine the microstructure of the Inconel 625 coating, but the phase composition has little change. The coating's hardness can also be improved by about 7.7%, reaching about 300 HV. Compared to Inconel 625 coating, the Y2O3-added composited coating shows superior high-temperature corrosion resistance, with the corrosion mass gain decreased by about 36.6%. The denser and tightly bonded Cr-rich oxides layer can be formed adjacent to the coating surface, which plays a predominant role in improving the coating corrosion resistance. [ABSTRACT FROM AUTHOR]

The mechanical properties and electrochemical stability of high-entropy alloys are substantially affected by their composition distribution and crystal structure. However, the details concerning the conditions of milling and sintering for sintered alloys have rarely been reported. In this work, a series of CrMnFeCoNi alloys were fabricated by ball milling and spark plasm sintering for different periods. Their crystal structure, density, hardness, and corrosion resistance were investigated. As a result, a partial alloying of Cr, Mn, Fe, Co, and Ni was achieved by ball milling. However, Cr-rich particles, including Mn, were formed in the milled powders. The sintered alloys inherited the Cr-rich particles to form Cr-rich zones. The formation and change of chromium carbide were also confirmed in sintered alloys. Extended milling or sintering to 12 h achieved high hardness and corrosion resistance for the sintered alloys. The Cr-rich zones showed high hardness and Kelvin potential, which affect both the hardness and the corrosion resistance. [ABSTRACT FROM AUTHOR]

Improving the wear resistance and corrosion resistance of 60Si2Mn steel is an important issue in agricultural machinery. A Rockit 606 coating layer may exhibit excellent performance in wear resistance and corrosion resistance. However, there are very a few public reports and articles involving the topic of a Rockit 606 laser cladding layer on a steel 60Si2Mn surface. It is of great importance to research Rockit 606 laser cladding layers. This work focuses on studying the microstructure and properties of Rockit 606 coating layers with different scanning speeds by disk laser cladding. Firstly, the laser cladding platform was designed and set up. Secondly, the laser cladding parameters were designed, and then the laser cladding experiment was conducted, and the Rockit 606 coating layers were obtained. And finally, the microstructure, phase distribution, corrosion resistance, surface hardness, and wear resistance of the coating layers were measured and analyzed. A scanning electron microscope (SEM), X-ray diffractometer (XRD), electrochemical workstation, and microhardness tester were used in this work. It was found that the microstructure Rockit 606 alloy coating consists of γ-Fe, V8C7, and Cr7C3. The microhardness of the Rockit 606 alloy coatings decreased with an increase in the scanning speed. When the scanning speed was 4 mm/s, the highest microhardness value reached 867.2 HV, which is about three times of that of the substrate. The average coefficients of friction (COFs) of the coatings decreased with an increase in the scanning speed, which led to the corresponding decrease of the wear rate. When the scanning speed was 4 mm/s, the wear behavior of the coating was mainly oxidative wear and a small amount of adhesive wear. The self-corrosion current density of the coatings prepared by laser cladding in a 3.5 wt.% NaCl solution is one order of magnitude lower than that of the substrate, indicating that the coatings have better corrosion resistance properties. [ABSTRACT FROM AUTHOR]

Improper thermal cycles on duplex stainless steels can lead to the formation of detrimental phases or alter the proportion of ferrite and austenite phases, thus influencing the material's mechanical properties and corrosion resistance. Therefore, this study aimed to evaluate the effect of aging (at 850 and 950 °C) and solubilization (at 1000 and 1150 °C) thermal treatments on microstructure, indentation hardness, elasticity modulus, and susceptibility to intergranular corrosion of UNS S32205 duplex stainless steel. The sigma phase (σ) formation in the aged samples, with hardness values between 8 and 10 GPa, was confirmed. Furthermore, the pieces treated from 1000 °C upwards showed that increased temperature favored the formation of more equiaxial grains and the ferrite fraction growth. The thermal treatments barely affected the elasticity modulus of austenite and ferrite grains, increasing the hardness of ferrite. The effect of sulfuric acid concentration in the intergranular corrosion was evaluated. Also, the deconvolution of the corrosion curves permits the determination of the influence of the different phases in the corrosion performance. These tests revealed sensitization only at the σ phase grain boundaries in the samples treated at 850 °C in electrolytes containing H2SO4 2.5 mol/L and HCl 1 mol/L. Although the treatment at 950 °C led to the σ phase formation, its higher corrosion resistance was ascribed to the lower volumetric fraction of this phase, its morphology, and its increased Cr mobility compared to the 850 °C treatment. Therefore, it was shown that the σ characteristics and the sulfuric acid concentrations are determining factors in the UNS S32205 intergranular corrosion resistance. [ABSTRACT FROM AUTHOR]

In the present work, the Q345B low-alloy steel with different contents and ER309L stainless steel were melted together to obtain new alloys. The aim was to design the composition of weld metal (Q345B low-alloy steel as the base material and ER309L welding wire as the filler material) and improve the corrosion resistance of the weld metal. During the welding process, the composition of the weld metal was controlled to match the new alloys by changing the welding heat input. A relationship curve between fusion ration and welding heat input was obtained. The research focused on analyzing the effect of mixed-smelting ratio between Q345B and ER309L and welding heat input on the microscopic structure and corrosion performance of the prepared samples. The results show that the melted alloys containing 20% to 30% Q345B consist of a ferrite (δ) phase and austenite (A) phase, the samples containing 45% to 50% Q345B consist of a martensite (M) phase and austenite (A) phase, and the sample containing 40% Q345B consists of a martensite (M) phase, ferrite (δ) phase, and austenite (A) phase. As the mixed-smelting ratio of Q345B/ER309L increased, the corrosion resistance of samples decreased gradually. For the weld metal, the fusion ration between Q345B base material and ER309L welding wire increases with the welding heat input. When the heat input changed from 0.645 kJ/mm to 2.860 kJ/mm, the composition of the weld metal was consistent with the melted alloys containing 20–45% Q345B. The microstructure and corrosion resistance of the weld metal could be designed by the melting means, which has important guiding significance for engineering applications. [ABSTRACT FROM AUTHOR]

This paper aims to study the corrosion resistance and interfacial bonding properties of the silver zinc-rich coating/substrate system and silicone zinc-rich coating/substrate system. The actual working state of the system in marine environment was simulated by the coupled effects of corrosion and pre-stretching. Scanning electron microscope (SEM) with an energy dispersive X-ray spectrometer (EDS) was used in corrosion test to analyze the surface morphology and corrosion products. Meanwhile, the degradation degree of the corrosion resistance was investigated based on the electrochemical impedance spectroscopy (EIS) and water absorption rate. Three-point bending test and tensile test combined with digital image correlation (DIC) were performed to evaluate the interfacial bonding properties of these two systems based on the elastic modulus and critical cracking strain. Results show that the dense accumulation of aluminum and zinc powders makes the silver zinc-rich coating have higher corrosion resistance compared to the silicone zinc-rich coating. The combined effects of corrosion and pre-stretching on the fracture toughness of silicone zinc-rich coating are larger than that of the silver zinc-rich coating. The interfacial bonding properties of the coating/substrate systems gradually degrade as the pre-stretching load approaches the critical cracking load of the coating. [ABSTRACT FROM AUTHOR]

Mullite–cordierite saggar materials commonly used in the industry are easily corroded by LiNixCoyMn1−x–yO2 (LNCM) materials during the synthesis of Li‐ion batteries. To extend their service life, the influence of varying the proportion of calcium hexaluminate (CA6) ranging from 0 to 12 wt% on the sintering behavior of the mullite–cordierite system was investigated. These samples were then tested to evaluate their physical characteristics, resistance to corrosion by LNCM materials, and thermal shock stability. The experimental results show that the open‐pore structure formed by the interstacking grains of CA6 effectively impedes further penetration of the corrosion phase. Moreover, the addition of CA6 resulted in the in situ formation of anorthite within the material, enhancing its sintering and bonding properties and significantly improving the material's corrosion resistance. Consequently, incorporating CA6 effectively enhances the saggar's thermal shock stability and corrosion resistance. [ABSTRACT FROM AUTHOR]

Metal corrosion is a challenge for the world with heavy impacts on the economy. Study on the development of effectiveness anticorrosion additives is a promising strategery for the protection industry. This research focuses on the modification of hydrotalcite Mg−Al (HT) loading tannic acid (TA) with 3‐(trimethoxy silyl) propyl methacrylate organo‐silane (TMSPM) for applicating as an anti‐corrosion additive for epoxy coating on the steel substrate. The suitable ratio of HT and modifiers was investigated and the suitable content of modified HT in epoxy matrix was found based on mechanical properties of the epoxy‐based coating. The characteristics of modified HT were assessed through infrared (IR) spectroscopy, X‐ray diffraction pattern (XRD), scanning electron microscopy (SEM), thermal gravimetry analysis (TGA), water contact angle (WCA), dynamic light scattering (DLS). Detailly, HT‐TA3‐S3 shows good stability in distilled water when HT/TA was modified with TMSPM which makes Zeta potential decreases significantly. Besides, SEM analysis presented HT‐TA‐S has a cylindrical shape about of 500 nm. Moreover, the crystallite size of HT/TA after being modified by TMSPM decreases sharply. All of these prove successfully synthesize HT loading TA with modified TMSPM. Water contact angle (WCA) decreases in case of loading TA and increases in case of modifying with TMSPM (WCA changed from HT (116.3°) to HT‐TA (102.4°) and HT‐TA‐S (120.1°) which indicates the increased hydrophobicity of the sample. The obtained results showed HT/TA was modified successfully with TMSPM. The modification affected the size distribution and surface properties of HT nanoparticles while it did not impact on the crystal structure of HT. After incorporating modified HT/TA into the epoxy coating, the adhesion of coating to steel substrate was improved significantly. Consequently, the adhesion of epoxy/3 wt. % modified HT/TA coating was increased 3 times as compared to epoxy neat (from 0.76 MPa to 2.77 MPa). In addition, the relative hardness and gloss retention of epoxy/3 wt. % modified HT/TA coating reached the maximum values as compared to the others. Owing to salt spraying results, the epoxy/3 wt. % modified HT/TA exhibited an excellent anticorrosion ability for the steel substrate. All the above results show the potential of HT nanoparticles loading TA modified with TMSPM as anticorrosive additives for protective coatings on steel substrates. [ABSTRACT FROM AUTHOR]

A corrosion study is performed on six variations of titanium grade 5 (Ti6Al4V) samples. Samples are prepared in different conditions by variation of preanodization, postanodization, and picosecond‐laser (ps‐laser) surface treatment, while polished and anodized samples serve as reference. Microcones and nanosized periodic surface features are successfully produced on Ti6Al4V samples. The morphology and topography of the structures are visualized by scanning electron microscopy and white light interference microscopy. Furthermore, the relative electrochemically active surface area (ECSA) is determined for the ps‐laser‐treated samples. It is determined that the preanodized and laser‐treated sample has 3.5 times larger ECSA than a polished sample, and that the laser‐treated sample has 4.1 times larger area. Moreover, Tafel analysis is performed to determine the corrosion properties of the samples. It is shown that the corrosion resistance improves for both laser‐structured samples after the anodization. To further study the surface of the samples, electrochemical impedance spectroscopy measurements are conducted. The study indicates that the ps‐laser‐treated and anodized Ti6Al4V is suitable to be used for the fabrication of bone screws and plates due to its improved corrosion resistance as compared to nonanodized samples. [ABSTRACT FROM AUTHOR]

Tensile properties and in vitro corrosion behavior of biodegradable Mg–xSi alloys and composites in the simulated body fluid (SBF) solution were investigated. Besides pure magnesium, the hypoeutectic (x = 0.1 and 0.5 wt%), near-eutectic (x = 1.2 wt%), and hypereutectic (x = 4 wt%) compositions were considered. The Si addition in the hypoeutectic range resulted in the grain refinement of as-cast ingots, formation of α–Mg/Mg2Si eutectic structure, and improvement of strength-ductility synergy. However, higher Si additions (1.2 and 4 wt%) led to poor tensile properties. Accordingly, the Mg–0.1Si and Mg–0.5Si alloys showed the best combination of tensile properties. The hot extrusion process resulted in a significant grain refinement induced by the dynamic recrystallization (DRX) and fragmentation of particles due to deformation, which led to a notable improvement of comprehensive tensile properties. For instance, the lean Mg–0.5Si alloy exhibited the highest tensile toughness value of 37.3 MJ/m3, which is much larger than the value of 5.2 MJ/m3 for the as-cast pure Mg. The extruded Mg–0.1Si sample showed the lowest corrosion current density (iCorr) of 10 μA/cm2 in the SBF solution compared to other samples, which was ascribed to the fine grain size and formation of appropriate protective film with a high Ca/P ratio. However, higher Si additions resulted in the deterioration of corrosion resistance due to the increased amount of Mg2Si phase. Accordingly, the Mg–0.1Si alloy was considered as a proper candidate for providing the best combination of tensile properties and corrosion resistance in biomedical implant applications. [ABSTRACT FROM AUTHOR]

The comparative investigation of the corrosion behavior of S32304 cast lean duplex and CF3M cast austenitic stainless steels was conducted in a chloride environment. The resistance to pitting corrosion of the S32304 alloy was "one" time higher than that of the CF3M alloy because the pitting potential, passive region, and critical pitting temperature of the low Ni-low Mo S32304 alloy were higher than those of the high Ni-medium Mo commercial CF3M alloy. There are two main reasons for the enhancement of the pitting corrosion resistance of high Cr-low Mo-medium N S32304 alloy compared to the low Cr-medium Mo CF3M alloy: First, the pitting resistance equivalent number (PRENδ+γ) value of the S32304 alloy is higher than that of the CF3M alloy. Second, the passive region of the S32304 alloy is larger than that of the CF3M alloy. It indicates that the synergistic effects of the three elements by adding high Cr and low Mo-medium N to the S32304 alloy enhance the passivity of the passive film, thereby increasing the resistance to pitting corrosion. It was verified that based on the PRENγ and PRENδ values calculated using an N-factor of 30, the pitting corrosion of the S32304 alloy was selectively initiated at the γ-phases and the inclusions of Mn oxy-sulfieds because the γ-phase's PRENγ value was smaller than the δ-phase's PRENδ, and finally propagated from the γ-phase to the δ-phase. [ABSTRACT FROM AUTHOR]

The effects of different solution temperatures on the microstructure and corrosion resistance of graphene nanoplatelets reinforced A380 (A380-GNPs) composites were investigated. The results show that the grain size of the composites was significantly refined by adding 0.9 wt% GNPs, and most of the Si phases in the A380-0.9 GNPs composite after solution treatment at 505 °C were spheroidal. Energy dispersive spectroscopy analysis indicated that most of the Al2Cu phases have been dissolved into the matrix. The hardness of the 505 °C solution treated composites increased by 28.8% compared to the A380-0.9 GNPs composites. Immersion corrosion tests revealed that the corrosion rate of the 505 °C solution-treated A380-0.9 GNPs composites (46.76 μg cm−2 d−1) was 24.9% lower than that of the non-solution-treated (58.41 μg cm−2 d−1). Electrochemical analyses showed that the corrosion voltage of the 505 °C solution-treated composites (− 507.41 mV) was 7.4% higher than that of the non-solution-treated (− 548.76 mV). The 505 °C solution-treated A380-0.9 GNPs composites had a high surface-area ratio between the anodic phases (α-Al) and the cathodic phases (Al2Cu, Si), and the anodic corrosion current densities were relatively weak, which resulted in the best corrosion resistance. The refinement and uniform distribution of cathodic phases, such as Al2Cu and eutectic Si, inhibit the occurrence of micro-galvanic corrosion and also reduce the corrosion rate of the composites. [ABSTRACT FROM AUTHOR]

Mg–Zn–Ca alloys have been widely used as biodegradable orthopedic and cardiovascular scaffolds because of their non-cytotoxicity, remarkable biodegradability, good biocompatibility and excellent mechanical properties similar to human bone. However, degradation causes poor corrosion resistance and mechanical properties. In this study, Mg-6%Zn-0.6%Ca alloys were produced using three distinct methodologies: casting, casting via the ultrasonic vibration process (USV), and casting via the mechanical vibration process (MV). Surface characterization, mechanical characteristics and corrosion resistance of the as-cast (untreated) and treated species were studied. The morphology and microstructure showed that the grain size of the as-cast, MV and USV specimens all had average grain sizes of about 191, 93 and 82 µm, respectively. The ultrasonic vibration treated specimen has the greatest degree of grain refinement. Mechanical tests showed that microstructure refinement promotes the mechanical characteristics of Mg alloy, such as compression, ultimate tensile strength as well as elongation. It was observed that the USV-treated sample has exceptional mechanical properties (Compressive strength 360.64 MPa, ultimate tensile strength (UTS) 178.41 MPa and Elongation 3.45%). Corrosion tests revealed that the USV-treated specimen exhibited uniform corrosion and low corrosion rate due to uniform compact fine grains with higher oxide concentration of about 42.82 wt%. The results of electrochemical analyses revealed that the average corrosion rate obtained from Potentiodynamic polarization curves of the as-cast, MV and USV specimens was about 5.3144, 4.5311 and 4.1087 mm/year, respectively and the passive film resistance (Rf) that was obtained from the electrochemical impedance spectroscopy (EIS) model of the USV, MV-treated samples and as-cast sample was 457 Ω, 430 Ω and 204 Ω, respectively. The results of immersion tests revealed that the USV-treated sample lost less weight and exhibits a relatively low degradation rate than the as-cast and MV-treated samples. After two weeks the weight of the as-cast, MV and USV samples decreased by about 18.6%, 18.5%, 16.8%., and the degradation rates were 7.304, 7.097 and 6.78 mm/y, respectively, and then gradually declining over the course of the immersion period. [ABSTRACT FROM AUTHOR]

In 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. [ABSTRACT FROM AUTHOR]

High‐temperature KCl‐induced corrosion in laboratory air was observed in situ utilizing X‐ray diffraction. High Cr‐containing model alloys (Fe‐13Cr, Fe‐18Cr‐12Ni, and Fe‐25Cr‐20Ni) were coated with KCl and exposed to dry air at 560°C. KCl‐free alloys were studied in the equivalent atmosphere as a reference. After exposure to KCl‐free environments, all alloys showed the formation of very thin oxide layers, indicating good corrosion resistance. In contrast, KCl‐bearing alloys showed distinct damage after exposure. [ABSTRACT FROM AUTHOR]

In the present study, the effect of varying titanium dioxide (TiO2) nanoparticles on the dielectric, thermal, and corrosion characteristics of PI-based composites prepared by spark plasma sintering was investigated. The results obtained revealed that the TiO2 nanoparticles were uniformly dispersed within the PI matrix. Addition of TiO2 into the neat PI markedly reduced its dielectric constant and electrical conductivity by 72.7% and 82.3%, respectively, as well as enhancing its breakdown strength by 16.7% at 8 wt% TiO2 loading. The nanocomposites depict better thermal stability and heat-resistance index characteristics when compared to the PI. Additionally, the produced nanocomposites exhibit improved corrosion resistance than that of the neat PI. The remarkable improvement in the dielectric, thermal stability, and corrosion resistance of the nanocomposites is achieved by better dispersion of the TiO2 particles in the polymer matrix. The enhancement in properties suggests TiO2/PI-based nanocomposites potential for a variety of applications in electrical insulation, thermal management, and harsh environment. [ABSTRACT FROM AUTHOR]