Search

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]

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]

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]

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]

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]

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]

Super austenitic stainless steel 254SMO (254SMO SASS) plates are joined by double‐sided double‐arc synchronous TIP TIG butt welding (DSSTTABW) using ER NiCrMo3 wire, and the micro‐structure, mechanical and corrosion properties of 254SMO SASS joints are investigated subsequently. Results show that solidification grain boundary and solidification sub‐grain boundary can be observed in fusion zone. A small amount of σ phase precipitates in the weld, while χ phase is found in the transition zone, but no solidification crack occurs in weld and heat affected zone (HAZ). 254SMO SASS joint has higher micro‐hardness and lower tensile strength and elongation compared to base metal. During transverse tensile process, 254SMO SASS joints fail in the weld zone in a ductile mode. Electrochemical corrosion performance tests indicate that 254SMO SASS joint achieve equivalent pitting corrosion resistance and similar passive mechanism to base metal in 3.5 wt% NaCl solution. The passivation film on the surface of both joint and base metal display as n‐p semi‐conductive character, but the film stability of 254SMO joint surface is slightly poorer compared to base material. The surface passivation film of 254SMO joint primarily consists of oxides of Fe, Cr, and Mo before potentiodynamic polarization, while hydroxides of Fe and Cr are also observed after polarization. [ABSTRACT FROM AUTHOR]

It is imperative to enhance the mechanical properties and corrosion resistance of magnesium (Mg)-based metallic glasses for orthopedic implants to further their development. The addition of yttrium (Y) significantly improves both of these characteristics. The Mg52.5Zn40.5Ca5Y2 alloy was chosen for its optimal glass-forming capabilities, as evidenced by thermodynamic parameter, PHHS. This alloy demonstrates remarkable enhancements in both mechanical and corrosion properties, despite the presence of a stable Mg12YZn phase in the liquid, which precludes the complete formation of glass. The Mg52.5Zn40.5Ca5Y2 alloy exhibits a substantial increase in hardness, surpassing the Mg66Zn30Ca4 metallic glass by up to 30 HV. The compressive strength of this alloy is 690 MPa, which is approximately 138 MPa greater than that of the Mg66Zn30Ca4 alloy. The Mg52.5Zn40.5Ca5Y2 alloy exhibits a higher noble corrosion potential and a lower corrosion current density demonstrating a corrosion current density of 6.970 µA/cm2 and a corrosion potential of − 1.240 V. These values suggest a significant increase in corrosion resistance when contrasted with the baseline alloy, Mg66Zn30Ca4. The primary cause of this improvement in mechanical behavior and corrosion resistance is the formation of Mg12YZn long-period stacking ordered (LPSO) phases and Mg3YZn6 icosahedral phases. The material's overall strength and durability are enhanced by these phases, rendering it a promising candidate for applications that necessitate high performance in both mechanical and corrosive environments. As per the results, Mg52.5Zn40.5Ca5Y2 alloy is an exceptional choice for advanced material applications due to its distinctive phase composition, which results in superior properties. [ABSTRACT FROM AUTHOR]

As maritime transport becomes increasingly important, metal corrosion results in significant economic losses. Superhydrophobic materials have significant potential for corrosion prevention. However, poor compatibility between superhydrophobic materials and resin reduces the long‐term corrosion resistance. Interfacial strengthening cells (IS‐Cells) are designed to maintain superhydrophobicity and retain active hydroxyl groups participating in resin‐curing. IS‐Cells also contribute to achieving the maze effect. A novel anti‐corrosion IS coating is fabricated by compatible IS‐Cells and epoxy. IS coatings feature smooth surfaces and vertical compactness, protecting against liquid and gaseous corrosive medium. Strong diffusion resistance and extended diffusion distance ensure long‐term corrosion resistance of IS coatings. Approximately 85 µm of IS coatings remain corrosion‐free after 112 days of immersion in the NaCl solution. The low‐frequency impedance, self‐corrosion potential, and self‐corrosion current density are 1.68 × 109 Ω cm2, −0.0708 V, and 5.38 × 10−11 A cm−2, respectively. IS coatings can also withstand 2400 h of neutral salt spray testing without corrosion in the artificial scratches. Due to the electrostatic repulsion between the hydrophobic C–F chains onto IS‐Cells and protein molecules, IS coatings maintain anti‐fouling properties after dry‐wet immersion tests in the natural marine environment for 90 days. IS coatings show great potential for marine anti‐corrosion applications. [ABSTRACT FROM AUTHOR]

With rapid economic development in China, new and aging road infrastructure is susceptible to premature distresses like potholes under environmental and traffic loading, posing safety risks. Although epoxy resins for crack repair materials exhibit favorable adhesion and mechanics, polyurethanes are emerging for roads to enhance the durability and wear resistance of epoxy resins. This paper summarizes polyurethane-modified epoxy resins for pavement repair, referring to their mechanical properties, adhesive properties, durability and toughness, corrosion resistance, and heat resistance. The polyurethane modification mechanism and the effect of curing agent on the properties of polyurethane-modified epoxy resins are discussed. Polyurethane-modified epoxy resins show potential to combine the strengths of both polyurethanes and epoxy resins for advanced pavement repair materials. [ABSTRACT FROM AUTHOR]

Aside from aesthetic appearance, recycling, ease of disassembly, decent resistance against corrosion, and no intense moisture condensing and thermal bridge, compared with steel fasteners, wooden fasteners also have the compatibility of stiffness with the assembled timber members, which reduces the risk of splitting of the assembled timber members. Due to higher mechanical properties, densified wood (DW) has become an alternative to natural wood as wooden fasteners. At present, investigations have mostly focused on timber-to-timber joints with single DW dowel, while multidowel timber joints are common in practice. In this study, the timber-to-timber joints with laterally loaded single and multiple DW dowels were tested under the loading parallel to the grain in order to explore the effects of the number of DW dowels, moisture content, and joint geometry, i.e., spacings and edge and end distances for DW dowels on mechanical behaviors of timber joints. The tests on the timber-to-timber joints with steel dowels were also performed to compare with those with DW dowels. The load-carrying capacities provided by individual DW dowels showed no reductions with the increases in the number of DW dowels and moisture content and the decrease in joint geometry. The experimental results suggest that the load-carrying capacity of multiple DW dowel joints can be estimated by using the load-carrying capacity of single DW dowel joints multiplied by the number of DW dowels in the range of joint geometries and numbers of DW dowels adopted in this study. The smaller spacings and edge and end distances for DW dowels adopted in this study than the minimum joint geometry requirements in Eurocode 5 are feasible. [ABSTRACT FROM AUTHOR]

In view of several reported cases of cracking in the piping of the fire extinguishing sector in the oil tanks, a detailed identification of the failure mechanisms was required for the safe continuation of gas processing. Therefore, this study investigated the damage of steel fire extinguishing pipes after a certain period of operation. Severe thinning of the wall thickness was observed in two parts of the pipe. Comprehensive analytical investigations, including optical microscope (OM), quantometer, XRD, FE-SEEM, EDS and microhardness were performed. In addition, the corrosion behavior of the material was investigated by polarization and EIS analysis and the most plausible reactions and corrosion mechanisms were elucidated. The corrosion products on the inside of the pipe included oxide compounds, while on the outside, it was mainly sulfides and oxides. A drastic and slight decrease in microhardness was observed near the inner and outer surfaces, respectively. Electrochemical tests proved the formation of a porous and non-protective layer of corrosion products. The corrosion resistance was found to be weak due to several factors: the nature of the AISI-1009 steel, several micropores, the periodic formation and removal of non-continuous oxide layers and the roughness that accelerated the strong thickness reduction. [ABSTRACT FROM AUTHOR]

After micro-arc oxidation, the surface properties of AZ31 magnesium alloy have been improved. However, micro-arc oxidation treatment leads to high insulation, which limits its application in electronic devices. To increase conductivity, a conductive coating was developed by adding multi-walled carbon nanotubes (MWCNTs) to the epoxy resin. The microstructure and performance of the coating were tested by SEM, thermogravimetric analyzer, four-probe conductivity meter, high-temperature friction and wear tester, and electrochemical workstation. The results indicate that the optimal conductivity with a resistivity of 303 Ω ⋅ m is obtained when the MWCNT content is at 4 wt%. In addition, MWCNTs are filled with a network structure of epoxy resin, which increases the density of the coating and enhances their wear and corrosion resistance. [ABSTRACT FROM AUTHOR]

The current study investigates the influence of immersion time (7, 14, 21, and 28 days) on the corrosion behaviour of American Petroleum Institute (API) X70 and X80 steel grades in freely aerated simulated concrete pore solution (pH ~ 12 to 13.8) utilizing electrochemical techniques such as electrochemical impedance spectroscopy, linear polarization, and cyclic polarization. The electrochemical results suggest that the corrosion resistance of X70 line pipe steel increases as immersion time increases (from 7 to 28 days) due to the formation of a stable protective oxide layer on the surface. In the case of X80 line pipe steel, however, the corrosion resistance increases as immersion time increases from 7 to 14 days due to the preferential dissolution of bainite as a result of its higher activity, which initiates the formation of passive film. Furthermore, after 21 days of immersion of X80 line pipe steel in simulated pore solution, a considerable decline in corrosion resistance was observed, which indicates de-passivation, as a result of an increase in oxide film thickness and subsequent spalling off. Intriguingly, as compared to X80 line pipe steel, X70 line pipe steel has a greater potential for producing a stable protective oxide layer without the appearance of minor cracks after a 28-day immersion period, thereby preventing further corrosion and enhancing corrosion resistance. [ABSTRACT FROM AUTHOR]

A novel (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 high entropy disilicate quaternary composition was synthesized from commercial oxide powders using ball milling and sintering processes as a candidate material for environmental barrier coatings (EBC). As-synthesized high entropy disilicate powders were sintered at different durations (12, 18, and 24 h) at 1600 °C in a muffle furnace before characterization. The XRD and SEM analyses revealed the single-phase monoclinic structure (β-type) with homogeneous elemental distribution for the sintered samples. The (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 samples exhibited low thermal diffusivity coefficient, low thermal conductivity, a close coefficient of thermal expansion (CTE) to SiC and a high temperature stability. The (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 samples were subjected to CMAS corrosion tests at 1300 °C with different durations (2, 12, and 24 h) to evaluate CMAS corrosion resistance. Additionally, Yb 2 Si 2 O 7 samples were prepared and subjected to molten CMAS in the same way for comparison. Based on the results, the CMAS corrosion resistance was improved with (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 composition. [Display omitted] • Novel (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 high entropy disilicates were firstly prepared by ball milling and sintering processes. • Close CTE values to SiC are obtained with (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 composition. • Reduced thermal diffusivity and conductivity values up to 1300 K are observed. • Enhanced CMAS corrosion resistance properties of (Y 0,25 Er 0,25 Tm 0,25 Yb 0,25) 2 Si 2 O 7 are reported compared to Yb 2 Si 2 O 7. [ABSTRACT FROM AUTHOR]

The utilization of in-situ ceramic combination effectively addressed the issue of weak bonding at the interface in low carbon Al 2 O 3 –C refractories, enhancing the material service performances. In this study, nano-MgSiN 2 synthesized from molten salt was utilized for incorporation of Al 2 O 3 –C refractories, as well as in assessment of mechanical properties, thermal shock stability, oxidation resistance and corrosion resistance. The findings demonstrate that the molten salt medium can lower synthesis temperature and decrease particle size of nano-MgSiN 2. In addition, nano-MgSiN 2 undergone phase reconfiguration at 1500 °C to form Mg (g) and Si 3 N 4(s). The folding structure Mg-Sialon/MgAl 2 O 4 were formed through phase reconfiguration of Mg (g) and Si 3 N 4(s). This change enhanced interfacial bonding strength of Mg-Sialon/Al 2 O 3 and MgAl 2 O 4 /Al 2 O 3. The mechanical properties and thermal shock stability of refractories were enhanced by novel reconfiguration technology, resulting in CCS value of 176.9 MPa. Simultaneously, Mg-Sialon transformation facilitated the interconnection of the oxide layer, enhancing oxidation resistance and corrosion resistance. [ABSTRACT FROM AUTHOR]

Incorporation of MAX phase to fabricate low-carbon refractories has been recently proposed. Among them, Cr 2 AlC was the undoubtedly one which was regarded as the most potential candidates for applications, due to the excellent chemical stability of chromium oxide. In this work, the influence of Cr 2 AlC on the thermal shock resistance and corrosion resistance of Al 2 O 3 -Cr 2 AlC-C refractories were investigated. The results indicated that the residual strength ratio still maintained stability when flake graphite content reduced from 9 wt% to 4 wt%. While the corrosion resistance of the sample with 4 wt% graphite and 5 wt% Cr 2 AlC increased approximately 40% compared with regular Al 2 O 3 -C refractories with 9 wt% graphite. The degradation mechanisms and interactions of Al 2 O 3 -Cr 2 AlC-C refractories in contact with MnO-rich slag were studied, and the role of Cr 2 AlC was elucidated. [ABSTRACT FROM AUTHOR]

The intrinsic characteristics of Yb 2 O 3 -Al 2 O 3 -SiO 2 (YbAS) glass-ceramics and their resistance to corrosion by molten calcium magnesium aluminosilicate (CMAS) at 1350 °C were systematically investigated. YbAS glass-ceramics, characterized by diverse compositions, maintaining phase stability over extended durations at elevated temperatures. After CMAS corrosion for 50 h, the main reaction phases were CaAl 2 Si 2 O 8 and Ca 2 Yb 8 (SiO 4) 6 O 2 , accompanied by multiple ion solid solution garnet in certain components. The glass component positioned along the eutectic line of Yb 2 Si 2 O 7 and mullite, with an OB value marginally exceeding that of CMAS, exhibits superior corrosion resistance to CMAS. This finding offers valuable insights for the subsequent design of environmental barrier coatings (EBCs). [ABSTRACT FROM AUTHOR]

Element additions in ceramic coatings played a positive role in electrochemical corrosion process, and Cr and C were doped into TiAlN coating by cathode arc ion plating. The effects of Cr and C additions on the structures and electrochemical properties of TiAlN coatings in 3.5 % NaCl solution were comparatively investigated, and the corrosion mechanisms were discussed with the density functional theory calculation. The results show that the particle size of TiAlCrN/and TiAlCN/TiAlN/TiN coatings are 31.6 and 25.7 nm, respectively, and the corresponding bonding strength is 16.18 and 37.93 N, respectively. The corrosion resistance of TiAlCrN/TiAlN/TiN coating is higher compared with the TiAlCN/TiAlN/TiN coating, which is attributed to the stronger oxidation reactions of TiAlCrN/TiAlN/TiN coating. The donor density of passive film on the TiAlCrN/TiAlN/TiN coating is lower than that on the TiAlCN/TiAlN/TiN coating, showing the minor susceptibility of TiAlCrN/TiAlN/TiN coating to corrosion. Moreover, the band gap and DOS of Cr 2 N and Cr 2 O 3 on the TiAlCrN/TiAlN/TiN coating are larger than those of Al 3 C 4 on the TiAlCN/TiAlN/TiN coating, presenting the stronger corrosion resistance. [ABSTRACT FROM AUTHOR]

A liquid-repellent and corrosion resistant surface was fabricated on AZ31B Mg alloy by the usage of CeO 2 and TiO 2 nanoparticles (NPs), plasma electrolyte oxidation (PEO) method, and subsequent surface modification. The whole process included two main steps: a) applying PEO with CeO 2 –TiO 2 NPs on AZ31B and b) decreasing surface energy by using a fluorinating agent. Elements that were present on the surface were investigated by XRD and EDS analyses. Surface morphology and its roughness were scrutinized by FESEM images and AFM tests, respectively. Contact angles (CA) of water and some oils (Ethylene glycerol and Glycerol) on the prepared surface were measured. CAs of water and ethylene glycerol were reported at 175.6° and 151.4°, respectively. Also, the corrosion behavior of the prepared surface was assessed by EIS and potentiodynamic polarization analyses. Results showed that the corrosion rate of the neat AZ31B decreased noticeably from 127.78 to 0.027 mpy for superamphiphobic PEO-NPs AZ31B. The prepared sample showed high mechanical durability, which was scrutinized by water floatation, abrasive with grit SiC paper, adhesive tape peeling, and bending tests. After immersion of the sample in 5 wt% NaCl solution for various hours, results showed that the prepared sample had a noticeable corrosion resistance stability. [Display omitted] • A durable superamphiphobic surface was fabricated on AZ31B. • The prepared surface showed a remarkable water and oil repellency. • A prepared superamphiphobic surface promoted noticeably the corrosion resistance of AZ31B. • A superamphiphobic surface showed brilliant corrosion resistance stability and mechanical durability. [ABSTRACT FROM AUTHOR]

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The microstructural evolution, mechanical properties, and bio-corrosion behavior of Ti-6Al-4V alloys processed by cold rolling and annealing were investigated to address the need for improved biomedical implants. This study aimed to determine and compare these properties in cold-rolled and annealed cold-rolled SLM-fabricated Ti-6Al-4V specimens. The specimens AMCR01 and AMCR02 revealed elongated grains due to cold rolling and phase compositions of 73% α-Ti and 27% β-Ti in AMCR01, and 87% α-Ti and 13% β-Ti in AMCR02, with inhomogeneous β-Ti clustering. Microhardness tests showed increased hardness in cold-rolled specimens, while tensile tests indicated enhanced strength compared to annealed specimens, which exhibited reduced strength due to grain enlargement. Fractography revealed combined ductile and brittle fracture modes in both conditions. Immersion corrosion tests in SBF solution demonstrated enhanced corrosion resistance with an increased rolling reduction ratio, with annealed specimens showing the lowest corrosion rate. The surface morphology supported these findings, indicating the augmenting effect of cold rolling and annealing on corrosion resistance. [ABSTRACT FROM AUTHOR]

The enhancement of the mechanical properties of an alloy is often accompanied by a decrease in corrosion resistance. Therefore, in this paper, thermal-cold cycling (TCC) treatment was used to process 7075-T83 aluminum alloy to improve its corrosion resistance on the basis of ensuring its mechanical properties. Intergranular corrosion (IGC) and electrochemical tests combined with transmission electron microscopy observation were carried out to investigate the effect of TCC treatment on the microstructure and corrosion resistance of the 7075-T83 aluminum alloy. The results showed that the corrosion resistance of the alloy was significantly improved and the microstructure was well optimized after two TCC treatments. The IGC depth of the alloy was the shallowest, at 25.8 μm, and the corrosion current density and corrosion rate reached the minimum values of 0.00148 mA/cm2 and 0.0484 mm/a, respectively. In addition, the average diameter of the matrix precipitates was the smallest, the volume fraction was the highest, the thickness of the passive film formed on the surface of the alloy was the thickest, reaching 3.81 nm, which effectively resisted the erosion of Cl−, while the agglomeration and coarsening of the grain boundary precipitates and the size and the distance between them increased, exhibiting a discontinuous distribution, which blocked the anodic corrosion channel and hindered the corrosion progress, thus improving the corrosion resistance of the alloy. [ABSTRACT FROM AUTHOR]

This study investigated the ability of an aluminium 6351 matrix strengthened with a combination of nano-ceramic particulates to resist corrosion and mechanical characteristics while varying the nano-zirconia weight percent. To create the composite material, nano-zirconium dioxide particles were added in increments of 3% (ranging from 3 to 9 wt.%) to the AA6351-nanoSiC (5 wt.%) composite using powder metallurgy. To assess the effect of incorporating nano-zirconium dioxide reinforcement on the corrosion behaviour of the composite material, we conducted electrochemical polarisation measurements in a 3.5% sodium chloride solution and hardness by Vickers hardness. The study demonstrated that the addition of greater quantities of nano-zirconium dioxide (ZrO2) particles to an aluminium alloy with a nano-silicon carbide (SiC) matrix resulted in an enhancement of its corrosion resistance. Quantitative analysis from microscopy data demonstrated a uniform distribution of reinforcing particles within the aluminium matrix, with minimal deviation from an even dispersion. Adding ZrO2 nanoparticles to AA6351-SiC composites significantly boosted microhardness, peaking at 144.3 HV with 9 wt.% ZrO2 content. These findings suggest that the incorporation of nano-zirconium dioxide particles in the aluminium alloy has the potential to improve its hardness and corrosion resistance, which could be valuable for a wide range of applications. [ABSTRACT FROM AUTHOR]

Electroless Ni–P coating has been validated for its exemplary corrosion resistance in the realm of oil and natural gas industries. Nevertheless, the precise corrosion mechanisms remain a subject of considerable debate and contention. In this study, we employed the variable in question, namely temperature, to emulate fluctuations in the driving forces of corrosive medium diffusion, offering an in-depth exploration into the corrosion behavior of Ni–P coatings within a saturated CO2 milieu. Our findings elucidate that diminished driving forces predispose the coating to localized corrosion, whereas augmented driving forces enhance uniform corrosion. Moreover, the empirical evidence predominantly supports the dissolution of Ni and the deposition of POx as the prevailing corrosion mechanisms, with the infiltration of the corrosive medium primarily contingent upon the magnitude of the diffusion-driven force, rather than the inherent nano-scale pores of the coating. Furthermore, employing in situ electrochemical analysis, we delineated the corrosion mechanisms of Ni–P coatings under varying diffusion-driven forces in this milieu and proffered a corrosion model adeptly explicating this phenomenon. [ABSTRACT FROM AUTHOR]

Medically relevant biodegradable materials assist in the recovery of damaged tissue in the bones. Oral, cardiovascular, and orthopedic implants frequently use metallic implants. The incorporation of biodegradable metals (BMs) in medical applications is growing as a result of their suitability for use as temporary implants and their capacity to degrade once they accomplished their intended use. BMs have strong biocompatibility, which is the capacity of the substance to function with the proper host interaction in a specific situation. The implant will disintegrate during the healing process, preventing long‐term negative effects and the requirement for surgical removal. Because magnesium (Mg) is the body's fourth‐most plentiful element, its broken‐down by‐products can either be stored in new bone or calluses, or they can be released into circulation and eliminated through the urine. Mg is a biodegradable substance, although it has far lower corrosion resistance than other orthopedic implants. Mg‐based biomaterials are the most thoroughly researched and often used BMs due to their elastic modulus matching that of human bones, as well as their biosafety, biodegradability, and radiographic visibility. Thus, under this review, BM alloys, specifically Mg‐based metal alloys, and their properties, advantages, and challenges of Mg alloy were reviewed. [ABSTRACT FROM AUTHOR]

Rare‐earth hafnates are gaining attention due to their excellent high‐temperature phase stability and low thermal conductivity. However, they still have shortcomings of low thermal expansion and poor calcium‐magnesium‐aluminum‐silicate (CMAS) corrosion resistance. In this study, we employed high‐entropy engineering and component design to synthesize three high‐entropy hafnates (La0.2Ce0.2Nd0.2Gd0.2T0.2)2Hf2O7 (T = Dy, Ho, Tm) as well as a single‐component hafnate Nd2Hf2O7, with the aim of preparing thermal barrier coatings with an excellent comprehensive performance. Test results indicate that the high‐entropy compositions have excellent thermal properties. The focus is on elucidating the corrosion process and failure mechanism of CMAS at 1300°C. Moreover, the analysis of residual CMAS and corrosion products was conducted to evaluate the discrepancies in CMAS corrosion behavior among the various compositions. [ABSTRACT FROM AUTHOR]

A critical issue in laser powder bed fusion (LPBF) additive manufacturing is the selective vaporization of alloying elements resulting in poor mechanical properties and corrosion resistance of parts. The process also alters the part's chemical composition compared to the feedstock. Here we present a novel multi-physics modeling framework, integrating heat and fluid flow simulations, thermodynamic calculations, and evaporation modeling to estimate and control the composition change during LPBF of nickel-based superalloys. Experimental validation confirms the accuracy of our model. Moreover, we quantify the relative vulnerabilities of different nickel-based superalloys to composition change quantitatively and we examine the effect of remelting due to the layer-by-layer deposition during the LPBF process. Spatial variations in evaporative flux and compositions for each element were determined, providing valuable insights into the LPBF process and product attributes. The results of this study can be used to optimize the LPBF process parameters such as laser power, scanning speed, and powder layer thickness to ensure the production of high-quality components with desired chemical compositions. [ABSTRACT FROM AUTHOR]

This article reports the synthesis of an eco‐friendly polyurethane composite system, which was successfully prepared in a one‐pot synthetic pathway by combining castor seed oil (CSO), bisphenol A (BPA), isophorone diisocyanate (IPDI), and functional hybrid nanoparticles (prepared by modifying the peripheral surface of silica with 3‐aminopropyltrimethoxysilane (APTMS). The urethane composites were cast as thin films on tin foils and mild steel and cured under atmospheric moisture. Attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy was used to characterise the cured composite films, scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), corrosion resistance, antimicrobial analysis, salt spray test, and water contact angle measurements. Our evaluations showed improved thermal and hydrophobic properties of the composite coatings. Also, the electrochemical and antimicrobial analyses clearly show resistance to corrosion and test organisms as the percentage composition of APTMS‐SiO2 increases in the urethane system. [ABSTRACT FROM AUTHOR]

Semi‐rebonded periclase‐chromite refractories are commonly utilized in the working lining section of the molten pool in oxygen‐enriched top‐blowing furnaces for nickel production. Its resistance to nickel slag corrosion determines the safety and service life of the melting furnace. The composition of nickel slag influences the corrosion resistance of semi‐rebonded periclase‐chromite refractories. By comparing and analyzing specimens corroded by primary and modified nickel slag, the influence mechanism of w(CaO)/w(SiO2) variations on corrosion resistance of semi‐rebonded periclase‐chromite refractories was clarified. The results show that a spinel isolation layer is preferred to form at a lower w(CaO)/w(SiO2) ratio (< 0.576) and enhance the corrosion resistance of semi‐rebonded periclase‐chromite refractories. As the ratio increases, the slag viscosity falls and the corrosion products contain larger levels of Ca3Cr2Si3O12 and Ca3MgSi2O8, which prevent the creation of the isolation layer and establish a conduit for Ca2+ and Si4+ transport and reaction into the interior of the refractory. [ABSTRACT FROM AUTHOR]

The study optimizes the corrosion resistance of an Al–Zn–Mg–Cu alloy by changing the sequence of cold-rolling (CR) and artificial ageing (AR) processes. The samples are artificially aged at 150 ºC for 45 min and subsequently cold-rolled by the cumulative deformation of 10%, 20%, 30%, and 36%, which are denoted as CR + AR samples. In comparison, the CR + AR samples are cold-rolled by a cumulative 30% reduction in thickness and then aged at 150 ºC for various periods from 1 min to 8 h. The hardness of AR + CR samples increases from 158.7 to 213.4 HV with the increasing cumulative CR passes. But in the CR + AR group, it increases from 166.2 to 228.3 HV for 30-min ageing and decreases slightly with the ageing time. η phase precipitates during artificial ageing are the dominant strengthening factor. The improved corrosion resistance in CR + AR samples is mainly attributed to the formation of discontinuous grain-boundary precipitates that obstruct the anodic corrosion pathway. The optimal corrosion resistance is achieved by 30% cold rolling and ageing at 150 ºC for 8 h. This sample owns the highest impedance (ǀZǀ = 985.0 Ω cm2) and the most positive corrosion potential (Ecorr = −0.748 V). [ABSTRACT FROM AUTHOR]

Magnesium alloys have a huge market and broad prospects due to their high specific strength, good ductility, and strong thermal conductivity. However, the active chemical properties of elemental magnesium and the negative standard electrode potential result in magnesium alloys being highly susceptible to corrosion and failure. Chemical conversion treatment of magnesium alloy can improve its corrosion resistance by preparing a chemical conversion film on its surface. Rare earth conversion treatment has the advantages of effortless process, moderate price, no pollution, good corrosion resistance, and synergistic effect with inorganic or organic additives, which is in line with the pursuit of “green chemical” in industrial production. At present, there is little research and application on lanthanum-based rare earth conversion coatings (La-RECC). This paper selects rare earth element lanthanum (La) to prepare La-RECC on the surface of AZ91D magnesium alloy through chemical conversion treatment. The microstructure, chemical composition, and protective properties of La-RECC were discovered, as well as their interrelationships, revealing the degradation process of La-RECC in 3.5% NaCl solution. La-RECC is composed of La(OH)3 and Mg(OH)2, exhibiting a crystal cluster structure with cracks, and there are a large number of needle-like crystals on the crystal cluster of La-RECC, with a thickness of 2.14 μm. The degradation process of La-RECC can be divided into three stages: Rapid degradation, slow degradation, and complete degradation. The complete degradation time of La-RECC in 3.5% NaCl solution is 82.5h. [ABSTRACT FROM AUTHOR]

The strategic design of traditional coating materials has long been pivotal in broadening their range of applications. In this work, europium‐doped TiO2 coatings are grown in situ on the surface of titanium substrate using plasma electrolytic oxidation technology. The core reaction took no more than five minutes. Incorporating europium into the coating preserved the inherent corrosion resistance of PEO coatings while imparting anticipated thermal‐sensitive luminescence capabilities. The intrinsic emission of TiO2 and the characteristic emission of Eu3+ (5D0 → 7F2) are employed as the self‐reference for the LIR thermometry. The absolute and relative temperature sensitivity of the coating reached 0.0087 K−1 and 0.739% K−1, respectively. Notably, the coating exhibited a signal discriminability of up to 5100 cm−1 and a temperature uncertainty of only 0.18 K, which is comparable to some TiO2: Eu nanoparticles. The ingenious fusion of corrosion resistance and thermal‐sensitive luminescence of the coating not only makes it a classic protective structure but also facilitates its applicability to diverse scenarios, including optical thermometry in extreme environments. [ABSTRACT FROM AUTHOR]

SiCf/SiC composites have emerged as one of the most promising materials for aero‐engine hot‐end structures. However, their performance is limited by their susceptibility to oxidation and corrosion reactions with oxygen and water vapor. To overcome this challenge, antioxidant‐modified phases are introduced into matrices of SiCf/SiC composites which improve their water and oxygen resistance. In this study, the resistance of SiCf/SiC composites modified by yttrium silicate matrix (SiCf/SiC‐YS composites) to air at 1000–1400°C and water‐oxygen environments at 1200°C was investigated. The diffusion paths of oxygen in SiCf/SiC‐YS composites and the antioxidant behavior of the yttrium silicate matrix were discussed. Additionally, the differences in oxygen and water‐oxygen corrosion resistance of SiCf/SiC‐YS composites at the same temperature were compared. The strength retention of SiCf/SiC‐YS composites after oxidation and water‐oxygen corrosion at 1200°C were 138.6% and 108.8%, respectively. This indicates that the addition of water vapor accelerated the degradation of SiCf/SiC‐YS composites. By comparing with SiCf/SiC composites, it can be concluded that the modification of the yttrium silicate matrix considerably improved the oxidation resistance of SiCf/SiC composites. [ABSTRACT FROM AUTHOR]

Titanium has been widely used in orthopedics and dental implants due to its excellent biocompatibility and mechanical properties. However, the surface of titanium is biologically inert and lacks biological activity, resulting in poor integration between titanium-based implants and surrounding natural bone tissue, which is a common challenge in its clinical application. Surface modification is currently an effective means to improve the biocompatibility and bioactivity of titanium implants. The natural tissues of the human body are assembled from nanomodules, so from a biomimetic perspective, nanostructures should have better biological activity. TiO2 nanotubes have unique physical and chemical properties due to their elastic modulus, large specific surface area, and regular hollow structure similar to those of bone tissue. This study used anodic oxidation technology to prepare TiO2 nanotubes on the surface of titanium. The surface properties of the nanotubes were evaluated using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), atomic force microscopy profilometry, contact angle measurements, etc. The corrosion resistance was tested using an electrochemical workstation. The results indicate that anodic oxidation can be used to successfully prepare titanium dioxide nanotube arrays on the surface of titanium. The nanotubes not only exhibit a good structure but also improve the surface hydrophilicity and corrosion resistance of titanium, thereby demonstrating potential for clinical application. [ABSTRACT FROM AUTHOR]