Search Results (1,098)

Since the first successful synthesis of borophene in 2015, this atomically thin boron allotrope has attracted extensive attention due to its polymorphic structures, metallic conductivity, and outstanding mechanical flexibility. As a new member of the two-dimensional (2D) materials family, borophene exhibits a unique triangular lattice with tunable hexagonal vacancies, leading to rich structural diversity and anisotropic physical properties. Recent breakthroughs in synthesis—particularly molecular beam epitaxy (MBE), chemical vapor deposition (CVD), and solvothermal-assisted liquid-phase exfoliation (S-LPE)—have significantly expanded the accessible structural phases and improved control over film quality and stability. Meanwhile, borophene’s distinctive combination of structural and electronic characteristics has enabled its rapid development in both energy and biomedical applications. In energy storage, borophene serves as a promising anode material for lithium/sodium-ion batteries and a lightweight medium for hydrogen storage and supercapacitors, owing to its metallic conductivity, high surface charge density, and large adsorption capacity. In biomedicine, borophene-based nanoplatforms exhibit excellent photothermal conversion efficiency, enabling multifunctional roles in cancer diagnosis and therapy. Despite these advances, several challenges—such as environmental instability, oxidation susceptibility, and limited scalable synthesis—continue to restrict practical implementation. Future progress will depend on chemical functionalization, surface passivation, and machine-learning-assisted materials design to achieve oxidation-resistant, large-area, and biocompatible borophene derivatives. This review summarizes recent advances in borophene synthesis, structural engineering, and multifunctional applications, while outlining key scientific challenges and future opportunities for the realization of borophene-based materials in next-generation energy and biomedical systems. Full article

In this paper, we report on the effect of combining porous silicon with aluminum microparticles (PS/Al-µPs) on the optical and electronic properties of multicrystalline silicon (mc-Si). An aluminum film was deposited on the mc-Si surface, annealed at 750 °C for 20 min, and partially remained on the surface after CP₄ treatment. The surface was subsequently treated with a stain-etching solution (HF/HNO₃/H₂O) to form a porous silicon (PS) layer. The resulting mc-Si with PS/Al-µPs modification led to a marked improvement in the optoelectronic performance of the treated mc-Si. Surface reflectance was reduced from 34.6% to 9.1% across 400–800 nm wavelength range, corresponding to a 74% decrease. Minority carrier lifetime increased from 2 µs in untreated samples to 1 ms after Al-µPs passivation and remained elevated at 285 µs following stain etching. Additionally, the effective surface recombination velocity dropped from 50 cm·s⁻¹ to 0.35 cm·s⁻¹ and a reduction in [Fe] after treatment confirms the effectiveness of the PS-Al-µPs gettering process. FTIR analysis confirmed the formation of Si–H and Al–O bonds, highlighting effective surface passivation and suppression of recombination losses. Full article

Austenitic stainless steels exhibit excellent corrosion resistance owing to the formation of passive films composed of a dense Cr-rich inner layer and porous Fe-rich outer layer. The corrosion resistance and passive film characteristics of N-containing austenitic stainless steel (NASS) were investigated in various pH and Cl⁻-containing environments and compared with those of commercial 304 SS. Microstructural analysis revealed that NASS had larger grains but more favorable crystal structures for the adsorption of passivating species. NASS exhibited a lower corrosion current density, higher pitting potential, and superior repassivation behavior in acidic and neutral environments, whereas 304 SS exhibited better corrosion resistance under strongly alkaline conditions. NASS formed a passive film with lower defect density and a higher fraction of compact Cr-rich species, contributing to its enhanced passive film stability and repassivation ability. Immersion tests demonstrated that pit initiation was delayed in the NASS group compared with the 304 SS group. These results indicate that the corrosion resistance of NASS in acidic and neutral environments originates from the improved stability and protective characteristics of the passive film. Full article

Dissimilar 7075-T6 and 6061-T6 aluminum alloy joints were fabricated using pulsed metal inert gas (P-MIG) welding with ER5356 filler wire. The effects of welding current (224 A, 234 A, and 244 A) on macro-morphology, microstructure, mechanical properties, and corrosion behavior were systematically investigated. As welding current increased, the top and bottom reinforcements first increased and then decreased, reaching maximum values at 234 A, while the front weld width exhibited the opposite trend. The weld zone consisted of equiaxed and dendritic grains, with partial remelting of AlFeMnSi intermetallic compounds observed in the heat-affected zones. The microhardness and tensile strength of the joints followed a similar trend of first decreasing and then increasing with welding current, achieving a maximum tensile strength of 203.9 MPa at 244 A, corresponding to 89.5% of the 6061-T6 base metal strength. Corrosion resistance varied across regions depending on the evaluation method. In intergranular corrosion tests, the 7075-HAZ showed the highest susceptibility due to grain boundary segregation of Mg and Zn. In electrochemical tests, the WZ exhibited the poorest corrosion resistance. For the 7075-HAZ, optimal corrosion resistance was achieved at 234 A, attributed to a stable passive film and uniform precipitate distribution. These findings provide valuable guidance for optimizing P-MIG welding parameters for dissimilar 7075/6061 aluminum alloy joints. Full article

The objective of this study was to systematically investigate the effect of welding speed on the microstructure, mechanical properties, and corrosion behavior of 7075-T6 aluminum alloy similar joints. Pulsed metal inert gas (P-MIG) welding with ER5356 filler wire was employed as the methodology to fabricate the joints, with welding speed as the sole variable parameter (450, 500, 550, and 600 mm/min) while maintaining constant welding current and voltage. The key results showed that increasing welding speed refined the dendritic structure in the weld zone (WZ) and promoted a more uniform distribution of precipitates. The tensile strength first increased and then decreased, reaching a maximum of 257.7 MPa at 550 mm/min, with a corresponding elongation of 8.1%. The microhardness of the WZ increased from 91 HV_0.1 (450 mm/min) to 107.4 HV_0.1 (600 mm/min). Corrosion resistance, assessed via intergranular corrosion tests and electrochemical analysis, varied significantly with welding speed; optimal performance was obtained at 450 mm/min, while the poorest occurred at 550 mm/min due to variations in precipitate distribution and passive film stability. The conclusion is that an optimal welding speed of 550 mm/min achieves the best balance between mechanical strength and ductility by refining the microstructure, while the corrosion resistance is primarily governed by the electrochemical activity of grain boundary precipitates induced by the welding thermal cycle. Full article

Background/Objectives: Electrolytes used in in vitro corrosion testing critically determine the behavior inferred for metallic dental implants, yet formulations and their justifications are inconsistently reported across the literature. This review compiles and compares electrolytes employed to simulate the oral cavity and the bone–implant interface, linking their chemical composition to the corrosion mechanisms they target. Methods: This structured narrative review synthesized peer-reviewed literature on simulated electrolytes used for in vitro corrosion testing of metallic dental implants and implant-related alloys. Literature was identified using database searches and targeted reference screening, with emphasis on artificial saliva formulations, physiological simulated fluids, challenge chemistries, protein-containing media, hydrodynamic conditions, and microbiological models. Relevant formulations were standardized to grams per liter and grouped according to application domain and targeted corrosion mechanisms. Results: The analysis maps electrolyte selection to corresponding corrosion modes, including uniform dissolution, pitting, crevice, galvanic, and microbiologically influenced corrosion. Consolidated composition tables highlight how pH, halide concentration, calcium–phosphate balance, proteins, gas control, and flow conditions modify passive-film stability and metal-ion release. Dental-specific gaps are identified, notably the lack of a standardized fluoride–pH matrix and limited guidance for microbiome-integrated assays. Conclusions: Aligning electrolyte formulations with the research question enhances reproducibility and mechanistic interpretation. However, current in vitro corrosion data should be interpreted cautiously because quantitative links between simulated-fluid testing and clinical outcomes such as peri-implantitis, peri-implant bone loss, and implant failure remain insufficiently established. The adoption of shared reporting standards, dynamic programmable chemistries, and interoperable datasets may improve the translational value of future corrosion studies. Full article

Background: Corrosion of orthodontic archwires raises biocompatibility concerns; yet, comparative multi-element data across manufacturers remain scarce. Methods: Ni, Cr, Fe, and Ti release was quantified by ICP-OES from SS and NiTi rectangular archwires (0.43 × 0.64 mm) from four manufacturers (Ormco, 3M Unitek, Dentaurum, and American Orthodontics) and immersed in artificial saliva (pH~7.0) and fluoride-containing saliva (+0.05% NaF) at six time points (days 1–35). Release was normalised to wire mass (mg g⁻¹). Non-parametric tests were applied. Results: NiTi wires released significantly more Ni than SS wires in +NaF at all time points (p = 0.029). An exploratory manufacturer effect on Ni release from NiTi was detected (Kruskal–Wallis H = 12.99, p = 0.005); American Orthodontics exceeded Dentaurum and Ormco. Ormco SS released ~3-fold more Fe than other SS wires (H = 13.68, p = 0.003). Ti was detectable exclusively in NiTi wires in +NaF; all specimens were below LOQ in pH~7.0. Cr release was uniformly low (0.017–0.023 mg g⁻¹). Conclusions: Manufacturer identity influences Ni and Fe release independently of alloy type. Fluoride selectively disrupts the NiTi passive film. These exploratory findings, derived from a single-specimen pilot design, may inform clinical material selection in nickel-sensitive patients pending replication. Full article

TC4 alloy samples were fabricated via selective laser melting (SLM) under different process parameters. The effects of scanning speed and build orientation on the microstructure and corrosion behavior were systematically investigated using optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), and electrochemical measurements. The results show that when increasing scan speed, TC4 alloy consists primarily of α/α’ phases with a minor amount of β phase, along with grain refinement and a higher fraction of low-angle grain boundaries. In 3.5% NaCl solution, the XOY-oriented sample processed at 1000 mm s⁻¹ exhibited higher impedance and formed a stable, highly protective passive film. In simulated body fluid, the XOY orientation at 1200 mm s⁻¹ displayed a larger capacitive arc, indicating superior corrosion resistance. These findings demonstrate that the corrosion performance of SLM-processed TC4 alloy can be optimized for specific service environments by tailoring both process parameters and build orientation. Full article

Chloride-induced corrosion of steel reinforcements is one of the main factors restricting the durability of reinforced concrete structures. Chromium (Cr) alloying is an effective strategy to enhance the corrosion resistance of steel. However, the appropriate Cr content for different environments remains undetermined. In this study, steels with three different Cr contents of 0, 5, and 10 wt.% were prepared. Electrochemical methods and physical characterization techniques were used to investigate the effects of Cr content on the passive film and corrosion behavior of steels in a simulated concrete pore solution under chloride attack. The results show that Cr alloying increases the critical chloride concentration for steel depassivation, passive film resistance, and charge transfer resistance. Specifically, the critical chloride concentrations of 0Cr, 5Cr, and 10Cr are 0.63, 0.81, and 1.56 mol/L, respectively. In a simulated pore solution with 0.6 mol/L chloride, the charge transfer resistances of 0Cr, 5Cr, and 10Cr are 4.1, 5.8, and 63.4 × 10⁵ Ω·cm², respectively, corresponding to corrosion rates that are 1.39- and 15.31-times lower for 5Cr and 10Cr relative to 0Cr. Therefore, in concrete exposed to marine chloride attacks, the use of high Cr alloying is necessary. Although the cost increases and the weldability deteriorates, the improvement in corrosion resistance is far superior to that of medium Cr alloying. The excellent corrosion resistance of high-Cr steel stems from its passive film mainly composed of stable Cr₂O₃ with a lower oxygen vacancy defect density, while that of 5Cr is dominated by less stable Cr(OH)₃, which weakens the corrosion resistance of the passive film. Full article

The anti-corrosion performance of epoxy coatings in saline solution environments is restricted by their surface hydrophilicity and microporous defects. Herein, we developed a modified epoxy (MEP)-based superhydrophobic anticorrosive coating by fluorinated resin matrix and incorporation of polyaniline@expanded graphite (FPANI@MEG) anticorrosive fillers. The FPANI@MEG fillers were fabricated via in situ polymerization of aniline on the surface of dopamine-modified expanded graphite to construct the micro-nano hierarchical structure required for superhydrophobicity, while providing barrier shielding and active passivation functions. The results showed that the final coating exhibited excellent superhydrophobicity with a water contact angle of 156.5 ± 1.8° and sliding angle of 3.0 ± 0.6°, along with excellent adhesion and adaptability to various complex environments. Meanwhile, the coating maintained superhydrophobicity after 400 cycles of Taber abrasion and 450 g of falling-sand impact, demonstrating hydrophobic robustness. Furthermore, the coating exhibited a low-frequency impedance modulus of 2.30 × 10⁷ Ω·cm² after immersion in NaCl solution for 15 days. The synergistic combination of air film shielding, physical barrier, and active passivation endowed the coating with good anticorrosion performance. This work may provide a theoretical reference for improving the corrosion protection of epoxy-based superhydrophobic coatings on carbon steel in aggressive saline solution environments. Full article

The electrochemical and surface behaviour of implant-grade commercially pure titanium (cp-Ti), Ti6Al7Nb, and Ti6Al4V clinically used alloys was investigated in phosphate-buffered saline (PBS), with and without albumin, at 37 °C using electrochemical techniques and SEM/EDS analysis. In PBS, the corrosion resistance followed the order Ti6Al4V < Ti6Al7Nb < cp-Ti, with cp-Ti serving as the benchmark reference material. The addition of albumin improved the corrosion resistance of all materials under the investigated static in vitro conditions, with the most pronounced effect observed for Ti6Al4V. Over time, the oxide layer stabilised and the differences between the materials decreased, with Ti6Al4V approaching the behaviour of more stable systems. Surface analysis revealed a comparatively more uniform (but not fully homogeneous) protein distribution on Ti6Al7Nb, whereas Ti6Al4V exhibited localised adsorption associated with greater surface heterogeneity. Protein adsorption acts as a stabilising interfacial factor, contributing to improved protective properties under static conditions. These findings highlight the key role of surface heterogeneity in governing protein adsorption and electrochemical behaviour of titanium alloys under biologically relevant conditions. Full article

The performance requirements of wear-resistant and anti-corrosion coatings for marine equipment continue to increase. Diamond-like carbon (DLC) film has become a preferred protective material due to its high hardness, low friction and chemical inertia. To reveal the tribocorrosion mechanism of Si-doped DLC films in a seawater environment, a Cr-WC-WC/C transition layer and DLC-Si films with different Si contents were prepared by high-power pulsed magnetron sputtering (HiPIMS) technology on 304 stainless steel. The tribocorrosion tests were carried out under open-circuit potential and dynamic polarization conditions in seawater. The results show that Si doping improved the tribocorrosion resistance of the films. The sample with Si content of 9.26 at.% has the lowest self-corrosion current density, the smallest volume loss, complete wear scar morphology and no obvious substrate exposure. The strengthening mechanism is attributed to Si doping, which induces the formation of a SiO_x passivation film and a hydrated silica gel lubrication layer. This establishes a synergistic solid-chemical lubrication system, inhibits sp² cluster growth, prolongs the diffusion path of corrosive media, and mitigates the damaging wear–corrosion synergy. This study confirms that moderate Si doping can significantly improve the wear resistance and corrosion resistance of DLC films in a seawater environment, and provides a theoretical basis for the design and application of carbon-based protective coatings for marine equipment. Full article

Long-gap esophageal atresia is a congenital anomaly that requires challenging repair procedures that are often associated with complications. This work proposes the use of nitinol to repair long-gap esophageal atresia. A first proof-of-concept with commercial nitinol is presented. Experimental tests and simulations were performed, including the application of electrical currents to promote nitinol heating and consequent contraction, tensile tests, chemical analysis, and ex vivo tests using porcine esophageal tissues. A preliminary experiment is also presented regarding NiTi sputtering deposition and the morphological, chemical, and crystallographic analysis of the thin-films, featuring the implementation of a microfabricated solution. The experimental electrical tests were in accordance with the simulations. The nitinol electrical resistance (0.8–1.5 Ω) decreased as its temperature increased (20–60 °C) with the application of electrical current (<1 A), which was consistent with the experimental Seebeck coefficient (6.49 ± 0.46 µV/K). The measured forces (6.5 N at 45 °C) are also in accordance with traction sutures. Chemical analysis revealed a passive titanium dioxide layer reported for nitinol. Regarding the ex vivo tests, the average nitinol final length was 28.5 mm, below 30 mm (threshold for long-gap esophageal atresia). Finally, preliminary results from NiTi sputtering confirmed well-controlled deposition and the viability of scaling this approach, opening new avenues for nitinol-based biomedical devices. Full article

The accelerating pace of global urbanisation is reshaping planning agendas toward integrating urban nature, yet dominant approaches continue to rely on designed or controlled interventions to produce engineered approximations of spontaneity. This study presents Rome as a striking example of spontaneous urban nature, where wild flora has reclaimed ruins, walls, and neglected spaces for centuries without planned intervention. By “wild” or spontaneous vegetation, this paper refers to unmanaged, self-seeding flora that establishes itself without deliberate planting, irrigation, or maintenance, colonising ruins, walls, abandoned lots, and urban margins through autonomous ecological processes. The paper adopts a critical narrative synthesis methodology, integrating historical–cultural evidence, contemporary ecological data drawn from peer-reviewed biodiversity surveys within Rome’s urban boundary, and a spatial analysis of georeferenced historical cartographic sources to build an interpretive framework for what is here called passive coexistence. The key findings demonstrate that Rome’s sub-Mediterranean climate and centuries of aesthetic conditioning through visual arts, literature, and film have together produced a tacit social acceptance of spontaneous vegetation, effectively substituting for the deliberate education campaigns and designed interventions required in comparable cities. The study proposes an alternative narrative of spontaneous urban nature, guided by ecological monitoring and grounded in heritage planning frameworks. Despite context-specific limits, Rome’s passive coexistence paradigm offers a provocation and existing proof for more-than-human cities that seek resilience without the resource burden of engineered green infrastructure. Full article

The corrosion behavior of high-entropy alloys under cyclic wet–dry conditions simulating the salt-lake atmosphere was investigated. The composition, morphology, and electrochemical properties of the corrosion products formed on the alloy surface after corrosion were systematically analyzed. The results show that in a chloride-containing environment with alternating temperature and humidity, the Cr-containing oxide passive film formed on the alloy surface effectively inhibits the corrosion process in the early stages. In addition, electrochemical results show that the charge transfer resistance in the MgCl₂ system reaches 4.96 × 10⁵ Ω·cm² at prolonged exposure, which is significantly higher than that in the NaCl system, indicating a lower corrosion rate. However, over time, the passive film undergoes localized rupture due to chloride ion attack and stress, leading to pitting corrosion and expansion toward the substrate. This study reveals the corrosion mechanism of high-entropy alloys in high-altitude salt-lake atmospheric environments and provides crucial insights for material design and performance optimization for their engineering applications in salt-lake scenarios. Full article