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Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for developing rechargeable zinc-air batteries (ZABs). Herein, an alloying-degree control strategy was employed to fabricate nitrogen-doped carbon sphere (NCS) decorated with dual-phase Co/Co 7 Fe 3 heterojunctions (CoFe@NCS). The phase composition of materials has been adjusted by controlling the alloying degree. The optimal CoFe 0.08 @NCS electrocatalyst displays a half-wave potential of 0.80 V for ORR and an overpotential of 283 mV at 10 mA·cm −2 for OER in an alkaline electrolyte. The intriguing bifunctional electrocatalytic activity and durability is attributed to the hierarchically porous structure and interfacial electron coupling of highly-active Co 7 Fe 3 alloy and metallic Co species. When the CoFe 0.08 @NCS material is used as air-cathode catalyst of rechargeable liquid-state zinc-air battery (ZAB), the device shows a high peak power-density (157 mW·cm −2 ) and maintains a stable voltage gap over 150 h, outperforming those of the benchmark (Pt/C+RuO 2 )-based device. In particular, the as-fabricated solid-state flexible ZAB delivers a reliable compatibility under different bending conditions. Our work provides a promising strategy to develop metal/alloy-based electrocatalysts for the application in renewable energy conversion technologies.

A series of electrochemical tests combined with the techniques of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray photoelectron spectroscopy (XPS) were used to study the effect of nitrogen content on the composition, structure and protectiveness of passive films, which were formed on the surfaces of high-nitrogen austenitic stainless steels (HNSS) in 0.5 mol/L NaCl solution. The results showed that the HNSS with higher nitrogen content had a larger proportion of low-angle grain boundaries, and it also had a lower corrosion current density in 0.5 mol/L NaCl solution and thus a lower corrosion rate. The existence of a larger proportion of stable oxides (e.g., Cr 2 O 3 ) in the passive films facilitates the passivation/repassivation process and contributes to the high corrosion resistance of HNSS.

The hot deformation behaviours of 316LN-Mn austenitic stainless steel were investigated by uniaxial isothermal compression tests at different temperatures and strain rates. The microstructural evolutions were also studied using electron backscatter diffraction. The flow stress decreases with the increasing temperature and decreasing strain rate. A constitutive equation was established to characterize the relationship among the deformation parameters, and the deformation activation energy was calculated to be 497.92 kJ/mol. Processing maps were constructed to describe the appropriate processing window, and the optimum processing parameters were determined at a temperature of 1107–1160°C and a strain rate of 0.005–0.026 s −1 . Experimental results showed that the main nucleation mechanism is discontinuous dynamic recrystallization (DDRX), followed by continuous dynamic recrystallization (CDRX). In addition, the formation of twin boundaries facilitated the nucleation of dynamic recrystallization.

The corrosion behavior of 304L stainless steel (SS) in 3.5wt% NaCl solution after different cavitation erosion (CE) times was mainly evaluated using electrochemical noise and potentiostatic polarization techniques. It was found that the antagonism effect resulting in the passivation and depassivation of 304L SS had significant distinctions at different CE periods. The passive behavior was predominant during the incubation period of CE where the metastable pitting initiated at the surface of 304L SS. Over the rising period of CE, the 304L SS experienced a transition from passivation to depassivation, leading to the massive growth of metastable pitting and stable pitting. The depassivation of 304L SS was found to be dominant at the stable period of CE where serious localized corrosion occurred.

Lanthanide perovskite materials are promising candidates for supercapacitor applications. In this study, a series of La1−xCaxCrO3 (x = 0–0.2) materials were prepared by sol-gel method, incorporating bivalent ions calcium at A-site. La0.85Ca0.15CrO3 exhibited the lowest charge transfer resistance and highest specific surface area. At 1 A/g, La0.85Ca0.15CrO3 achieved a maximum specific capacitance of 306 F/g, about 2.3 times higher than that of the LaCrO3 (133 F/g). Based on the observed data, a mechanism involving oxygen anion charge storage during the charging-discharging process is proposed. After 5000 long cycle, the coulomb efficiency of the electrode remains above 94%. These results demonstrate that Ca-substituted compounds exhibit significant potential for A-site engineering in supercapacitor applications.

The CoCrFeNiMn High-Entropy Alloy (HEA) with 0, 0.5 and 1.0 at.% Carbon (C) addition has been evaluated by mechanical and corrosion testing, including tensile, wear and corrosion resistance testings. The result shows that the medium of 0.5 at.% C addition into HEA brings higher tensile toughness with 27,213.6 MPa%, less wear damage (0.37 mm3) and superior thermodynamic stability (0.73 VSCE), compared with that of the other two compositions. The tensile fracture observation points out that the high C addition embrittles the HEA with poorer toughness and wear resistance with content increasing to 1.0 at.%. The HEA material with 0.5 at.% C addition has high corrosion potential and the lowest corrosion current density, indicating that the appropriate C-alloying plays a significant role in determining the corrosion properties of HEA. The current study shall provide meaningful instruction for high-performance C-alloyed HEA development.

To clarify the correlation of single-crystalline structure with corrosion performance in high-strength TiAl alloys, electrochemical and surface characterization was performed by comparing Ti-45Al-8Nb dual-phase single crystals with their polycrystalline counterparts in NaCl solution. Polarization curves show a lower corrosion rate and a higher pitting potential of ∼280 mV for the dual-phase single crystals. Electrochemical impedance spectroscopy and potentiostatic polarization plots revealed a higher impedance of the charge transfer through the compact passive film. Surface composition analysis indicated a compact film with more content of Nb, as twice as that in the film on the polycrystals. Our results reflect that the dual-phase Ti-45Al-8Nb single crystals possess a higher corrosion resistance in NaCl solution, compared with their polycrystalline counterpart, arising from a more homogeneous microstructure and composition distribution.

The effects of laser scanning speed on the microstructure, microhardness, and corrosion behavior of Ni45 coatings were investigated by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness, and electrochemical measurements. The results showed that increasing laser scanning speed promotes the transformation from planar crystals to dendrites and refines the grains concurrently. The γ-(Ni, Fe), FeNi3, and M23(C,B)6 are identified as the primary phase composition in the Ni45 coatings regardless of the laser scanning speed. Thereinto, the formation and growth of M23(C,B)6 precipitates can be inhibited with increasing laser scanning speed due to the higher cooling rate, which affects the microhardness distribution and corrosion resistance of the coating. On the one hand, the microhardness of the whole coating presents a downtrend with increasing laser scanning speed due to the reduction of M23(C,B)6 phase. On the other hand, the corrosion resistance in 0.5 M NaCl solution is improved to some extent at higher laser scanning speed because the less precipitation of M23(C,B)6 reduces the depletion of Cr around the precipitates. In contrast, all the coatings exhibit undifferentiated but poor corrosion resistance in the highly corrosive 0.5 M NaCl + 0.5 M H2SO4 solution.

X-ray diffraction (XRD), scanning electron microscope (SEM), immersion, electrochemical, and tensile tests were employed to analyze the phase constitution, microstructure, corrosion behaviors, and tensile properties of a Ti-6Al-4V alloy and a newly-developed low cost titanium alloy Ti-4Al-2V-1Mo-1Fe. The results showed that both the Ti-6Al-4V and Ti-4Al-2V-1Mo-1Fe alloys were composed of α and β phases. The volume fractions of β phase for these two alloys were 7.4% and 47.3%, respectively. The mass losses after 180-day immersion tests in 3.5 wt.% NaCl solution of these alloys were negligible. The corrosion resistance of the Ti-4Al-2V-1Mo-1Fe alloy was higher than that of the Ti-6Al-4V alloy. The tensile tests showed that the Ti-4Al-2V-1Mo-1Fe alloy presented a slightly higher strength but a lower ductility compared to the Ti-6Al-4V alloy.

Manganese-based oxides, particularly β-MnO2, have emerged as promising cathode materials for aqueous zinc-ion batteries (ZIBs) due to their high theoretical capacity, low cost, and intrinsic safety. However, their sluggish reaction kinetics, limited active sites, and poor conductivity often lead to suboptimal electrochemical performance. To address these limitations, we propose a facile ethanol-mediated hydrothermal strategy to engineer rod-like β-MnO2 nanostructures with tailored oxygen vacancies. By precisely adjusting ethanol addition (3–5 mL) during synthesis, oxygen vacancy concentrations were optimized to enhance electronic conductivity and active site exposure. The experimental results demonstrate that β-MnOx-2-5 synthesized with 5 mL of ethanol delivers an exceptional areal capacity of 4.87 mAh cm−2 (348 mAh g−1, 469.8 Wh kg−1) at 200 mA cm−2 under a high mass loading of 14 mg cm−2. Further, a hybrid electrode combining oxygen-deficient β-MnO2-x-3 (air-calcined) and structurally stable β-Mn5O8-y-3 (Ar-calcined) achieves a retained capacity of 3.9 mAh cm−2 with stable cycling performance, achieving an optimal equilibrium between high capacity and long-term operational durability. Systematic characterizations (XPS, ESR, XANES, FT-EXAFS) confirm vacancy-induced electronic structure modulation, accelerating ion diffusion and redox kinetics. This scalable vacancy engineering approach, requiring only ethanol dosage control, presents a viable pathway toward industrial-scale ZIB applications.