Search Results (605)

In this study, C/N-containing Fe₃O₄ oxide films over an inner nitride layer were fabricated on 45# steel by oxynitriding to improve corrosion resistance in chloride-containing environments. The films exhibited a dense polyhedral structure, with nanoscale Fe₃O₄ precipitates at grain boundaries. Nitrogen and carbon were uniformly distributed within the oxide grains, inducing lattice expansion and modifying the Fe-O bonding environment. First-principles calculations based on C/N substitution models suggested that C/N incorporation may increase the unit cell volume, strengthen lattice bonding, and enhance the theoretical hardness of Fe₃O₄. The optimally doped films exhibited outstanding corrosion resistance, with a corrosion potential of 0.115 V_SCE, a corrosion current density of 3.16 × 10⁻¹⁰ A/cm² in 3.5 wt.% NaCl solution, and a corrosion-free lifetime of up to 3600 h in neutral salt spray testing. This superior performance is attributed to the synergistic effects of the compact single-phase magnetite layer, grain boundary precipitates, and modified electronic structure, which collectively inhibit chloride ingress and convert localized electrochemical attack into uniform corrosion. The experimental results are consistent with first-principles predictions, which clarified the mechanism of nitrogen doping in material corrosion protection from a mechanistic perspective. Full article

Magnesium (Mg) alloys are promising for automotive lightweighting and the low-altitude economy, yet their reliability is challenged by stress corrosion cracking (SCC). To realize a quantitative and physics-based evaluation of SCC resistance, this study develops a mesoscale simulation framework coupling dislocation density-based crystal plasticity with an anodic dissolution phase-field model. A 2D representative volume element is constructed for randomly textured polycrystalline Mg to investigate the synergistic acceleration of corrosion by dislocation slip and hydrostatic stress. Results show that heterogeneous dislocation multiplication induced by pre-deformation is the decisive factor in corrosion path selection. In soft-oriented grains, high dislocation densities elevate the interface kinetic coefficient to levels substantially higher than those in hard-oriented regions. Notably, within such soft grains, the contribution of dislocation density to the interface kinetic coefficient can be up to 7.7 times that of hydrostatic stress, establishing dislocation-induced lattice disorder as the primary accelerator for transgranular corrosion. Hard-oriented grains effectively impede corrosion propagation due to restricted dislocation proliferation. This study elucidates how grain orientation-dependent dislocation evolution regulates corrosion morphology, revealing that the random texture delays overall structural failure based on a “weakest-link” mechanism. Full article

FeCoCrNi coating and FeCoCrNiNb_0.5 HEA coatings were deposited onto the surface of a stainless-steel motor main shaft using laser cladding technology. This study investigated the effect of Nb addition on the microstructure, phase composition, crystallographic properties, nanoindentation response, and wear behavior of the FeCoCrNi coating. The results indicated that the FeCoCrNiNb_0.5 coating consisted of an FCC phase and a Laves phase. Furthermore, the solid solution of Nb increased the lattice distortion of the FCC phase and enhanced its solute strengthening effect. The addition of Nb significantly improved the nanohardness of the coating. The nanohardness of the FeCoCrNiNb_0.5 coating reached 6.47 ± 0.23 GPa, markedly higher than that of the Nb-free FeCoCrNi coating. In addition, the FeCoCrNiNb_0.5 coating exhibited higher H/E and H³/E² ratios, suggesting improved resistance to plastic deformation. Owing to the increased nanohardness, the FeCoCrNiNb_0.5 coating demonstrated superior wear resistance, with an average friction coefficient of 0.52 and a wear volume of 5.49 × 10⁵ μm³. The dominant wear mechanisms were identified as abrasive wear, adhesive wear, and oxidative wear. Full article

The pure and xDy³⁺-doped SrMoO₄ series (x = 0.5, 1.0, 1.5 and 2.0 at.%) were synthesized using a direct mechanochemical route. We found that a milling speed of 850 rpm and a milling time of 30 min result in a complete chemical reaction at different concentrations of dopant ions. The phase formation, structural units, and optical properties of the obtained samples were investigated by XRD, IR, UV-Vis and PL analyses. It has been established that Dy₂O₃ mainly influences the lattice parameters, unit cell volumes, crystallite sizes, and microstrains. The symmetry of MoO₄ groups was investigated using IR spectroscopy, and it showed that pure and Dy³⁺-doped SrMoO₄ samples are built up of deformed structural units. The calculated optical band gap of the obtained crystal phases decreases with increasing concentrations of Dy³⁺ ions. The host SrMoO₄ matrix shows broad blue emission centered at 430 nm under an excitation wavelength of 230 nm. All doped samples display a strong yellow emission at 570 nm, belonging to the ⁴F_9/2 → ⁶H_13/2 transition of Dy³⁺ ions. The highest luminescence intensity was observed when the concentration of the Dy³⁺ ion was 0.5 at.%. The mechanism of concentration quenching was mainly caused by the electric dipole–dipole interaction. The calculated CIE chromaticity coordinates of the doped samples fall in the yellow range. This study demonstrates that mechanochemical treatment is an appropriate route for the fast preparation of yellow phosphors. Full article

Fully dense monoclinic zirconia ceramics were successfully fabricated by pressureless sintering and/or HIP. Although monoclinic zirconia exhibits unique physicochemical properties, fabrication of fully dense polycrystalline bodies has remained challenging due to catastrophic volume expansion during the tetragonal-to-monoclinic transformation. By introducing a synergistic ternary (Ga₂O₃-ZnO-TiO₂) sintering aid, a relative density exceeding 99.6% with an average grain size of 0.5–2 µm was achieved by sintering under an oxygen atmosphere at 1070 °C for 3–100 h, well below the phase-transition temperature. X-ray diffractometry confirmed a single-phase monoclinic structure. Subsequent hot isostatic pressing at 1080 °C and 180 MPa for 2 h eliminated residual porosity, yielding a 4-point bending strength of 328 MPa, a fracture toughness of 2.7 MPa·m^0.5, and a Vickers hardness HV₁ of 805. This monoclinic zirconia ceramic exhibited ~30% total transmittance, while in-line transmittance remained below 0.1% due to intrinsic birefringence of the monoclinic lattice. These results established a low-temperature route for densifying phase-sensitive ceramics while achieving long-term stability. Full article

With the growing global demand for sustainable resources, recycling spent lithium-ion batteries has become a strategic priority. Conventional pyrometallurgical and hydrometallurgical methods suffer from high energy consumption, severe pollution, and structural destruction, making them unsuitable for regenerating high-nickel cathodes. In this work, spent polycrystalline high-nickel LiNi_0.9Mn_0.1O₂ cathodes were selected, and an upcycling strategy integrating acid etching, hydrothermal relithiation, short-time annealing, and simultaneous Li₄Ti₅O₁₂ (LTO) coating was developed. This process directly transformed degraded polycrystalline cathodes into single-crystal cathode materials with excellent structural stability and electrochemical performance. During regeneration, lithium compensation and lattice recrystallization effectively repaired lithium loss, reduced Li/Ni cation mixing, reactivated the degraded structure, and reconstructed a highly ordered layered single-crystal framework. The LTO coating further stabilized the cathode/electrolyte interface, suppressed side reactions, alleviated volume strain, and promoted Li⁺ transport kinetics. Electrochemical measurements showed that the regenerated single-crystal cathode exhibited superior structural integrity, strong resistance to crack propagation, low polarization, excellent rate capability, and long-term cycling stability. A capacity retention of 84.3% was achieved after 300 cycles at 1C, outperforming commercial polycrystalline cathodes. This strategy provides an efficient and promising route for the direct regeneration of spent high-nickel ternary cathodes. Full article

Magnetic photonic crystal microspheres (MPCMs) have emerged as a versatile platform for intelligent sensing and display applications, owing to their integration of magnetic actuation with structural coloration. However, their practical implementation is limited by a fundamental structural constraint: most reported MPCMs adopt anisotropic architectures, resulting in angle-dependent optical responses that require continuous magnetic alignment to maintain uniform coloration. Herein, we propose a different structural paradigm based on non-close-packed, optically isotropic MPCMs. Driven by electrostatic repulsion in solutions, monodisperse Fe₃O₄@tannic acid (TA) core–shell nanoparticles spontaneously assemble into non-close-packed amorphous colloidal arrays, also known as photonic glasses, which are subsequently immobilized within stimuli-responsive polymer networks via emulsification-assisted thermal polymerization. By integrating poly(2-hydroxyethyl methacrylate-co-N-vinylpyrrolidone) (HEMA–NVP) or poly(N-isopropylacrylamide) (PNIPAM) as responsive matrices, the resulting MPCMs exhibit sensitive solvent- or thermo-dependent optical responses. Crucially, structural isotropy ensures angle-independent coloration, eliminating the need for continuous magnetic alignment during optical readout. As evidenced by the unchanged structural color and reflection peak under various magnetic field orientations, this design effectively decouples optical sensing from magnetic actuation. The intrinsic free volume of the non-close-packed architecture allows for isotropic lattice expansion and contraction, leading to broad spectral tunability. Collectively, this work establishes a promising design framework for magnetic photonic microsensors. Full article

Yellow and pink calcite samples from the Huanggangliang and Xilingol mining areas in Inner Mongolia were investigated to elucidate the relationships among chemical composition, unit-cell parameters, coloration, and luminescence. Electron probe micro-analysis, laser ablation inductively coupled plasma mass spectrometry, X-ray diffraction, infrared spectroscopy, Raman spectroscopy, UV-Vis absorption spectroscopy, and photoluminescence measurements show that samples of yellow and pink calcite differ significantly in impurity incorporation and optical behavior. Yellow calcite is relatively enriched in Mg and rare earth elements, especially Y and Ce, whereas pink calcite contains markedly higher Mn and Fe contents. The pink calcite has smaller lattice parameters and unit-cell volume, consistent with greater substitution of Ca²⁺ by smaller-radius cations. Spectra reveal that the pink coloration is mainly related to Mn-associated absorption bands at 402 and 527 nm, whereas the yellow color is attributed to weak impurity- and defect-related absorption. Under ultraviolet excitation, yellow calcite exhibits a broad blue–white emission centered at ~470 nm, whereas pink calcite shows an intense orange–red emission near 625 nm characteristic of Mn²⁺. Variable-temperature photoluminescence further demonstrates that the pink calcite has higher thermal stability, with a thermal-quenching activation energy of 0.218 eV, compared with 0.074 eV for the yellow calcite. These results demonstrate that trace element incorporation plays a key role in regulating the coloration and luminescence of calcite and provide useful insight into the optical behavior of carbonate minerals. Full article

This study investigates the influence of the depth of lattice-array micro-pillar surface microstructures on the cavitation erosion (CE) of nickel-aluminum bronze (NAB) in a saline solution using both experimental and simulation methods. Mass-loss measurements, electrochemical tests, and morphological characterizations (SEM, white-light interferometry, EBSD) were conducted to clarify the erosion, corrosion, and synergistic components. Pressure distribution, vapor volume fraction, and bubble dynamics were revealed by numerical simulation in the cavitation region. Results show that shallow microstructures (0.02 and 0.07 mm depths) significantly reduce the CE by up to 74% compared to the smooth surface. This structure can form a shielding field and suppress the mechanical erosion component. In contrast, deep microstructures (0.18 and 0.22 mm depths) aggravate CE, which is attributed to increased bubble nucleation and localized vapor content, and intensified pressure difference. The pure erosion component dominates the damage, followed by synergistic action, and the pure corrosion component is the least. This trend is independent of the change in the microstructure. These findings extend the knowledge on how to design the microstructure depth to alleviate CE. Full article

Mechanically activated pyrite plays an important role in gold extraction and coal utilization, but its reactivity may change markedly during storage. This study investigates how air deactivation during storage affects the crystal structure and subsequent thermal decomposition behavior of mechanically activated pyrite. Pyrite was mechanically activated and then stored in air for 0, 7 and 180 days. X-ray diffraction (XRD) combined with Rietveld refinement was used to characterize variations in lattice parameters and unit-cell-related structural features, while non-isothermal thermogravimetric–differential scanning calorimetry (TG-DSC) under an argon atmosphere, together with the Flynn–Wall–Ozawa (FWO) method, was applied to evaluate the decomposition kinetics. Air deactivation induced a non-monotonic evolution of lattice parameters and unit-cell volume, which is attributed to combined effects of residual stress relaxation and air-induced surface-related modification during storage. All samples exhibited two mass-loss stages during heating, reflecting stepwise thermal decomposition, and their decomposition behavior varied systematically with deactivation time. The apparent activation energy depended on both conversion fraction and deactivation degree, and nucleation-and-growth-type mechanisms were found to dominate the decomposition process, with their relative contributions evolving with storage time. These results clarify how prior air-deactivation history influences the structural evolution and subsequent thermal decomposition behavior of mechanically activated pyrite and provide useful insight for its storage and utilization in related processes. Full article

Polycrystalline La_2−xBi_xNiMnO₆ (x = 0.2, 0.5, 1.0) samples were synthesized via a high-temperature and high-pressure method, with their structural, magnetic, and electrical properties systematically characterized. X-ray diffraction (XRD) confirms a monoclinic double perovskite structure (space group P2₁/n) for all samples, while Bi³⁺ induces a lattice volume expansion trend inferred from XRD peak shifts due to its larger ionic radius than La³⁺. Magnetically, all exhibit ferromagnetism and soft magnetic features, with magnetization decreasing as Bi content increases. The x = 0.2 and 0.5 samples show two distinct Curie temperatures, both decreasing with Bi substitution, whereas the higher Curie temperature vanishes in the x = 1.0 sample, likely due to Bi-induced structural changes. Electrically, all display semiconducting behavior (resistivity: x = 0.5 > x = 0.2 > x = 1.0) and negative magnetoresistance (MR) at 200 K, peaking at 12% (x = 0.5) and 7.5% (x = 1.0). For the x = 1.0 sample, negative magnetoresistance strengthens with decreasing temperature (130–200 K), with magnetoresistance-field (MR-H) curves showing herringbone and arc shapes. Full article

The study of wide-bandgap nanomaterials has gained considerable attention in recent years, especially in the case of semiconductor oxides that exhibit full or partial optical transparency in fundamental research and technological applications. These include optoelectronic devices, gas sensors and photovoltaic cells, among others. The activation or adjustment of optical and structural properties, especially the bandgap and the parameters of unit cell lattice, can be achieved by varying the dopant concentration during the synthesis of semiconductor thin films in these applications. In this context, copper oxide has emerged as a valuable material, owing to its thoroughly analyzed structural behavior and its broad potential across multiple technological fields. The present work focuses on the synthesis of zinc-doped copper oxide (Zn_xCu_1−xO) thin films on silicon and quartz substrates through ultrasonic spray pyrolysis. The effects of varying the zinc doping concentration (0.0, 5.0, 10.0 and 20.0 at. %) on the morphological, structural, and optical characteristics of the Zn_xCu_1−xO films were analyzed. Scanning electron microscopy (SEM) analysis indicated a gradual increase in nanoparticle size, rising from 221 nm for CuO to approximately 322 nm for the Zn_0.2Cu_0.8O samples as the zinc content increased. Structural characterization via X-ray diffraction (XRD) confirmed a monoclinic crystal arrangement belonging to the $C_{2h}^6$ (c2/c) space group. As the percentage of zinc increased, the XRD peaks shifted to lower angles, consequently increasing the volume and crystal lattice parameters of the Zn_xCu_1−xO structure; this finding was additionally supported by a redshift observed in the Raman analysis. The transmittance spectra of the films showed low transmittance between 40 and 44%. The optical bandgap of the Zn_xCu_1−xO thin films was estimated from the transmittance data by applying the Tauc plot method. A decrease in the band gap was observed at higher doping concentrations. It can be confirmed that no secondary phases are observed at a doping level of 20.0 at. % of zinc, indicating good solubility of zinc in CuO. The analysis and discussion of these findings are included throughout this work to elucidate the controversies noted in the literature. Full article

Although 45 steel is widely used in the manufacture of mechanical parts, its application in harsh working conditions is limited owing to its low hardness, poor wear resistance, and corrosion resistance. Laser cladding can enhance the performance of the working surface without sacrificing substrate toughness. CoCuNiTi HEACs with different cBN additions were successfully prepared on a 45-steel substrate. The phase structure, microstructure, elemental composition, wear, and corrosion behavior of CoCuNiTi + x cBN (x = 0.0, 0.5, and 1.0 wt.%) HEACs were investigated using XRD, OM, SEM, EDS, friction and wear tester, and electrochemical workstation, respectively. The results show that all three coatings exhibit a dual-phase structure composed of FCC and BCC phases. The addition of cBN transforms the alloy phase structure from the original FCC main phase to the BCC main phase. The incorporation of cBN significantly reduces the lattice constant and cell volume of the alloy phase. The change in the alloy phase density is negatively correlated with the cell volume. CoCuNiTi + x cBN (x = 0.0, 0.5, and 1.0 wt.%) alloys have a dendritic structure. No pores were observed in the cBN-containing sample. The content of Ti in the primary phase is the highest. Co is enriched in the dendrite region, and Cu is enriched in the interdendrite region. The significant reduction in the average segregation coefficient for cBN-containing samples is attributed to the heterogeneous nucleation of the alloy melt at lower undercooling levels and the significant increase in the diffusion rate. The friction coefficient of the alloy decreases significantly with increasing cBN content. The sample with 1.0 wt.% cBN shows the best wear resistance, mainly due to the combined effects of hard particle support, solid solution strengthening, phase interface reduction, and high thermal conductivity of cBN. The sample with 1.0 wt.% cBN has the largest capacitive arc radius and charge-transfer resistance, along with the lowest annual corrosion rate, indicating optimal corrosion resistance. This is primarily related to the reduction in pore defects caused by cBN addition, hindrance of uniform penetration of the corrosive medium by dispersed cBN particles, and increased complexity of the anodic dissolution process. CoCuNiTi HEACs reinforced by cBN can simultaneously improve the wear and corrosion resistance of the surface of the 45-steel substrate, providing a feasible strategy for the design of high-performance protective coatings. Full article

Background: An increasing number of reports showed patients with bulky tumors after lattice radiation therapy (LRT) treatment achieved good local control. However, in these reports, LRT was previously used primarily for palliation. We reported a case that LRT plays a synergistic role in the radical treatment of locally advanced bulky cervical cancer (LABCC) combined with INTERLACE study protocol. Methods: The patient was a 54-year-old female with LABCC and treated with LRT combined with the INTERLACE study protocol. She received three fractions of 3 Gy each to the gross tumor volume (GTV) and three fractions of 9 Gy each to the lattice therapy volume (LTV), on an emergent basis, using volumetric modulated arc therapy (VMAT). Subsequently, according to the INTERLACE study protocol, chemotherapy and radiotherapy were carried out and the standard follow-up examinations were conducted. Adverse events (AEs) were assessed according to the Common Terminology Criteria for AEs (CTCAE) version 5.0. Results: The patient initially received LRT, which reduced the tumor burden and controlled bleeding. After this was combined with the INTERLACE study protocol, the complete clinical response (cCR) was achieved and they maintained this status for 13 months after the completion of concurrent chemoradiotherapy (CCRT), with only manageable grade IV hematological toxicity observed after the completion of CCRT. During this period, only manageable grade IV hematological toxicity (platelet count 16 × 10⁹/L, white blood cell count 0.33 × 10⁹/L) was observed. Conclusions: In this case, LRT combined with INTERLACE study protocol appears to be a safe and effective for the treatment of LABCC which improved the patient’s quality of life without uncontrolled treatment-related toxicity. Full article

The trade-off between strength and ductility remains a pivotal challenge in the development of multi-principal element alloys (MPEAs) for structural applications. Here, we report a dual-scale ordering strategy to achieve triple strengthening in a Ni-26.6Co-18.4Cr-5.4Nb-4.1Mo-2.3Al-0.3Ti-0.05Y (wt.%) MPEA through the synergistic interplay of L1₂ nanoprecipitates and local chemical order (LCO). The alloy was processed via cold rolling followed by aging at 750 °C for 8 h, resulting in a high density of coherent L1₂ precipitates (average size 47 ± 1 nm, volume fraction ~27%) with an ultra-low lattice misfit of 0.5%. Additionally, sub-nanoscale LCO domains with an average diameter of 0.62 nm were identified within the face-centered cubic matrix. This hierarchical microstructure yields an exceptional combination of mechanical properties at room temperature: yield strength of 1480 ± 6 MPa, ultimate tensile strength of 1678 ± 10 MPa, and a total elongation of 13.9 ± 0.2%. Quantitative strengthening analysis reveals that precipitation strengthening (697 MPa) is the dominant contributor, followed by dislocation strengthening (397 MPa). Transmission electron microscopy characterization of deformed samples reveals that the low stacking fault energy, promoted by LCO, facilitates the dissociation of perfect dislocations and the formation of extensive stacking faults. The intersection of stacking faults on different {111} planes generates a large number of Lomer–Cottrell locks, which significantly enhance work hardening and delay plastic instability. The findings demonstrate that engineering dual-scale ordered structures offers a promising pathway for developing MPEAs with a superior strength-ductility combination. Full article