Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.11.002
Silicon carbide mechanical seal rings in marine rotary equipment suffer severe wear, demanding coatings that simultaneously deliver high hardness, low friction, and corrosion resistance. This study fabricates diamond/diamond-like carbon (DLC) duplex coatings via hot-filament chemical vapor deposition (HFCVD) followed by magnetron-sputter-assisted ion-beam deposition. Microcrystalline diamond (MCD) and ultra-nanocrystalline diamond (UNCD) underlayers are grown on SiC, then capped with a hydrogenated DLC lubricating topcoat, forming a rigid-underlayer/lubricating-top-layer architecture. Tribological tests in simulated seawater reveal that DLC reduces MCD surface roughness from 155.33 nm to 123.77 nm and UNCD roughness from 92.43 nm to 81.90 nm. The MCD/DLC coating lowers steady-state friction coefficient and specific wear rate by 32.08% and 12.22%, respectively; UNCD/DLC achieves 26.67% and 20.92% improvements. SEM, Raman, and XPS analyses of worn surfaces indicate that the DLC top layer mitigates interfacial shear stress, enhances boundary lubrication, and accelerates friction-induced graphitization. The composite coating also reduces counterface ball damage and debris accumulation, extending the service life of mating components. These findings demonstrate that the duplex architecture overcomes the inherent limitations of monolithic diamond coatings, offering a viable route for durable marine seal applications.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-025-01683-7
High-nickel ternary cathodes hold a great application prospect in solid-state lithium metal batteries to achieve high-energy density, but they still suffer from structural instability and detrimental side reactions with the solid-state electrolytes. To circumvent these issues, a continuous uniform layer polyacrylonitrile (PAN) was introduced on the surface of LiNi0.8Mn0.1Co0.1O2 via in situ polymerization of acrylonitrile (AN). Furthermore, the partial-cyclized treatment of PAN (cPAN) coating layer presents high ionic and electron conductivity, which can accelerate interfacial Li+ and electron diffusion simultaneously. And the thermodynamically stabilized cPAN coating layer cannot only effectively inhibit detrimental side reactions between cathode and solid-state electrolytes but also provide a homogeneous stress to simultaneously address the problems of bulk structural degradation, which contributes to the exceptional mechanical and electrochemical stabilities of the modified electrode. Besides, the coordination bond interaction between the cPAN and NCM811 can suppress the migration of Ni to elevate the stability of the crystal structure. Benefited from these, the In-cPAN-260@NCM811 shows excellent cycling performance with a retention of 86.8% after 300 cycles and superior rate capability. And endow the solid-state battery with thermal safety stability even at high-temperature extreme environment. This facile and scalable surface engineering represents significant progress in developing high-performance solid-state lithium metal batteries.
Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2025•DOI: 10.1016/S1003-6326(25)66926-3
The bending collapse and energy absorption of 7003 aluminum alloy bumper beams under four aging conditions (pre-aging, under-aging, peak-aging, and over-aging) were investigated through three-point bending tests. Microstructural characterization was performed using scanning electron microscopy and transmission electron microscopy. Based on the Swift−Hockett−Sherby constitutive model combined with the Gurson−Tvergaard−Needleman damage model, the plastic response and fracture behavior of the 7003 aluminum alloy under uniaxial tension and three-point bending were accurately predicted. The results showed that the peak bending force of the beams was proportional to the strength under different aging states, while stress triaxiality governed the cracking failure. Pre-aged and under-aged beams resisted cracking until reaching 250 mm displacement due to stress transition from tensile to compression on the bottom surface. The under-aged beam exhibited optimal energy absorption (7.86 kJ) and a higher peak force (38.75 kN).
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.03.010
The energy-focusing blast is an innovative and ingenious method to achieve directional fracturing. Understanding its energy regulation mechanism is critical to enhancing its practical effectiveness. This study investigates the energy regulation mechanism and explores the medium-filling effects within the energy-focusing blast by employing theoretical analysis, numerical simulations, and model tests. The findings by theoretical and numerical analysis first reveal that two stages of the fracturing and tensile stage govern the directionally crack propagation, in which the explosion energy in the non-energy-focusing direction is suppressed, compressing the borehole wall, while redirected energy produces tensile stress in the energy-focusing direction, driving the formation of directional cracks. The choice of filling medium significantly affects directional cracking due to its impact on energy distribution and regulation, and key properties such as wave impedance and compressibility of the filling medium are critical. Experimental comparisons using air, sand, and water as filling media further disclose the distinct effects of the medium on energy regulation and directional crack growth of the energy-focusing blast. The maximum shaped-energy coefficients for air, sand, and water are 1.30, 4.41, and 6.12 in the energy-focusing direction, respectively. Meanwhile, the stress attenuation rate of air, sand, and water increases in that order. The higher wave impedance and lower compressibility of water support efficient and uniform energy propagation, which subtly enhances the tensile actions in the focusing direction and intensifies the overall stress impact of the energy-focusing blast. In addition, the stresses in the non-energy-focusing directions decrease as the angle from the energy-focusing direction increases, while the stresses are relatively uniform for both air and water but noticeably uneven for sand; meanwhile, the fractal dimensions of blasting cracks in the case of air, water, and sand are 1.076, 1.068, and 1.112, respectively. Sand as a filling medium leads to increased crack irregularities due to its granularity and heterogeneity. The water medium strikes an optimal balance by promoting the blasting energy transition and optimizing the energy distribution, maintaining the least flatness of the directional crack during energy-focusing blasts.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25070031
Photonic crystal surface emitting lasers (PCSELs) utilize the Bragg diffraction of two-dimensional photonic crystals to achieve single-mode output with high power and small divergence angle. While GaAs-based PCSELs have demonstrated exceptional performance, GaN-based PCSELs offer shorter emission wavelengths covering visible to deep ultraviolet, enabling applications in material processing, laser illumination, underwater communication, and more. However, their development has been hindered by small refractive index and immature fabrication technologies. In this work, we report regrowth-free GaN-based PCSELs grown on sapphire substrates, achieving room-temperature electrically pumped lasing with a threshold current density of 13.7 kA/cm2. The device structure incorporates a photonic crystal layer etched on the p-side, eliminating the need for p-AlGaN cladding and simplifying fabrication. Through theoretical optimization based on coupled-wave theory, the photonic crystal layer thickness was set to 300 nm, and the lattice constant to 167 nm, targeting a lasing wavelength around 415 nm. The fabricated devices exhibit a dominant lasing peak at 415.1 nm with a full width at half maximum of approximately 1 nm. This demonstration of regrowth-free GaN-based PCSELs provides a cost-effective approach for mass production, advancing the practical application of GaN-based surface-emitting lasers.
Nano-Micro Letters•2025•DOI: 10.1007/s40820-024-01570-7
Efficient and stable photocathodes with versatility are of significance in photoassisted lithium-ion batteries (PLIBs), while there is always a request on fast carrier transport in electrochemical active photocathodes. Present work proposes a general approach of creating bulk heterojunction to boost the carrier mobility of photocathodes by simply laser assisted embedding of plasmonic nanocrystals. When employed in PLIBs, it was found effective for synchronously enhanced photocharge separation and transport in light charging process. Additionally, experimental photon spectroscopy, finite difference time domain method simulation and theoretical analyses demonstrate that the improved carrier dynamics are driven by the plasmonic-induced hot electron injection from metal to TiO2, as well as the enhanced conductivity in TiO2 matrix due to the formation of oxygen vacancies after Schottky contact. Benefiting from these merits, several benchmark values in performance of TiO2-based photocathode applied in PLIBs are set, including the capacity of 276 mAh g−1 at 0.2 A g−1 under illumination, photoconversion efficiency of 1.276% at 3 A g−1, less capacity and Columbic efficiency loss even through 200 cycles. These results exemplify the potential of the bulk heterojunction strategy in developing highly efficient and stable photoassisted energy storage systems.