The Chinese Journal of Process Engineering•2026•DOI: 10.12034/j.issn.1009-606X.225162
The effects of tempering temperature on the microstructure, strength-toughness balance, and precipitates of a quenched Cu-Cr-Ni ultra-high strength weathering steel were systematically investigated. The steel was austenitized at 920°C, quenched, and then tempered at 500°C, 550°C, and 600°C. Microstructural characterization was performed using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), while mechanical properties were evaluated via tensile and low-temperature impact tests. Results showed that as the tempering temperature increased from 500°C to 600°C, the microstructure transformed from lath-shaped tempered sorbite to a non-lath morphology. The fraction of rod-like cementite decreased, while spheroidized cementite increased, and the size of MC (M = Ti, Nb, V, Mo) precipitates decreased from an average of 12.2 nm to 9.9 nm. Consequently, yield strength and tensile strength decreased from 935 MPa and 958 MPa to 866 MPa and 888 MPa, respectively, whereas total elongation and impact energy at -40°C increased continuously, reaching maximum values of 5.0% and 280 J at 600°C. When tempered at 550°C, the steel exhibited a yield strength of 895 MPa, tensile strength of 921 MPa, elongation of 4.3%, and impact energy of 271 J at -40°C, demonstrating an optimal combination of strength and toughness. This improvement is primarily attributed to the spheroidization of cementite and the uniform dispersion of fine MC precipitates, which alleviate stress concentration, along with the softening of the acicular ferrite matrix during tempering.
Journal of Environmental Engineering Technology•2026•DOI: 10.13205/j.hjgc.202606017
Against the backdrop of global green transition and tightening resource constraints, China's Dual Carbon Goals and Zero-Waste City initiative have positioned waste valorization as a critical pathway for sustainable development. Zinc, a fundamental metal, faces high external dependence and nearing primary resource limits, making the regenerated zinc industry essential. However, the previous standard YS/T 1093-2015 lagged in classification, technical indicators, and environmental requirements. This paper analyzes the revision to YS/T 1093-2024, which renames the standard to 'Recycled Zinc Raw Materials' and clarifies its role as front-end smelting intermediate feedstock. The new standard establishes a classification system covering six typical zinc-bearing materials, expanding utilization of low-grade complex materials (zinc content 5%-15%). It tightens limits on harmful elements (fluorine, chlorine, lead, arsenic) and introduces moisture control and appearance evaluation indicators, enhancing operability and environmental risk control. Compared with EU standards, it shows systematic improvements in raw material coverage, process adaptability, and environmental risk prevention. The revision is expected to drive the regenerated zinc industry toward intensification, high-value utilization, and clean production, improving resource recycling efficiency and supporting China's zinc resource strategic security and low-carbon development.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3944-9
Hard carbon (HC) is a promising anode material for sodium-ion batteries (SIBs) but suffers from low initial Coulombic efficiency (ICE) and unstable solid electrolyte interphase (SEI). Here, we report a dual-functional strategy combining surface engineering and solution chemical pre-sodiation. A graphitic carbon coating on HC acts as a conductive buffer network and shields surface defects, while sodium biphenyl (Na-Bp) pre-sodiation drives sodium ions into the material via a potential difference, inducing a pre-SEI layer that matures into a thin, dense, NaF-rich inorganic SEI during cycling. This approach compensates for irreversible sodium loss and enhances cycling stability. The pre-sodiated electrode (pCH4-HC) achieves an ICE of 99.5% and a reversible capacity of 321.7 mAh g−1, compared to 54.2% for untreated HC. Long-term cycling shows 74.0% capacity retention after 1000 cycles at 300 mA g−1. In full-cells with NaNi1/3Fe1/3Mn1/3O2 (NFM) cathode, pCH4-HC||NFM delivers 81.9 mAh g−1 after 100 cycles, demonstrating excellent stability and rate performance. This dual-strategy approach validates the adaptability of pre-sodiation technology for high-performance SIBs.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4079-4
Utilization of ultrahigh-nickel LiNi_xCo_yMn_1-x-yO_2 (NCM) (x > 0.97) in Li-ion batteries can distinctively boost energy density through enhanced discharge capacity. However, capacity and thermal stability deteriorate as Ni content approaches the limit. Here, we propose a facile strategy by introducing high-valence tungsten (W) into ultrahigh-nickel polycrystalline LiNi_0.98Co_0.01Mn_0.01O_2 (PCNCM98). W-doped PCNCM98 (W-PCNCM98) exhibits refined, compactly stacked primary particles, whereas PCNCM98 shows equiaxial, non-uniform larger particles. The refined microstructure enhances mechanical strength: average particle hardness of W-PCNCM98 is 104 MPa, 1.5 times higher than PCNCM98 (68 MPa). This improved mechanical property suppresses lattice volume changes and relieves microcrack formation from H2–H3 phase transition. Consequently, cycling performance in pouch-type full cells is significantly enhanced, with capacity retention of 73% after 2000 cycles at 1 C and 25 °C, 54% higher than PCNCM98. Enhanced structural stability and strong electron affinity of W6+ also improve thermal stability: exothermic peak for W-PCNCM98 is postponed to 203 °C with heat generation of 1287 J g−1, versus 190 °C and 1528 J g−1 for PCNCM98. This high-valent doping strategy stabilizes ultrahigh-nickel NCM cathodes, accelerating large-scale EV applications.