Ni-based single crystal (NBSC) superalloys employed as turbine blades are generally vulnerable to elevated-temperature fretting fatigue (FF) damages during services. To prolong lifetime, ultrasonic surface rolling (USR) was adopted to NBSC in this study, with its FF performance investigated at 650 °C. Results reveal that USR induced a wave texture with reduced roughness and a heterostructure layer characterized by gradient slip trace (ST) network on DD6 surface. These modifications enhance the surface microhardness by 68.6% and yield compressive residual stress (CRS) with amplitude of 941.25 MPa, thus raising FF lifetime by 210.6% compared to as-received sample. During FF test, the wave texture considerably mitigates surface stress concentration and protects the sample bulk from the direct contact of the pad, while CRS effectively reduces the actual stress and compels the inward migration of crack source. These alleviate the synergistic damages from the fretting and fatigue components. Besides, the octahedron-dominated ST networks facilitate dodecahedral slip activations to accommodate cyclic plastic strains, and serve as skeletons to collect free dislocations to fulfill recrystallizations. Slip mode transitions and intense recrystallizations in USR sample require additional dissipated energies. Unlike common rafting in FF-failed as-received sample surfaces, the gradient ST networks manipulate crack propagations through the formations of inclined γ’-raft domains. Frequent crack deflections elevate the critical fracture thresholds and consequently extend FF lifetimes. The findings provide new insights to understand the deformation mechanisms of DD6 during FF and guide their anti-FF designs.
Radio-frequency (RF) and microwave dielectric ceramics are key materials for high-frequency electronic devices. Among them, perovskites outperform conventional dielectrics due to their high quality factor ( Q = 1/dielectric loss) and exceptional reliability. However, their practical application is limited by the trade-off between Q & times; f and the temperature coefficient of resonant frequency ( rf ), as well as by their high densification temperature ( >= 1500 degrees C). Here, a synergistic strategy combining B-site complex-ion modification with composite sintering-aid engineering is proposed. The optimized 95CZT05CMN composition exhibits excellent microwave dielectric properties of dielectric constant sr = 32.4, Q & times; f = 34,240 GHz, and rf = + 16.8 ppm/ degrees C at 1540 degrees C. More importantly, the 5G1L0.5C-modified ceramics can be densified at 950-1050 degrees C while retaining favorable dielectric properties ( sr = 27.3-31.9, Q & times; f = 12,920-13,400 GHz, rf = -6.1 to -11.6 ppm/ degrees C), together with a high flexural strength of 212 MPa. Furthermore, a C-band dielectric resonator antenna delivers radiation efficiency above 85%, while multilayer ceramic capacitors (MLCCs) fabricated show excellent C0G-type stability ( AC / C25 degrees C within +/- 0.3%) and a dielectric loss of similar to 0.06% at 1 MHz. These results establish a viable route toward low sintering temperature, low-loss and thermally stable CaZrO3 -based perovskites for advanced RF and integrated electronic applications. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
Polarisation in covalent organic framework (COF) catalysts has emerged as an effective strategy to reduce strong excitonic binding and to improve charge transport through built-in electric fields. Unlike conventional inorganic ferroelectrics or polar materials, COFs enable programmable polarisation through molecular and lattice design, allowing internal fields to be tuned in strength and direction. In this review, we provide a comprehensive analysis of polarisation in COFs, from its physical origins to its functional roles in catalysis. We first examine the multiscale origins of polarisation in COFs, encompassing bond-level electronic asymmetry, conjugation-mediated propagation, and framework-level structural organisation that governs dipole alignment and cancellation. We then summarise how polarisation is characterised experimentally and theoretically across different electronic and catalytic states, including ground-state electrostatic potential landscapes, photoexcited-state charge dynamics, and polarisation effects at solid-liquid catalytic interfaces. Finally, through representative photocatalytic and electrocatalytic case studies, we illustrate how deliberate polarisation engineering reshapes charge separation, transport, and reaction pathways across diverse catalytic reactions, and conclude by discussing the key opportunities and challenges for translating polarisation into a predictive design principle for COFs. By connecting the origins, characterisations, regulating strategies, and catalytic mechanisms, this review provides a more integrated perspective on polarisation phenomena in next-generation COF catalysts.
Phosphite is a reduced inorganic phosphorus species increasingly reported in aquatic environments but often overlooked in conventional dissolved reactive phosphorus monitoring. Owing to its high solubility and redox lability, Phi can function as a transient, speciation-sensitive P pool and a substrate for microbial metabolism, thereby linking phosphorus availability to redox dynamics and potentially influencing eutrophication-relevant nutrient fluxes. Here, we synthesize current evidence on the occurrence, environmental partitioning, and transformation of Phi across various aquatic environments, and waters impacted by industrial wastewater and agricultural inputs. We first summarize recent methodological advances facilitating robust quantification of Phi at environmentally relevant concentrations. We then synthesize current knowledge of Phi biogeochemical cycling across freshwater systems, sediment and soil matrices, and marine environments, collating reported distribution patterns and disentangling the key environmental drivers governing Phi persistence and turnover dynamics. Furthermore, we delineate the core chemical and microbial transformation pathways of Phi in aquatic environments, encompassing anabolic phosphite oxidation, dissimilatory phosphite oxidation, and abiotic/engineered oxidation processes (e.g., UV/H2O2, Fenton-like reactions, PMS-based oxidation, and electrochemical methods). Additionally, we address the ecological and biogeochemical implications of Phi cycling for eutrophication mitigation, microbial community assembly, and aquatic ecosystem stability. Finally, we emphasized and elaborate on the priorities of future research endeavors. This work provides an in-depth and holistic understanding of the intricate phosphorus cycling processes, laying a robust scientific foundation for the design and implementation of efficient and sustainable phosphorus management strategies tailored to diverse aquatic environments.
The widespread use of ciprofloxacin (CIP), a fluoroquinolone antibiotic, has led to its persistence as a pollutant, promoting antibiotic resistance. Conventional wastewater treatment methods have limited efficacy in removing CIP, necessitating advanced technologies. This study investigated the synthesis and photocatalytic performance of CoxMg0.6− XCd0.2Ba0.2Fe2O4 (X = 0, 0.3) ferrite nanoparticles for the degradation of CIP and other organic pollutants. The nanoparticles were synthesized via Sol-gel auto-combustion and characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy. XRD revealed a decreased lattice constant (8.3893–8.3664 Å) and crystallite size (25.056–20.540 nm) with cobalt doping. BET analysis showed increased surface area (12.36–14.95 m²/g) and pore volume (0.0185–0.0263 cm³/g) with cobalt. The band gap narrowed from 2.88 to 2.61 eV, improving visible-light absorption. Photocatalytic tests showed that cobalt-doped ferrite achieved 100
