Polymer-derived ceramics are prepared via forming precursors through the polymerization of tiny molecules and cracking at high temperatures. Compared to conventional ceramics, their advantage lies in an ability to precisely control the microstructure and crystalline phase composition through the design of the molecular structure and elemental composition of the precursor and subsequent thermal treatment, thereby producing the optimal final properties. Among these, SiBCN ceramics stand out within the polymer-derived ceramics due to their flexible molecular structure designability. This enables the in-situ formation of multi-phase synergistic loss systems incorporating SiC, BN and graphitic carbon, coupled with a unique oxidation resistance mechanism, which excel particularly within polymer-derived ceramic systems. However, SiBCN ceramics primarily exist in an amorphous state at lower temperatures (i.e., < 1400 ℃), thus limiting their application in electromagnetic wave absorption. The paper was to introduce Ti nanopowder during the ceramicization process to catalyze the formation of nano-dielectric crystals such as SiC, TiC, and crystalline graphite. These crystals could enhance the dielectric imaginary part of SiBCN ceramics, thereby strengthening their electromagnetic wave attenuation capabilities.

For the synthesis of polymer precursor, tetrahydrofuran (THF)-methylvinyl dichlorosilane and borane dimethyl sulfide complex were mixed into a three-neck flask and conducted in argon for 24 h. Also, methyl dichlorosilane and hexamethyldisilazane were introduced, and the reaction was continued at the ambient temperature for 24 h. Subsequently, the mixture was then heated from room temperature to 170 ℃ for amide copolymerization reaction. After holding at this temperature for 3 h, vacuum distillation was performed, and filtrated for three cycles, thus producing a pale yellow polyborosilazane (PBSZ). For the synthesis of SiBCN ceramibs, polyborosilazane (PBSZ) was placed in a tube furnace and heated to 280 ℃ for 2 h to fully cure the precursor. The cured sample was subjected to ball grinding. The resultant ground powder was mixed with Ti nanopowder at different Ti mass contents (i.e, 0%, 5%, 10%, and 15%), and then was ground to produce different composite powders, . The composite powders were pressed into discs with the diameter of φ20 mm. The discs were heat-treated in a vertical tube furnace(i.e., firstly heating at 800 ℃ for 1 h, and thenheating at 1000 ℃ for 2 h) to allow enough molecular diffusion for TiC crystal formation, resulting in SiBCN ceramics.

The analysis of the four-component doped ceramics reveals that Ti nanoparticles doping positively affects both the phase composition and dielectric properties of SiBCN ceramics. The XRD patterns indicate that pure SiBCN ceramics remain amorphous after heat treatment at 1000 ℃, whereas the addition of Ti nano-particles promotes the formation of TiC crystals within the ceramics, thereby enhancing their crystalline properties. The SEM and TEM images demonstrate that varying the nano-Ti doping content alters the microstructure of SiBCN ceramics. Nano-Ti addition promotes the formation of a porous structure within the ceramics and facilitates the growth of crystals such as TiC and carbon nanotubes, enriching the phase composition of the ceramics. Varying Ti nanoparticles doping contents alters SiBCN's electromagnetic wave absorption and loss capabilities. Compared to pure SiBCN ceramics, Ti nanoparticles doping confers higher electromagnetic parameters and lower reflection loss, and 10% Ti nanoparticles-doped SiBCN exhibits the optimum electromagnetic wave absorption performance. The incorporation of Ti nanoparticles optimizes the ceramic structure, with synergistic interactions among various crystals and structural components, thus enhancing the overall performance.

This study demonstrated that doping Ti nano-particles into SiBCN ceramic could enhance the ceramic dielectric loss and impedance matching qualities. Ti nano-particles enhanced the low-temperature crystallization property of SiBCN. The crystallinity and microstructure of SiBCN ceramics could be adjusted by varying the nano-Ti doping content. The ceramics heat-treated at 1000 ℃ could develop porous architectures, TiC, and crystalline phases such as crystalline carbon. Ti nanoparticles improved the electromagnetic wave attenuation properties of SiBCN. The formation of TiC and carbon nanotubes, along with the heterogeneous interfaces formed with the amorphous matrix, could boost the electromagnetic wave attenuation performance of SiBCN ceramics. The crystallinity of SiBCN ceramics and the presence of abundant atomic defects resulted in a significant polarization loss, thereby enhancing the ceramic's electromagnetic wave absorption capability. At Ti nanoparticles content of 10%, the RLmin value of SiBCN ceramics at 6.24 GHz achieved -44.5 dB, with an EAB as high as 3.43 GHz, indicating that adding Ti nanoparticles could effectively enhance the electromagnetic wave absorption capacity of low-temperature heat-treated SiBCN ceramics.

High-temperature vibration sensors are indispensable key components for the health detection of core equipment in fields such as aerospace and nuclear energy. The BiScO₃-PbTiO₃(BS-PT) system has attracted much attention due to its high Curie temperature (T_C≈450 ℃) and excellent piezoelectricity (d₃₃≈450 pC/N). However, the poor insulation properties of this material hinder its application in high-temperature vibration sensors because high electrical resistivity (ρ) and a long time constant (τ) are critical to prevent thermal runaway and ensure signal integrity. Manganese (Mn) doping is a commonly used modification method for piezoelectric ceramics. Previous studies on Mn-doped BS-PT were controversial regarding the valence state distribution and substitution positions of Mn ions, which could not be conducive to the design of high-temperature piezoelectric ceramics with the collaborative optimization of multiple electrical parameters. Therefore, this work was to clarify the defect chemical mechanism associated with manganese doping through refined structural characterization combined with electrical performance analysis, and to obtain the modified BS-PT piezoelectric ceramic components suitable for high-temperature vibration sensors.

0.365BiScO₃-0.635PbTiO₃-x% MnO₂ (BSPT-x% MnO₂, x=0.00, 0.01, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00) ceramics were synthesized by a conventional solid-state reaction method. The powders were firstly calcined at 800 ℃ for 2 h and then sintered at 1050 ℃ for 2 h. The phase composition was analyzed by X-ray diffraction (XRD). The rietveld refinements were performed using a software named GSAS. The microstructure and elemental distribution were examined by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS). The average grain size was estimated by a software named Nano Measurer. The Mn valence states were determined by X-ray photoelectron spectroscopy (XPS). For electrical measurements, poled samples (120 ℃, 5 kV/mm, 30 min) were used. The piezoelectric coefficient (d₃₃) was measured by a model CAS ZJ-6A quasi-static meter. The electromechanical coupling coefficient (k_p) was measured by a model Agilent 4294A impedance analyzer. The temperature-dependent dielectric properties were measured by a model Agilent E4980A LCR analyzer. The high-temperature DC resistivity (ρ) was measured by a model Keithley 6517B high-resistance electrometer. The in-situ d₃₃ was measured by a model Julang TZFD-600 variable temperature quasi-static d₃₃ measurement system.

The Mn doping mechanism and high-temperature performance of BS-PT ceramics are systematically clarified. The XPS results confirm the coexistence of Mn²⁺ and Mn³⁺. To quantitatively verify the substitution site, the rietveld refinement reveals a non-monotonic evolution of unit cell volume. Based on the EDS evidence of Sc segregation without Ti precipitation, Mn ions preferentially substitute for B-site Sc³⁺. The dominant aliovalent substitution introduces defect dipoles accompanied with strong local random electric fields, significantly enhancing a relaxor behavior, while triggering a "hardening" effect that reduces tanδ and ε_r. The decoupling of piezoelectric and dielectric properties is achieved in specific compositions due to the grain boundary effect compensating for the hardening effect, especially obtaining the optimal piezoelectric voltage constant (g₃₃) at the component with x of 1.00. For high-temperature capabilities, the optimal composition (x=1.00) demonstrates a superior stability, with in-situ d₃₃ variation remaining within 20% up to 400 ℃. The thermally stable defect dipoles effectively trap oxygen vacancies, leading to a high resistivity of 10⁹ Ω·cm and an enhanced time constant of 0.072 s at 350 ℃. Consequently, the ceramic with x of 1.00 exhibits a high g₃₃ of 0.012 V·m/N when evaluated at a unified service temperature of 350 ℃, which is 50% higher than that of the undoped counterpart. These results indicate that the modified ceramic achieves an optimal balance of sensitivity and insulation for high-temperature vibration sensors.

This work clarified the Mn doping mechanism in BS-PT ceramics. The results of correlative XPS, Rietveld refinement, and EDS analysis confirmed that Mn ions could preferentially substitute for B-site Sc³⁺. The dominant aliovalent substitution induced a hardening effect, while the recovery of d₃₃ was dominated by grain size restoration. The optimal composition (x=1.00) exhibited a robust stability with d₃₃ variation within 20% at 400 ℃. The thermally stable defect dipoles could obtain a high resistivity (10⁹ Ω·cm) and time constant (0.072 s) at 350 ℃. Meanwhile, a superior piezoelectric voltage coefficient (g₃₃) of 0.012 V·m/N was achieved at 350 ℃, which was 50% higher than that of the undoped counterpart, validating its potential for high-temperature sensors.

With the advancement of the era, the demand for ultraviolet photodetectors in environmental monitoring and communication security continues to grow, leading to increasingly stringent performance requirements. In this case, self-driven ultraviolet photodetectors emerge to meet the needs of energy conservation and device miniaturization. However, conventional self-driven ultraviolet photodetectors still face some challenges such as low efficiency in photo-generated carrier separation, poor photoresponse performance, and limited response speed. Ferroelectric thin films with a high remnant polarization can form a depolarization field that penetrates the entire bulk material, enabling an effective separation of internally generated photo-generated electrons and holes. This provides a promising solution to the aforementioned issues. Pb(Zr_xTi1-x)O₃(PZT) is a typical ABO₃-type perovskite ferroelectric material. This material is widely used in ferroelectric memories, micro-electromechanical systems, and photodetectors due to its excellent ferroelectric, piezoelectric, and photoelectric properties. Extensive studies show that the composition significantly affects the crystal phase structure and ferroelectric properties of PZT thin films. However, its impact on the photoelectric performance requires a further systematic investigation. This work was to analyze the photoelectric characteristics of PZT thin films with different Zr/Ti ratios, in order to elucidate the influence of compositional modulation on the photoelectric effect.

Pb(Zr_xTi₁-x)O₃ ferroelectric thin films with different Zr/Ti ratios were prepared by a sol-gel method. The selected precursors and solvents were high-purity lead acetate [Pb(CH₃COO)₂·3H₂O], zirconium n-propoxide (C₁₂H₂₈O₄Zr), and titanium isopropoxide (C₁₂H₂₈O₄Ti) as sources for lead, zirconium, and titanium, respectively, glacial acetic acid as a chelating agent, and n-propanol as a stabilizer. Semitransparent gold electrodes were deposited on the surface of the thin films by a model VZZ-300 high-vacuum thermal evaporation system (VANNO Co., China) to fabricate self-driven ultraviolet photodetectors with an Au/PZT/FTO vertical structure. The crystal structure of the films was characterized by a model D8 Advance X-ray diffractometer (XRD, Bruker Co., USA). The surface roughness of the films was determined by an atomic force microscope (AFM, Bruker Dimension Edge Co., USA). The optical properties of the films were analyzed by a model UV-3600 Plus ultraviolet-visible-near-infrared spectrophotometer (UV-Vis-NIR, Shimadzu, Japan). The ferroelectric properties were measured by a model Precision LC II ferroelectric test system (Radiant Co., USA). The current-time (I-t) curves were obtained by a model Keithley 2400 source meter, with a 150 W ultraviolet-enhanced xenon lamp as a light source.

The XRD patterns indicate that the three prepared PZT thin films with different Zr/Ti ratios all exhibit a typical perovskite structure, and no diffraction peaks from impurity phases appear aside from those originating from the FTO substrate. As the Zr content increases, the surface morphology of the films transitions from elongated needle-like structures to island-like structures, and finally to wavy undulations. The lowest root mean square (RMS) roughness of 2.62 nm is obtained at a Zr/Ti ratio of 0.52:0.48. The remnant polarization first increases from 27.9 μC/cm² (Zr/Ti=0.49/0.51) to a maximum of 33.2 μC/cm² (Zr/Ti=0.52/0.48), and then decreases to 31.1 μC/cm² (Zr/Ti=0.55/0.45) as the Zr content increases. A higher remnant polarization is beneficial to forming a stronger built-in electric field, thereby improving the separation efficiency of photogenerated carriers. The PZT films with different Zr/Ti ratios are all wide-bandgap semiconductors (>3.6 eV). As the Zr content increases, the bandgap widens from 3.60 eV to 3.68 eV, showing a blue-shift trend. When a negative poling voltage is applied, the depolarization field inside the PZT aligns with the built-in field induced by the interfacial Schottky barrier, synergistically enhancing the driving force for carrier separation and leading to a significant increase in photocurrent. For the sample with a Zr/Ti ratio of 0.52:0.48 at a poling voltage of -2 V, the responsivity and detectivity reach 3.2 mA/W and 0.33×10¹¹ Jones, respectively. Even under a weak illumination of as low as 0.17929 mW/cm², the device still generates a photocurrent of 1.02 nA, demonstrating the excellent detection sensitivity.

Pb(Zr_xTi₁-x)O₃ ferroelectric thin films with different zirconium-to-titanium ratios (i.e., Zr/Ti=0.49:0.51, 0.52:0.48, 0.55:0.45) were fabricated by a sol-gel method, and self-driven ultraviolet photodetectors with an Au/PZT/FTO structure were constructed. The structural characterization revealed that all PZT thin films exhibited a pure perovskite phase with a good crystalline quality. The AFM analysis indicated that the film surfaces were smooth, dense, and displayed a uniform grain distribution. The ferroelectric property measurements further confirmed that all films with different Zr/Ti ratios showed characteristic ferroelectric hysteresis loops and possessed a high remnant polarization, having a maximum value of 33.2 μC/cm² at Zr/Ti=0.52:0.48. The results of photoelectric tests demonstrated that the device based on this optimal composition exhibited stable and reproducible photocurrent responses. At a poling voltage of -2 V, its responsivity and detectivity were significantly enhanced. In summary, the rational adjustment of the Zr/Ti ratio could effectively optimize both the ferroelectric properties of PZT thin films and the photoelectric characteristics of the corresponding devices. This work could innovatively utilize the inherent bulk depolarization field of PZT ferroelectrics as a driving force to achieve an efficient separation of photogenerated electron-hole pairs. Moreover, it could provide a systematic optimization strategy from the perspectives of compositional design and polarization modulation, offering an effective material- and physics-based solution to overcome the key bottlenecks of low responsivity and detectivity in self-driven ultraviolet photodetectors.

Quartz ceramics (SiO₂) possess unique properties such as low thermal expansion, excellent chemical stability, and outstanding dielectric performance, making them widely used in semiconductor manufacturing, optoelectronic devices, and high-frequency electronic components. Traditional sintering of quartz ceramics typically requires temperatures above 1000 ℃, which inevitably induces polymorphic transformations from α-quartz to β-quartz or cristobalite, hindering the preparation of single-phaseα-quartz ceramics. Recently, the cold sintering process (CSP) has emerged as a promising low-temperature densification route for ceramics, utilizing transient liquid phases to induce "dissolution-precipitation" or interfacial reaction mechanisms. However, for low-solubility ceramics such as quartz, CSP often fails to achieve full densification and crystallization due to insufficient dissolution kinetics and weak interfacial reactivity. The critical scientific problem addressed in this work is how to effectively trigger the amorphous-to-crystalline phase transition of low-solubility quartz at low temperature, thereby enabling the preparation of denseα-quartz ceramics.

This study systematically investigates the cooperative effects of transient solvent alkalinity, sintering temperature, and uniaxial pressure on the amorphous-to-α-quartz phase transition during CSP. A transient alkaline liquid phase is introduced to regulate interfacial reactions and crystallization kinetics, aiming to provide a theoretical basis and technical strategy for the low-temperature processing of low-solubility ceramics.

Amorphous mesoporous silica (SBA-15) powders were used as the starting material. The powders were homogeneously mixed with different transient solvent phases: deionized water (neutral), 5 mol·L^-1 NH₃·H₂O (weak alkaline), and NaOH solutions of varying concentrations (0.5-10.0 mol·L^-1, strong alkaline). Approximately 0.4 g of powder was thoroughly ground with the liquid phase in a mortar and then loaded into a 10 mm diameter steel die. Uniaxial pressures ranging from 200 MPa to 600 MPa were applied, while the sintering temperature was varied between 200 ℃ and 350 ℃. Heating was conducted at a rate of 15 ℃·min^-1 and held for 40 min at the target temperature. After natural cooling, the sintered pellets were mechanically polished for further characterization.

The density of the cold-sintered ceramics was calculated by dimensional and weight measurements using a vernier caliper and electronic balance, and relative density was determined based on the theoretical density of quartz (2.2 g·cm^-3). Phase composition and structural evolution were analyzed using X-ray diffraction (XRD, Cu Kα radiation, λ = 0.154 06 nm, 50 kV, 100 mA, scanning range 10 °-90 °, step size 0.01). Fourier-transform infrared spectroscopy (FTIR-ATR) was used to identify bonding characteristics and confirm phase transitions. Microstructural evolution and fracture features were observed by field-emission scanning electron microscopy (FE-SEM). The mechanical properties of the sintered ceramics were evaluated by Vickers hardness tests (3 kgf load, 10 s dwell), flexural strength using the modified small punch (MSP) method, and fracture toughness (K_IC) calculated by the Anstis equation. Poisson's ratio and Young's modulus were determined by ultrasonic measurements.

This experimental design allows for a systematic investigation of how transient solvent alkalinity, temperature, and pressure cooperatively affect densification and amorphous-to-crystalline transformation during CSP of quartz.

The phase composition of the sintered bodies was strongly influenced by the type and concentration of transient solvent. Without a liquid phase or with neutral water, the sintered samples remained largely amorphous and exhibited low relative density (~80%). Weak alkaline NH₃·H₂O increased compaction and relative density (~92%) but failed to trigger phase transformation. In contrast, strong alkaline NaOH solutions (≥3 mol·L^-1) effectively promoted the dissolution of Si-OH surface species, forming soluble silicate intermediates. These intermediates subsequently underwent reprecipitation and recrystallization under external pressure and temperature, leading to complete transformation into α-quartz at 300 ℃ and 500 MPa. XRD and FTIR confirmed the disappearance of the amorphous broad peak and the emergence of α-quartz characteristic double peaks at 798 cm^-1 and 778 cm^-1, indicating a complete amorphous-to-α-quartz transition.

A clear alkalinity-dependent phase transition sequence was identified: amorphous → keatite (0.5 mol·L^-1 NaOH) → keatite +stishovite (1 mol·L^-1) → keatite + α-quartz (3 mol·L^-1) → α-quartz (≥5 mol·L^-1). Simultaneously, relative density increased from 71% (no solvent) to 95.7% (10 mol·L^-1 NaOH). SEM revealed that strong alkalinity produced well-defined grain boundaries and uniform microstructures, while weak or neutral conditions resulted in porous, poorly bonded networks.

The phase transition was also sensitive to sintering temperature and pressure. At 200 ℃, no crystallization occurred even at 600 MPa. Crystallization initiated at 250 ℃ and 300 MPa, and complete α-quartz formation occurred at ≥300 ℃ and ≥400 MPa. Increasing pressure facilitated particle rearrangement, pore elimination, and enhanced atomic diffusion at the interface, accelerating phase transition. A comprehensive temperature-pressure-phase diagram was established, clearly delineating the non-crystalline, partially crystalline, and fully crystalline regions.

Mechanical properties were strongly correlated with microstructure and phase composition. The α-quartz ceramics cold-sintered with 5 mol·L^-1 NaOH exhibited a Vickers hardness of 5.1 GPa, Young's modulus of 67.8 GPa, fracture toughness of 0.98 MPa·m^1/2, and flexural strength of (58 ± 7) MPa. These values represent increases of 30%, 40%, and 110% in hardness, modulus, and toughness, respectively, compared to the amorphous samples. The enhanced mechanical properties are attributed to the formation of well-bonded crystalline interfaces that enable efficient stress transfer and crack deflection, unlike the disordered amorphous structure.

This work demonstrates a controllable strategy to induce amorphous-to-α-quartz transformation in low-solubility silica ceramics through the regulation of transient solvent alkalinity during cold sintering. By introducing strong alkaline NaOH solutions (≥3 mol·L^-1), the activation energy for crystallization can be significantly reduced, enabling complete transformation at 300 ℃ under 500 MPa. The critical crystallization threshold was identified at 250 ℃ and 200 MPa, and a detailed temperature-pressure-phase diagram was established to illustrate the transition pathways. The resulting ceramics achieved a relative density above 95% and exhibited excellent mechanical performance, including a Vickers hardness of 5.1 GPa, Young's modulus of 67.8 GPa, fracture toughness of 0.98 MPa·m^1/2, and flexural strength of (58 ± 7) MPa. These results clearly indicate that alkaline regulation during CSP not only enables precise control of phase structure but also produces dense, mechanically robust α-quartz ceramics at dramatically reduced sintering temperatures. This approach provides both fundamental insights and practical guidance for the low-energy fabrication of advanced low-solubility ceramic components.

Ti-6Al-4V (TC4) titanium alloy is widely used in industrial and biomedical fields due to its excellent mechanical properties and biocompatibility. However, its inherently poor wear resistance significantly limits its further application. Plasma electrolytic oxidation (PEO) as a green and efficient method for in-situ fabrication of ceramic coatings with strong adhesion to the substrate, offering an excellent solution for surface protection of titanium alloys. However, conventional PEO coatings exhibit a porous outer layer composed mainly of high friction TiO₂, resulting in insufficient wear and friction reduction performance. To overcome this limitation, incorporating MoS₂ (a solid lubricant with a layered structure) can be introduced to the PEO coating to form a composite coating, which has been demonstrated as an effective approach to enhance its tribological properties. Although previous studies have confirmed the potential value of TiO₂/MoS₂ composite coatings in antifriction, most studies rely on high concentrations of MoS₂ additives or prolonged treatment times, which often lead to particle agglomeration and high energy consumption. Even at lower concentrations, the friction coefficient remains high, and systematic studies on the influence of key process parameters, such as applied voltage are still lacking. Therefore, this study aims to systematically investigate the effects of different PEO voltages on the microstructure, chemical composition, and tribological properties of TiO₂/MoS₂ composite coatings under low MoS₂ concentration and short processing time, so as to provide theoretical and practical guidance for the design and fabrication of high-performance wear resistant and antifriction coatings.

In this study, Ti-6Al-4V alloy was employed as the substrate. TiO₂/MoS₂ composite coatings were fabricated in a single-step process via PEO with incorporation of MoS₂ nanoparticles. The applied voltage was varied at 400, 500 V, and 600 V. The influence of voltage on the coating surface morphology was characterized using scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Localized chemical analysis of different regions on the coating surface was performed by energy dispersive spectroscopy (EDS) attached to the SEM. Phase composition was further determined by X-ray diffraction (XRD). Finally, the tribological properties of the coatings were evaluated using a ball-on-disk friction and wear tester.

The test results demonstrate that as the PEO applied voltage increases, the pore size, coating thickness, surface roughness, and deposited MoS₂ content of the coatings all increase. Tribological tests on samples prepared at different voltages demonstrated that the coating produced at 500 V exhibited the lowest friction coefficient of approximately 0.2, representing a 69.2% reduction compared to the substrate, indicating excellent antifriction performance. In contrast, coatings prepared at 400 V and 600 V exbibited significantly higher friction coefficients of 0.75 and 0.82, respectively, and suffered from severe adhesive and abrasive wear. The primary reasons for this behavior are as follows: At the lower voltage (400 V), the coating thickness is thin and the MoS₂ content is insufficient to provide effective lubrication. During the running-in stage, the coating lacks adequate capacity to accommodate wear debris, leading to inadequate debris removal. This results in pronounced abrasive wear, rapid penetration of the coating, and direct interaction between the substrate and the counterface, thereby increasing the friction coefficient. At the higher voltage of 600 V, although the coating thickness and MoS₂ content increase substantially, the surface roughness rises significantly ((4.7 ± 0.3) μm). This leads to the generation of large, coarse debris during the initial running-in stage. Before the coating can effectively accommodate these debris particles, they cause rapid spallation of the coating, generating even more debris and accelerating wear. Under these conditions, the MoS₂ particles embedded in the outer layer fail to provide any meaningful lubrication, and the coating is quickly worn through, resulting in a sharp increase in the friction coefficient. At the applied voltage of 500 V, the coating exhibits moderate thickness and surface roughness, maintaining adequate coating thickness and MoS₂ content without excessive surface roughness. The friction and wear mechanism of the TiO₂/MoS₂ composite coating under this voltage can be elucidated as follows: The inherent porous outer layer of the PEO coating undergoes initial smoothing of surface asperities during friction, generating wear debris containing embedded MoS₂ particles that fill surface depressions and inherent pores. With continued sliding, the MoS₂ particles within the debris gradually spread across the contact interface. Owing to their unique two-dimensional layered structure, these particles undergo interlayer sliding under shear stress, forming a continuous surface film with excellent lubricating properties. Furthermore, the porous structure of the coating not only accommodates wear debris but also functions as a reservoir for MoS₂ particles, enabling continuous replenishment of lubricant to areas where the surface lubricating film becomes locally depleted, thereby achieving remarkable self-lubricating performance.

At the optimized voltage of 500 V, the TiO₂/MoS₂ composite coating exhibits a moderate thickness ((28.0 ± 0.6) μm) and surface roughness ((3.0 ± 0.2) μm), along with a relatively high MoS₂ content. This combination results in the lowest friction coefficient of 0.2, representing a 69.2% reduction compared to the uncoated Ti-6Al-4V substrate; During the friction process, MoS₂ particles embedded in the TiO₂/MoS₂ composite coating are progressively exposed under shear stress and undergo interlayer sliding. This leads to the formation of a lubricating film on the wear track, which provides effective self-lubrication and significantly enhances the tribological performance of the Ti-6Al-4V alloy.

In summary, with the increasing service temperature of aero-engines, the abradable/environmental barrier coatings (A/EBCs) that match SiC_f/SiC ceramic matrix composites (CMCs) become a key research direction. This review represents the research progress of A/EBCs in material design, microstructural regulation and performance evaluation, and points out that the current challenges mainly include thermal expansion mismatch between conventional coating materials and CMC substrate, poor high-temperature stability of lubricants, difficult balance between multi-scale pore structure and multi-performance, and lack of standardized evaluation systems and test standards suitable for multi-field coupling service environment. In the future, the research and development of A/EBCs should focus on the multi-objective synergistic design of material composition, multi-scale microstructure and performance evaluation system. It is necessary to strengthen the analysis of failure mechanism under multi-physical field coupling environment, develop new high-temperature stable matrix and lubricant materials, realize the precise regulation of multi-scale pore and interface structure, and establish a standardized preparation and performance evaluation system. Through the breakthrough of the above key technologies, the comprehensive performance and service durability of A/EBCs will be effectively improved, so as to promote the leapfrog development of high-temperature sealing technology and provide an important support for the performance improvement of next-generation aero-engines.

The multi-levelled control of multiphase microstructures by the reactive-melt is analogous to "dissolution-reprecipitation" process for liquid-phase sintering in the transformable microstructures of silicon-based ceramics, with silicate-melts and glassy phases at grain boundaries. In contrast to the monolithic ceramics of high-entropy MB₂ and MC, the multi-levelled solid-solutions and the associated multiphase microstructures of M^ⅠB₂-M^ⅡC UHTCs offer ample and novel routes for comprehensive control, better optimization and further enhancement in high-performance UHTCs. The coherent hetero-interfaces created from the multi-levelled solutions via solid-state phase-separations and their interconnected dislocation networks can further improve the high-temperature strength, and those phase-boundaries, grain-boundaries, and solute-segregates allow a precise control over the multiscale semi-coherent microstructures. The research on this synergistic evolution of intergranular phases and sintering-melts at high temperatures along with the multiphase transformation has a promising potential for future advancements in ceramic genomes and levelled structure-property relationship for multiphase UHTCs governed by solid-solutions as enthalpy-regulation.

It is effective to introduce self-healing components, network intermediate oxides and rare-earth silicates into the SiC_f/SiC composite matrix to fill the pores and cracks of the material via generating self-healing components during the oxidative corrosion process, and forming a dense oxide layer on the surface of the material to resist further erosion by the oxidizing medium, thus improving the water and oxygen corrosion resistance of the composites. However, there are still some challenges. Firstly, the research on the oxidation corrosion mechanism of composite materials is still in-depth, and there is a lack of data on oxidation kinetics, oxidative corrosion rate and oxidative corrosion depth, and the basic research on the damage evolution mechanism of materials in different environments is still relatively weak. It is thus necessary to construct a complete and reliable performance database of SiC_f/SiC composites modified with different substrates, clarify the oxidative corrosion damage mechanism, and provide design parameters and theoretical support for the practical application of composites. Secondly, the effective temperature range of a single modified substance to improve the oxidative corrosion performance of composites is limited. The temperature range of B group is below

1000 ℃, and the temperature range of Al group is 1000-1300 ℃. The synergistic effect of multiple modification strategies is explored via introducing multiple modified substances into the matrix of composites at the same time. It is expected to achieve the oxidation and corrosion properties of SiC_f/SiC composites in a wide temperature range and achieve a long-life cycle protection. Finally, it is also worth to develop new preparation processes, such as nano-infiltration and transient eutectic (NITE), or use hybrid processes to achieve material densification and improve the performance of SiCf/SiC composite substrates while modifying them.

In this review, we summary various strategies for surface reconstruction of quantum dots, discuss the selection and design principles of surface and ligands for quantum dots applied in electroluminescence, and finally represent recent research progress in the integration of lead halide and its quantum dots with active-matrix displays. To further promote the realization of efficient full-color active drive LEDs, a key interim goal in the next step is to break through the pixelization technology for lead halide quantum dots, thereby achieving the integration of red, green, and blue colors onto the active-matrix TFT backplane simultaneously. Many scientific and technical issues need to be solved in this process. For instance, how to ensure that the morphology and photoelectric performance of the lead halide quantum dot film are not damaged during pixelization. The need for high resolution means that thousands of pixel points should be arranged very closely, having high requirements for the precise positioning of pixelization technology. In addition, avoiding color crosstalk caused by ion exchange between pixel points is also a technical problem that must be solved due to the easy ion exchange of halogen ions.

The Faraday effect was discovered 180 years ago, but this phenomenon has been still utilized for practical applications as mentioned above. In particular, Tb³⁺-rich and Eu²⁺-rich oxide glasses are important for both fundamentals and applications. The Tb³⁺-rich glasses show a high transparency even in blue to ultraviolet region, so that the magneto-optical figure of merit is large enough to apply for an optical isolator. The Eu²⁺-rich glasses are ferromagnetic, so that they notably show a large Faraday effect. A new technique of glass formation such as containerless processing is effective to produce new glass compositions with further higher concentrations of rare-earth ions that are expected to exhibit a larger Verdet constant. Besides, the possible enhancement of Faraday effect based on plasmonics and Mie-tronics, i.e., the usage of localized surface plasmon resonance of metal nanoparticles and the Mie resonance of dielectric nanoparticles to increase the Verdet constant, becomes an important subject in the near future. With the development of high-power lasers, the demand for optical isolators that can operate in a wide wavelength range must increase. The oxide glasses have a promising application in such fields.

Bismuth-doped fibers (BDFs) have already proven themselves as active materials that can be used to develop optical devices with unique characteristics in previously inaccessible spectral ranges. Optical amplifiers based on these active fibers exhibit high gain and low noise across all telecommunication spectral bands (from O- to U-band), while BDF-based lasers offer the benefits of high efficiency and wide wavelength tunability. However, existing research still faces significant challenges in achieving a reliable technology for reproducing the parameters of BDFs, as well as in fabricating optical fibers with increased Bi concentrations and low unsaturable losses. Developing a high-gain, ultra-wideband amplifier that can be effectively integrated into existing communication systems remains a challenge. Future research should focus on balancing cost, energy efficiency, and device performance, which can be partially addressed by optimizing the BDF design and the device itself. All of this is necessary to meet the growing demand for high-speed data transmission over fiber-optic communication systems, which is crucial in the context of rapidly evolving artificial intelligence technologies. In this regard, the ability to utilize all available telecommunications bands appears very promising. We believe that progress in this area will undoubtedly lead to the development of optical communication systems with significantly increased bandwidth, where bismuth-doped optical amplifiers are key components. Moreover, thanks to ongoing advances in optical materials and process technology, bismuth-doped fiber technology can pave the way for efficient, reliable, and scalable solutions for next-generation fiber-optic systems.

Across diverse application domains, glass materials are engineered to meet increasingly stringent criteria with regard to performance, reliability, and sustainability. It is worth mentioning that the most advanced display modules and semiconductor chips are currently manufactured mostly in East Asia. This geographic imbalance provides unique opportunities and challenges for both of the glass industry and academia. New applications such as ultra-thin glass for flexible display modules and glass core substrate for semiconductor packaging will present unprecedented functionalities and benefits to glass materials.

The issue of electromagnetic pollution has become increasingly severe with the development of the electronic communication technology. The excessive electromagnetic waves pose risks to the national security and the human health in daily life. Consequently, wave-absorbing materials have gradually garnered public attention. Biomass, with its inherent network structure, can be used to produce porous carbon for addressing electromagnetic pollution. Among various biomass sources, coconut shells are widely distributed in China and have long been treated as agricultural by-products or waste. Recycling and utilizing coconut shells to prepare wave-absorbing materials not only helps mitigate electromagnetic pollution but also offers a new approach for the high-value application of agricultural by-products such as coconut shells.

The experimental materials included coconut shells purchased from Hainan Wenchang Coconut Shell Co., Ltd.. Potassium hydroxide (KOH), calcium carbonate (CaCO₃), hydrochloric acid (HCl), and paraffin wax (C₂₅H₅₂) purchased from Shanghai Titan Scientific Co., Ltd. The coconut shells were processed into 1-2 cm pieces, cleaned, and dried at 80 ℃ for 24 h. The dried pieces were then ground into powder using a pulverizer and sieved through a mesh with an aperture of 250-300 μm. The coconut shell powder was mixed with CaCO₃ and KOH at mass ratios of 1.0∶1.0∶0.5, 1∶1∶1, 1∶1∶2, and 1∶1∶3, respectively. The mixtures were uniformly ground in a pulverizer to obtain alkalized coconut shell powder, which was subsequently dried. The dried alkalized powder was placed in a tube furnace, which was purged with nitrogen gas (N₂), and then carbonized at 700 ℃ for 2 h. The resulting product was neutralized with hydrochloric acid (HCl) under magnetic stirring for 12 h, washed with deionized water until neutral, and finally dried at 80 ℃ for 24 h , then the coconut shell-based porous carbon was obtained.

In this study, coconut shell was utilized as the carbon source, based on its inherent multi-level network structure and high carbon content. Using KOH and CaCO₃ as dual activators, a one-step carbonization method was employed to prepare coconut shell-based carbon wave-absorbing materials with superior microwave absorption performance. Compared to pure coconut shell carbon and coconut shell carbon activated solely with an equal mass of KOH, the sample prepared with dual activators exhibited more uniform surface pore distribution and hierarchical structure. This specific structure played a critical role in enhancing the electromagnetic wave absorption performance. Consequently, the dual-activator method offered a novel approach for preparing porous carbon materials with complex three-dimensional micro/mesoporous structures. At 700 ℃, the gradual addition of activator resulted in enlarged pores and increased defects in the porous carbon structure, ultimately causing pore collapse. Higher activator concentrations led to larger pore diameters, which reduced electromagnetic wave reflection efficiency and consequently diminished microwave absorption performance.

A coconut shell-based porous carbon material with excellent wave-absorbing performance was successfully prepared via a one-step carbonization method combined with a dual-activator (KOH and CaCO₃) activation process. By adjusting the mass ratios of KOH to CaCO₃, the pore structure of the resulting carbon material was modulated, leading to varied electromagnetic wave absorption properties. The optimal absorption performance was achieved under the conditions of a carbonization temperature of 700 ℃ and a mass ratio of coconut shell powder : CaCO₃∶KOH = 1∶1∶1. The material obtained under these conditions exhibited a minimum reflection loss (RL_min) of -45.79 dB at a sample thickness of 5.0 mm and a frequency of 5.12 GHz. This study utilized a simple one-step carbonization process to produce effective wave-absorbing materials with abundant coconut shell waste, providing valuable theoretical guidance for the development of high-performance absorbers and significantly broadening the application prospects for biomass-derived wave-absorbing materials.

With the continuous pursuit of higher efficiency and larger thrust-to-weight ratio in aero-gas-turbine engines, the turbine inlet temperature has already exceeded 1300 ℃, imposing increasingly stringent requirements on the thermal resistance and protective capability of hot-section structural materials. Environmental barrier coatings (EBCs) have become a crucial technology to ensure efficient and reliable service of ceramic matrix composite (CMC) turbine components under such extreme working conditions. However, the service environment of EBCs is exceptionally complex. Coatings are continuously exposed to corrosive gaseous species within combustion products, among which the ingression and reaction of molten calcium-magnesium-aluminum-silicate (CMAS) deposits represent one of the most detrimental degradation mechanisms.

To mitigate CMAS-induced deterioration, numerous strategies have been proposed, including compositional modification (doping, high-entropy ceramics), structural design optimization (multilayer or graded coatings), and surface engineering (laser or ion beam treatments). Although these approaches can improve corrosion resistance to some extent, most of them inevitably alter the coating chemistry or structural system, which tends to induce thermal expansion mismatch with the substrate and promotes premature failure during thermal cycling. Therefore, how to enhance CMAS-corrosion resistance while maintaining thermomechanical compatibility remains a critical challenge. Laser glazing (LG) is a surface-modification technique that locally melts and rapidly solidifies the coating surface to form a dense glaze layer. It improves surface compactness and seals microdefects without altering the coating composition, thereby presenting a promising method for improving CMAS-corrosion resistance. In this work, laser glazing is introduced to enhance the CMAS-resistance of EBCs, and the CMAS-corrosion behavior together with the underlying improvement mechanisms are systematically investigated.

SiC ceramic substrates were purchased from Fuzhou Pengkun Optoelectronics Co., Ltd. The samples were cylindrical (diameter 25.4 mm, thickness 3 mm) and mechanically grit-blasted prior to coating deposition. Yb₂Si₂O₇/Si (YbDS) EBCs were deposited on the substrates by atmospheric plasma spraying (APS). Commercial Yb₂Si₂O₇ and Si powders (Shanghai Shuitian Materials Technology Co., Ltd.) were used, and the bond coat consisted of 90% (in mass fraction) Si and 10% Yb₂Si₂O₇. A picosecond ultraviolet pulsed-laser system was subsequently applied to modify the surface microstructure of APS YbDS coatings. Four sets of parameters (L1-L4) were obtained by adjusting the laser power (6 W or 20 W) and scanning speed (100-300 mm/s). CMAS bulk material was synthesized by high-temperature melting. CMAS powder was mixed with ethanol and uniformly brushed onto the coating surface, followed by drying to achieve a coating mass of 5 mg/cm². The coated samples were exposed at 1350 ℃ for 10, 60 h, and 120 h. After corrosion, the evolution of microstructure and phase composition was analyzed to reveal the degradation behavior.

The APS-prepared YbDS coating exhibited a surface roughness of ~3.7 μm and a porosity of ~4.87%, with typical APS defects such as pores, unmelted particles, and microcracks. After laser glazing, four modified surfaces were obtained. Among them, sample L2 demonstrated the most favorable structural morphology and was selected for subsequent corrosion tests. The L2 coating showed a reduced surface roughness of ~1.824 μm and a homogeneous, dense glaze layer of ~9.6 μm thickness. Moreover, the glazed surface phase completely transformed from Yb₂Si₂O₇ to Yb₂SiO₅. During CMAS corrosion, the YbDS coating surface was continuously covered by a loose mixture of Ca₂Yb₈(SiO₄)₆O₂ and CMAS residual glass. In contrast, the laser-modified L2 coating was covered by a compact Ca₂Yb₈(SiO₄)₆O₂ reaction layer. After corrosion, both coatings displayed Ca₂Yb₈(SiO₄)₆O₂ and secondary Yb₂Si₂O₇ phases; however, their structural evolution differed significantly. After 120 h of corrosion, the YbDS coating suffered severe structural degradation, including interfacial delamination and partial spallation in cross-sectional observations. Conversely, the L2 coating maintained structural integrity, and its corrosion depth was consistently lower under the same conditions.

The improved CMAS resistance of the L2 coating can be attributed to three synergistic mechanisms: Surface densification, Laser glazing produced a dense, continuous glaze layer that sealed APS-induced pores and cracks, effectively delaying CMAS infiltration pathways; Protective reaction-layer formation, The Yb₂SiO₅ glaze reacted with CMAS to form a dense Ca₂Yb₈(SiO₄)₆O₂ layer, which further hindered molten-salt penetration ;Enhanced non-wettability, Laser glazing significantly reduced surface roughness and improved hydrophobicity. As a result, molten CMAS appeared as aggregated hemispherical droplets rather than fully spreading, making it more easily removed by high-velocity gas flow during service.

The findings of this study demonstrate that laser glazing effectively enhances the CMAS-corrosion resistance of YbDS coatings. The improvement originates from the combined effects of surface densification, pore/crack sealing, phase transformation to Yb₂SiO₅, and subsequent formation of a compact Ca₂Yb₈(SiO₄)₆O₂ reaction layer during corrosion. Additionally, the smoother and less wettable glazed surface reduces the adhesion and spreading tendency of CMAS, enabling molten deposits to be removed more easily under aerodynamic forces. As a result, the degradation rate of the coating is substantially suppressed, delaying the propagation of corrosion-induced cracks and maintaining structural integrity over prolonged exposure. Moreover, the laser-induced modifications do not alter the coating architecture or introduce thermal expansion mismatch, making the technique compatible with existing EBC design frameworks. Overall, laser glazing represents a promising strategy for improving the durability and service lifetime of EBC systems in next-generation high-temperature aero-engine applications.

Cement production accounts for approximately 12% of China's total CO₂ emissions, having a significant challenge to achieving the national "dual carbon goals". Carbon capture, utilization, and storage (CCUS) represent a pivotal innovative technology for mitigating these emissions. However, conventional amine-based CO₂ capture requires an energy-intensive high-temperature desorption, hindering its industrial implementation in cement plants. Also, the limited utilization pathways for captured CO₂ pose another challenge for cement CCUS. Diethanolamine (DEA) offers a promising solution as it functions both as a CO₂ absorber and a cement additive. This dual capability enables a potential carbonation utilization of CO₂ absorbed DEA solutions without requiring the desorption step within cementitious systems. This study was thus to investigate the effect of CO₂-absorbed diethanolamine (DEAC) on the early hydration behavior and strength development of cementitious systems. The findings could propose a novel approach for low-energy CO₂ capture coupled with efficient in-situ utilization within cement industry.

Cement mortars with a water-to-cement ratio (W/C) of 0.50 were prepared with P·I 42.5 Portland cement (GB 8076) and ISO standard sand. The specimens were designated as REF, D0.1%C0%, D0.1%C0.02%, D1.0%C0%, and D1.0%C0.22%, respectively. DEA and its equivalent CO₂ admixture were added as percentages of cement mass. All associated cement paste mixtures were prepared at a W/C ratio of 0.3. DEAC was prepared by continuously bubbling CO₂ gas (≥99% purity) at a flow rate of 200 mL/min through a 5 mol/L DEA solution maintained at 40 ℃ until saturation was achieved. An eight-channel microcalorimeter recorded the hydration heat of cement paste specimens at 25 ℃ for 72 h. The phase composition of hardened cement pastes was determined by X-ray diffraction (XRD). The contents of bound water, CH, and CaCO₃ were analyzed by thermogravimetric analysis (TGA). The cumulative porosity and pore size distribution of hardened paste samples at 7 d were characterized by mercury intrusion porosimetry (MIP). The compressive strength was measured on mortar specimens at 1, 3 d and 7 d of curing in accordance with the standard GB/T 17671.

The hydration calorimetry results demonstrate that D0.1%C0.02% and D0.1%C0% both accelerate the hydration rate of silicate phases, as evidenced by an increased second exothermic peak rate, while leaving the induction period duration unaffected. Conversely, D1.0%C0% and D1.0%C0.22% significantly reduce the second exothermic peak rate. D1.0%C0.22% extends the hydration induction period to 240 min, while D1.0%C0% has a negligible effect on its duration. The XRD patterns and TG analyses reveal that the impact of DEAC on the cement hydration depends critically on its specific DEA and CO₂ dosage. At a low dosage (i.e., D0.1%C0.02%), a mild carbonation promotes a concurrent hydration of silicate and aluminate phases. However, a high dosage (i.e., D1.0%C0.22%) substantially inhibits early hydration of silicates. The MIP results indicate that DEAC and DEA both refine the pore structure of hardened cement paste. The pores below 20 nm are significantly reduced in D0.1%C0% and D0.1%C0.02% systems, aligning with their enhanced early hydration kinetics. This refinement also occurres in D1.0%C0% and D1.0%C0.22% systems despite inhibited silicate hydration. The results of compressive strength tests show that D0.1%C0.02% and D0.1%C0% can enhance mortar strengths at 1, 3 d, and 7 d, respectley. The strengths of D0.1%C0.02% systems can be increased by 8.4%, 10.2%, and 16.8% at these ages, respectively, primarily due to the DEA component with the weak carbonation contributing minimal additional enhancement. The 3-day and 7-day strengths of D1.0%C0.22% and D1.0%C0% systems both are increased (more significantly in the carbonated system), indicating a synergistic hydration-carbonation effect. However, the 1-day strength of D1.0%C0.22% system drastically is reduced by 52.2%, with silicates hydration inhibition by D1.0%C0% identified as a primary factor underpinning early strength reduction. According to the analysis of bound water content, calcium hydroxide (CH) content, porosity, and compressive strength relationships, a linear correlation between CH content and mortar strength is proposed. This demonstrates that silicate phase hydration kinetics can be modulated differently by DEAC and DEA formulations-fundamentally governed compressive strength development.

The addition of 0.1%DEA with 0.02% CO₂ (D0.1%C0.02%) as DEAC enhanced the flexural and compressive strengths of cement mortar at 1, 3 d, and 7 d. In contrast, the addition of 1.0% DEA with 0.22% CO₂ (D1.0%C0.22%) significantly reduced the 1-day strength. In D0.1%C0.02% system, the CO₂ component reacted with dissolved Ca²⁺ released from cement minerals to precipitate CaCO₃. This reaction promoted cement hydration, refined the pore structure of the hardened paste by reducing the volume of harmful pores, and facilitated a synergistic enhancement of hydration and carbonation. D1.0%C0.22% addition significantly retarded cement hydration within the first 24 h, primarily by inhibiting the dissolution of silicate phases and extending the induction period, leading to the reduced early strength. Although carbonation exacerbated the retardation of silicate phase hydration via DEA interaction, the hydration process recovered normal kinetics after 7 d.

Phosphorus (P) is an essential nutrient for aquatic ecosystems. However, excessive phosphorus discharge into surface water is one of the primary causes of eutrophication, thus triggering algal blooms, degrading water quality, and threatening aquatic life as well as human health. It is widely recognized that even low concentrations of phosphorus can significantly accelerate eutrophication processes, making efficient phosphorus removal a critical issue in water pollution control. Among the existing treatment technologies, adsorption has attracted increasing attention due to its operational simplicity, high efficiency for low-concentration phosphorus, and limited risk of secondary pollution.

Coal fly ash is one of the most abundant industrial solid wastes that are generated in large quantities in coal-fired power plants. Although its comprehensive utilization rate is increased, a considerable fraction of fly ash is still disposed of by landfilling or stockpiling, posing long-term environmental risks. Fly ash is a promising precursor for the preparation of ceramic materials due to its high contents of SiO₂ and Al₂O₃. Moreover, the presence of Ca, Mg, and other alkaline components endows fly-ash-derived materials with a potential chemical affinity toward phosphate species. Transforming fly ash into functional ceramsite for water treatment therefore represents a typical "waste-to-resource" strategy.

Previous studies explored fly-ash-based ceramsite or related materials for phosphorus removal. However, most of them focused primarily on adsorption performance evaluation, while systematic optimization of preparation parameters and in-depth clarification of phosphorus removal mechanisms remained insufficient. Such limitations hinder the rational design and engineering application of these materials. In this work, fly ash was used as a main raw material, supplemented with municipal sludge, furnace slag, and cement to prepare porous ceramsite for phosphorus removal. The adsorption behavior, comprehensive physicochemical characterization, preparation conditions, and removal mechanism were systematically investigated.

Fly-ash-based ceramsite was prepared by a disc granulation method. Fly ash was mixed with municipal sludge as a pore-forming component, furnace slag as a functional additive, and cement as a binder. After granulation with deionized water, green pellets with a controlled particle size were obtained and subjected to preheating and high-temperature sintering. To optimize the preparation process, a Taguchi L25 (5⁶) orthogonal experimental design was employed, considering six factors, i.e., fly ash-to-sludge ratio, preheating temperature, preheating time, sintering temperature, sintering time, and heating rate. Phosphate removal efficiency was selected as an evaluation index to determine the optimal preparation parameters.

Batch adsorption experiments were conducted using simulated phosphate solutions prepared from potassium dihydrogen phosphate. The effects of dosage, initial pH value, coexisting ions, and humic acid were systematically investigated to evaluate adsorption adaptability under different water chemistry conditions. Adsorption isotherms were analyzed using the Langmuir, the Freundlich, the Sips, and the Dubinin-Radushkevich models, while adsorption kinetics were interpreted using pseudo-first-order, pseudo-second-order models, i.e., Elovich, and intraparticle diffusion models.

The physicochemical properties and adsorption mechanisms of the ceramsite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, the leaching risk of heavy metals was also assessed using standard toxicity characteristic leaching procedures to evaluate environmental safety.

The results of orthogonal experimental analysis reveal that sintering temperature is the most dominant factor affecting phosphate removal performance, following by sintering time and heating rate. The excessively high sintering temperature leads to pore collapse and crystallization of stable mineral phases, thereby reducing adsorption capacity. The optimal preparation conditions obtained are a fly ash-to-municipal sludge ratio of 7∶3, preheating at 600 ℃ for 5 min, sintering at 1050 ℃ for 5 min, and a heating rate of 5 ℃/min. Under the optimal conditions, the ceramsite achieves a phosphate removal efficiency of 90.77%, which is significantly higher than that of all orthogonal experimental groups.

The SEM images show that the optimized ceramsite has a rough surface with abundant interconnected pores, originating from the thermal decomposition of organic matter in municipal sludge and gas evolution during high-temperature reactions. The XRD patterns indicate that mullite and anorthite are the dominant crystalline phases, while Ca- and Mg-containing components are retained in reactive forms. The results of batch experiments demonstrate that phosphate removal efficiency increases with increasing dosage but decreases under strong alkaline conditions. The ceramsite maintains effective phosphorus removal in a wide range of pH values, with optimal performance under weakly acidic to neutral conditions.

The coexisting anions exhibit varying degrees of inhibition on phosphate removal, following a decreasing order CO₃^2- >HCO₃^- > SO₄^2- > NO₃^- > Cl^-, whereas common monovalent cations show a negligible influence. In contrast, the presence of Ca²⁺ and Mg²⁺ significantly enhances phosphate removal due to additional precipitation reactions. Humic acid notably suppresses adsorption via competing for active sites and altering phosphate speciation.

Adsorption isotherm analysis shows that the Langmuir and Sips models both fit the experimental data, while the Sips model provides a better physical interpretation, indicating a heterogeneous surface adsorption. The kinetic analysis reveals that the pseudo-first-order model can describe the adsorption process, indicating that surface reactions are dominant the rate-controlling step. The XPS spectra confirm the formation of Ca- and Mg-phosphate species on the ceramsite surface after adsorption, showing that phosphate removal occurs based on a synergistic mechanism involving physical adsorption and chemical precipitation.

The results of leaching tests indicate that the concentrations of heavy metals released from the ceramsite are well below regulatory limits, having its environmental safety for water treatment applications.

A fly-ash-based ceramsite was prepared using municipal sludge and furnace slag as auxiliary components for efficient phosphate removal in water. The ceramsite exhibited a high removal efficiency, a broad pH value adaptability, and a stable performance under complex water chemistry conditions via systematic optimization of preparation parameters and comprehensive adsorption studies. The phosphate removal mechanism was dominated due to the synergistic effect of surface adsorption and Ca/Mg-induced chemical precipitation. Moreover, the ceramsite showed a negligible heavy-metal leaching risk, indicating a good environmental compatibility. This study could provide a feasible approach for the large-scale resource utilization of fly ash and offer a promising adsorbent for phosphorus control in aquatic environments.

The hydration of binder is an exothermic reaction, which results in an obvious temperature increase in concrete in the early hydration period. The shrinkage of hardened concrete due to the temperature drop is a main cracking trigger of concrete. A kind of temperature rising inhibitor is developed to decrease the hydration heat of binder in early hydration age, which can reduce the cracking risk of concrete. Cyclodextrin is a main functional composition of the temperature rising inhibitor. C₃A is an important clinker mineral influencing the early exothermal characteristics of Portland cement. In this paper, the effect of cyclodextrin on the hydration of tricalcium aluminate-gypsum (C₃A-CaSO₄·2H₂O) was investigated. This work could favor understanding the action mechanism of the temperature rising inhibitor to reduce the cracking risk of concrete structures.

Pure C₃A was calcined, the chemical pure gypsum and cyclodextrin was used. The hydration exothermal curves of C₃A-CaSO₄·2H₂O pastes containing different dosages of cyclodextrin were measured. The hydration products of C₃A-CaSO₄·2H₂O pastes containing different dosages of cyclodextrin in different ages were in-situ determined by quantitative X-ray diffraction (QXRD). The morphology of hydration products on the surface of C₃A particles immersed in different solutions was characterized by scanning electron microscopy (SEM). The etching situation on the surface of C₃A particles washed by different solutions was determined by three-dimensional white light interferometric surface profilometry.

The beginning time of second hydration of C₃A moves up and its exothermic rate decreases, but its reacting time prolongs with the increase of cyclodextrin dosage. The heat output of C₃A during its second hydration stage varies little. The consumption of C₃A and CaSO₄·2H₂O increases continuously and the exhausting time of gypsum reduces with the increase of cyclodextrin dosage. The forming quantity of ettringate in the paste containing cyclodextrin is greater than that in controlling paste. The transformation of ettringate to AFm is suppressed after the exhaust of gypsum. Cyclodextrin can expedite the dissolution of C₃A in CaSO₄ solution to form more deeper etch pits on the surface of C₃A particles, which speeds up the hydration of C₃A. Needle-like ettringite changes to stick-like one, and the transformation of ettringite to AFm restrains when cyclodextrin exists in pastes.

Cyclodextrin could promote the initial hydration of C₃A to move up the beginning of the second hydration of C₃A. The consumption of C₃A and CaSO₄·2H₂O increased continuously in the first hydration stage and the exhausting time of gypsum reduced with the increase of cyclodextrin dosage. Cyclodextrin reduced the reaction speed and prolonged reacting time of C₃A during its second hydration stage, its heat output changed little. Cyclodextrin could enhance the dissolution of C₃A in gypsum solution to form more deep etch pits on the surface of C₃A particles, speeding up the hydration of C₃A. Cyclodextrin could change needle-like ettringate to stick-like one and suppress the transformation of ettringate to AFm.

A cathode with mixed hole, oxygen vacancy, and proton conductivity extends the reactive zone for the oxygen reduction to water beyond the triple phase boundary, making the whole cathode surface an active electrocatalyst. The defect chemistry (i.e., concentrations and mobilities of point defects) of such materials with three charge carriers is complex, and some of the desired properties for a PCFC cathode material are in mutual conflict (i.e., proton uptake, electronic conductivity, catalytic activity, and long-term chemical stability). And the promising protonic cathode material needs a high catalytic activity for the oxygen reduction reaction to water to improve its performance. Nevertheless, the reactions both require the dissociation of the strong oxygen-oxygen bond.

The mechanism for this reaction is not exactly identical to that in oxide-ion-conducting cells (where the resulting oxide ions are incorporated into the cathode material, while on PCFC cathode, they are desorbed in the form of steam). The dependence of proton uptake on cation composition in cathode perovskites in order to extract the parameters that are most important for a high proton concentration. Regarding the optimization of PCFC cathode materials, refraining from striving for very high electronic conductivities is anticorrelated with proton uptake. It is prospected that the role plays due to oversized dopants in barium ferrate for enhancing the hydration properties. The beneficial effect on protonation is attributed to a higher degree of disorder in the local structure of doped samples, which translates in B-O-B bonds buckling. The B-O-B buckling reduces the Fe-O bond covalency (i.e., less Fe 3d-O 2p orbital overlap), thus decreasing the hole transfer from iron to oxygen. This leaves more negative charge density on the oxide ions, which increases their basicity and propensity for protonation.

In addition, although the existing thermogravimetric and electrical conductivity relaxation methods still have certain limitations in measuring proton concentration in mixed ionic conductors. The in-situ characterization techniques (such as in-situ transmission electron microscopy, in-situ spectroscopy, neutron diffraction, etc.) can be used to analyze the process of proton absorption and transport in mixed ionic conductors. Also, combining multi-scale simulations with experiments can further analyze numerical values such as the binding energy of proton absorption and the activation energy of diffusion. For instance, in-situ transmission electron microscopy is used to directly observe water entering Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ via introducing a small amount of water vapor into the TEM chamber. Electron energy loss spectroscopy is also used to determine the formation of oxygen bubbles on the material surface, while the protons ultimately remain within the material. This result provides the most direct evidence for studying the reactions of water and protons in mixed ionic conductors.

Although composite titanium salt coagulants demonstrate excellent performance, there are still some issues and challenges that need to be addressed. Future research can focus on the following aspects: (a) Enhancing Adaptability to Real Water Bodies. Currently, the complex composition of various actual water bodies imposes higher demands on the application of composite titanium salt coagulants. To ensure stable and efficient coagulation performance under complex water quality conditions, future efforts should focus on developing novel composite titanium salt coagulants with stronger specificity and broader applicability, thereby meeting the needs of more complex and demanding application scenarios. (b) Lower- Cost Preparation of Composite Titanium Salt Coagulants. At present, the preparation of composite titanium salt coagulants largely relies on complex processes such as SAT, ED, and sol-gel methods, which hinders their large-scale application. Future research should aim to develop simpler, greener, and more economically viable preparation pathways—for instance, utilizing industrial by-products or waste materials as raw materials—while optimizing the preparation process to reduce energy consumption and production costs. (c) Ensuring Ecological and Health Safety. Current research on the toxicity assessment of titanium-based coagulants has predominantly focused on TiCl₄ and Ti(SO₄)₂. Future studies should strengthen investigations into titanium residue and its ecotoxicological effects during the use of composite titanium salt coagulants. Meanwhile, it is essential to employ a wider range of aquatic organisms (e.g., fish, shellfish, and aquatic plants) for ecotoxicity studies, and to further explore the migration, transformation, and long-term accumulation of residual titanium in water bodies and organisms. This will provide a scientific basis for comprehensively safeguarding water environments and human health.

In transition towards a decarbonized energy system globally, hydrogen plays a crucial role as a zero carbon energy carrier. In this context, solid oxide electrolysis cell (SOEC) technology with its advantages in high-temperature operation significantly reduces material costs and improves overall system energy efficiency, compared to low-temperature solutions such as alkaline and proton exchange membrane electrolysis. SOEC system adopts a non-precious metal ceramic structure. When operating at 650-1000 ℃, electrochemical kinetics acceleration mechanism achieves a conversion efficiency of > 80%, providing a feasible approach to reduce cost of green hydrogen leveling. The existing domestic demonstration projects are limited to a scale of tens to hundreds of kilowatts, and the commercial implementation needs to break through bottleneck of "three highs and one low", thus increasing power density of fuel cell stack, extending its service life, and optimizing system integration, while reducing assets and operation and maintenance costs. Solving these obstacles requires collaborative efforts in three major fields, and innovation in materials and structures must break through conventional design framework of electrodes, electrolytes, and sealing glass. With precise microstructure design and interface stress control, system can maintain a high current density of 2 A·cm^-2, while controlling degradation rate at 1 mV per thousand hours, significantly extending lifespan of battery pack. Multi-energy coupling optimization is crucial, which requires integrating the SOEC with industrial waste heat and renewable resources, thus utilizing low-grade thermal energy (i.e., 200-300 ℃), efficiently offsetting internal heating demand, reducing external electricity consumption by approximately 30%, and comprehensively improving energy utilization efficiency. For those localized supply chains, establishing a complete domestic production capacity from precursor powder to single cell manufacturing, stacking and assembly to system integration is particularly crucial. The goal is to control stacking cost at RMB 2500 per kW and achieve an operating life of 5×10⁴ h, laying a foundation for large-scale applications. At present, although the SOEC has significant energy efficiency advantages, its promotion and application still face multiple constraints, i.e., gradual decay of oxygen electrodes under high temperature and high vapor partial pressure, mechanical and electrochemical damage caused by power fluctuations, and daunting initial capital investment. Subsequent exploration should focus on preparing new electrode materials with a higher stability, establishing flexible thermoelectric synergistic regulation mechanisms to adapt to fluctuating renewable energy, and promoting standardization and cost reduction and efficiency improvement throughout entire industry chain. The cost of photovoltaic and wind power continues to decrease, coupled with increasing demand for green hydrogen in chemical and metallurgical fields. Solid oxide electrolysis cell technology is expected to be widely applied in "electricity hydrogen ammonia/methanol" integrated system, distributed energy system, and sustainable refining scenarios. This technology will undoubtedly become a key pillar technology supporting the dual carbon goals in China.

In summary, SOCs thin film preparation technologies can form a diversified system, but some common challenges remain. Although vapor-phase technologies have excellent performance, they generally face high equipment costs and great difficulty in scaling up. Liquid-phase technologies are prone to film cracks or pores due to drying and sintering stress. Future research should focus on three core directions, i.e., 1) promoting intermediate and low-temperature operation, further expanding the low-temperature application range of batteries through interface regulation and film formation process optimization; 2) pursuing high performance, developing three-dimensional structured films to expand reaction interfaces and improve mass transfer and catalytic efficiency; and 3) accelerating commercialization, optimizing low-cost preparation processes combined with intelligent manufacturing technologies, and breaking through the key technical bottlenecks of new film formation technologies. Thin film preparation technology will continue to be a core breakthrough to solve the high-temperature dependence and performance attenuation of SOCs, promoting their transition from laboratory research to commercial application.