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In this work, stacked SiC fibers paper‐reinforced SiC ceramic matrix composites (SiCnf/SiC CMCs) were prepared by nanoimpregnation and transient eutectic (NITE) process using ultra‐long single‐crystal SiC nanofibers. The effect of the SiCnf surface modification via boron nitride (BN) interphase deposition as well as the sintering additive (Al2O3–Y2O3) content on the density, microstructure, and mechanical properties of SiCnf/SiC CMCs has been investigated systematically. The results revealed that the laminated SiCnf/SiC CMCs feature a significant saw‐tooth‐like curve on the load–displacement test, which indicates that the obtained laminated structure with the weak interlayer binding owning to the BN coating treatment possesses significant toughening to the SiC ceramics. Specifically, the SiCnf/SiC CMCs with the sintering additive content of 12 wt% revealed a fracture toughness of over 10 MPa m1/2 after 60 min of BN interface deposition, which is 104.31% higher than that of the composites prepared without BN coating. [ABSTRACT FROM AUTHOR]

In this paper, two new ternary layered MAX phase ceramics, Sc2GaC and Sc2InC, were successfully synthesized by spark plasma sintering. The crystal structures of two new compounds were determined by X‐ray diffraction. The lattice parameters were a = 3.3609(0) Å and c = 14.5849(9) Å for Sc2GaC, and a = 3.3453(6) Å and c = 15.2236(3) Å for Sc2InC, wherein the Sc atoms were located at (1/3, 2/3, 0.07330[Ga]/0.08268[In]), the A atoms were located at (1/3, 2/3, 3/4), and the C atoms were located at (0, 0, 0). Scanning electron microscopy images of two new MAX phase ceramics were also given in this paper, showing obvious layered characteristics. [ABSTRACT FROM AUTHOR]

High‐temperature piezoelectric sensing is usually used in the aerospace, automotive, and power plant fields. High temperature piezoelectric ceramics are considered the key materials in these fields. In this paper, Ca1−x(Ba1/2Sr1/2)xBi2Nb1.985(W3/4Mn1/4)0.015O9 (x = 0.05, 0.10, 0.15 and 0.20) (C1−xBSxBNWM) has been synthesized by a traditional solid state reaction method. The effects of substitution of calcium at the A‐site by barium and strontium on phase evolution and piezoelectric properties of the CaBi2Nb2O9 orthorhombic Aurivillius phases were investigated. The crystal structure of piezoelectric ceramics was characterized by XRD, Rietveld refinement, and Raman spectroscopy. Co‐substitution of barium/strontium (Ba2+/Sr2+) and tungsten/manganese (W6+/Mn4+) resulted in lattice distortion of C1−xBSxBNWM ceramics. The results induce that the tetragonal crystal structure increase with increasing the co‐substitution cations. Isothermal impedance spectroscopy confirmed intrinsic thermally activated conduction in the system. The C1−xBSxBNWM ceramics with x = 0.15 exhibit a very high Curie temperature (TC ∼ 923°C), a reasonable piezoelectric coefficient (d33 = 13.3 pC/N). Remarkably, even after thermal annealing at temperatures up to 800°C, it still retains a high d33 of 13 pC/N. In addition, the C0.85BS0.15BNWM ceramic had a relatively high resistivity (3.82 × 106 Ω·cm, 500°C). The Ca0.85(Ba1/2Sr1/2)0.15Bi2Nb1.985(W3/4Mn1/4)0.015O9 ceramics make possible their application in high‐temperature acceleration transducers. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the effect of processing parameters and composite regulation on the structure and property relationship of lightweight low‐permittivity Li2O–Al2O3–B2O3 dielectric system. Li2BAlO4 ceramic and (1 − x)Li2BAlO4–xSrTiO3 ceramics were synthesized using a conventional solid‐state reaction method. Thermodynamic analysis, sintering temperature, phase formation, crystal structure, and microwave dielectric properties were investigated. Thermal analysis revealed a melting temperature of 847°C, suggesting a comparatively low temperature for the sintering of Li2BAlO4 ceramics. Li2BAlO4 crystalized into a monoclinic structure with P21/c space group, with [Al2B2O8] rings connected by [BO3] triangles and [AlO4] tetrahedra through Al–O–Al bridges. Dense Li2BAlO4 ceramics with a relative density of ∼97.7% were sintered at 750°C and had optimal microwave dielectric properties with relative permittivity (εr) of 5.13, quality factor (Q × f) of 22 610 GHz, and the temperature coefficient of resonance frequency (τf) of −112.5 ppm/°C. The 0.88Li2BAlO4–0.12SrTiO3 composite ceramic has excellent microwave dielectric properties with εr = 8.83, Q × f = 14 000 GHz, τf = 4.6 ppm/°C. The ceramics also demonstrated an inert behavior with silver electrodes proving its application in low‐temperature cofired ceramic (LTCC) technology. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the effect of processing parameters and composite regulation on the structure and property relationship of lightweight low‐permittivity Li2O–Al2O3–B2O3 dielectric system. Li2BAlO4 ceramic and (1 − x)Li2BAlO4–xSrTiO3 ceramics were synthesized using a conventional solid‐state reaction method. Thermodynamic analysis, sintering temperature, phase formation, crystal structure, and microwave dielectric properties were investigated. Thermal analysis revealed a melting temperature of 847°C, suggesting a comparatively low temperature for the sintering of Li2BAlO4 ceramics. Li2BAlO4 crystalized into a monoclinic structure with P21/c space group, with [Al2B2O8] rings connected by [BO3] triangles and [AlO4] tetrahedra through Al–O–Al bridges. Dense Li2BAlO4 ceramics with a relative density of ∼97.7% were sintered at 750°C and had optimal microwave dielectric properties with relative permittivity (εr) of 5.13, quality factor (Q × f) of 22 610 GHz, and the temperature coefficient of resonance frequency (τf) of −112.5 ppm/°C. The 0.88Li2BAlO4–0.12SrTiO3 composite ceramic has excellent microwave dielectric properties with εr = 8.83, Q × f = 14 000 GHz, τf = 4.6 ppm/°C. The ceramics also demonstrated an inert behavior with silver electrodes proving its application in low‐temperature cofired ceramic (LTCC) technology. [ABSTRACT FROM AUTHOR]

In this paper, macroporous high‐entropy spinel oxide (HESO) (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 monoliths were successfully fabricated via a sol–gel method followed by calcination. Appropriate polyacrylic acid and propylene oxide contents allow the formation of three‐dimensional co‐continuous xerogel monoliths, and the water/glycerol ratio controls the macropore size of monoliths. Subsequent calcination achieves the precipitation of HESO (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 with a singular phase and exceptional structural stability. The macroporous HESO (Fe0.2Ni0.2Co0.2Mn0.2Zn0.2)3O4 demonstrates remarkable performance in the oxygen evolution reaction (OER) with an overpotential of 333 mV at 100 mA cm−2 and a Tafel slope of 43.2 mV dec–1, surpassing that of RuO2 (391 mV) under identical conditions. Furthermore, the catalytic stability of the HESO catalyst remains superior even after 24 h of testing. This process offers a promising avenue for the development of macroporous high‐entropy oxide OER catalysts for overall water splitting. [ABSTRACT FROM AUTHOR]

ABSTRACT Low‐εr (the low dielectric constant) microwave dielectric ceramics play an important role in sub‐6 GHz band communication by virtue of their small signal delay. In this paper, Ba2CoSi2O7 ceramics were synthesized by the solid‐phase reaction method, and X‐ray diffraction (XRD) confirms that they belong to a new melilite structure, with C2/c (No.15) space group, and the ceramics have good microwave dielectric properties with an εr ∼ 7.37, a Q×f (Q = 1/dielectric loss, f = resonant frequency) ∼ 26,320 GHz and a TCF (the temperature coefficient of resonant frequency) ∼ −55 ppm/°C after being sintered at 1150°C, and the theoretical dielectric constants derived from the Clausius–Mosotti as well as the porosity equation, respectively, are also used to further demonstrate the low‐εr properties. Based on the group theory, the one‐dimensional integrable representations of Γacoustic (the phonon modes) and Γoptical (optical modes) of Ba2CoSi2O7 are obtained, and the internal vibrational modes of Ba2CoSi2O7 are deconstructed and the main modes of influence of the electronic polarization are analyzed in conjunction with the results of the validly fitted peaks of the 17 Raman and 25 IR tests. A microstrip Yagi antenna is also designed based on the ceramic properties, which can achieve a gain of 9.65 dBi at the center tuning frequency of 5.47 GHz, with a S11 (return loss) close to −60 dBi. Based on the above results, the Ba2CoSi2O7 ceramic is a low‐εr microwave dielectric ceramic with significant potential for communication application. [ABSTRACT FROM AUTHOR]

Defect chemistry that results in the thermal processing of dielectric and piezoelectric films, crystals and ceramics ultimately controls the properties and long‐term performance of materials and devices. This paper reviews several thermochemical defect reactions using important perovskite base composition dielectrics including Pb(Zr,Ti)O3, (Na,K)NbO3, (Bi0.5Na0.5)TiO3‒BaTiO3, and Ca(Hf,Ti,Mn)O3. Within this group of perovskite‐based functional materials, we note ways the point defects can be formed to create non‐stoichiometric compositions changing the overall cation‐to‐anion ratios during the synthesis process. These reactions can be developed with the loss of volatile species such as metal and oxygen ions. The relative concentrations of these can impact the over conductions in terms of the mixed contributions of ionic conductivity from the oxygen vacancies and the electronic conductivity, along with microstructure and properties in some cases. [ABSTRACT FROM AUTHOR]

In this paper, a new micromechanical hysteresis loop constitutive model of C/SiC composites with different interphases was developed considering the probabilistic‐statistical matrix fragmentation process. The lengths of matrix fragmentation were divided into three types, that is, long matrix fragments (LMFs), medium matrix fragments (MMFs), and short matrix fragments (SMFs). The distributions of the LMFs, MMFs, and SMFs with increasing tensile stress were determined using the probabilistic‐stochastic model by assuming the two‐parameter matrix strength distribution. The micro stress field of the LMFs, MMFs, and SMFs upon unloading and reloading was obtained and adopted to determine the corresponding stress‐strain relations. The interaction of matrix fragmentation lengths, especially for the LMFs with large debonding energy (LDE) and SMFs, was considered in the closed‐form constitutive model and hysteresis‐based inverse tangent modulus (ITMs) damage parameter. Synergistic effects of the fiber volumes, peak stresses, and interface debonding energy on the interface damage state, mechanical hysteresis loops, and related ITMs with small debonding energy and LDE were also analyzed. Comparisons of the mechanical hysteresis loops using the new hysteresis models considering matrix stochastic fragmentation and hysteresis models considering constant matrix fragmentation were also discussed. Experimental cyclic tensile hysteresis loops and unloading/reloading ITMs of C/(PyC)/SiC and C/(PyC+SiC)/SiC composites with different interphase thickness (i.e., t = 300, 600, 1000, and 2000 nm) were predicted using the developed constitutive model. Evolution of the unloading/reloading interface slip ratio was analyzed for different tensile peak stresses. [ABSTRACT FROM AUTHOR]

In situ metallization of Ag+ conductive glass was successfully achieved by applying electric and temperature fields to the glass to ensure the controlled migration of ions inside the glass. The transport and kinetic characteristics of Ag+ under the combined effect of electric field and temperature field were investigated by calculating and analyzing Ag+ diffusion coefficient. The correlations between ion transport and current were characterized with potential energy equations. The simulations and experiments of ion transport in the conducting glass were implemented, which revealed the mechanisms of ion transport and interfacial precipitation within the conducting glass. Further more, the existence of Ag+ deprivation layer was confirmed and it was clarified that the depth of the deprivation layer reached 30 µm under thermal polarization conditions of 60 V and 300°C. The microscopic morphology of in situ silver deposition layer was observed using SEM and TOF–SIMS. In addition, It was determined that the in situ metallization of conductive glass under the polarization condition of 60 V at 250°C was the best, and the thickness of deposited silver dendrites reached 1000 nm in the side of cathodically. This paper provides theoretical and experimental references for the optimization of the in situ metallization process for the ion conductive glass. [ABSTRACT FROM AUTHOR]

Increasing the active site of redox reactions on the surface of photocatalysts and accelerating the separation and transfer of photogenerated electron‐hole pairs are effective methods to improve the hydrogen evolution of composite photocatalysts. Non‐precious metal Ni photo‐deposition is anchored in situ on the ZnIn2S4 surface to generate the cocatalyst Ni(OH)2, which improves the photocatalytic hydrogen evolution performance of the composite sample. Under visible light irradiation, the ZnIn2S4 semiconductor stimulates photon‐generated carriers. Ni2+ acts as the defect center of photogenerated electron‐hole pairs to promote the separation of carriers. It serves as the capture site of light‐generated holes to reduce the carrier recombination rate so that the light‐generated electrons on the ZnIn2S4 surface promote H+ reduction in H2. Ni(OH)2 provides the active site for oxidation reaction on the surface of semiconductor materials, allowing the carrier to be consumed faster and improving the photocatalytic stability of semiconductor materials. The addition of 2 wt% Ni2+ resulted in a hydrogen evolution rate of 10 066 µmol·g−1 ·h−1 for ZnIn2S4/Ni(OH)2, which was 2.5 times higher than that of pure ZnIn2S4. This paper presents a reference case for enhancing the stability of sulfide to promote its photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

In this paper, Ni was introduced into the matrix of carbon fiber reinforced SiOC (C/SiOC) composites by the precursor infiltration and pyrolysis method to catalyze the generation of in situ formed nanostructures including carbon nanotubes (CNTs), turbostratic carbon, and SiC. The effect of in situ formed nanostructures catalyzed by Ni on the properties of the C/SiOC composites was investigated. The results demonstrated that the presence of in situ formed nanostructures in the matrix improved the densification and mechanical properties of C/SiOC composites. In addition, the incorporation of in situ formed nanostructures facilitated the formation of thermal conductivity pathways within the composites, thereby enhancing the thermal conductivity of C/SiOC composites. Furthermore, in situ formed nanostructures‐containing C/SiOC composites developed a carbon friction layer comprising CNTs and turbostratic carbon, which significantly enhanced the abrasion resistance, endowing C/SiOC composites stable friction coefficients, and lower levels of wear. [ABSTRACT FROM AUTHOR]

In ceramic injection molding, the conventional solvent‐debinding process encounters limitations such as solvent cost and environmental pollution. In this paper, a suitable thermal‐debinding process from room temperature to 250°C using carbon/alumina embedding powders with nano and submicron size was developed to remove the soluble binders replacing the conventional solvent debinding of injection molding ZrO2 ceramic. The effects of the embedding powders on microstructure and debinding ratio were studied in detail. The results showed that the main factor influencing debinding ratio was associated with the sufficient dispersing of mixed particles, which was characterized by the relative change ratio of tap volume. A debinding mechanism was proposed to explain the effects of carbon/alumina mixed powders on the debinding ratio and surface cracks. Based on the influencing mechanism, the debinded green part with the elimination of soluble binders and optimal surface was achieved using the mixed powders with C/A = 8/2 on the top and C/A = 4/6 on the bottom. [ABSTRACT FROM AUTHOR]

Powder synthesis is crucial for achieving the densification and facilitating widespread applications of high entropy carbide (HEC). Specifically, the production of fine particle‐size powders is essential to enhance the densification of HECs. Consequently, this paper proposes the molten salt method for synthesizing HEC powders. The synthesis process successfully yielded (Ta Nb Ti V) C powders with a particle size of only 0.44 µm at 1400°C, exhibiting a uniform distribution of each element. Subsequent densification of (Ta Nb Ti V) C within the 1700–1900°C temperature range was carried out using spark plasma sintering. It was observed that as the densification temperature increased, the densification and mechanical properties of HEC significantly improved. This study presents innovative ideas for the preparation of HEC at lower temperatures. [ABSTRACT FROM AUTHOR]

Ytterbium disilicate (Yb2Si2O7) is a potential environmental barrier coating (EBC) material. In this paper, the microstructure and phase composition of plasma‐sprayed Yb2Si2O7 coatings with different spraying process were systematically investigated to optimize the spraying power and spraying distance. Furthermore, in order to obtain Yb2Si2O7 coating with single phase, a certain proportion of SiO2 was added to the Yb2Si2O7 powder to compensate for the volatilization of SiO2 during plasma‐spraying process, and the influence of spraying powder composition on the microstructure and phase structure (composition and content) of Yb2Si2O7 coatings were also characterized in detail. The results showed that the Yb2Si2O7 coating was dense with fewer pores and cracks at the spraying power of 40 kW and the spraying distance of 100 mm. Yb2Si2O7 coating with the "sandwich" structure was composed of Yb2Si2O7, Yb2Si2O7 + Yb2SiO5, and Yb2SiO5 three microstructures, which was mainly caused by the volatilization of SiO2 in Yb2Si2O7 spraying powder. The Yb2Si2O7 coating contained 90.68 mol.% Yb2Si2O7 phase and 9.32 mol.% Yb2SiO5 phase after crystallization at 1300°C for 20 h. The coating was composed of Yb2Si2O7 phase and amorphous phase after SiO2 addition. Yb2SiO5 phase precipitated from the coating after heat treatment at 1300°C, and its content decreased with the increase of SiO2 content. The content of the Yb2Si2O7 phase was as high as 99.41 mol.% when SiO2 content was 10 mol.%, which would provide a scientific basis for further research on stoichiometric Yb2Si2O7 EBCs with excellent properties. [ABSTRACT FROM AUTHOR]

A large adiabatic temperature change along with a wide operating temperature region is usually required for the electrocaloric materials to fulfill their refrigeration function. In general, doping foreign ions into BaTiO3 is the frequently utilized strategy in order to obtain excellent electrocaloric materials for the practical application. In the current paper, BaTiO3 lead‐free ferroelectric ceramics were doped by Ca2+ and Sn4+ simultaneously in order to generate a coexistence state at room temperature, where ferroelectric domains and nanodomains exit. As a result, a large polarization and a wide operating temperature range were finally induced. It is found that Ba0.9Ca0.1Ti0.85Sn0.15O3 has a maximum adiabatic temperature change of 0.85 K and an excellent working temperature region (65 K, ∆T > 90% Tmax) was achieved under an electric field of 50 kV/cm. The above phenomenon indicates that the modified BaTiO3 ceramics can be a good potential electrocaloric material in the state of cross‐existence of ferroelectric domains and nanodomains. [ABSTRACT FROM AUTHOR]

The full matrix parameters of a piezoelectric material are crucial for designing and evaluating piezoelectric devices. However, due to their inverse problematic nature, commonly used single‐sample characterization methods heavily depend on the accuracy of initial values and mode matching. In this paper, we propose a quasi‐31‐vibrator method to directly evaluate these parameters by designing the sample geometry and establishing the relationship equation between the parameters. This approach completely bypasses the need for characteristic spectrum simulation and mode identification processes. Subsequently, we tested the full matrix parameters of PZT‐5H ceramics and compared the simulated impedance spectra with the measured ones. The presence of well‐fitting spectra validates the feasibility of the method. This method will contribute to characterize the parameters of new piezoelectric materials and advance the intelligent implementation of measuring full matrix parameters. [ABSTRACT FROM AUTHOR]

In this paper, X‐ray‐activated super long persistent ultraviolet A luminescence from Ca3(PO4)2: Ce3+ has been observed. The crystal structure analysis has shown that the as‐prepared samples are pure β‐Ca3(PO4)2 phases with rhombohedral structure and R3c space group. The photoluminescent spectra of the samples all consist of a broad band in 340–400 nm UVA1 region, which is assigned to the 5d1–4f1 electronic transition of Ce3+ ions. More important, under the 3 min X‐ray irradiation, Ca3(PO4)2: Ce3+ show super long persistent luminescence in the UVA1 region, which can persist for more than 16 h. And its afterglow intensity after 16 h decay is still 4.10 times stronger of the back ground intensity. Furthermore, only 10 s X‐ray irradiation can induce excellent long persistent UVA luminescence of Ca3(PO4)2: 0.08Ce3+, which can persist for more than 5 h and afterglow emission intensity is about 3.03 times of the background intensity. The trap analysis has confirmed that the different X‐ray irradiation time do not create new traps and there is the same trap with 0.75 eV trap depth existing even under the extremely low X‐ray dose (10 s X‐ray irradiation). Furthermore, under 10 s X‐ray irradiation, the thermoluminescence (TL) intensity of Ca3(PO4)2: 0.08Ce3+ still reaches 0.32 times of the initial TL intensity even after 120 min, which thus leads to the super long persistent luminescence. Thus, the large amounts of trapped electrons induced by the high energy X‐ray irradiation are the principal cause for super long persistent UVA luminescence of Ca3(PO4)2: Ce3+. [ABSTRACT FROM AUTHOR]

As a luminescent center ion in materials for deep red and near‐infrared light, Cr3+ has been extensively studied in octahedral host materials. In this study, using zinc aluminate (ZnAl2O4) and magnesium aluminate (MgAl2O4) spinels with abundant octahedra as substrates, a series of Zn1−xMgxAl2O4:0.5%Cr3+ (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) fluorescent powders were first prepared via a high‐temperature solid‐state method. The influence of different Mg/Zn ratios on (Zn/Mg)Al2O4:0.5%Cr3+ optical properties was thoroughly explored. Experimental results show that an increase in the Mg/Zn ratio reduces the crystal field strength (Dq) and leads to distortion of the [AlO6] octahedra, resulting in broadening of the photoluminescence emission spectrum. Furthermore, the addition of Mg gradually reduces the formation of inverse spinel. An appropriate Mg/Zn ratio can improve luminescent intensity and quantum efficiency. In summary, this paper, through bandgap engineering by adjusting the Mg/Zn ratio, provides a detailed account of the changes in optical properties and the underlying mechanisms during the transition from ZnAl2O4:0.5%Cr3+ to MgAl2O4:0.5%Cr3+ spinels. It offers valuable insights for further research on the practical applications of Cr3+ in areas such as lighting displays and bioimaging. [ABSTRACT FROM AUTHOR]

With the emergence of 5G–6G communication technology, the miniaturization and integration of electronic components are crucial. Ba3Ti4Nb4O21 (BTN) ceramics with hexagonal structures have attracted special attention due to their high dielectric constant, which shows greater application potential in communication base stations and dielectric resonators. However, its high sintering temperature and low‐quality factors also greatly limit the application field. In this paper, boric acid (H3BO3) as a dopant, was used to investigate the influence on the structure, microstructure, Raman spectrum, and microwave properties for Ba2.92Cu0.08(Zn1/3Nb2/3)2Ti2Nb4O21 (BCZTN)‐xHB (0.25≤x≤1.25 wt%) ceramics. The results reflected that H3BO3 was an effective additive, which could promote ceramic densification, accelerate grain growth and uniform distribution, and enhance its microwave performance. Among them, high densification was 93.92 ± 0.35%, and the Q × f value ∼16981 ± 340 GHz at x = 0.75, was more than 2∼3 times higher than other BTN‐based ceramics. Superior microwave dielectric properties were achieved for 0.75 wt% H3BO3‐doped BCZTN ceramic sintered at 900°C: εr∼42.35 ± 0.48, Q×f∼16981 ± 340 GHz, and τf∼40.02 ± 1.43 ppm/°C. More encouragingly, BCZTN‐0.75HB ceramic did not chemically react with Ag, which suggested that it had the potential to be a candidate material for low‐temperature co‐fired ceramics base station communication devices. [ABSTRACT FROM AUTHOR]

In this paper, X‐ray‐activated super long persistent ultraviolet A luminescence from Ca3(PO4)2: Ce3+ has been observed. The crystal structure analysis has shown that the as‐prepared samples are pure β‐Ca3(PO4)2 phases with rhombohedral structure and R3c space group. The photoluminescent spectra of the samples all consist of a broad band in 340–400 nm UVA1 region, which is assigned to the 5d1–4f1 electronic transition of Ce3+ ions. More important, under the 3 min X‐ray irradiation, Ca3(PO4)2: Ce3+ show super long persistent luminescence in the UVA1 region, which can persist for more than 16 h. And its afterglow intensity after 16 h decay is still 4.10 times stronger of the back ground intensity. Furthermore, only 10 s X‐ray irradiation can induce excellent long persistent UVA luminescence of Ca3(PO4)2: 0.08Ce3+, which can persist for more than 5 h and afterglow emission intensity is about 3.03 times of the background intensity. The trap analysis has confirmed that the different X‐ray irradiation time do not create new traps and there is the same trap with 0.75 eV trap depth existing even under the extremely low X‐ray dose (10 s X‐ray irradiation). Furthermore, under 10 s X‐ray irradiation, the thermoluminescence (TL) intensity of Ca3(PO4)2: 0.08Ce3+ still reaches 0.32 times of the initial TL intensity even after 120 min, which thus leads to the super long persistent luminescence. Thus, the large amounts of trapped electrons induced by the high energy X‐ray irradiation are the principal cause for super long persistent UVA luminescence of Ca3(PO4)2: Ce3+. [ABSTRACT FROM AUTHOR]

In this paper, we examine the cleavage fracture anisotropy in tantalum carbides, namely, TaC, α‐Ta2C, and ζ‐Ta4C3 − x, using density functional theory (DFT) calculations. Our investigation identifies the presence of multiple low‐energy cleavage planes indicating multiple potential pathways for crack propagation in these ceramics, even the low symmetry compounds. The anisotropy characteristics of cleavage fractures exhibited by α‐Ta2C and ζ‐Ta4C3 − x closely align with the intrinsic fracture anisotropy observed in TaC. Notably, there exist at least three pyramidal planes in ζ‐Ta4C3 − x whose cleavage energies are less than those of the carbon‐depleted basal planes, previously reported to have the lowest cleavage energy. The observed preference in experiments for cleavage along carbon‐depleted basal planes, exclusive of other identified low‐energy planes, points to factors beyond cleavage energy influencing cleavage plane preference. [ABSTRACT FROM AUTHOR]

The penetration of copper‐smelting slag into refractories is a major challenge to the research of chromium‐free refractories for copper‐smelting furnace. In this paper, Y2O3 was added to regulate the pore structure of periclase refractories, which enhanced their various properties, especially corrosion resistance to copper converter slag. The results showed that the periclase refractories doped with 1.0 wt.% Y2O3 (1Y sample) possessed the optimum properties. Compared to the sample without Y2O3, the apparent porosity of 1Y sample was decreased by 7.3%, and its average pore diameter was only 3.7 μm. The addition of Y2O3 filled the pores among MgO grains and promoted the expansion of high melting point silicates, thereby reducing the pore size and causing more complex pore structures. This was beneficial to improving the corrosion resistance of periclase to copper slag, especially to prevent the penetration of Cux+ and Na+. After static slag corrosion, the permeability index was significantly decreased by 41% compared to periclase refractories without Y2O3. Moreover, compared to industrial MgO–Cr2O3 refractories, the 1Y sample possessed better resistance to copper slag erosion based on rotating finger tests, and its permeability index and penetration depth decreased by almost 50%. [ABSTRACT FROM AUTHOR]

So far, developed microwave absorbers exhibit significant changes in absorption with temperature, which hinder their operation within a wide temperature range. In this paper, a microwave absorber based on SiBCN ceramics was prepared. Due to the excellent high‐temperature stability of SiBCN ceramics, its permittivity changes less with temperature, avoiding the issue of performance deterioration or even failure that traditional refractory absorbers face at high temperatures. The experiment proves the absorption bandwidth for –15 dB of the SiBCN metamaterials absorber (SMA) is 12 GHz at 800°C, with a maximum absorptivity of 99.99%. According to the computed data, the resonance loss contributes 81.9 to 94.5% of the microwave absorption of SMA. This work demonstrates significant potential for applications in radar stealth under harsh conditions. [ABSTRACT FROM AUTHOR]

Functionally graded ceramics (FGCs), which combine the properties of various composite ceramics, have been widely used in the aerospace, armament, and other industries. One of the newest melt‐growth ceramic additive manufacturing techniques, laser directed energy deposition (LDED), enables the creation of gradient materials by controlling the ratio of powder delivery. Ceramic–ceramic type gradient materials are the subject of fewer studies, and the majority of LDED gradient material systems now in research are metal–metal type and metal–ceramic type gradient materials. In this paper, LDED is used to create TiCp reinforced Al2O3 FGCs with three different transition paths. The results indicate that the longitudinal section of the gradient samples distinctly exhibits characteristics of gradient distribution. Furthermore, as the proportion of TiCp increases, there is a corresponding increase in the proportion of TiCp particles in the samples. The microstructure of Al2O3 transforms from columnar crystals to irregular shapes. Regarding the mechanical properties of the gradient samples, the area containing 30 wt.% of TiCp shows a significant improvement in wear resistance, with a 48.13% increase compared to the Al2O3 region. Additionally, this region demonstrates a 12.62% rise in hardness and a 9.48% increase in fracture toughness. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing demand for broadband near‐infrared (NIR) phosphor. The paper proposes a novel Cr3+ doped Ca2Y3Sb3O14 phosphor through basic research of Ca2Ln3Sb3O14: Cr3+ (Ln = Sc, Lu, and Y) phosphor. Under 467 nm excitation, Ca2Y3Sb3O14: Cr3+ phosphor shows a broad NIR emission band (650–950 nm) centered at 776 nm with a full width at half‐maximum of 110 nm. The optimal Cr3+ doping concentration is 0.05, with an internal quantum efficiency of 78%. Meanwhile, the photoluminescence emission intensity at 373 K remains 61.3% of that at room temperature. Using phosphor‐in‐glass technology, a glass–ceramic plate showed a slight improvement in its thermal stability compared to the pure phosphor. Combining Ca2Y3Sb3O14: 0.05Cr3+ phosphor with a commercial blue‐light‐emitting chip presents an output power of 44.51 mW with a photoelectric conversion efficiency of 14.78% at a drive current of 100 mA. These results suggest that the Ca2Y3Sb3O14: Cr3+ phosphor has great potential in the pc‐light‐emitting diodes. [ABSTRACT FROM AUTHOR]

Dielectric capacitors have been widely studied in advanced electronics systems due to their rapid discharge rate and high-power density. Among them, relaxor ferroelectrics characterized by nanodomains possess broad application prospects as dielectricmaterialswith high energy density and high efficiency. In this paper, the dielectric characteristics, energy storage performance, and charge--discharge behavior of rare-earth Yb-doped Sr0.7Bi0.2TiO3 ceramics are systematically investigated. The Yb-doped SBT ceramics reduced the grain size, improved the insulation and thermal conductivity, and significantly improved the dielectric breakdown strength. Finally, a high recoverable energy density of 2.32 J/cm³ and an excellent energy storage efficiency of 92.2% were obtained at 300 kV/cm. In addition, pulsed charge--discharge tests show that Sr0.7Bi0.15Yb0.05TiO3 possesses a rapid discharge rate and high-power density with superior thermal stability. Based on these outstanding characteristics, Sr0.7Bi0.15Yb0.05TiO3 exhibits promising applications in pulsed power systems. [ABSTRACT FROM AUTHOR]

BaTiO3‐based compounds are recognized as the most common dielectric material used in multilayer ceramic capacitors (MLCCs), among which, BaTiO3‐BiMeO3 is extensively investigated to improve the thermal stability and extend the service life of MLCCs, which are strongly dependent on the conductivity at high temperatures. Despite numerous efforts have been made, the mechanism of oxygen vacancy conduction, which makes the major contributions to the conduction mechanism of BaTiO3‐based compounds at high temperatures below 450°C, is still unclear. In this paper, BaTiO3, 0.88BaTiO3‐0.12Bi(Zn2/3Nb1/3)O3, 0.88BaTiO3‐0.12Bi(Mg2/3Nb1/3)O3, and 0.88BaTiO3‐0.12Bi(Mg2/3Ta1/3)O3 ceramics have been prepared by solid‐state reaction method, and their electrical and dielectric properties have been studied in detail. Meanwhile, first principles were applied to study the mechanisms of the increase of electrical resistivity and the decrease of dielectric loss. It is found that B‐site dopants (Zn, Mg, Nb, and Ta) are effective in reducing the conductivity by inhibiting the migration of oxygen vacancies, which is a kinetics process with an increase of energy barrier. Notably, the greater ability of Zn to inhibit oxygen vacancies migration is a combination of thermodynamics (a strong ability to trap oxygen vacancies) and kinetics (an effect of block the migrating defects in the lattice). This work reveals a new insight into the mechanism of oxygen vacancies migration in BaTiO3‐based perovskite compounds, which makes BaTiO3‐BiMeO3 prospective in designing efficient and durable medium‐temperature solid oxide capacitor devices. [ABSTRACT FROM AUTHOR]

Ceramic matrix composites (CMCs) and environmental barrier coatings (EBCs) are key technologies that can enable improvements in the thermal and propulsive efficiency of gas turbine engines. However, CMCs and EBCs are susceptible to various life limiting damage modes associated with the engine operating environment such as oxidation, recession, thermomechanical stress/strain, corrosion, foreign object damage (FOD), and solid particle erosion (SPE). Despite its importance, there is a limited understanding of the SPE behavior of CMCs and EBCs in the literature. This paper reviews the status of SPE research for CMCs and EBCs and provides a perspective towards future research. [ABSTRACT FROM AUTHOR]

High‐temperature corrosion resistance is one of the major challenges for hot‐section components in gas turbines. In this paper, the interaction of a novel high entropy (HE) (Y0.2Gd0.2Ho0.2Er0.2Yb0.2)3Al5O12/Al2O3 directionally solidified eutectic (DSE) with molten calcium–magnesium–aluminosilicate (CMAS) at 1500°C for 4 to 200 h was investigated and the results indicate that (Y0.2Gd0.2Ho0.2Er0.2Yb0.2)3Al5O12/Al2O3 DSE possesses excellent CMAS resistance, with a true recession depth about 219.5 μm after corroded by CMAS at 1500°C for 200 h. Moreover, possible explanations on the outstanding CMAS corrosion resistance, including the protective diffusion‐blocking garnet layer and the actively adjustment on the corrosion activity of CMAS melt by both the rapid dissolution of Al2O3 phase and the synergetic effects of multicomponent RE elements, are deduced based on the identification, distribution and evolution analysis of the reaction products over the corrosion time. The current results can cast light on new mechanisms and strategies with respect to multilevel optimization to develop new high‐temperature structural materials with enhanced CMAS corrosion resistance ability. [ABSTRACT FROM AUTHOR]

Knowledge of thermodynamics and phase equilibria of oxidic materials is crucial for advancement in the field of ceramics and glass. With the development of computational thermodynamics, predicting phase diagrams and chemical reactions of multicomponent systems has become possible. However, there are still plenty of oxides, the thermodynamic properties of which have not been identified due to the challenges in conducting experiments. Therefore, a key to the advancement in thermodynamic modeling would be to develop a universal model that can be used to estimate the thermodynamic properties of oxides with reliable extrapolation capacity. Atomistic (or molecular) scale models are still insufficient in predicting the thermodynamic properties of oxides at any scale. Alternatively, among group contribution–based methods, the polyhedron model has presented its potential in the estimation of the thermodynamic properties of ionic crystals. However, this model still demands improvements that increase the model's accuracy and extrapolation capacity. In this paper, the background and the state‐of‐the‐art of polyhedron model will be presented together with its strengths and shortcomings. Subsequently, it will be briefly discussed how the field of artificial intelligence could be exploited to devise the next generation of the polyhedron model, the modified polyhedron model. [ABSTRACT FROM AUTHOR]

Glass is a versatile material with a remarkable history and many practical applications. It plays a critical role in our everyday lives, the advancement of science, and the development of many technologies. The Edisonian type trial‐and‐error method was commonly used for conventional design of glass compositions, which was time‐consuming and costly. With the urgent need to develop new glass compositions for technology applications rapidly, it has become necessary to develop precise property models with predictive powers using large databases and efficient formulation approaches. This paper reviews the design of glass compositions using these analytical and numerical models of composition–structure–property relations of glasses, some based on large databases and machine learning approaches. Aspects of data collection, model fitting, feature extraction, model evaluation, and uncertainty quantification will be covered. Furthermore, advances in the glass optimization framework and available tools are summarized with examples. The outlook and perspective for further glass property model development and formulation approaches are discussed. [ABSTRACT FROM AUTHOR]

Ceramic aerogels are attractive for their promising applications in thermal insulation, ultrafiltration, catalysis, and many other areas, owing to their high porosity, low density, high specific surface area, low thermal conductivity, and thermal stability. However, the practical applications of conventional ceramic aerogels are usually impeded by brittleness. Resilient ceramic aerogels overcame the brittleness of conventional ceramic aerogels and realized reversible compressibility, but they usually show brittleness under tensile stress and limited load‐bearing ability. In this short review paper, we reviewed the strategies to modify the mechanical properties of resilient ceramic aerogel. These strategies were achieved through tuning the deformation and moving ability of the nanowire building blocks and the deformation resistance provided by the aerogel architecture. Perspectives for further modifying the mechanical properties of resilient ceramic aerogel are also discussed. [ABSTRACT FROM AUTHOR]

The thermodynamics and kinetics of interdiffusion are analyzed for the case of glass ion exchange, a process by which alkali ions from a glass inter‐diffuse with different, usually larger, alkali ions from a surrounding salt bath. The spontaneity of the ion exchange reaction is driven by entropy production. This paper details the first derivation and quantification of the entropy produced during this process. We present models for the evolution of the ion concentration profile for both common and extreme conditions, validate against experimental literature, and derive the entropy produced due to ion exchange as a function of time, temperature, composition, diffusivity, and glass and salt bath dimensions. Results reveal that when considering typical industrial parameter sets, the entropy produced in the glass accounts for <10% of the total entropy production, with the entropy produced in the salt bath being the dominant factor driving reaction spontaneity. Using the equations derived in this work, one can calculate concentration profile and entropy production for a two‐ion interdiffusion process between a low‐viscosity liquid and materials including, by not limited to, glass‐forming systems. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings have been widely employed in high‐temperature turbine blades to enhance their resistance against corrosion, oxidation, and foreign object damage. Yttria‐stabilized zirconia (YSZ) coatings, both conventional and nano‐structured, exhibit distinct characteristics. Notably, nano‐structured coatings demonstrate remarkable reductions in oxygen permeability and thermally grown oxide (TGO) layer thickness owing to the presence of nano‐zones (NZs). This paper focuses on elucidating the formation mechanisms, dispersion patterns, and behavior of NZs under varying conditions. Furthermore, it investigates the shock resistance performance of YSZ coatings subjected to furnace heating and water quenching. The findings reveal that the incorporation of NZs effectively restricts oxygen penetration and TGO growth and significantly enhances the overall performance of the coatings. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) has received extensive research and attention due to its excellent piezoelectric, electromechanical, and other properties. In particular, tetragonal relaxor ferroelectric single crystals have shown greater application potential in high‐temperature devices due to their higher Curie temperature and better stability. However, the low piezoelectric performance of tetragonal crystals also greatly limits its application, and research on its optical properties is not sufficient. In this paper, the tetragonal phase Sm–PIN–PMN–PT single crystal was obtained by the Bridgman method, and its piezoelectric and electro‐optical properties are studied. At the same time, we gave a complete set of piezoelectric, dielectric, and elastic coefficient matrices. The results show that the crystal has excellent piezoelectric and electromechanical properties. The piezoelectric coefficient can reach 905pC/N, the electromechanical coupling coefficient k33 is 85%, and the kt is 72%. The transmittance of the sample polarized along [001] direction can reach 66%. The effective electro‐optical coefficient γc is 60 pm/V at room temperature and can reach 86 pm/V at 70°C. It has a wide operating temperature range and stable performance with frequency variation, which has certain reference significance for application in new electro‐optical devices. [ABSTRACT FROM AUTHOR]

The effect of resting time on the rheological properties of cement suspensions is generally explained by early formed structure and overconsumption of polycarboxylate superplasticizers (PCEs). In this paper, we propose that the influence of resting time on the rheological properties is closely related to size variation of non‐absorbed PCE. To identify this, glass bead suspensions were prepared with various amounts of PCE and ionic solution, and their rheological properties were evaluated at various times. We found that the yield stress increases with time at higher PCE concentrations and higher ionic strength solutions. Adsorbed PCE during resting tends to bridge the particles rather than disperse them. In addition, it was found that hydrodynamic radius of PCE increased with resting time, and depletion forces resulting from non‐absorbed PCE size changes correlate well with the increased yield stress. [ABSTRACT FROM AUTHOR]

Thermal stability and phase transition rate are two important issues that restrict the engineering applications of phase change memories. In this paper, GeSb/Sb multilayer films were prepared by multilayer stacking, and their phase transition properties were investigated. GeSb/Sb multilayer films had higher crystallization temperature, better data retention, and lower resistance drift than pure Sb films, which indicated that they had excellent thermal stability and accuracy of resistance identification. The test results of X‐ray diffraction and atomic force microscopy showed that GeSb spacer layers could inhibit grain growth of Sb film layers, thus reducing the roughness and potential fluctuation of the film surface. X‐ray reflectivity experiments showed that the GeSb/Sb multilayer films before and after crystallization had small volume changes. The devices based on [GeSb(7 nm)/Sb(3 nm)]8 multilayer films could achieve reversible resistive transition operation between SET and RESET at a pulse width of 10 ns, showing satisfactory transition rate and operational power consumption. The low resistance drift and ultra‐fast phase transition speed make GeSb/Sb multilayer films one of the promising choices for phase change memories. [ABSTRACT FROM AUTHOR]

In this paper, synthesis and sintering of MAX phases in the Zr–Al–C system is described. Different mixtures of initial Zr/Al/C and Zr/Al/ZrC powders were used to synthesize the MAX phases of Zr2AlC and Zr3AlC2 compositions by a combined method (high‐temperature sintering followed by spark plasma sintering [SPS]). The highest content of the Zr3AlC2 MAX‐phase was obtained using initial Zr/Al/ZrC powders in a component ratio of 1:1.5:2—51.1 vol.%. The optimal temperature for the synthesis of a material based on the Zr2AlC MAX phase is 1525°C, and a material based on Zr3AlC2 is 1575°C. During subsequent SPS at a temperature of 1500°C, a pressure of 50 MPa, within 5 min, it was obtained a material containing up to 71.1 vol.% Zr3AlC2. The relative density of the samples synthesized and consolidated by the SPS method reaches 98.9%. The structure of the obtained synthesized MAX materials includes elongated grains of the composition Zr2AlC and Zr3AlC2, which determines their high strength. The influence of the sintering time and temperature on the formation of the MAX phase of Zr3AlC2 from the initial powders of Zr/Al/ZrC is shown. Zirconium carbide, as an intermediate phase, is always present in the final products. Due to the large evaporation of aluminum, the ZrAl2 phase is also present in the synthesis products. An excess of aluminum contributes to the greatest formation of the Zr2AlC and Zr3AlC2 phases during the combined synthesis. [ABSTRACT FROM AUTHOR]

This paper introduces a fast, low‐temperature, pressureless process to chemically bind ceramic parts with the help of infrared (IR) irradiation and phosphate binder condensation. Ceramic components are synthesized from slurries of ceramic powders and Al(H2PO4)3 binder that are irradiated with short‐waved IR light capable of heating the system to 350°C. This irradiation is found to be sufficient to drive phosphate condensation, binding the ceramic powders together within a matter of seconds. The IR‐irradiated components show an increase in density and Vickers hardness. Layer‐by‐layer spraying and irradiation is demonstrated as a route to additive manufacturing using various ceramic chemistries. While further optimization is needed to control desired microstructure, this process of using chemically bonded ceramic binders with IR heating for additive manufacturing shows the potential to find applications in various ceramic systems, including refractories, bone implants, electronics, and thermal barrier coatings. [ABSTRACT FROM AUTHOR]

This document is an editorial from the Journal of the American Ceramic Society titled "Advances in computational ceramics and glasses." It discusses the increasing importance of computational modeling and simulation in materials research, driven by advancements in computing power and algorithms. The editorial highlights the application of artificial intelligence and machine learning in computational methods, which has expanded the scope of materials design. The document also presents a collection of research papers on computational ceramic and glass materials, covering various modeling methodologies and material systems. The editorial acknowledges the rapid growth of computational methods in ceramic and glass research and expresses gratitude to the contributing authors, reviewers, and associate editors. [Extracted from the article]