With the rapidly development of 5G and 6G technologies, developing ceramics with a moderate dielectric constant, a high quality factor, and a resonant frequency temperature coefficient close to 0 becomes a research hotspot. A novel series of microwave dielectric ceramics Ca_0.95-xCu_0.05(Na_0.5B_i0.5)_xMoO₄ were synthesized by a solid-state reaction method. The influences of sintering temperature and component change on the microwave dielectric properties were investigated. The ceramic property was analyzed by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The results show that the ε_r of Ca_0.45Cu_0.05(Na_0.5Bi_0.5)_0.5MoO₄ ceramic with NB content of 0.5 sintered at 640 ℃ is 15.8, Q_f is 21 361 GHz, and τ_f is 3.8×10^-6/℃. Also, Ca_0.45Cu_0.05(Na_0.5Bi_0.5)_0.5MoO₄ ceramic is compatible with Al electrode, indicating that Ca_0.95-xCu_0.05(Na_0.5B_i0.5)_xMoO₄ ceramic has a great potential application as a low-temperature co-fired ceramic material.

Garnet-based phosphor materials have some advantages of multi-site of doping icons, a wide option of doping ions, and a high efficiency of energy transfer, thus becoming a research hotspot for inorganic luminous materials. Compared with rare-earth ions, transition metal ions have superior features of spectral regulation and low cost. However, its luminous efficiency, valence, and luminous mechanism in complex lattice structures are still unclear. This review summarized the spectral characteristics and luminescent behavior of transition metal ions, especially Cr³⁺, Mn^2+/4+. In addition, the application of transition metal ions in the fields of solid-state lighting, displays, biomedical imaging, and plant lighting was also represented.

The thermal shock resistance of mullite castable with different steel fiber contents (i.e., 0-2.5% (mass fraction)) was evaluated by a wedge splitting method and a thermal stress factor. The thermal shock resistance of the castable was also analyzed by three different thermal shock resistance characterization methods (i.e., the residual ratio of modulus of rupture, modulus of elasticity and ultrasonic wave velocity in air at 1 100 ℃. The results show that the fracture energy (R'''') and fracture toughness increase with the increase of steel fiber content from 1.0% to 2.0%, thus improving the thermal shock resistance of castable. The rapid generation and propagation of cracks can lead to a decrease of R'''' and thermal shock resistance when the addition of steel fiber exceeds 2.0%.

The limited lithium resources and the great risk of conventional liquid-state electrolyte can affect the development of all-solid-state sodium-ion batteries. As a core component of all-solid-state sodium battery, sodium-ion solid-state electrolyte can play an important role in improving the safety and electrochemical performance of the battery. NASICON-type solid-state electrolyte Na_1+xZr₂Si_xP_3-xO₁₂(0≤x≤3) is widely concerned due to its unique 3D open structure and good chemical/thermal stability. This review represented recent research work on the crystal structure, ion transport mechanism, powder preparation methods and sintering methods of Na_1+xZr₂Si_xP_3-xO₁₂. Two major issues of Na_1+xZr₂Si_xP_3-xO₁₂ were discussed, i.e., a low ionic conductivity and a poor contact issue at the electrode-electrolyte interface, and the relevant modification methods were summarized. In addition, the optimization scheme of Na_1+xZr₂Si_xP_3-xO₁₂ and the possible development trend in the future were prospected. This review could play a guiding role in the future research of NASICON solid-state electrolyte and solid-state sodium battery.

Ca₂Mg₂Al₂₈O₄₆ (C₂M₂A₁₄) refractory has a superior high-temperature performance for high-temperature kilns. In this paper, a ternary compounds-C₂M₂A₁₄ was synthesized via high-temperature solid-state reaction sintering. Effects of firing temperature and Fe₂O₃ addition on the phase composition, fabric and densification evolution of the specimens were investigated. The results show that the C₂M₂A₁₄ is generated by the reaction of CaAl₁₂O₁₉ (CA₆) with spinel at 1 650 ℃, and is produced in large quantities at 1 750 ℃. The densification evolution is accelerated with the transformation from hexagonal lamellar CA₆ to polyhedron C₂M₂A₁₄ and the appearance of eutectic liquid. The hexagonal plate of (1,1,15) preferred orientation is changed to the rhombohedral of (119) preferred orientation after adding Fe₂O₃, and the densification evolution is promoted, and more dense synthetic products can be obtained at the same firing temperature due to the solid solution strengthening of Fe ions. The apparent porosity, water absorption, and bulk density of C₂M₂A₁₄ (1% Fe₂O₃) specimen fired at 1 780 ℃ for 3 h are 12.5%, 3.9%, and 3.20 g·cm^-3, respectively. A high-temperature refractory is obtained.

Y₃Al₅O₁₂-Al₄SiC₄ composite refractory was prepared via pressureless sintering with Al₄SiC₄ as a raw material and Y₂O₃ as an additive. The effect of Y₂O₃ addition (i.e., 0-5% in mass fraction) on the phase composition, microstructure and mechanical properties of the composite was investigated, and the effect of Y³⁺ ions on the surface energy of Al₄SiC₄ different crystal faces was calculated via the DFT simulation. The results show that the addition of Y₂O₃ can form an eutectic liquid phase with anintrinsic oxide layer on the surface of Al₄SiC₄ at a high temperature, Y₃Al₅O₁₂ and a small amount of Y₂SiO₅ appear at the grain boundary of the composite.The addition of Y₂O₃ promotes the growth of Al₄SiC₄ grains along the two-dimensional plane and the transformation from irregular to hexagonal flakes due to the reduction of surface energy of different crystal faces of Al₄SiC₄ by Y³⁺ in the additive, according to the DFT results. The flexural strength of the composite first increases and then decreases with the increase of Y₂O₃ addition. At theY₂O₃ addition of 3%, the hexagonal lamellar Al₄SiC₄ grains with a uniform size form a staggered skeleton structure, and Y₃Al₅O₁₂ dispersesat the grain boundary of Al₄SiC₄, which is conducive to the improvement of the mechanical properties of Y₃Al₅O₁₂-Al₄SiC₄ composite. The bulk density, apparent porosity and flexural strength of the composite are 2.44 g·cm^-3, 20.15% and 52.7 MPa, respectively.

Density functional theory (DFT) is a quantum mechanical method for electronic structure calculations, which becomes an effectivecomputational tool in materials science and chemistry. In the study of fluorescent materials, DFT calculations can be used to determine the crystal structure, calculate the materials band structure, and density of states information to clarify the nature and characteristics of fluorescent materials, thus providing a basis for material design and optimization. In addition, high-throughput computations based on DFT calculations can rapidly evaluate the properties of numerous materials, accelerate the development process of new materials, and reduce research costs. This review introducedthe application of DFT calculations in the study of fluorescent materials and discussed the future development prospects.

Phosphorus-based anode materials have a high theoretical capacity and a medium redox potential, and the related raw materials have some advantages in reserves and costs, thus having promising application prospects in sodium and lithium-ion battery anode materials. However, red phosphorus has a fast decay rate of electrochemical activity and a poor cycling performance due to the extremely low electronic conductivity and excessive volume expansion, while black phosphorus conductivity can reach 10⁵ S/m, and its dense structure leads to a poor intrinsic rate performance, thus restricting the practical application of elemental phosphorus as an anode material. A unique metal phosphorus-rich phosphides MP_x (x≥2) can be formed by introducing a small amount of metal elements into elemental phosphorus. The electronic conductivity of metal phosphorus-rich phosphides MP_x can be greatly improved via metal element electron injection, and a relatively empty crystal structure can be formed to provide faster reaction kinetics and effectively inhibit volume expansion. Therefore, metal phosphorus-rich phosphides MP_x with a high capacity and superior electron/ion transport characteristics is a potential sodium and lithium-ion battery anode material. This review mainly represented the composition and structural characteristics of metal phosphorus-rich phosphides, focusing on the latest progress in the energy storage mechanism and modification strategy of metal phosphorus-rich phosphides.

Pb_0.9625Sm_0.025[(Mg_1/3Nb_2/3)_0.71Ti_0.29]O₃ ceramic material with a high piezoelectricity wasprepared by a two-step oxide solid reaction method. The effects of driving field amplitude and temperature on the radial resonance characteristics were investigatedby a large signal resonant response test system. The results show that the resonant response at a low driving field can maintain a single resonant peak until complete depolarization. However, the resonant response becomes complicated, and some multiple resonant peaks appear even at a low temperatureas a driving field increases. The resonant properties areclosely related to the mechanical quality factor Q_m, ferroelectric domain size and phase composition. The thermal effect produced by applying a high driving field on the low Q_m material accelerates the splitting of macro-domains and induces a first-order ferroelectric phase transition. The instability of resonant characteristics and the large resonant frequency temperature coefficient restrictthe application of Sm-doped PMN-PTrelaxor ferroelectric ceramics, especially at a high driving field.

Ceramic cores have an impact on the precious casting of the engine hollow blades. 3D printing technology, as a novel generation of molding technology, is replacing the conventional ceramic core manufacture process due to the advantages of no mold, short manufacturing cycle, and high accuracy. This review summarized the existing 3D printing technologies for ceramic cores such as light-curing technology, selective laser sintering, direct-write forming technology and layered extrusion, and discussed the current research work on the performance optimization for ceramic cores prepared by 3D printing based on their shortcomings (i.e., low printing accuracy, poor compatibility between mechanical property and porosity, and anisotropy in structure and property). In addition, the future development of this technology was also prospected.