Using a solid-state reaction strategy, nominal Li₃TiO₃F oxyfluorides ceramics were fabricated, and its sintering behavior, microstructure, phase assemblages, as well as microwave dielectric performances were all investigated. The main phase of Li₃TiO₃F with cubic structures accompanied with small amounts of the LiF or Li₂TiO₃ secondary phase was identified by XRD analysis. SEM analysis showed that a uniform and dense microstructure was obtained for 750 °C-sintered samples. The dielectric constant (ε_r) and quality factor (Q × f) were found to be strongly correlated with porosity and grain size distribution, whereas the temperature coefficient of resonance frequency (τ_f) was mainly dominated by the phase assemblages. In particular, the 750 °C-sintered Li₃TiO₃F samples exhibited good microwave dielectric performances: ε_r = 18, Q × f = 57,300 GHz (under 9.2 GHz), τ_f = −43.0 ppm/°C.

In this work, a BiFeO₃ film is prepared via a facile sol–gel method, and the effects of the relative humidity (RH) on the BiFeO₃ film in terms of capacitance, impedance and current–voltage (I–V) are explored. The capacitance of the BiFeO₃ film increased from 25 to 1410 pF with the increase of RH from 30% to 90%. In particular, the impedance varied by more than two orders of magnitude as RH varied between 30% and 90% at 10 Hz, indicating a good hysteresis and response time. The mechanism underlying humidity sensitivity was analyzed by complex impedance spectroscopy. The adsorption of water molecules played key roles at low and high humidity, extending the potential application of ferroelectric BiFeO₃ films in humidity-sensitive devices.

Bilayer zirconia restoration is one of the most commonly used restorations in dental practice, but the high frequency of the cohesive/adhesive fracture of veneered porcelain is still a problem. This paper focuses on the development of nanostructured glass-zirconia to improve the interface stability of dental zirconia substrate and veneered porcelain. A novel SiO₂-Li₂O-Al₂O₃ (SLA) glass was prepared and infiltrated into the surface of fully sintered dental zirconia to obtain nanostructured glass-zirconia structure. The prepared glass-zirconia was analyzed with scanning electron microscopes (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD). The wettability, roughness and 3D morphology of zirconia were altered, and shear bonding strength (SBS) test demonstrated almost double increase in SBS values of the nanostructured glass-zirconia structure. The failure modes and microstructure characteristics also verified the improved interfacial stability. This investigation provides a promising method for enhancing the structural stability of bilayer zirconia restorations.

With the development of high-speed and high-temperature equipment, thermal barrier materials are facing increasingly harsh service environments. The addition of YAG to Y₂Hf₂O₇ has been proposed in order to improve its long-term high-temperature performance. In this work, Y₂Hf₂O₇/Y₃Al₅O₁₂ composite powders were synthesized by combustion synthesis with urea, glycine, EDTA, citric acid, and glucose as fuels, while hafnium tetrachloride, yttrium nitrate hexahydrate, and aluminum nitrate nonahydrate were used as raw materials. The effects of fuels on the morphology and phase composition of synthetic powders were studied. Chemical reaction kinetic parameters were established by the Kissinger, Augis and Bennett, and Mahadevan methods. Y₂Hf₂O₇ and Y₃Al₅O₁₂ are the main components in the powders synthesized with urea as fuel, while YAlO₃ and Y₂Hf₂O₇ are the main phases with the other fuels. SEM and TEM analysis reveal that the powders prepared by the solution combustion method exhibit a typical porous morphology. When urea is used as fuel, the powders show a uniform elemental distribution, distinct ceramic grain crystallization, clear grain boundaries, and a uniform distribution of alternating grains. Compared to several other fuels, urea is more suitable for the preparation of Y₂Hf₂O₇/Y₃Al₅O₁₂ composite powders. In the process of preparing powders with urea, the activation energies for the combustion reaction calculated using the three methods are 100.579, 104.864, and 109.148 kJ·mol⁻¹, while the activation energies related to crystal formation are 120.397, 125.001, and 129.600 kJ·mol⁻¹, respectively.