Lightweight β-Li₂TiO₃ ceramics are promising microwave dielectrics for the large-scale deployment of 5.5G extremely large antenna arrays (ELAAs). However, their practical application is hindered by the limited Q×f value (where quality factor Q = 1/dielectric loss (tanδ), and f represents the resonant frequency) and large positive temperature coefficient of resonant frequency (TCF), while the underlying phase transition and regulatory mechanisms remain elusive. Here, a unique monoclinic–cubic dual-phase architecture is constructed in Li₂Ti_1−x(Sc_1/2Nb_1/2)_xO₃ (LTSN_x, 0 ≤ x ≤ 0.5) ceramics. In situ structural characterizations reveal that the substitution-induced reduction in the phase transition temperature (T_c) and concomitant lattice distortion synergistically impede the reversed-phase transformation, stabilizing the high-temperature cubic phase at room temperature. Consequently, the inherent negative TCF of the cubic phase effectively compensates for the positive value of the monoclinic matrix, achieving exceptional temperature stability. Furthermore, the reconstructed superlattices and suppression of lattice defects significantly minimize dielectric loss. Of particular importance is that the studied LTSN_0.25 ceramic exhibits excellent microwave dielectric properties, featuring a relative permittivity (ε_r) of 18.6, ultra-high Q×f of 102,330 GHz (at 7.76 GHz), and a near-zero TCF of −2.3 ppm/°C. Simultaneously, the stable THz response and simulated filter performance confirm its great potential for 5.5G applications.

A porcelain was prepared with Kaolin clay, potassium feldspar and quartz as raw materials and zirconium silicate as a reinforcing material. The effects of zirconium silicate content, firing temperature and holding time on the properties of porcelain were investigated, and the strengthening mechanism of zirconium silicate particle dispersion on the porcelain was analyzed. The results show that the optimum porcelain reinforcement can be obtained at zirconium silicate content of 6%, firing temperature of 1300 ℃ and holding time of 30 min. The bending strength increases from (58±6) MPa to (106±11) MPa, and the growth rate is 83%. The radial compressive stress and tangential tensile stress are generated in the matrix during the cooling process due to the difference of thermal expansion coefficient between zirconium silicate particles and matrix, resulting in the increased porcelain strength.

γ-Ce₂S₃ is a kind of non-toxic environmental protection red inorganic pigment due to its bright color, intense hiding power and superior ultraviolet resistance. However, its antioxidant temperature is 350 ℃. To improve the oxidation resistance temperature of γ-Ce₂S₃, a mullite coated Na⁺ ion-doped γ-Ce₂S₃ (i.e., γ-[Na]-Ce₂S₃@mullite) was synthesized by a sol–gel method and a subsequent sulfuration-heating process. The synthetic conditions of mullite as well as the effect of pre-firing temperature on the morphology of precursor and chromaticity value of the coated pigments were investigated, and the thermal stability of the coated pigments was also analyzed. The results show that short rod-like and spheroidal mullite crystals can be synthesized at 1300 ℃ for 3 h as n_Al:n_Si=3.2:2.0, and the optimum chromaticity value (i.e., L*=36.24, a*=41.86, b*=36.26) of the coated pigment can be obtained when the pre-firing temperature is 400 ℃. The pigment has a good chromaticity value (i.e., L*=29.84, a*=20.83, b*=18.17) when being in air at 800 ℃ for 10 min. This study indicates that γ-[Na]-Ce₂S₃@mullite can increase the antioxidant temperature of γ-Ce₂S₃ from 350 ℃ to 800 ℃.