Ferroelectric barium strontium titanate (BST) glass–ceramics doped with different content of La2O3 were prepared via the melt-quenching technique followed by controlled crystallization. The microstructures of crystallized samples were examined by X-ray diffraction and scanning electron microscopy. Dielectric properties were also investigated. The aliovalent substitution of Ba by La induced dispersion of semiconducting BaxSr1−xTiO3 crystallites sealed in a glassy silicate matrix, which increased the εr and loss tangent values of the BST glass–ceramic. The experimental results indicate that aliovalent substitution is an effective method to process glass–ceramics with better dielectric properties.

Densification behaviors of SrO–BaO–Nb2O5–SiO2 based glass–ceramics prepared by conventional sintering were investigated with an emphasis on the influence of P2O5 content. Although P2O5 dopant did not modify the surface crystallization mechanism, it resulted in a decrease of the glass transition temperature, which facilitates the viscous glass flow necessary for sintering. However, premature crystallization of (Sr,Ba)Nb2O6 induced by addition of excess amount of P2O5 essentially retarded sintering due to the formation of closed pores in the matrix. The SrO–BaO–Nb2O5–SiO2 glass with 1.0 mol% P2O5 (SBN-1P) showed the best sinter densification, which was accomplished at about 850 °C.

The crystallization kinetics in the glass system BaxSr1−xTiO3–Al2O3–SiO2 prepared via the conventional melt-quenching technique has been studied by isothermal method using differential scanning calorimetry (DSC). X-ray powder diffraction studies carried out on heat-treated (850–1100 °C) glasses reveal the evolution of BaxSr1−xTiO3 crystalline phase along with a second phase of BaAl2Si2O8. The exponent n in the Johnson–Mehl–Avrami (JMA) equation applied to the isothermal process is in the range of 2.3–2.73. The apparent activation energy for BaxSr1−xTiO3 crystal growth obtained from JMA equation under isothermal condition is 457 kJ mol−1, which is close to the dissociation energy of Si–O bonds. Moreover, there is no remarkably different effect between one-stage and two-stage heat treatment procedures on the microstructures and dielectric properties of barium strontium titanate based glass–ceramics in the present study, according to structure–property analysis.

Aluminum–matrix composites reinforced with 3D-SiC network were prepared by pressureless infiltration technology at 900 °C. A reaction layer with thickness of ∼60 μm was observed. In addition, cracking in the reaction layer was also found.