Bismuth–Titanium–Silicate–Oxide Glass Ceramics for Various Dielectric Applications

Ceramics based on bismuth titanate with added SiO₂ and Nd₂O₃ were synthesized from the Bi₂O₃-TiO₂-SiO₂-Nd₂O₃ system through rapid melt quenching followed by controlled cooling. By adjusting the initial compositions and applying heat treatments between 1450 °C and 1100 °C, either homogeneous crystalline products or multiphase glass-ceramics were obtained. The identified crystalline phases included Bi₁₂TiO₂₀ and Bi₄Ti₃O₁₂, coexisting with amorphous networks enriched in silicon, bismuth, titanium, and aluminum oxides. In previous investigations, the materials were characterized using X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy, which collectively confirmed the presence of both ordered and disordered structural domains within the bulk samples. Electrical properties were evaluated through measurements of conductivity (4 × 10^-9 S/m to 30 S/m), dielectric constant (real part from 10 to 5 × 10³ and imaginary part from 5 to 5 × 10⁴), and dielectric loss (0.02 to ~100) over the frequency range 1 Hz-1 MHz. These results provide a foundation for rational control of phase evolution in this quaternary oxide system and highlight strategies for tailoring the functional properties of glass-ceramic materials for dielectric applications. The aim of the present study is to investigate the relationship between phase composition, structural features, and dielectric behavior in cast Bi-Ti-Si-Nd glass-ceramics. Particular attention is given to the influence of the amorphous network containing SiO₂ as a traditional glass former, as well as the formation of amorphous crosslinking Si-O-Ti structures acting as non-traditional glass formers.