Effect of B₂O₃ doping on the properties of 0.69CaTiO₃-0.31LaAlO₃ microwave dielectric ceramics

The effects of B₂O₃ additive on the sintering and microwave dielectric properties of 0.69CaTiO₃-0.31LaAlO₃ ceramics prepared by conventional solid-state route were investigated. The results of X-ray diffraction analysis showed that the addition of B₂O₃ does not change the crystal phase of ceramics. Moderate addition of B₂O₃ could not only effectively lower sintering temperature and promote the densification but also improve the dielectric properties. The 0.3wt% B₂O₃-doped 0.69CaTiO₃-0.31LaAlO₃ ceramic sintered at 1500°C exhibits the optimal dielectric properties: ε_r≈45.4, Q_f≈52800 GHz, τ_f≈8.78 ppm/°C.