Densification and microwave dielectric properties of Ca1.15Sm0.85Al0.85Ti0.15O4 ceramics with B2O3 addition

Ca1.15Sm0.85Al0.85Ti0.15O4 ceramics with 0.1-1.0 wt% of B2O3 additive were prepared and characterized. Ca1.15Sm0.85Al0.85Ti0.15O4 - x wt% B2O3 ceramics exhibited a significant reduction of densification temperature (∼200 °C) while the acceptable microwave dielectric properties could be obtained. The dielectric constant (εr) varied inconspicuously with the B2O3 content, and the temperature coefficient of resonant frequency (τf) changed toward more negative. While, the Q × f value varied slightly up to x = 0.15 and degraded monotonously with further increasing x. The residual amorphous glass phase in the matrix and the appearance of secondary phase should be responsible for the deterioration. The best combination of microwave dielectric properties (εr = 19.8, Q × f = 89,420 GHz and τf = −1.38 ppm/°C) was obtained for the present ceramics with x = 0.15 wt% sintered at 1325 °C.