Improved high q value of MgTiO3-CaTiO3 microwave dielectric ceramics at low sintering temperature

Abstract MgTiO 3 -based ceramics have been prepared with conventional solid-state route. With 5 mol% CaTiO 3 addition, 0.95MgTiO 3 -0.05CaTiO 3 ceramics can give e r ∼20–21, Q×f values ∼56,000 (at 7 GHz) and a τ f value of ∼0 ppm/°C. However, sintering temperature still remained above 1400°C. Doping with B 2 O 3 (up to 5 wt%) can effectively promote the densification and the dielectric properties of 0.95MgTiO 3 -0.05CaTiO 3 ceramics. It is found that 0.95MgTiO 3 -0.05CaTiO 3 ceramics can be sintered at 1200°C due to the liquid phase effect of B 2 O 3 addition observed by Scanning Electronic Microscopy. The effect of B 2 O 3 addition on the microwave dielectric properties and the microstructures of 0.95MgTiO 3 -0.05CaTiO 3 ceramics are also investigated. For practical applications, 0.95MgTiO 3 -0.05CaTiO 3 ceramics with 2 wt% B 2 O 3 addition gives: e r ∼21.2, Q×f values ∼62,000 (at 8 GHz), and a τ f value of ∼4 ppm/° C.