Microwave Dielectric Properties of Co2La4Ti3Si4O22 Ceramics

Co2La4Ti3Si4O22 ceramic was synthesized by the conventional solid-state ceramic route. The structure and microstructure of the sintered ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopic techniques. XRD study showed the presence of SiO2 as a secondary phase. Attempts were made to obtain phase-pure material by preparing nonstoichiometric Co2La4Ti3Si(4-x)O(22-delta) (where x=0.02, 0.05, 0.1, 0.25, and 0.5) ceramics. The secondary phase of SiO2 could be effectively suppressed for x=0.1 with good microwave dielectric properties. The Co2La4Ti3Si3.9O(22-delta) has epsilon(r)=17.4, Q(u) x f=48 700 GHz, and tau(f)=-155 ppm/degrees C.