Microwave properties and microstructures of La23TiO3 stabilized with NiO

(1–x)La2/3TiO3–xTiNiO3 ceramics with x ranging from 0.01 to 0.2, were elaborated by conventional solid-state reaction starting from TiO2, La2O3, and NiO powders. These compositions have been identified as secondary phases detected in (Zr,Sn)TiO4 ceramics sintered with La2O3 and NiO. Microwave resonators were sintered at temperatures ranging from 1340 to 1380°C. These sintering temperatures have been determined taking into account thermodilatometric data. Microwave dielectric properties and microstructures were investigated. Perovskite phase La23TiO3 was identified by XRD, SEM and EDS together with minor phases. Dielectric constants are in the 50–70 range and QF values, measured at 3 GHz, are close to 20 000 GHz. One significant composition is characterized by k=69 and QF=17,000 GHz at 3 GHz.