Microwave properties and microstructures of La2/3TiO3 stabilized with NiO

(1-x)La2/3TiO3-xTiNiO(3) ceramics with x ranging from 0.01 to 0.2, were ela borated by conventional solid-state reaction starting from TiO2, La2O3, and NiO powders. These compositions have been identified as secondary phases d etected in (Zr,Sn)TiO4 ceramics sintered with La2O3 and NiO. Microwave reso nators were sintered at temperatures ranging from 1340 to 1380 degreesC. Th ese sintering temperatures have been determined taking into account thermod ilatometric data. Microwave dielectric properties and microstructures were investigated. Perovskite phase La2/3TiO3 was identified by XRD, SEM and EDS together with minor phases. Dielectric constants are in the 50-70 range an d QF values, measured at 3 GHz, are close to 20 000 GHz. One significant co mposition is characterized by k = 69 and QF= 17,000 GHz at 3 GHz. (C) 2001 Elsevier Science Ltd. All rights reserved.