Microstructure and dielectric properties of LiTaO3 ceramics with MnO2 addition fabricated by hot-pressing sintering

Abstract

Lithium tantalite (LiTaO3) is an excellent single crystal, only a few studies focused on polycrystalline LiTaO3 ceramics, because it is difficult to sintering densification in fabrication process by common sintering. In this paper, LiTaO3 composite ceramics with added 3 wt% MnO2 were obtained by hot-pressing sintering at different temperatures from 1200 to 1350 °C. The sinterability, microstructure and dielectric properties of LiTaO3 ceramics fabricated at sintering temperatures were investigated. The relative density of the LiTaO3 ceramics was significantly enhanced as the sintering temperature increases first and then decreased. The LiTaO3 ceramics achieved the highest relative density (98.6%) and shown homogeneous microstructure when sintered at 1300 °C. The LiTaO3 and manganese oxide phases were observed in the MnO2/LiTaO3 ceramics fabricated at different sintering temperatures. The dielectric properties of MnO2/LiTaO3 ceramics were significantly influenced by the sintering temperatures. The study of dielectric properties revealed that the specimen had excellent dielectric properties when sintering temperature was 1300 °C and the dielectric constant was 78, as it tends to stay invariable at room temperature.