In this study, microwave dielectric ceramics of TeO2 with various amounts of CaTiO3 and SrTiO3 were prepared. The densification, microstructural evolution, and dielectric properties of the ultra-low-fire ceramic composites were characterized. Three phases including TeO2, TiTe3O8, and CaTe2O 5 or SrTe2O5 were observed in the CaTiO 3- or SrTiO3-added TeO2 system. Eutectic reactions of the CaTe2O5-TeO2 and SrTe 2O5-TeO2 systems occurred at 650° and 590°C, respectively, enhancing the densification through liquid-phase sintering. The X-ray diffraction observations were confirmed as the Raman spectra located at 450-520 and 780-820 cm-1 corresponded, respectively, toTiTe3O8 and CaTe2O5 or SrTe2O5. The densification temperaturesof TeO 2-CaTiO3 ceramics ranged from 630° to 670°Cdepending on the CaTiO3 content, while all TeO 2-SrTiO3ceramics were densified at 610°C. TeO 2-10 wt% CaTiO3and TeO2-15 wt% SrTiO 3 ceramics were found to sustainbest performance in CaTe 2O5-TeO2 and SrTe2O 5-TeO2 systems. They showed the following major microwave dielectricproperties: eεr-28.6, Q×f≈15 600 GHz, and τf≈-3.24 ppm/°C, and eεr≈28.7, Q×f≈12 400 GHz, and τf≈-3.81 ppm/°C,respectively.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry