Microwave dielectric properties of low-fired Li2TiO3–MgO ceramics for LTCC applications

• Temperature stability of Li2TiO3 ceramics were improved by doping MgO.
• The low-fired Li2TiO3–MgO ceramics are fabricated.
• LiF liquid phase reduced sintering temperature of Li2TiO3–MgO ceramics to 850 °C.
• The low-fired Li2TiO3–MgO ceramics possess well microwave dielectric properties.
• The sample was compatible with Ag electrodes and suitable for LTCC applications.

We fabricated the low-fired Li2TiO3–MgO ceramics doped with LiF by a conventional solid-state route, and investigated systematically their sintering characteristics, microstructures and microwave dielectric properties. The results showed that temperature stability of Li2TiO3 ceramics were improved by doping MgO. Well microwave dielectric properties for Li2TiO3–13 wt%MgO (LTM) ceramics with ɛr = 16.4, Q × f = 87,500 GHz, and τf = −1.2 ppm/°C were obtained at 1325 °C. Furthermore, addition of LiF enhanced the sinterability and optimized the microwave dielectric properties of LTM ceramics. A typically sample of LTM-4 wt%LiF ceramics with optimum dielectric properties (ɛr = 15.8, Q × f = 64,500 GHz, and τf = −0.2 ppm/°C) were achieved at 850 °C for 4 h. Such sample was compatible with Ag electrodes, suitable for the low-temperature co-fired ceramics (LTCC) applications.

This figure gives the Q × f and τf of Li2TiO3–MgO ceramics sintered at various temperatures with different LiF contents. Addition of LiF enhanced the sinterability and optimized the microwave dielectric properties of Li2TiO3–MgO ceramics. The excellent microwave dielectric properties (ɛr = 15.8, Q × f = 64,500 GHz, and τf = −0.2 ppm/°C) of Li2TiO3–MgO ceramics sintered at 850 °C illustrated that LiF is a simple effective sintering aids for Li2TiO3–MgO ceramics. Such sample was compatible with Ag electrodes, suitable for the low-temperature co-fired ceramics (LTCC) applications.Figure optionsDownload as PowerPoint slide