Microwave dielectric properties of low-fired Li2SnO3 ceramics co-doped with MgO–LiF

• Low-fired Li2SnO3 ceramics co-doped with MgO–LiF are fabricated.
• A novel phase Li2Mg3SnO6 was observed with increasing MgO content.
• Addition of LiF lowered sintering temperature of Li2SnO3–MgO ceramics to 880 °C.
• The microwave dielectric properties of ceramics were optimized by Li2Mg3SnO6 phase.
• Ceramics with well dielectric properties are suitable for LTCC applications.

Low-fired Li2SnO3 ceramics co-doped with MgO–LiF were fabricated by a conventional solid-state route, and their sinterability, microwave dielectric properties were investigated. With increasing MgO content, a novel phase Li2Mg3SnO6 was formed. A near-zero τf value was obtained at 1325 °C for Li2SnO3-8 wt% MgO ceramics. Furthermore, LiF addition not only successfully lowered the sintering temperatures to 880 °C but also promoted formation of Li2Mg3SnO6. The microwave dielectric properties of Li2SnO3-8 wt% MgO ceramics were further optimized with increasing Li2Mg3SnO6 content. The excellent microwave dielectric properties (εr = 14.7, Q × f = 78,400 GHz, and τf = −0.9 ppm/°C) were achieved at 880 °C for Li2SnO3-8 wt% MgO-2 wt% LiF ceramics, which is compatible with Ag electrodes and suitable for the low-temperature co-fired ceramics (LTCC) applications.

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