Microwave dielectric properties of SiO2 ceramics with addition of Li2TiO3

• Li2TiO3 added SiO2 ceramics were synthesized and investigated.
• The performances were affected by thermal phase transition of Li2(TiO)(SiO4).
• Microwave dielectric properties of the tridymite were reported for the first time.
• 0.945SiO2–0.055Li2TiO3 ceramics sintered at 1050 °C exhibited a high performance.

Using a conventional solid-state reaction method SiO2 ceramics with addition of Li2TiO3 were synthesized and their phase evolution, chemical reactions, microstructure and microwave dielectric properties were studied. The microwave dielectric properties of SiO2 ceramics with addition of Li2TiO3 strongly depend on the formation and the decomposed of Li2(TiO)(SiO4) intermediate phase. The tridymite phase was formed for all samples sintered above 1150 °C and its microwave dielectric properties were reported for the first time (ϵr = 2.58, Q × f = 25,800 GHz,τf = −17.8 ppm/°C). The promising ceramics of 0.945SiO2–0.055Li2TiO3 sintered at 1050 °C were found to possess good microwave dielectric properties: ϵr = 3.21, Q × f = 10,180 GHz and τf ∼ 0.17 ppm/°C.

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