Microstructure and sintering behavior of low temperature cofired Li4/5Mg4/5Ti7/5O4 ceramics containing BaCu(B2O5) and TiO2 and their compatibility with a silver electrode

Abstract

Li_4/5Mg_4/5Ti_7/5O₄ (LMT) ceramics were prepared via a solid-state reaction method. The LMT ceramics, sintered at 1100 °C, presented good microwave dielectric properties with ε_r = 22.8, Q × f = 100 000 GHz and τ_f = −15.0 ppm °C⁻¹. BaCu(B₂O₅) (BCB) was added to lower the sintering temperature of the ceramics. The addition of BCB reduced the sintering temperature, but slightly degraded the microwave dielectric properties of the LMT ceramics. The 0.97LMT–0.03BCB ceramic showed a low sintering temperature of 900 °C and good microwave dielectric properties with an appropriate ε_r of 20.9, high Q × f of 42 104 GHz and negative τ_f of −24.0 ppm °C⁻¹. TiO₂ was added to improve the ε_r and adjust the τ_f value. The 0.85(0.97LMT–0.03BCB)–0.15TiO₂ ceramic, sintered at 875 °C, showed good dielectric properties, with a high Q × f of 37 700 GHz, appropriate ε_r of 23.1 and near-zero τ_f of −5.9 ppm °C⁻¹. Obviously, the 0.85(0.97LMT–0.03BCB)–0.15TiO₂ ceramic is a good candidate for low temperature co-fired ceramic devices.