Temperature stability and high-Qf of low temperature firing Mg2SiO4–Li2TiO3 microwave dielectric ceramics

In this work, a series of low-temperature-firing (1− x )Mg 2 SiO 4 – x Li 2 TiO 3 –8   wt% LiF ( x = 35–85   wt%) microwave dielectric ceramics was prepared through conventional solid state reaction. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that the Li 2 TiO 3 phase was transformed into cubic phase LiTiO 2 phase and secondary phase Li 2 TiSiO 5 . Partial substitution of Mg 2+ ions for Ti 3+ ions or Li + Ti 3+ ions increased the cell volume of the LiTiO 2 phase. The dense microstructures were obtained in low Li 2 TiO 3 content ( x ≤ 65   wt%) samples sintered at 900   °C, whereas the small quantity of pores presented in high Li 2 TiO 3 content ( x ≥ 75   wt%) samples sintered at 900   °C and low Li 2 TiO 3 content ( x = 45   wt%) sintered at 850 and 950   °C. Samples at x = 45   wt% under sintering at 900   °C for 4   h showed excellent microwave dielectric properties of ε r = 10.7, high Q × f = 237,400   GHz and near-zero τ f = − 3.0   ppm/°C. The ceramic also exhibited excellent chemical compatibility with Ag. Thus, the fabricated material could be a possible candidate for low temperature co-fired ceramic (LTCC) applications.