Low-loss and temperature stable (1-x)Ba3P2O8-xMg2B2O5 composite ceramics with low sintering temperature.

In this study, the Ba 3 P 2 O 8 and Mg 2 B 2 O 5 were fabricated by the solid-state reaction method separately, and the (1-x)Ba 3 P 2 O 8 -xMg 2 B 2 O 5 (x = 0.2–0.4) low-temperature co-fired ceramic (LTCC) materials were obtained in the sintering temperature range of 880–960 °C. The phase compositions, microstructures, elemental compositions, and microwave dielectric properties of the (1-x)Ba 3 P 2 O 8 -xMg 2 B 2 O 5 composite ceramics were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and TE 01δ mode dielectric resonator method, respectively. The results revealed that the Mg 2 B 2 O 5 phase and Ba 3 P 2 O 8 phase could coexist well in the (1-x)Ba 3 P 2 O 8 -xMg 2 B 2 O 5 composite ceramics without formation of any new phases. The abnormal grain growth of Ba 3 P 2 O 8 grains was inhibited by the addition of Mg 2 B 2 O 5. In addition, through composition of Ba 3 P 2 O 8 and Mg 2 B 2 O 5 , the temperature coefficient of resonant frequency (τ f) and quality factor (Q×f) were effectively optimized, and the sintering temperature was reduced to 880–960 °C. The optimal performance of 0.8Ba 3 P 2 O 8 -0.2Mg 2 B 2 O 5 composite ceramic was achieved at a sintering temperature of 920 °C, τ f = −1.9 ppm/°C, Q×f = 61,250 GHz, and a low permittivity ε r = 10.7. The chemical compatibility test demonstrated that the composite ceramic could coexist well with silver, which indicated that the 0.8Ba 3 P 2 O 8 -0.2Mg 2 B 2 O 5 composite ceramic is a candidate LTCC material with wide application prospects. [ABSTRACT FROM AUTHOR]