Improving sintering characteristic and dielectric properties of kermanite (Ca2MgSi2O7) ceramics by Bi2O3-B2O3 addition

Phase constitution, microstructure and dielectric properties of Ca2MgSi2O7 ceramics were studied, and CaTiO3 demonstrated an effective compensation in adjusting temperature coefficient of capacity (TCC) of Ca2MgSi2O7 ceramic. However, Ca2MgSi2O7 or Ca2MgSi2O7-CaTiO3 ceramics showed high dielectric loss due to porous structure. The addition of ≤3.0 wt% B2O3 was very effective in lowering sintering temperature, and dense structure could be obtained at 1100 °C. The addition of Bi2O3-B2O3 can significantly decrease dielectric loss. Ca2MgSi2O7-CaTiO3 ceramic with 5 wt% Bi2O3-2 wt% B2O3 sintered at 1100 °C shows excellent dielectric properties: εr=12.53, tan δ<10−4 (at 1 MHz), and TCC between −26.4 and 29.5 ppm/°C.