Low Temperature Sintering and Microwave Dielectric Properties of B 2 O 3 ‐added LiAlSiO 4 Ceramics

The sintering temperature of the LiAlSiO 4 (LAS) ceramics, which exhibited the microwave dielectric properties of ε r = 4.8, Q × f = 36 000GHz, and τ f =8.0 ppm/°C, decreased below 960°C when B 2 O 3 was added. The B 2 O 3 ‐related liquid phase was formed and assisted the densification of the LAS ceramics at low temperatures. The average grain size of the specimen sintered at 950°C increased with the addition of B 2 O 3 but decreased when B 2 O 3 exceeded 12.0 mol%, probably due to the presence of a large amount of liquid phase. The LAS ceramics containing 12.0 mol% of B 2 O 3 sintered at 950°C exhibited the excellent microwave dielectric properties of ε r = 5.3, Q×f = 212 000GHz and τ f =‐7.7 ppm/°C.