The microwave dielectric properties and microstructures of Ba 2Ti9O20-based ceramics were investigated as a function of B2O3content and sintered at 940°C for 2 h. Densities of the specimens were enhanced with an increase of B 2O3 up to 3 mass% and then decreased. The specimens could be sintered at 940°C without the degradation of the microwave dielectric properties of the specimens. The results of X-ray diffraction (XRD) indicate the presence of five crystalline phases, Ba2Ti9O 20, BaZr(BO3)2, BaZrO3, BaTi 4O9, and Zn3B2O6, in the sintered ceramics, depending upon the amount of B2O3 addition. Moreover, the microstructure of Ba2Ti9O 20-based ceramic with 3 mass% B2O3 addition was analysed by using a transmission electron micrograph, which the composition of dendrite phase should be BaZr(BO3)2. The specimens with 3 mass% B2O3 sintered at 940°C for 2 h showed εr of 28.3, Q × f value of 10784 (Q = 1477), and TCF (τf ) of -8.2 ppm/°C.
All Science Journal Classification (ASJC) codes
- 化學 (全部)