Investigation of chemical bonds in the ordered Ba3Zn(Nb2-xMox)O9+x/2 ceramics and its effects on the microwave performance

摘要

1:2 ordered Ba3Zn(Nb2-xMOx)O9+x/2(BZNM) ceramics with space group P(3)over-barml were prepared by solid-state method. The nature of chemical bonds in Ba3Zn(Nb2-xMox)O9+x/2(BZNM) ceramics was investigated for the first time. Firstly, the bond energy was closely related to the lattice vibration. High bond energy would lead to weak non-harmonic interactions, which were the main factors of improving Qf. Secondly, polarization of the chemical bond was the principal contributor to the relative permittivity of microwave ceramics. Compared with the traditional method, the calculated result based on the P-V theory reduced the error from 81% to 4.4%. Through the discussion, it was confirmed that the analysis method based on chemical bond was highly feasible and scientific in the microwave ceramics. At last, the system of Ba3Zn(Nb1.992Mo0.008)O-9.004 sintered at 1435 degrees C for 6 h and annealed at 1300 degrees C for 10 h had excellent microwave dielectric properties: epsilon(r) = 38.9, Qf = 102,931 GHz, tau(f) = 19.2 ppm/degrees C, which, to our best knowledge, provided a alternative for the application of millimeter-wave communications.