Preparation and Characterization of a New Microwave Dielectric Ceramic Ba_4ZnTi_(11)O_(27)

摘要

Preparation, sintering behavior, and microwave dielectric properties of Ba_4ZnTi_(11)O_(27) ceramic were investigated. The single-phase Ba_4ZnTi_(11)O_(27) ceramic can be well densified in the temperature range from 1175° to 1250℃ with a relative density about 97%. X-ray diffraction data show that Ba_4ZnTi_(11)O_(27) has a monoclinic structure (C2/m), with lattice parameters of a = 19.81549 A, b = 11.43072 A, and c = 9.91129 A when the sintering temperature is 1200℃. Pure monoclinic Ba_4ZnTi_(11)O_(27) ceramic sintered at 1200℃ for 2 h exhibits good microwave dielectric properties with a permittivity about 36.8, Q ×f value about 16460 GHz, and temperature coefficient of resonant frequency about 17.2 ppm/℃. The addition of BaCu(B_2O_5) can effectively lower the sintering temperature from 1200° to 925℃ and does not induce degradation of the microwave dielectric properties. Obviously, the Ba_4ZnTi_(11)O_(27) ceramic can be applied to microwave low-temperature cofired ceramics devices.