Low-temperature sintering and microwave dielectric properties of Ba3Ti4-xZrxNb4O21 ceramics with the substitution of Zr for Ti

Abstract

The effects of substitution of Zr for Ti on the microwave dielectric properties of Ba3Ti4-xZrxNb4O21 (0 <= x <= 4) ceramics were studied. The dielectric constant and the quality factor of the Ba3Ti4-xZrxNb4O21 ceramics decreased slightly with increasing composition x, which could be attributed to a change in the ion polarization and the microstructure caused by the substitution of Zr for Ti. The temperature coefficient of the resonant frequency of Ba3Ti4-xZrxNb4O21 ceramics changed from +50 to +100 ppm/degrees C. Meanwhile, Ba3Ti4-xZrxNb4O21 (x = 1) with a 5 wt% glass frit was densified at a relatively low sintering temperature below 900 degrees C. Ba3Ti4-xZrxNb4O21 (x = 1) ceramics with 7 wt% glass sintered at 875 degrees C exhibited good microwave dielectric properties: k = 52, Qxf = 3000 GHz, and tau(f) = +5 ppm/degrees C.