Preparation and microwave dielectric properties of 3ZnO•B2O3 ceramics with low sintering temperature

The preparation and dielectric properties of 3ZnO center dot B2O3 ceramics were investigated. Dense 3ZnO center dot B2O3 ceramics were obtained as sintered in the temperature range from 950 to 1000 degrees C for 3 h. The X-ray diffraction showed that the obtained ceramics were of a monoclinic 3ZnO center dot B2O3 structure. The ceramic specimens fired at 955 degrees C for 1 h exhibited excellent microwave dielectric properties: epsilon(r) similar to 6.9, Q x f similar to 20,647 GHz (@6.35 GHz), and tau(f) similar to -80 ppm/degrees C. The dependences of relative density, epsilon(r). and Q x f of ceramics sintered at 955 degrees C on sintering soaking time showed that they all reached their plateaus as the soaking time was up to 60 min. Meanwhile, 3ZnO center dot B2O3 ceramics had no reaction with silver during cofiring, indicating it is a potential candidate for low-temperature cofired ceramic (LTCC) substrate. (C) 2011 Elsevier Ltd. All rights reserved.