Low-temperature sintering and microwave dielectric properties of (1-x)Mg4Nb2O9-xCaTiO3 ceramics

The effect of V2O5 additive on the sinterability, microstructure and microwave dielectric properties of (1 - x)Mg4Nb2O9-xCaTiO(3) (0 <= x <= 0.7) ceramics was investigated. Two-phase system was confirmed by the X-ray diffraction patterns and Raman spectra analysis. The specimens with 1.7 wt% V2O5 addition can be well-sintered at the temperature as low as 1150 degrees C. As the x value increased from 0.2 to 0.7, the tau f of specimens can be promoted from - 44 to 134 ppm/degrees C. In particular, a new 0.5Mg(4)Nb(2)O(9)-0.5CaTiO(3) ceramics sintered at 1150 degrees C for 5h exhibited excellent microwave dielectric properties of epsilon(r)=20, Q x f=48000 GHz and tau(f)=-12ppm/degrees C. It is proposed as a candidate material for today's 3G application. (C) 2009 Published by Elsevier B.V.