Structure, sintering behavior, and microwave dielectric properties of (1-x) CaWO4-xYLiF4 (0.02 ≤ x ≤ 0.10) ceramics

Structures and sintering behaviors of (1-x) CaWO4-xYLiF(4) (0.02 <= x <= 0.10) ceramic have been investigated by X-ray powder diffraction (XRD), dilatometry, scanning electron microscopy (SEM) in this work. The microwave dielectric properties were measured with a network analyzer at the frequency of about 8-15 GHz. Limited solid solution could be formed within the compositional range of x< 0.1. The sintering temperature of CaWO4 could successfully be reduced to similar to 750 degrees C/2 h by doping with small amount of YLiF4. An optimized microwave dielectric properties with epsilon(r) = 10.5, Q x f = 73 000 GHz and tau(f) = -37.7 ppm/degrees C could be obtained after sintered at the 750 degrees C for 2 h for x= 0.04 compositions. XRD and back scattering SEM analysis indicated that the (1 x) CaWO4-xYLiF(4) (x= 0.04) ceramic could be chemically compatible with Ag after sintering at 750 degrees C/2 h. (C) 2014 Elsevier Ltd. All rights reserved.