Bond ionicity, lattice energy, bond energy, and microwave dielectric properties of Ca1-xSrxWO4 ceramics

Abstract The Ca1-xSrxWO4 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) ceramics were fabricated through solid-state reaction, and the relationships among microwave dielectric properties of Ca1-xSrxWO4, bond ionicity, lattice energy and bond energy were systematically investigated for the first time. The patterns of X-ray diffractions of Ca1-xSrxWO4 presented tetragonal scheelite structure and no second phase appeared throughout the entire compositions. Dielectric properties of Ca1-xSrxWO4 were proved to be related to the microstructures: dielectric constant (er) of Ca1-xSrxWO4 was dependent on the bond ionicity; the quality factor (Q×f0) of Ca1-xSrxWO4 was affected by W-site lattice energy when intrinsic loss is dominant; the temperature coefficient of resonant frequency (|τf|) would increase if B-site bond energy decreased. Ca1-xSrxWO4 ceramic showed excellent microwave dielectric properties, er = 9.42, Q×f0 = 79876 GHz and τf = −18.8 ppm/°C when x = 0.08 and sintered at 1100 °C for 4 h.