Extrinsic effects on microwave dielectric properties of high-Q MgZrTa2O8 ceramics

Abstract

MgZrTa2O8 ceramics with excellent microwave dielectric properties had been prepared through conventional mixed oxide route. All the sintered samples exhibited a single phase with wolframite structure type belonged to P2/c (C2h4) space group. The Raman spectrum revealed a similar lattice vibration in all samples with different sintering temperature. Emphatically, the extrinsic effects on microwave dielectric properties had also been investigated. The microwave dielectric properties of MgZrTa2O8 ceramics presented a significant dependence on the sintering condition. The porosity-corrected permittivity (e-pc) was calculated to investigate the influence of the porosity to the dielectric constant (er). For the high-dense MgZrTa2O8 ceramics, the main factors which had influences on quality factors (Q × f) were the grain size and grain-size distribution. The temperature coefficient of resonant frequency (τf) was depended on the dielectric constant and pores. The typical microwave dielectric properties of MgZrTa2O8 ceramics were er = 22.76, Q × f = 131,500 GHz, τf = −33.81 ppm/°C, sintered at 1475 °C.