Effects of cerium doping on the microstructure, mechanical properties, thermal conductivity, and dielectric properties of ZrP2O7 ceramics

Abstract

A two-step method, combined with cold isostatic pressing, was used to prepare CeO2-doped ZrP2O7 ceramics, and their microstructure, mechanical properties, thermal conductivities, and dielectric properties were determined. It was found that CeO2 doping could increase the Zr–P and P–O bond lengths, which in turn decreased the thermal conductivity of the ZrP2O7 matrix. Doping with 12 wt% CeO2 simultaneously reduced the sintering temperature and improved the mechanical properties of the ZrP2O7 ceramics, while retaining its low thermal conductivity and good dielectric properties. The maximum cold modulus of rupture of a sample at 1250 °C was 75.91 MPa, which met most conditions for use at room temperature. A COMSOL model was used to predict the thermal conductivity, based on the microstructure, with a relatively high degree of accuracy. The thermal conductivity of the CeO2-doped samples was lower than 1.083 W/(m·K). The dielectric constant was in the range of 5.93–6.52 at 20–40 GHz, and the dielectric loss was less than 4 × 10−3. The ZrP2O7-doped ceramics have potential for application in millimetre wave technology, satellite communication, and vehicle radar fields, because they can meet the high thermal insulation requirements for these applications.