Optimization on dielectric properties of Y2Ti2O7 ceramics with Bi2O3-Nd2O3-Nb2O5 co-doping

The present work aimed to explore a kind of microwave dielectric materials with middle-permittivity, high Qf, near-zero τf, and lower sintering temperature. A series of Y2Ti2O7 microwave dielectric ceramics were synthesized by conventional solid-state method. For improving the dielectric properties of Y2Ti2O7 system, Bi2O3, Nd2O3 and Nb2O5 were added and their effects on phase composition, microstructure, and dielectric properties at microwave frequencies were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The queuing score method for multi-target orthogonal design was used to obtain the optimum prescription. The results showed that the Y2Ti2O7 ceramics with 8 wt.% Bi2O3 and 1 mol.% Nd2O3-Nb2O5 were well sintered at 1350 °C, exhibiting excellent dielectric characteristics, i.e. ɛr≈76, Qf≈18980 GHz, τf=+25.5 ppm/°C.