Optimization on dielectric properties of Y₂Ti₂O ₇ ceramics with Bi₂O₃-Nd₂O ₃-Nb₂O₅ co-doping

The present work aimed to explore a kind of microwave dielectric materials with middle-permittivity, high Qf, near-zero τ_f, and lower sintering temperature. A series of Y₂Ti₂O₇ microwave dielectric ceramics were synthesized by conventional solid-state method. For improving the dielectric properties of Y₂Ti ₂O₇ system, Bi₂O₃, Nd ₂O₃ 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-Nb ₂O₅ were well sintered at 1350 °C, exhibiting excellent dielectric characteristics, i.e. ε_r≈76, Qf≈18980 GHz, τ_f=+25.5 ppm/°C.