Microwave dielectric properties of B 2O 3-doped ZnTiO 3 ceramics made with sol–gel technique

Abstract

Nano-sized B 2O 3-doped ZnTiO 3 particles were successfully synthesized through sol–gel technique. The crystallization temperature of ZnTiO 3 from sol–gel process was confirmed at 800 °C by the X-ray diffraction (XRD), thermo gravimetric (TG) and differential scanning calorimetry (DSC) analysis. The B 2O 3 content, the high molding pressure and the sintering temperature had great influence on microstructure and the dielectric properties of materials. According to scanning electron microscopy (SEM) analysis, when sintering reagent (B 2O 3) content was 1 wt.%, the grain growth of ZnTiO 3 sintered at 900 °C was anisotropic, and the grain became regular disc structure with a diameter of 2 μm and thickness of 0.3 μm, which might be attributed to the selective growth of crystal grain in a preferential direction. As-prepared 1.0 wt.% B 2O 3-doped ZnTiO 3 sintered at 900 °C for 4 h possessed excellent dielectric properties: Q × f = 49,000 GHz, ɛ r = 8.87, τ f = −32.35 ppm/°C. The nano-sized, uniform grains contributed to the high quality factor. The porous bulk ceramics contributed to the low dielectric constant.