Synthesis of fine-crystalline Ba0.6Sr0.4TiO3–MgO ceramics by novel hybrid processing route Original Research Article

We report the use of a novel powder-in-sol precursor hybrid processing route to synthesize dense, homogeneous, and fine-crystalline Ba0.6Sr0.4TiO3–MgO (BST–MgO) ceramics as well as the study of the sintering behavior, microstructures, and dielectric properties of the ceramics. Nanosized BST powders are dispersed into BST sol–gel precursor and uniformly distributed BST slurry is obtained after ball-milling mixing. Mg(NO3)·6H2O solution is added to the BST slurry to give homogeneous BST–MgO slurry upon ball-milling mixing. The BST–MgO slurry is dried and calcined prior to pressing and sintering at low temperatures of 1200–1300 °C to form the ceramics. The ceramics possess very low dielectric loss tangent below 0.005 for frequency above 1 kHz and for temperature in the range −190–80 °C. The dielectric constant and dielectric tunability increase, while the ferroelectric transition broadening decreases, with increasing average grain size.