Preparation and characterization of hafnium doped barium titanate ceramics

BaHfxTi1−xO3 powders and ceramics with x varying from 0 to 0.15 were prepared via a solid-state reaction technique. Probable reaction pathways were elucidated by employing simultaneous thermogravimetry analysis and differential scanning calorimetry (TGA and DSC). Phase variations in compounds were analyzed by X-ray diffraction (XRD). The microstructures and composition of the powders and ceramics were measured and confirmed by SEM images and EDX spectra. Dielectric properties and piezoelectric properties were investigated. The results suggested that the three transitions in BaTiO3 were pinched by substituting titanium with hafnium and the Curie temperatures decreased as the hafnium content rose in the compounds. A high piezoelectric parameter (d33 ∼ 305 pC/N) was obtained between the orthorhombic and rhombohedral phases.