Ultra-Wide Temperature Stable Dielectrics Based on Bi0.5Na0.5TiO3-NaNbO3 System

The microstructure, phase structure, ferroelectric, and dielectric properties of (1-x)Bi0.5Na0.5TiO3-xNaNbO(3) [(1-x)BNT-xNN] ceramics conventionally sintered in the temperature range of 1080 degrees C-1120 degrees C were investigated as a candidate for capacitor dielectrics with wide temperature stability. Perovskite phase with no secondary impurity was observed by XRD measurement. With increasing NN content, (1-x)BNT-xNN was found to gradually transform from ferroelectric (x=0-0.05) to relaxor (x=0.10-0.20) and then to paraelectric state (x=0.25-0.35) at room temperature, indicated by P-I-E loops analysis, associated with greatly enhanced dielectric temperature stability. For the samples with x=0.25-0.35, the temperature coefficient of capacitance (TCC) was found <11% in an ultra-wide temperature range of -60 degrees C-400 degrees C with moderate dielectric constant and low dielectric loss, promising for temperature stable capacitor applications.