Superior temperature-stable dielectrics for MLCCs based on Bi0.5Na0.5TiO3-NaNbO3 system modified by CaZrO3

An ultra-wide temperature stable ceramic system based on (1-x) [0.94(0.75Bi(0.5)Na(0.5)TiO(3)-0.25NaNbO(3))-0.06BaTiO(3)]-xCaZrO(3) (CZ100x) is developed for capacitor application in this study. All samples exhibit characteristics of pseudocubic structures in XRD patterns. With CaZrO3 addition, the coupling effect of polar nanoregions (PNRs) is weakening, leading to greatly improved temperature stability of dielectric properties. Among all samples, the most attractive properties are obtained in the composition of CZ10 at <15% variation in dielectric permittivity spanning from -55 degrees C to 400 degrees C and lower than 0.02 of dielectric loss of between -60 degrees C and 300 degrees C, accompanied by high DC resistivity (10(7) m at 300 degrees C, calculated by fitting Jonscher's power law). Furthermore, tentative multilayer ceramic capacitors (MLCCs) composed of CZ10 dielectric and Ag:Pd (70:30) internal electrode layers were fabricated by tape casting and cofiring processes. Temperature-stable dielectric property in formation of MLCC was successfully realized, with small C/C-25 degrees C (<15%) and loss factor ( 0.02) between -55 degrees C and 340 degrees C. Meanwhile, CZ10-based MLCC showed temperature-insensitive energy storage density of 0.31-0.35 J/cm(3) and high-energy efficiency of above 77% at 120 kV/cm in the range of -55 to 175 degrees C. All of these exhibit wonderful temperature-stable dielectric properties and indicate the promising future of CZ10 dielectric as high-temperature ceramic capacitors.