High-Temperature Capacitor Materials Based on Modified BaTiO3

High-temperature capacitor materials sintered at 1120°C were prepared in a BaTiO 3 (BT)-Na 0.5 Bi 0.5 TiO 3 (NBT)-Nb 2 O 5 -ZnO-CaZrO 3 system. The Curie temperature of BaTiO 3 was increased by NBT doping, and a secondary phase occurred when adding ≥5 mol% NBT. The effects of Nb 2 O 5 , ZnO, and CaZrO 3 on the dielectric properties and the microstructure of BT ceramics doped with 1 mol% NBT were analyzed. The overall dielectric constant decreased when the Nb 2 O 5 content increased, and increased when the ZnO content increased. The dielectric constant peak at the Curie temperature was effectively depressed, and a broad secondary dielectric constant peak appeared at 60°C when the ZnO concentration was ≥4.5 mol%. Significant grain growth was observed by scanning electron microscope (SEM) analysis as the amount of ZnO increased. The high-temperature capacitor specification (-55°C to +175°C, AC/C 25°C less than ±15%) is met when 7 mol% to 8 mol% CaZrO 3 is added.