Temperature stability of dielectric properties for xBiAlO3-(1 − x)BaTiO3 ceramics

xBiAlO3-(1 − x)BaTiO3 [xBA-(1 − x)BT] polycrystalline ceramics were prepared by solid-state reaction method and sol-gel method, respectively. The ceramics were in tetragonal phase when x ≤ 0.1, transformed to pseudocubic at x > 0.1. The temperature stability of the dielectric constant for BA-BT was improved with BA contents increasing. Of particular interest was that the ceramics prepared by sol-gel method had less secondary phase, exhibiting much improved dielectric behavior. Among them, 0.3BA-0.7BT met the requirement of capacitance variation (ΔC/C ≤ ±15%) in the temperature range of −55 to 440 °C with moderate dielectric constant (ɛ = 660) and low dielectric loss (tan δ = 1.2%) at room temperature (1 kHz). Nb-doped 0.2BA-0.8BT ceramics were investigated to improve the dielectric temperature stability at high-temperature end. It is found that all samples with 0.01-0.04 mol Nb addition satisfied the X8R specification.