Modification of high-temperature electrical properties in CaTiO3 ceramics by Sm3+ and Al3+ doping

Passive electronic components made from dielectric ceramics can hardly operate at extremely high temperatures, which is attributed to the sharply increasing dielectric loss and leakage conductance. In this work, the widely applicated CaTiO 3 ceramics are used as the matrix, and the high-temperature electrical properties are modified by doping Sm 3+ and Al 3+ . The Sm-doping in CaTiO 3 ceramics can significantly suppress the dielectric relaxation at low frequencies and reduce the high-temperature leakage conductance. Continued doping of Al in Ca 0.6 Sm 0.27 TiO 3 ceramics can further reduce the high-temperature dielectric loss and conductivity. These changes are associated with tighter crystal structures and fewer defects in the ceramics. With Sm and Al doping, the high-temperature dc conductivity of the ceramics is reduced by about 4 orders of magnitude, and a dielectric loss of less than 0.02 and a low temperature cofficient of capacitance (TCC) of − 25 ppm/℃ are obtained over a wide temperature range of room temperature to 530 ℃. Outstanding temperature stabilities are exhibited over a temperature range of 25 ∼ 200 ℃ in energy storage performance and charge-discharge property. Extremely fast discharge speed ( t 0.9 = 16 ns) makes it suitable for pulsed power electronic systems. Such linear dielectric materials are expected to be used in harsh environment of high temperatures.