Temperature-dependent resistivity performance of Mn/Y-doped Ba1-xSrxTiO3 compositions with potential thermal control applications

摘要

Doped BaTiO3 ceramics exhibit an attractive application prospect in the adaptive thermal control of electronic devices in spacecraft that originate from its remarkable positive temperature coefficient (PTC) characteristics. However, the Curie temperature of most current BaTiO3-based PTC materials is much higher than the normal operating temperature range of electronic devices. In this work, we successfully synthesized Ba1-xSrxTiO3 ceramics with a room temperature Curie point. The crystal structure, surface morphology and temperature dependence of resistivity are investigated. The Curie temperature where the crystal structure of the composition changes from a paraelectric phase to a ferroelectric phase is adjusted by increasing the doping level(x). In the temperature range 18-120 degrees C, the variation amplitude of resistivity exceeds 10(4), and the positive temperature coefficient effect is as high as 10.7 degrees/0/degrees C. The potential thermal control properties were discussed based on the experimental and theoretical analysis. The heating power of compositions can be automatically changed by varying the operating temperature. At the same initial heating power, the equilibrium temperature of the controlled equipment using the PTC heating element is lower than that when adopting an ordinary heater. Moreover, the effect of thermal control becomes more prominent as the resistivity-temperature coefficient increases.