(Ba,Sr)TiO3半导化陶瓷PTC效应的改善

he PTC behavior of (Ba,Sr)TiO3 ceramics was modified by sintering temperature, acceptor doping and liquid-phase additives. Their influence was discussed with combining the microstructural changes and the theoretical studies. The results show that lower sintering temperature is not desirable for low room-temperature resistivity and high resistance jump, whereas high sintering temperature is favorable for good resistance jump. With the increase in MnO2 content and the addition of BN, PTC effect is enhanced due to the high effective acceptor-state density and the improved microstructure, respectively. The room-temperature resistivity almost remains the same, the resistance jump is elevated by 2.5 orders and the resistivity-temperature coefficient is increased from 4.0 %/ oC to 13.8 %/ oC after MnO2 content increases from 0.04mol.% to 0.05mol.% and 2mol.% BN is introduced.