열에이징이 Pb(ZrxTi1-x)O3 + y [wt%] Cr2O3 세라믹스의 온도 안정성에 미치는 영향

Abstract

PZT ceramics is a representative piezoelectric materials together with quartz, and has been used as the substrates of piezoelectric igniters, transformers, transducers, speakers, electric resonators, filters and ultrasonic motors. The stabilities of the operating frequencies of the resonators and the filters are very important. If the operating frequency in a electronic system was changed due to unstability of the devices, the system might be useless. And SMD type devices easily undergo thermal shock when they are mounted to a electric circuit board. So strict tolerance to thermal shock is required in them. In this paper, the ceramics of the six compositions, Pb(ZrxTi1-x)O3 + y[wt%]Cr2O3 in which x=0.56(rhombohedral phase), 0.53(morphotrophic phase), 0.50(tetragonal phase) and y=0, y=0.3 in respective x were fabricated. Thermal aging shifts the point of zero temperature coefficient resonance frequency to Zr-rich side in PZT system Cr2O3 addition shifts the point of zero temperature coefficient resonance frequency to Ti-rich side in PZT system. Temperature stability of length extensional vibration mode of those specimens was investigated. Both ceramic resonators of the composition with x=0.56, y=0 and the composition with x=0.53, y=0.3 had better temperature stability frequency than the others, and thermal aging could improve temperature stability in those cases.