| 0-3 cement-based piezoelectric composites and 1-3 cement-based piezoelectric composites are fabricated by compressing technique and cut-filling process,respectively. The piezoelectric properties,dielectric properties and ferroelectric properties of two kinds of composites are studied in detail,and its application is investigated.Effect of forming pressure on piezoelectric and dielectric properties of the composites are studied.The results show that the piezoelectric strain factor d33 and dielectric constantεr increase with the forming pressure increasing, but the forming pressure has little effect on the electromechanical coupling coefficient. The higher the pressure is, the steeper the rate of variation of the dielectric constant with increasing frequency in the range of 40100kHz.Influences of different cement matrix and ceramic on the piezoelectric properties, dielectric properties and ferroelectric properties of the 0-3 cement-based piezoelectric composites are studied.The results indicate that the d33 ,εr and the electromechanical coupling coefficient of the composites made from Portland cement and PLN is superior than that of other cement-based composites. In the range of -40℃20℃,theεr increases slowly with the increasing temperature .In the range of -40℃100℃, the dielectric loss increases with the temperature increasing,and has little change between 100℃and 150℃. In the range of -40℃60℃, the resistivity decreases with the temperature and has little change between 60℃and 150℃.Piezoelctric and dielectric properties of the 1-3 cement-based composites at varied relative humidity are measured and investigated.The results show that the piezoelectric constant and theεr is nearly independent of the humidity below 85%.The piezoelectric voltage factor g33 decreases sharply with increase of the humidity above 85%,but theεr increase. In the range between 50% and 100% ,the humidity has little effect on the Kp and Kt, which exhibits good stability.
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