| Summary: | 碩士 === 國立高雄應用科技大學 === 土木工程與防災科技研究所 === 102 === Absract
Cement-based piezoelectric composites consist of PZT inclusions and cement binder, where both are 50% by volume, called as PP material. Several silica-based materials such as quartz flour, diatomaceous earth, silica fume, glass powder, kaolin, carbon black and titanium dioxide, were added to PP material as the replacement of partial cement. Specimens were drily mixed and pressed by 80MPa. After 1 day’s curing, specimens were polarized by 1.5kV/mm at 150℃ for 40 minutes. Microspopic structures and piezoelectric properties of cement piezoelectric compsites were investigated with respect to admixtures and pretreatment temperature.
Experimental results indicate that piezoelectric strain constant (d33) and dielectric constant (r) of PP material increase with increasing temperature pretreatment. The d33 value increases from 57pC/N to 106pC/N and the r from 275 to 455 while the temperature changes from 23℃ to 150℃. Those values are the highest piezoelectric factors up to now. From the observations of optical microscope, the porosity of the composites first decreases, and then increases again as increasing the content of admictures. Lower porosity of the composites has higher d33 and r. Nevertheless, no regularity has found for piezoelectric voltage constant g33. PP materials containing 2% quartz flour has the highest d33 with 134pC/N, compared with the other composites. Adding silica-based materials to PP material can adequately promote electromechanical coupling coefficient Kt and dielectric loss D. Higher dielectric loss of the composites is not easy to be poled during the polarizations.
Keywords: Cement-based composites, Polarization, lead zirconate titanate (PZT), piezoelectric strain constant, silica-based materials
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