Effect of Conductive Graphene on Electric and Piezoelectric Propertie of PZT/Cement Composites and its Mircostructure

• Main Authors: CHEN, JYUN-AN, 陳俊安
• Other Authors: PAN, HUANG-HSING
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/cck9e4

碩士 === 國立高雄應用科技大學 === 土木工程與防災科技研究所 === 106 === ZT/Cement composites containing conductive graphene as the admixture were investigated to explore electric and piezoelectric properties and its microstructure. The PZT/Cement composite consists of cement and PZT, with the equality of 50 vol.%. Graphene was mixed in a PZT/Cement composite as the conductive filler with multi-layers (MG), few-layers (FG) and single-layer (SG) graphene respectively by extra addition. Graphene has been dispersed by ultrasonic in three different solvent, ethanol, acetone and DI Water, before the constituents were mixed. Specimens undergo a temperature treatment before the polarization. The microstructure and surface porosity of specimens were observed by optical microscopy (OM) and scanning electron microscope (SEM). Material properties include relative dielectric constant (εr), dielectric loss (D), resistivity (ρ), impedance (Z), piezoelectric strain factor (d33) and electromechanical coupling coefficient (κt) were measured, and the specimen with no adding graphene was as the counterpart. Results indicate that MG graphene in ethanol solvent following by ultrasonic oscillation for 4 h has a better dispersion. However, more sonication time is needed for FG and SG. More graphene more agglomeration in specimens is observed. This is because the manufacturing of specimens was blended and molded by dried powders. The specimen with 0.1% graphene has less agglomerated, compared with the others. Surface porosity of specimens decreased with the increase of graphene. Before the polarization, the values of εr and D increase and that of ρ and R decrease if the content of graphene increases. The electric properties tended to be stable after 30 days due to specimens were placed in the environment of 50% relative humidity that causes less hydration of cement. After the specimens were polarized by 1.5 kV/mm electric field, the value of d33 and εr grow with the age. The highest values of d33 and εr with d33 = 75.3 pC/N (23℃)、d33=101.7 pC/N (140℃)、εr =250 (23℃)、εr =371 (140℃) were measured for 0.1% MG specimens. Adding graphene to PZT/Cement composites can promote electromechanical coupling coefficient κt, the optimum content for MG is 0.5 vol%, and 0.3 vol.% for both FG and SG.