Influence of aluminium inclusions on dielectric properties of three-phase PZT–cement–aluminium composites

Abstract

Novel three-phase piezoelectric composites that comprised lead zirconate titanate (PZT), aluminium and Portland cement were fabricated at a low poling voltage of 0 . 6 kV/mm and temperature of 1608C. Aluminium and PZT particles were distributed in a Portland cement matrix, and the dielectric constant, tan ä and strain coefficients were experimentally investigated as a function of inclusion volume fraction. The three-phase piezoelectric composites were found to possess higher piezoelectric strain coefficients, d 33 , than their two-phase counterparts (PZT and Portland cement composites). The highest value of d 33 observed for the three-phase composite was 8 . 1 pC/N for volume fractions of 0 . 7 and 0 . 2 for PZT and aluminium respectively, which was 164% of the value observed for the two-phase composite, at the same PZT volume fraction. An analytical model was used to predict values for the effective dielectric constant of the three-phase composites, and these values compared reasonably well to the empirical data. An investigation of sample degradation as a function of time was performed. Samples showed the highest degree of reduced dielectric performance occurred within two days of data capture, and minimal subsequent reduction in performance after 300 d. Electrical properties of the composites are influenced by the oxidation of aluminium by the alkaline constituents in the cement matrix, distribution of PZT and aluminium within the matrix, particle agglomeration, inclusion size, contact resistance between particles and air voids. The increased dielectric and piezoelectric strain coefficients, demonstrate that these types of materials may be useful in applications such as structural health monitoring and energy harvesting.

Dielectric and piezoelectric properties of percolative three-phase piezoelectric polymer composites

“…Two-phase piezoelectric composites, comprised of piezoelectric particles embedded within a continuous polymer matrix, have attracted much attention due to their flexibility and ease of processing, 1,2 and applications to dielectric, [3][4][5] sensing/actuating, [6][7][8][9] energy harvesting, 1,9,10 and acoustic damping [11][12][13] applications. However, these materials suffer from relatively small values of piezoelectric and dielectric properties due to the inherent insulative properties of the polymer matrix phase, [14][15][16][17][18] which is associated with difficulties in the polarization of these materials 19 and contact resistance at the particle/matrix interface.…”

Cement-Based Piezoelectric Ceramic Composites for Sensing Elements: A Comprehensive State-of-the-Art Review

“…However, the difference in fabrication parameters and various raw materials sources leads to a great variety in the final piezoelectric performance. [40] 2.64-3.37 [37,40] 3.0-4.2 [37,40] Acoustic impedance (MRayl) 21.2-30 [37] 3.5-8 [41] 6.9-10.4 [42] Elasticity modulus (GPa) 50-75 [38,43] 10-20 [44] 19.0-48.6 [45] In the last two decades, the performance improvement of CPCs has been performed. The significant variety in the final piezoelectric performance illustrates the existing shortcoming and insufficient understanding around the composite.…”

Fabrication and Characterization of Flexible Three-Phase ZnO-Graphene-Epoxy Electro-Active Thin-Film Nanocomposites: Towards Applications in Wearable Biomedical Devices

“…Furthermore, these properties can be tailored for application in biomedical wearable devices based on the composite bulk and microstructural properties and the working frequency ranges [38]. Thus, graphene nanoplatelets are incorporated as the third phase in the composite to enhance the electrical and mechanical properties [39][40][41][42]. Due to its high conductivity, the electron transport properties or the sensing properties of the composite can be enhanced [34][35][36].…”