Dielectric and piezoelectric properties of piezoceramic/polymer 1–3 composites fabricated by a modified align-and-fill technique

Abstract

Piezoelectric ceramics with compositions (Pb0.94Sr0.04) (Zr0.52Ti0.48)O3 (PZT) and (Ba0.95Pb0.05) (Ti0.99Co0.01)O3 (BT) were synthesized by conventional solid state reaction technique. Three series of 1–3 composites; PZT/monothane-A70, BT/monothane-A70 and PZT/araldite-F were fabricated by a modified align-and-fill technique using the above mentioned piezoceramic compositions. Each series of the fabricated composite comprise five samples with variable ceramic contents (12–35 vol.%) and four samples with fixed ceramic volume fraction (28%) and varied ceramic aspect ratio (0.34–1.00). Dielectric, elastic and resonant characteristics of theses samples were measured. Effects of active piezoceramic composition and polymer influence on the electrical and mechanical properties of fabricated composites as a function of ceramic volume fraction were investigated. Results revealed that PZT based composites exhibit superior properties due to high piezoelectric charge coefficient (d33 ∼ 335 pC/N) and high electromechanical coupling coefficient (k33 ∼ 67%) compared to those of BT composites. It was also observed that electromechanical properties of composites are highly affected by the stiffness of the passive polymer matrix. Low stiffness (C33D ∼ 21–55 GPa) PZT/monothane-A70 composites have better acoustic impedance (Z ∼ 6–14 Mrayl), high piezoelectric charge coefficient (d33 ∼ 202–271 pC/N), high hydrostatic charge coefficient (dh ∼ 136–171 pC/N), high hydrostatic voltage coefficient (gh ∼ 33–114 × 10−3 Vm/N) and high figure of merit (FOM ∼ 4488–19,364 fm2/N) compared to PZT/araldite-F composites encompassing high stiffness (C33D ∼ 23–60 GPa). The influences of ceramic aspect ratio on the electrical properties of fabricated 1–3 composites are also discussed.