Alkaline niobate based lead-free ceramic fiber/polymer 1-3 composites: processing and electromechanical properties

Abstract

The 1-3 type lead-free piezofiber/epoxy composites were prepared using Li, Ta and Sb modified (Na, K)NbO3 compositions as the ceramic phase by means of fiber arrangement and epoxy cast. The dense and smooth piezoelectric ceramic fibers with a diameter of 250 μm or less were fabricated by extruding plastic mud pie through micro-holes drilled in a hard mould by means of a laser-cutter. The dielectric, piezoelectric, electromechanical coupling properties and acoustic impedance characteristic of the as-prepared 1-3 composites with different ceramic volume fractions were characterized and compared with the theoretical values as well as those of monolithic ceramics. A nearly pure thickness vibration mode with a resonance frequency over 2 MHz (sample thickness ~1 mm) was formed, together with a high electromechanical coupling coefficient (k t ~ 0.55–0.6), low acoustic impedances (Z ~ 9–14 MRayl) and relatively high piezoelectric voltage coefficient (g 33 ~ 30 × 10−3 m2/C). The results indicate that those composites have potential to be transducer elements in various applications.