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

摘要

The 1-3 type lead-free piezofiber/epoxy composites were prepared using Li, Ta and Sb modified (Na, K)NbO 3 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 m 2/C). The results indicate that those composites have potential to be transducer elements in various applications.