Piezoelectric properties of polymer/lead-free ceramic composites

ABSTRACT

Thermoplastic/lead-free piezoelectric ceramic composite have been prepared. Sodium niobate (NaNbO₃) has been chosen for its high Curie temperature. Moreover, it could be synthesized with two different morphologies: NaNbO₃ nanowires (NN NW's) and NaNbO₃ particles (NN P's). The filler has been dispersed in thermoplastic matrices with different dielectric permittivities ${ϵ}_{\mathrm{M}}$: PA11 ( ${ϵ}_{\mathrm{M}}= 2)$ and polyvinylidene fluoride (PVDF) (${ϵ}_{\mathrm{M}}= 10)$. Due to polarization conditions, only ceramic particles are poled. The piezoelectric coefficient (d₃₃) has been measured in composites. The higher d₃₃ is recorded in composites based on PA11 (d₃₃ = 6.5 pC.N⁻¹ for 30 vol. % NN NW's). The influence of the NN aspect ratio on PVDF/NN composites has been analysed: the higher d₃₃ (d₃₃ = 2.6 pC.N⁻¹ for 25 vol. %) is recorded in PVDF/NN P's. The major interest of these hybrid lead-free piezoelectric composites is mild poling conditions, ductility and thermal stability of piezoelectric performances.

KEYWORDS:

• Lead-free ceramic
• sodium niobate
• polymer/piezoelectric ceramic composite
• thermoplastic polymer
• nanowire
• aspect ratio

Disclosure statement

No potential conflict of interest was reported by the authors.