Square cross-section piezoelectric fiber composites: structure and ferroelectric properties

Square cross-section lead zirconate titanate (PZT5) fibers were fabricated by viscous polymer processing. Fibers were perpendicularly arranged in glass tubes and infiltrated with bisphenol-A epoxy resin E51 to form 1–3 composite structures. Phase, micromorphology, mechanical properties and electric properties were identified for fibers and composites. As a result, PZT5 ceramic fibers sintering at high temperature above 1280 °C have pure trigonal perovskite phase and side length of ~300 μm. A brittle broken mechanism was put forward by the linear stress–strain curves of PZT5 fibers. 1–3 composites with 30 % fiber volume fraction demonstrated closed and saturated P–E loops, high remnant polarization P _r of 15.94 μC/cm² and low coercive field E _c of 0.91 kV/mm. Moreover, the composites performed high piezoelectric strain constant d ₃₃, piezoelectric voltage constant g ₃₃ and high anisotropy parameters k _t/k _p. The acoustic impedance Z was about one-third of PZT5 ceramics. The above performances of PZT5 composites showed an excellent application prospect in the fields of ultrasonic medical imaging systems and nondestructive testing.