Novel piezoelectric ceramic-polymer aligned composites via the freeze casting method for high frequency transducer applications

Novel piezoelectric ceramic-polymer aligned (2-2) composites were prepared via the freeze casting method. The dielectric constant of the composites versus temperature was determined. The polarization versus field plots for the PZT-5A and the PMN-10PT aligned composite samples show an good ferroelectric behavior for both samples. K_t of PZT-5A composite was measured to be 0.54, which is similar to that of single phase ceramic. The piezoelectric coefficient (d₃₃) of PZT-5H composite was determined to be ~250 pC/N. The measured pulse echo waveform and the normalized frequency spectrum of the PZT-5A aligned composite single element ultrasound transducer showed that the center frequency of the transducer was 58 MHz and the bandwidth at -6 dB was around 70%.