Effect of BaTiO3 templates on the electrical characteristics of (Ba, Ca)(Ti, Sn, Hf)-based ceramics under the reducing atmosphere for actuator applications

Abstract

In this research, a cylindrical rotary linear piezoelectric motor was first fabricated using a textured (Ba0.968Ca0.032)(Ti0.96Sn0.005Hf0.035)O3 lead-free piezoelectric plate as the motor vibrator in the first bending vibration mode. The d31 and Qm values of the proposed ceramics were determined to be the key factors affecting ultrasonic motors. Therefore, the tape casting method was used to successfully prepare textured (Ba0.968Ca0.032)(Ti0.96Sn0.005Hf0.035)O3 + 2 mol% MnCO3 + 2 mol% Li2CO3 (BCTSHML) ceramics at 1280 °C under 10−7atm oxygen pressure. The maximum figure of merit for the -d31 × Qm value occurred with the addition of a 3 wt% BT textured template. Values of -d31 = 137 pC/N, Qm = 426 for the proposed samples were obtained. The dynamic characteristics of linear piezoelectric motors based on the proposed samples were also studied. The output characteristics of the fabricated devices had a left-pull velocity = 2.38 mm/s, a right-pull velocity = 2.03 mm/s, and a thrust = 2.37 N at 63.6 kHz for an applied voltage of 200 Vp-p. The fatigue behavior of the P-E measurements for the BT template-doped BCTSHML ceramics after 105 bipolar cycles are also shown. The polarization deviation achieved the smallest change rate of 9.1% for the samples with 3 wt% BaTiO3 templates. To suitably inject insulin in diabetes patients, the modified piezoelectric motor can launch a small amount of insulin aqueous solution in a limited time with limited linearity error (<2.3%). This is first reported result on the use of textured lead-free piezoelectric ceramics under a reduced atmosphere with sintering temperatures <1300 °C for high-power piezoelectric devices.