High performance Aurivillius-type bismuth titanate niobate (Bi3TiNbO9) piezoelectric ceramics for high temperature applications

This paper reports the significant improved piezoelectric properties of high temperature bismuth titanate niobate (Bi3TiNbO9, BTN) polycrystalline ceramics. The piezoelectric performance of BTN ceramics is significantly enhanced by cerium modifications. The dielectric measurements indicate that the Curie temperature T-c gradually decreases over the temperature range of 907-889 degrees C with cerium contents increasing up to 0.7 wt%. The BTN-5Ce (BTN + 0.5 wt% CeO2) exhibits optimized piezoelectric properties with a piezoelectric constant d(33) of 16 pC/N, which is five times the value of unmodified BTN (d(33) similar to 3 pC/N), while BTN-5Ce maintains a high Curie temperature T-c of 894 degrees C. The temperature-dependent electrical impedance and electromechanical coupling factors (k(p), and k(t)) reveal that the BTN-5Ce exhibits thermally stable electromechanical coupling characteristics up to 500 degrees C but significantly deteriorates at 600 degrees C due to high conductivity at a higher temperature. The thermally stable electromechanical properties in combination with the ceramics' high electrical resistivity (10(6) Omega cm at 500 degrees C) and high Curie temperature (similar to 900 degrees C) demonstrate that cerium-modified BTN ceramics are good materials for high temperature sensing applications. (c) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.