Electric fatigue of BCZT ceramics sintered in different atmospheres

Abstract

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics with excellent piezoelectric properties and environment friendliness are very potential alternatives for PbZrxTi1−xO3 (PZT) ceramics. The stability and reliability of ferroelectricity and piezoelectricity in BCZT ceramics under cyclic electric field are crucial to its long-term application. Herein, BCZT ceramics were synthesized by sol–gel method and different sintering atmospheres and the influences of sintering atmosphere on the fatigue behaviors of ferroelectric and piezoelectric properties have been investigated. XPS results confirm that the oxygen vacancy concentration of BCZT ceramics sintered in oxygen, air, and nitrogen atmosphere gradually increases. After 106 cycles, the polarization of all BCZT ceramics decreases to some extent and the fatigue resistance of polarization of BCZT ceramics sintered in the air is superior to BCZT ceramics sintered in oxygen and nitrogen atmospheres, which may result from the additional contribution of higher leakage current caused by relatively poor densification of BCZT ceramics sintered in air to polarization. The internal bias field of BCZT ceramics sintered in air, O2 and N2 atmospheres after fatigue decreases, and the reduced amplitude of internal bias field in BCZT ceramics with less oxygen vacancies sintered in air and oxygen atmospheres is obviously higher than that in BCZT ceramics with more oxygen vacancies sintered in nitrogen atmosphere, which is due to the redistribution of oxygen vacancy under the repetition of external electric field. After 106 cycles, the maximum electric field-induced strain and d33* of BCZT ceramics sintered in the air and oxygen atmospheres decrease and that of BCZT ceramics sintered in nitrogen atmosphere increases. The enhanced fatigue resistance of piezoelectric response of BCZT ceramics sintered in nitrogen atmosphere results from the interaction of (100) orientation, grain refinement, and “wake up” effect caused by the repetition of enough external electric field.