Fatigue responses of lead zirconate titanate stacks under semibipolar electric cycling with mechanical preload

Abstract

Phase diagrams, dielectric response, and piezoelectric properties of epitaxial ultrathin (001) lead zirconate titanate films under anisotropic misfit strains Lead zirconate titanate ͑PZT͒ stacks that had an interdigital internal electrode configuration were tested to more than 10 8 cycles. A 100 Hz semibipolar sine wave with a field range of +4.5/ −0.9 kV/ mm was used in cycling with a concurrently-applied 20 MPa preload. Significant reductions in piezoelectric and dielectric responses were observed during the cycling depending on the measuring condition. Extensive partial discharges were also observed. These surface events resulted in the erosion of external electrode and the exposure of internal electrodes. Sections prepared by sequential polishing technique revealed a variety of damage mechanisms including delaminations, pores, and etch grooves. The scale of damage was correlated with the degree of fatigue-induced reduction in piezoelectric and dielectric responses. The results from this study demonstrate the feasibility of using a semibipolar mode to drive a PZT stack under a mechanical preload and illustrate the potential fatigue and damages of the stack in service.

Fatigue-free unipolar strain behavior in CaZrO3 and MnO2 co-modified (K,Na)NbO3-based lead-free piezoceramics

“…8,9 For the PZT family, many fatigue studies can be found in the literature. [10][11][12][13] One of the most accepted mechanisms explaining unipolar fatigue behavior of PZT ceramics is a charge agglomeration model, embodied by the redistribution of charge carriers during cycling and their agglomeration at the grain boundaries and internal defects. 9,[14][15][16][17] However, recent fatigue studies on newly developed lead-free ceramics have revealed that the models commonly used to describe fatigue in PZT-based systems do not always fit.…”

Performance of piezoelectric actuators in a hydrogen environment: Experimental study and finite element modelling

“…Using an end screw and a spring (k ¼ 25 N mm À1 ), a compressive preload was applied to the actuator in order to tighten it between the moving end and the fixed end. Such a preload is also present in fuel injectors for the purpose of alignment, counteracting stress concentrations and other design requirements [20,22]. A preload of 2 MPa was applied during quasi-static loading and 15 MPa during dynamic loading which was measured using a force sensor (Futek ® ) placed between the shaft and the moving end.…”

“…Performance of piezoelectric stack actuators under quasistatic electric loading [20], dynamic electric loading [21] and cyclic fatigue loading [22] has been investigated in the past under conditions that are similar to the operating and ambient conditions of a fuel injector. Senousy et al [23] investigated self-heat generation in the actuators and its resulting effects on performance.…”

Investigation of partial discharge in piezoelectric ceramics

“…Furthermore, it should also be noted that repetitive PDs may cause progressive long-term deterioration of the piezoelectric system when the operating voltage is higher than the PD inception voltage, although a single PD magnitude is small. Partial discharge has been reported to be a reason for electrical fatigue [11], crack growth [12], and electrical failure [13] of piezoelectric ceramics. Hence, it is essential to investigate the PD characteristics of piezoelectric ceramics.…”