FERROELECTRIC POLARIZATION FATIGUE IN PZT-BASED RAINBOWS AND BULK CERAMICS

The ferroelectric fatigue behavior of high-displacement reduced and in ternally biased oxide wafer (RAINBOW) actuators was investigated and c ompared with that of conventional bulk ceramics. Piezoelectric lead zi rconate titanates (PZT-5H and PZT-5A) as well as electrostrictive lead lanthanum zirconate titanate (PLZT 9/65/35) materials were studied. P iezoelectric bulk ceramics experienced a 25% decrease in remanent pola rization over 10(8) switching cycles, whereas RAINBOW polarization deg raded by 33%-53%. Bulk ceramic and RAINBOW electrostrictors both fatig ued only 8%. Bulk ceramics fatigued as a result of reorientation of th e polar axes away from the electric-field direction, RAINBOW fatigue w as believed to have been caused by degradation at the interface betwee n the oxide and chemically reduced layers.