Temperature dependence of unipolar fatigue behavior of lead-free alkali niobate ceramics

Abstract

The unipolar fatigue behavior of undoped Li 0.06 Na 0.52 K 0.42 NbO 3 (LNKN6-a) and the same compound with additives (LNKN6-b) were observed. Unipolar cycling was performed between room temperature and 150°C under a high unipolar electric field of 4 kV/mm. LNKN6-a fatigued under crack formation throughout the examined temperature range. The switchable polarization 2P r of LNKN6-a decreased for 20% (=2¯C/cm 2 ) at 150°C. In contrast, mechanical degradation was not observed in LNKN6-b. The switchable polarization 2P r of LNKN6-b decreased for 15% (=3.2¯C/cm 2 ) at 150°C. It should be noted that at 50°C, fatigue-free behavior was observed for LNKN6-b over at least 10 6 cycles. The influence of phase transition on this fatigue-free behavior was discussed.

Electrical Reliability and Segregated Manganese Behavior on Multilayered (Li,Na,K)NbO₃ Piezoceramics with Pd Electrodes

“…comparable to PZT-based piezoceramics. Therefore, we concentrated on developing improved LNKN electrical and mechanical reliability using microstructural control 17,18) , and mechanical fatigue evaluations 19,20) .…”

Cyclic properties and impedance analysis of (Li,Na,K)NbO3-based multilayered piezoceramics

“…Polarization-electric field (P-E) curves and impedance spectra were recorded 24 h after poling treatment and after the fatigue test to account for aging effects. 14,15) Impedance measurements were conducted at 10 °C intervals in the temperature range from 400 °C to 500 °C with a downward sweep in a 0.5 V mm −1 oscillating field using a frequency response analyzer (NF FRA5097) connected to a current amplifier (NF CA5350). Piezoceramics have resonance frequencies, and the permittivity of these materials jumps near these frequencies.…”

“…27) The amplitude during the poling and fatigue tests was approximately three times that of the coercive field (E C ) of LNKN6-a. 15) The decrease in impedance as the as-poled sample was fatigued [Fig. 3(c)] could have been due to an increase in the volume fraction of domains that oriented toward the applied field, which was facilitated by DW pinning.…”

(Li,Na,K)NbO3-based multilayer piezoceramic with Ag/Pd inner electrodes

“…Thus, LNKN-based piezoceramics physical properties, [7][8][9][10][11][12][13][14][15] fatigue characteristics, [16][17][18][19] and improvement of the piezo properties [20][21][22][23][24][25][26][27] have been studied by various researchers. Moreover, alkaline niobate piezoceramic-based applications are being developed, such as ultrasonic motors, inkjet heads, electric buzzers, and knocking sensors.…”