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

Abstract

Multilayered (Li,Na,K)NbO 3 lead-free piezoceramics with Pd inner-electrodes were fabricated by controlling the additive amounts of x mol% MnCO 3 (x = 0.0, 0.5, 1.0, and 2.0) together with other additives. The multilayered samples containing the Mn compound had a markedly increase in electric resistivity from the order of 10 7 to 10 11 Ω•cm at 100°C. Moreover, the normalized electric-field-induced strains for x = 1.0 were over 350 pm/V at 5 kV/mm. The Mn distributions in several multilayered samples were investigated using a scanning electron microscope with an energy dispersive X-ray spectrometry. The segregated Mn phases were observed almost in the vicinity of Pd inner electrodes. In addition, mapping of Mn content for x = 2.0 indicated that segregated Mn phases existed in the ceramic layers. We hypothesize that this complex Mn distribution was related to the results of a continuous driving fatigue test. The multilayered sample with x = 2.0 only maintained a stable state of driving current for fatigue tests over 10 6 cycles using 0~6 kV/mm triangle wave form at 100°C. This significant electrical reliability was provided by the segregated Mn phases in the ceramic layers.

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

“…The driving electric field of 16 kV mm −1 in MLPC-L had markedly high electric fields than other multilayer piezoceramics using alkaline niobate ceramics. [33][34][35][36][37][38][39][40] This is due to the high densification of MLPC-L, as discussed previously.…”

“…In terms of additive effects, our previous study of Li, Si, and Mn additives in LNKN ceramic concluded that these compounds do not provide a large shift of phase transition and Si and Mn compounds were segregated in the LNKN ceramic body. 38,40) Moreover, the addition of Ba at 0.5 at% did not change the phase transition of the (Na,K)NbO 3 ceramic. 43) Therefore, the changes in the Curie temperature and the monoclinictetragonal phase transition temperature of MLPC-L imply the existence of solid solutions of Ag in the perovskite structure, as also shown by the SEM-EDS results.…”

“…[28][29][30][31][32] Forming multilayered piezoceramics increases the displacement per unit volume. Many researchers [33][34][35][36][37][38][39][40] have fabricated multilayered piezoceramics using alkaline niobate ceramics because the d 33 values are lower than those of PZT-based piezoceramics. Therefore, to obtain a LNKN multilayered piezoceramic displacement performance similar to that of PZT-based multilayered piezoceramics, the number of stacking layers should be increased, and the thickness of one layer should be less than that of PZT.…”

High-power properties of (Sr,Ca)2NaNb5O15piezoelectric ceramics in a longitudinal mode

“…The various candidate materials such as (K,Na) NbO 3 -based and (Bi,Na)TiO 3 -based materials and (Sr,Ca) 2 NaNb 5 O 15 , and bismuth layer-structured ferroelectrics have been actively studied not only from the viewpoint of environmental conservation but also for deriving new values from the lead-free materials the advantages of which are deficient in PZT ceramics. [11][12][13][14][15][16][17][18][19][20][21][22][23] That is, PZT ceramics easily experience a large strain and produce a noticeable nonlinearity under practical use condition as the high-power properties, which increase heat generation with decreasing quality factor and deteriorate the piezoelectric performance. Some lead-free piezoelectric materials have high heat resistance and strength and superior high-power properties and so on, respectively.…”

High-power properties of crystal-oriented (Sr,Ca)2NaNb5O15piezoelectric ceramics and their application to ultrasonic motors

“…The various candidate materials, such as (K,Na)NbO 3 -based and (Bi,Na)TiO 3 -based materials and (Sr,Ca) 2 NaNb 5 O 15 , and bismuth layer-structured ferroelectrics, have been actively studied not only from the viewpoint of environmental conservation but also for deriving new values from the lead-free materials, the advantages of which are deficient in PZT ceramics. [9][10][11][12][13][14][15][16][17][18][19][20][21] That is, PZT ceramics easily experience a large strain and produce a notable degree of nonlinearity under practical use conditions as the high-power properties, which increase heat generation with decreasing quality factors and deteriorate the performance of PZT ceramics. The lead-free piezoelectric materials have high heat resistance, strength and superior high-power properties and so on, respectively.…”