Applications of ferroelectric ceramics, ranging from components for sensors, memory devices, microelectromechanical systems, and energy convertors, all involve planar and rigid layouts. The brittle nature of such materials and their high-temperature processing requirements limit applications to devices that involve only very small mechanical deformations and narrow classes of substrates. Here, we report a strategy for integrating nanoribbons of one of the most widely used ferroelectric ceramics, lead zirconate titanate, in “wavy” geometries, on soft, elastomeric supports to achieve reversible, linear elastic responses to large strain deformations (i.e., stretchable properties), without any loss in ferroelectric or piezoelectric properties. Theoretical and computational analysis of the mechanics account for these characteristics and also show that the amplitudes of the waves can be continuously tuned with an applied electric field, to achieve a vertical (normal) displacement range that is near 1000 times l...

Stretchable ferroelectric nanoribbons with wavy configurations on elastomeric substrates.

High-efficiency compressive-mode energy harvester enhanced by a multi-stage force amplification mechanism

Mechanical, piezoelectric and dielectric properties of PZT ceramics (Pb 0.98 M 0.02 [(Zr 0.535 Ti 0.465 ) 0.995 ]O 3 , M=Er, Gd, Eu, Nd, La and Bi) have been studied. The fraction of A sites occupied by the different additives is estimated and is found to increase with the ionic radius of the additive ion. The density is high in Bi-, Gd- and Eu-PZT samples. Small amounts of the pyrochlore phase are present in Gd- and Eu-PZT. A maximum strength of 80–100 MPa and K IC of ∼1.5 MPa m 1/2 are obtained in Gd- and Eu-PZT. The R -curve behavior becomes more pronounced in Gd- and Eu-PZT, and it is observed that the strength and K IC increase with the slope of the K IC versus c 1/2 plot. Very good piezoelectric properties, i.e. d 33 of 410 PCN −1 , dielectric constant of 1005, κ p of 0.49 and the hydrophone figure of merit, d h g h , of 2760 are obtained for Nd-PZT. The piezoelectric properties in Bi-PZT are also higher than for the undoped composition, while for the Gd-PZT, these are slightly inferior. For all other compositions, the piezoelectric properties are not affected much.

Effect of rare earth (Er, Gd, Eu, Nd and La) and bismuth additives on the mechanical and piezoelectric properties of lead zirconate titanate ceramics

Power applications generate high stresses which can damage piezoceramic components. In this study tensile fracture of several types of PZT (hard/soft) is investigated. After validation of the specimen geometry by means of numerical simulation, samples are led to failure using a specific device. Weibull law parameters enable the characterisation of the tensile strength distribution and highlight clear differences between soft and hard ceramics. A fractographic approach emphasises the specificities of the fracture mode and the fracture origin for each type of samples.

Tensile fracture of soft and hard PZT

Influences of temperature and electric field on the bending strength of lead zirconate titanate ceramics

Fracture strength and stress-strain behavior under tensile stress in piezoelectric ceramics have been investigated with special emphasis on the effects of poling conditions. The materials used in this work are the commercial piezoelectric ceramics, PbZrO3-PbTiO3 (PZT) and BaTiO3. First, an attempt was made to evaluate the tensile strength properties of samples having a specially designed specimen geometry. In the actual tensile test, fracture did not occur at the gripping portion at all, indicating usefulness of the present tensile test method. Not only fracture strength, but also elastic properties, tensile modulus and Poisson's ratio, were evaluated. Second, an investigation was performed on the stress-strain behavior under tension in this material. As a result, stress-strain response under tension was confirmed to be nonlinear. The nonlinearity in the stress-strain relationship under compression loading has already been reported by some investigators. However, very little work has been done on the tensile stress-strain relationship studied in this paper. Third, acoustic emission monitoring was performed simultaneously during tensile tests, and thus the tensile failure process in piezoelectric ceramics was discussed.

https://iopscience.iop.org/article/10.1143/JJAP.32.4233/pdf

Tensile Stress-Strain Behavior of Piezoelectric Ceramics

Fracture strength and stress-strain behavior under tensile stress in piezoelectric ceramics have been investigated with special emphasis on the effect of environmental temperature. The materials used in this work are the commercial piezoelectric ceramics, PbZrO/sub 3/-PbTiO/sub 3/ (PZT) and PLZT. An attempt was first made to evaluate the tensile strength properties at the room temperature of PZT samples having a specially designed specimen geometry. Not only fracture strength, but also elastic properties, tensile modulus and Poisson's ratio, were evaluated and then the stress-strain behavior under tension was investigated. As a result, stress-strain response under tension for piezoelectric ceramics, PZT and PLZT, was confirmed to be nonlinear. The nonlinearity in the stress-strain relationship under compression loading has already been reported by some investigations. However, very little work has been done on the tensile stress-strain relationship, as studied in this paper. The results of tensile test for PZT samples at the various environmental temperatures indicated that the stress-strain response of poled and nonpoled samples was nonlinear independent of test temperature. The strength of both the poled samples and the nonpoled samples increased linearly against test temperature. Moreover, acoustic emission monitoring was performed simultaneously during tensile tests, and thus the tensile failure process in piezoelectric ceramics was discussed. It was also pointed out that the tensile strength of PLZT increased monotonically against the amount of La.

Nonlinear stress-strain behavior of piezoelectric ceramics under tensile loading

This study deals with the tensile stress-strain behavior of piezoelectric ceramics under various environmental temperatures. The material used is commercial piezoelectric ceramics, PbZrO 3 -PbTiO 3 (PZT). The tensile test was performed under various temperatures in the environmental chamber for poled and nonpoled samples having a specially designed specimen geometry, in order to discuss the effects of temperature on the stress-strain behavior. It was clarified that the stress-strain response of poled and nonpoled samples was nonlinear independent, of test, temperature, and the nonlinearity was stronger with the increase of test temperature. Moreover it was clarified that the stronger the nonlinearity is, the higher the fracture strength is

Kohji Yamamoto

Papers

Tensile Stress-Strain Behavior of Piezoelectric Ceramics

Nonlinear stress-strain behavior of piezoelectric ceramics under tensile loading

Nonlinear stress-strain behavior of PbZrO3-PbTiO3 under various temperatures