Related Experiment Video
Updated: Aug 15, 2026
09:38
Strain Sensing Based on Multiscale Composite Materials Reinforced with Graphene Nanoplatelets
Published on: November 7, 2016
Giant Electrostrain from Inherent Strain for KNN-Based Ceramics
Zhenyong Cen1, Zhaoyang Li1, Sixie Chen2
1MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and Materials, Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials, School of Resources, Environment and Materials; Guangxi University, Nanning530004, China.
ACS Applied Materials & Interfaces
|August 13, 2026
Summary
Researchers developed lead-free potassium sodium niobate (KNN) piezoelectric ceramics. Thinning samples enhanced inherent electrostrain, showing promise for low-cost piezoelectric actuators.
Area of Science:
- Materials Science
- Solid State Physics
- Ceramic Engineering
Background:
- Lead-free piezoelectric ceramics are crucial for replacing lead-based materials.
- Potassium sodium niobate (KNN)-based ceramics offer a promising alternative.
- Optimizing their performance, especially electrostrain, is key for applications.
Purpose of the Study:
- To investigate methods for enhancing inherent electrostrain in lead-free KNN ceramics.
- To establish a reliable method for distinguishing bending deformation from electrostrain.
- To explore the role of material thickness and dopant ions in piezoelectric performance.
Main Methods:
- Preparation of KNN-based piezoelectric ceramics with varying thicknesses, sintered in a reducing atmosphere.
- Analysis of frequency dependence of unipolar strain to differentiate deformation types.
- Characterization of material composition and defect structure using techniques sensitive to ion valence and site occupancy.
Main Results:
- A method was developed to distinguish bending deformation from inherent electrostrain.
- Reducing ceramic thickness to 200 μm significantly enhanced inherent electrostrain.
- A correlation was found between manganese ion valence state, defect concentration, and ceramic thickness.
- Giant electrostrain of 1068 pm/V at 15 kV/cm was achieved in thin ceramics.
Conclusions:
- Reducing sample thickness is an effective strategy to enhance inherent electrostrain in KNN ceramics.
- The observed enhancement is attributed to synergistic effects of dipole defects and domain structures.
- These findings offer a pathway for designing high-performance, lead-free piezoelectric ceramics for actuators.
Related Concept Videos
01:19Thermal Strain
Thermal strain is a concept that arises when we consider how temperature changes affect structures. Unlike the conventional assumption that structures remain constant under load, real-world scenarios often involve temperature fluctuations that can significantly impact these structures. Consider a homogeneous rod with a uniform cross-section resting freely on a flat horizontal surface. If the rod's temperature increases, the rod elongates. This elongation is proportional to the temperature...
01:20Strain-Energy Density
Understanding the strain energy density in materials under axial load is crucial for evaluating their mechanical behavior and durability. When a rod is subjected to such a load, it elongates and stores energy, known as strain energy, as potential energy within the material. This energy is measured in terms of energy per unit volume.
In the elastic region of a material, the relationship between the stress and the strain is linear and follows Hooke's Law. The strain energy density in this region...
In the elastic region of a material, the relationship between the stress and the strain is linear and follows Hooke's Law. The strain energy density in this region...
01:26Residual Stresses
Residual stresses reside in a structure even after removing the original stress inducer. This phenomenon often arises from varied plastic deformations across different parts of a structure. Consider a rod stretched beyond its yield point. It will not regain its original length due to permanent deformation. Even after load removal, the rod does not entirely lose stress because of uneven plastic deformations, resulting in residual stresses. The computation of these stresses in structures is...
01:27Thermal expansion and Thermal stress: Problem Solving
San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55 °C.
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55 °C.
01:27Measurements of Strain
Strain quantifies the deformation of a material under force, typically measured as normal strain, which represents the change in length when compared with the original length. Electrical strain gauges are used for enhanced accuracy. These devices consist of a conductive wire mounted on a paper backing that adheres to the material's surface. These gauges operate on the piezoresistive effect, where the wire's electrical resistance changes in response to mechanical deformation. The strain gauge...
01:22Elastic Strain Energy for Normal Stresses
Strain energy quantifies the energy stored within a material due to deformation under loading conditions, a fundamental concept in materials science and engineering. The strain energy can be modeled when a material is subjected to axial loading with uniformly distributed stress. In this scenario, the stress experienced by the material is the internal force divided by the cross-sectional area, and the strain induced is directly proportional to this stress through the modulus of elasticity.
If...
If...