Bailibo Testing: High-temperature piezoelectric performance testing of piezoelectric ceramics

1. Detection background and significance

As an important functional material, piezoelectric ceramics are widely used in sensors, transducers, ultrasonic imaging and other fields. However, in harsh application scenarios such as aerospace, engine monitoring, and oil drilling, piezoelectric ceramics often need to serve in high-temperature environments for a long time, so the detection of high-temperature piezoelectric performance is crucial.

2. Core test parameters

High-temperature piezoelectric performance testing mainly focuses on the following key parameters:

Piezoelectric constant d33: reflects the electromechanical coupling ability of piezoelectric ceramics in the polarization direction and is the core indicator for evaluating piezoelectric performance. Industrial grade piezoelectric ceramic d33 is usually ≥300pC/N, and medical grade can reach more than 500pC/N.

Curie temperature Tc: When the ambient temperature exceeds the Curie temperature, the ceramic crystal structure changes from an asymmetric configuration to a symmetric configuration, and the piezoelectric properties completely disappear. The Curie temperature of traditional PZT ceramics is about 195-365°C, and the new BS-PT system can reach 450°C.

Electromechanical coupling coefficient kp: Characterizes the energy conversion efficiency between piezoelectric materials and mechanical systems. The radial mode usually requires ≥0.60.

Dielectric properties: including dielectric constant and dielectric loss.

3. Testing standards and methods

National standard GB/T 3389-2008 "Piezoelectric Ceramic Material Performance Test Methods" Testing of Performance Parameters" stipulates the test process of the system:

Curie temperature test: Use an impedance analyzer to measure the permittivity mutation point to determine

Piezoelectric constant test: Calculate the electric displacement fraction through the quasi-static method Quantity

Dielectric performance test: Use high-voltage Xilin bridge to measure free relative permittivity and dielectric loss angle tangent

Pyroelectric coefficient test: Use charge integration method to measure the change of residual polarization with temperature

4. Testing equipment configuration

High-temperature piezoelectric performance testing requires professional equipment:

High-temperature test platform: precision impedance analyzer: quasi-static piezoelectric meter: ferroelectric analyzer, etc.

5. High-temperature stability challenge

Research shows that the phase structure and domain structure of piezoelectric ceramics are closely related to temperature. In high-temperature environments, the increase in oxygen vacancy concentration will cause the piezoelectric performance to decay. New doped materials such as Bi4Ti3-2xNbxTa3O12 show excellent stability at high temperatures and can still maintain more than 91% of the initial piezoelectric constant at 650°C.

6. Application fields

High temperature piezoelectric performance testing mainly serves:

High temperature sensor and actuator design, aerospace thermal environment monitoring system, nuclear safety system sensor development, oil drilling downhole detection equipment, etc. High-temperature piezoelectric performance testing is a key guarantee to ensure that piezoelectric ceramics work reliably in high-temperature environments. The accuracy of its test results directly affects the performance and life of related equipment.