CN106932662A - A kind of device and method for detecting phase transformation ferroelectric ceramics remanent polarization - Google Patents

Abstract

The present invention relates to a kind of device and method for detecting phase transformation ferroelectric ceramics remanent polarization, the device includes：Sample, integrating capacitor, electrometer, presser unit, pressure sensing cell and control unit；The sample is placed in the presser unit, the sample is connected in parallel with the integrating capacitor and electrometer respectively, the control interface of the electrometer is connected to described control unit, and the pressure sensing cell is placed in the presser unit, and the pressure signal that will be detected is transferred to described control unit.The present invention enables phase transformation ferroelectric ceramics depolarization under stress field action, so as to measure the remanent polarization of ferroelectric ceramics.

Description

A device and method for detecting remnant polarization of phase-change ferroelectric ceramics

technical field

The invention relates to the measurement of electrical performance parameters of ferroelectric materials, in particular to a device and method for detecting remnant polarization of phase-change ferroelectric ceramics.

Background technique

Remanent polarization is an important parameter to evaluate the energy storage characteristics of ferroelectric ceramics, and has important practical significance. Therefore, it is necessary to establish a test device and method to measure the actual stored energy of ferroelectric ceramics. The energy stored in ferroelectric ceramics is usually represented by remanent polarization, and the commonly used test method is thermal depolarization method.

Polarized ferroelectric ceramics store energy, and depolarization will occur under the action of an external field. Due to different practical applications, the external field can be a temperature field or a stress field. Ferroelectric materials can generate large voltage or large current under the action of stress field, which has important application value. Therefore, it is necessary to establish a detection device and method for the remanent polarization of materials under stress loading.

Contents of the invention

In view of the above, the technical problem to be solved by the present invention is to provide a device and method for detecting the remnant polarization of phase-change ferroelectric ceramics, so that phase-change ferroelectric ceramics can be depolarized under the action of a stress field, thereby measuring Remanent polarization of ferroelectric ceramics.

In order to solve the above technical problems, on the one hand, the device for detecting the remnant polarization of phase-change ferroelectric ceramics provided by the present invention includes: a sample, an integrating capacitor, an electrometer, a pressurizing unit, a pressure detecting unit, and a control unit; The sample is placed in the pressurizing unit, the sample is respectively connected in parallel with the integrating capacitor and the electrometer, the control interface of the electrometer is connected to the control unit, and the pressure detection unit is placed in the pressurizing unit. In the pressure unit, the detected pressure signal is transmitted to the control unit.

The invention applies pressure to the phase-change ferroelectric ceramics through a pressure unit, and measures the electric charge released by the phase-change ferroelectric ceramics during the process of applying pressure, so as to obtain the remanent polarization intensity of the ceramics. Therefore, the present invention can measure the remanent polarization intensity of the ceramic by measuring the depolarization charge under the stress field of the phase-change ferroelectric ceramic.

Moreover, in the present invention, it is also possible that the pressurizing unit includes a hydrostatic pressure testing machine containing a pressure transmission medium, and the sample is placed in the pressure transmission medium of the hydrostatic pressure testing machine.

According to the present invention, pressure can be applied to the phase-change ferroelectric ceramics through a hydrostatic pressure testing machine, and during the process of applying pressure, the electric charge released by the phase-change ferroelectric ceramics can be measured, so as to obtain the remanent polarization intensity of the ceramics.

Preferably, the pressure detection unit includes a pressure sensor, and the pressure sensor transmits the detected pressure signal to the control unit through an A/D conversion card.

On the other hand, the present invention also provides a method for detecting the remnant polarization of phase-change ferroelectric ceramics, comprising the following steps: measuring the effective electrode area A of the sample, and measuring the capacitance C of the integral capacitance; placing the sample in In the pressurizing unit, the samples are respectively connected in parallel with the integrating capacitor and the electrometer; the two ends of the integrating capacitor are short-circuited with wires; The short-circuit wire at the end; during the pressurization process, record the pressure value; at the same time, use the electrometer to record the voltage value V at both ends of the integrating capacitor, and continuously increase the pressure until the voltage value V is basically unchanged, and record the voltage value at this time V: Substituting the effective electrode area A of the sample, the capacitance value C of the integral capacitor, and the voltage value V into the formula Pr=C×V/A to calculate the remanent polarization of the ceramic.

According to the invention, the residual polarization intensity of the ceramic can be measured by measuring the depolarization charge under the stress field of the phase-change ferroelectric ceramic.

Moreover, in the present invention, it is also possible that the pressurization unit includes a hydrostatic pressure testing machine containing a pressure transmission medium, and the step of pressurizing the pressurization unit includes setting the hydrostatic pressure test machine. The hydrostatic pressurization range of the machine, start the hydrostatic pressurization program.

According to the present invention, the stress is applied to the phase-change ferroelectric ceramics by a hydrostatic pressure testing machine, and the stress is added to exceed the phase-transition stress of the material. strength.

The above contents and other objects, features and advantages of the present invention will be better understood according to the following detailed description and with reference to the accompanying drawings.

Description of drawings

Fig. 1 shows a schematic structural view of a device for detecting the remnant polarization of a phase-change ferroelectric ceramic according to an embodiment of the present invention;

Fig. 2 shows the voltage-stress relationship curve measured by the phase-change ferroelectric ceramic PZT under hydrostatic pressure integrating capacitance measured by the device and method shown in Fig. 1;

Fig. 3 shows the remanent polarization-stress relationship curve of the phase-change ferroelectric ceramic PZT under hydrostatic pressure measured by using the device and method shown in Fig. 1 .

Reference signs:

1. Sample,

2. Integral capacitance,

3. Electrometer,

4. Pressure transmission medium,

5. Hydrostatic pressure testing machine,

6. Pressure detection unit,

7. A/D conversion card,

8. Control unit.

detailed description

The present invention will be further described below in conjunction with the drawings and the following embodiments. It should be understood that the drawings and the following embodiments are only used to illustrate the present invention rather than limit the present invention.

In order to meet the demand for detecting the remanent polarization of ferroelectric ceramics, the present invention provides a device and method for detecting the remanent polarization of phase-change ferroelectric ceramics, the device includes: samples, integrating capacitors, electrometers, pressurization units, A pressure detection unit and a control unit; the sample is placed in the pressurizing unit, the sample is connected in parallel with the integrating capacitor and the electrometer respectively, the control interface of the electrometer is connected to the control unit, and the The pressure detection unit is placed in the pressurization unit, and the detected pressure signal is transmitted to the control unit.

Specifically, Fig. 1 shows a schematic structural diagram of a device for detecting the remnant polarization of a phase-change ferroelectric ceramic according to an embodiment of the present invention. As shown in Figure 1, the device for detecting the remanent polarization of phase-change ferroelectric ceramics in this embodiment includes: a sample 1, an integrating capacitor 2, an electrometer 3, a hydrostatic pressure testing machine 5 containing a pressure transmission medium 4, A pressure detection unit 6 , an A/D conversion card 7 and a control unit 8 .

Sample 1 is placed in the pressure transmission medium 4 of the hydrostatic pressure testing machine 5 , the sample 1 is connected in parallel with the integrating capacitor 2 and the electrometer 3 , and the control interface of the electrometer 3 is connected to the control unit 8 . The pressure detection unit 6 is placed in the pressure transmission medium 4 , and the detected pressure signal is transmitted to the control unit 8 through the A/D conversion card 7 . The above-mentioned pressure detection unit 6 may be, for example, a device for detecting pressure such as a pressure sensor.

A method for realizing the remanent polarization of phase-change ferroelectric ceramics by using the above-mentioned device, the method includes the following steps:

First, measure the effective electrode area value A of the sample 1; and measure the capacitance value C of the integrating capacitor 2.

Subsequently, connect the entire detection device according to the schematic diagram of the device structure shown in FIG. 1 , and place the sample 1 in the pressure transmission medium 4 of the hydrostatic pressure testing machine 5 .

Then, turn on the power supply of each component in the above-mentioned device, and each component starts to work.

Next, short-circuit the two ends of the integrating capacitor 2 with wires; set the hydrostatic pressure range, start the hydrostatic pressure program, and disconnect the short-circuit wires at both ends of the integrating capacitor 2 at the same time.

During the pressurization process, record the stress value; at the same time, use the electrometer 3 to record the voltage value V at both ends of the integrating capacitor 2, and continuously increase the pressure until the voltage value V is basically unchanged, and record the voltage value V at this time.

Finally, the effective electrode area A of sample 1, the capacitance value C and voltage value V of the integral capacitor 2 were substituted into the formula Pr=C×V/A, and the remanent polarization of the ceramic was calculated.

The invention applies stress to the phase-change ferroelectric ceramics through a hydrostatic pressure testing machine until the stress exceeds the phase-transition stress of the material, and measures the electric charge released by the phase-change ferroelectric ceramics during the pressurization process to obtain its residual polarization intensity.

The measuring device and method realize the measurement of the remnant polarization intensity of the phase-change ferroelectric ceramics under the action of stress field loading.

Below in conjunction with preferred specific embodiment, further elaborate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

Example 1

Connect according to the schematic diagram of the device structure shown in Figure 1, and measure the remnant polarization of the phase-change ferroelectric ceramic samples. Fig. 2 shows the voltage-stress relationship curve measured by the integrated capacitance of the phase-change ferroelectric ceramic PZT under hydrostatic pressure measured by the device and method shown in Fig. 1; The obtained phase-change ferroelectric ceramic PZT remanent polarization-stress relationship curve under hydrostatic pressure.

The measurement parameters are as follows: the effective electrode area of the sample is 281.25mm ² , the thickness is 2mm, the capacitance value of the integral capacitor is 10μF, and the applied hydrostatic pressure ranges from 0 to 300MPa. The test results are shown in Figure 2 and Figure 3. With the increase of the hydrostatic pressure, the sample gradually releases the charge, and the pressure continues to increase until the voltage value V across the integrating capacitor is basically unchanged, and the voltage across the integrating capacitor is 0.61V at this time. Substituting the sample area of 281.25mm ² , the integral capacitance of 10μF and the voltage across the capacitor of 10.3V into the formula Pr=C×V/A, the remanent polarization Pr is 36.6μC/cm ² .

The test results show that phase-change ferroelectric ceramics gradually release charges as the applied hydrostatic pressure increases. When the pressure increases to the phase-change pressure, the charge increases sharply, and the charge remains basically unchanged when the pressure continues to increase. After the applied hydrostatic pressure exceeds the phase transition pressure, the released charge is basically guaranteed to be unchanged, and the basically constant value is the depolarization charge of the sample under stress loading, so as to calculate the remanent polarization.

Finally, it is necessary to explain here that: the above examples are only used to further describe the technical solutions of the present invention in detail, and cannot be interpreted as limiting the protection scope of the present invention. Non-essential improvements and adjustments all belong to the protection scope of the present invention.

Claims (5)

1. it is a kind of detect phase transformation ferroelectric ceramics remanent polarization device, it is characterised in that including：

Sample, integrating capacitor, electrometer, presser unit, pressure sensing cell and control unit；

The sample is placed in the presser unit, the sample is connected in parallel with the integrating capacitor and electrometer respectively, the control interface of the electrometer is connected to described control unit, and the pressure sensing cell is placed in the presser unit, and the pressure signal that will be detected is transferred to described control unit.

2. device according to claim 1, it is characterised in that the presser unit includes accommodating the hydrostatic pressing pressure testing machine of transmission medium, the sample is placed in the transmission medium of the hydrostatic pressing pressure testing machine.

3. device according to claim 1 and 2, it is characterised in that the pressure sensing cell includes pressure sensor, the pressure sensor is transferred to described control unit by the pressure signal that A/D transition cards will be detected.

4. it is a kind of detect phase transformation ferroelectric ceramics remanent polarization method, it is characterised in that comprise the following steps：

The effective electrode area A of sample is measured, the capacitance C of integrating capacitor is measured；

The sample is placed in presser unit, the sample is connected in parallel with the integrating capacitor and electrometer respectively；

The terminal shortcircuit of the integrating capacitor two is connected with wire；

The presser unit is pressurizeed, simultaneously switch off the short-circuit conductors at the integrating capacitor two ends；

In pressure process, pressure value is recorded；

The magnitude of voltage V at the integrating capacitor two ends is recorded with the electrometer simultaneously, constantly increases pressure, until magnitude of voltage V is basically unchanged, record magnitude of voltage V now；

The effective electrode area A of the sample, the capacitance C of the integrating capacitor and the magnitude of voltage V are substituted into formula Pr=C × V/A, the remanent polarization of ceramics is calculated.

5. method according to claim 4, the presser unit includes accommodating the hydrostatic pressing pressure testing machine of transmission medium, hydrostatic pressing pressurization scope of the step of the making the presser unit be pressurizeed including the setting hydrostatic pressing pressure testing machine, starts hydrostatic pressing pressurization protocols.