High-temperature-resistant piezoelectric acceleration sensor

Abstract

The invention discloses a high-temperature-resistant piezoelectric acceleration sensor, relates to the technical field of piezoelectric sensing, and solves the problem that an existing sensor cannot stably work in a high-temperature environment of 530-550 DEG C. The sensor comprises a shell, a piezoelectric ceramic component, a mass block, an elastic piece and an electrode lead, and is characterized in that a piezoelectric ceramic material adopts a bismuth layered perovskite system formula, bismuth neodymium titanate is used as a substrate, gallium oxide and yttrium oxide are doped for modification, the Curie temperature is greater than or equal to 600 DEG C, and excellent piezoelectric performance can be kept in an environment of 530-550 DEG C. The shell is made of high-temperature alloy and is provided with a heat insulation buffer layer, the electrode leads and the elastic piece are made of high-temperature-resistant materials, and the whole structure achieves multiple high-temperature-resistant protection. The sensor still keeps high sensitivity and stability in a high-temperature environment, the measurement precision error is smaller than or equal to + / -2%, the service life is long, the sensor can be widely applied to vibration monitoring of extreme high-temperature scenes such as nuclear power and aerospace, localization of core components is achieved, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric sensing technology, specifically to a piezoelectric accelerometer suitable for extreme high-temperature environments of 530℃~550℃, which can be widely used in vibration acceleration monitoring in scenarios such as nuclear power reactors, aerospace engines, and high-temperature industrial equipment. Background Technology

[0002] Piezoelectric accelerometers are widely used in vibration measurement due to their advantages such as wide bandwidth, high sensitivity, and simple structure. With the development of industries such as nuclear power and aerospace, the operating environment temperature of key equipment components is constantly increasing, and the monitoring temperature requirement in some scenarios reaches 530℃~550℃ or even higher.

[0003] The core limitation of existing piezoelectric accelerometers lies in the high-temperature resistance of the piezoelectric materials. Conventional piezoelectric ceramic materials, such as lead zirconate titanate, have a Curie temperature of only 386℃, and their operating temperature limit is difficult to exceed 300℃, which cannot meet the requirements of high-temperature scenarios. Although domestically developed 482℃ series sensors have been developed, their sensitivity stability and lifespan are still insufficient for extreme environments of 530℃~550℃. Furthermore, the formulation of core ceramic materials has not yet achieved domestic breakthroughs, resulting in a large reliance on imports for high-temperature sensor products.

[0004] As the core sensing element of sensors, the formulation design of piezoelectric ceramic materials directly determines the high-temperature resistance and measurement accuracy of the sensors. Existing high-temperature piezoelectric ceramics suffer from problems such as insufficient Curie temperature, excessive dielectric loss at high temperatures, and decreased resistivity, making it difficult to operate stably for a long time in environments of 530℃~550℃, thus limiting the application expansion of piezoelectric sensors in extreme high-temperature scenarios. Summary of the Invention

[0005] To address the issues of existing piezoelectric accelerometers being unable to operate stably in high-temperature environments of 530℃~550℃ and the insufficient high-temperature resistance of the core piezoelectric ceramic material formulation, a high-temperature resistant piezoelectric accelerometer is provided. By optimizing the ceramic material formulation and the overall sensor structure, accurate and long-term vibration acceleration measurement can be achieved in high-temperature environments.

[0006] The piezoelectric ceramic material adopts a bismuth layered perovskite system formulation, with bismuth neodymium titanate as the base and gallium oxide and yttrium oxide as modifiers. By adjusting the proportion of each component, the Curie temperature and high temperature stability of the material are improved, so that it maintains excellent piezoelectric performance in an environment of 530℃~550℃.

[0007] The sensor body includes a housing, a piezoelectric ceramic component, a mass block, an elastic element, and electrode leads. The housing is made of high-temperature resistant alloy material and has an internal heat insulation buffer layer to reduce the conduction of external high temperature to the core component.

[0008] The piezoelectric ceramic component adopts a layered structure and is formed by high-temperature sintering. The electrode leads are made of high-temperature resistant precious metal materials, and together with the ceramic insulating sleeve, a reliable electrical connection is achieved in high-temperature environments.

[0009] The mass block and the piezoelectric ceramic assembly are fixed together with a high-temperature adhesive, and the elastic element is made of high-temperature resistant alloy spring to ensure a stable elastic coefficient at high temperatures and to guarantee the dynamic response performance of the sensor.

[0010] Beneficial effects The piezoelectric ceramic material formulation has been specifically optimized, achieving a Curie temperature of over 600℃. It can operate stably for a long time in high-temperature environments of 530℃~550℃, solving the problem of insufficient high-temperature resistance of existing materials.

[0011] The sensor's overall structure employs multiple high-temperature resistant designs. The heat insulation layer on the outer shell and the internal high-temperature resistant components work together to effectively reduce the impact of high temperatures on core components, ensuring that the sensor's service life exceeds 5,000 hours in extreme environments.

[0012] It maintains high sensitivity and good linearity even under high temperature conditions, with a piezoelectric constant d33≥55pC / N, dielectric loss≤0.03, resistivity≥10^8Ω・cm, and measurement accuracy error not exceeding ±2%.

[0013] The material formulation and preparation process are easy to scale up for production, and the core components are domestically produced, which reduces the production cost of sensors and breaks the technological monopoly of imported products.

[0014] With its compact structure and flexible installation method, it can meet the high-temperature vibration monitoring needs of different scenarios such as nuclear power, aerospace, and industrial equipment. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Appendix Figure 1 This is a schematic diagram of the overall structure of the high-temperature resistant piezoelectric accelerometer sensor of the present invention; Appendix Figure 2 This is a schematic diagram of the stacked structure of a piezoelectric ceramic component; Appendix Figure 3 This is a schematic diagram of the temperature-sensitivity characteristic curve of the sensor; In the picture: 1-Piezoelectric ceramic component, 2-Mass block, 3-Elastic element, 4-Shell, 5-Electrode lead, 6-Ceramic insulating sleeve. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] like Figure 1-3 As shown; A high-temperature resistant piezoelectric accelerometer.

[0018] This implementation plan addresses the technical problems existing in the prior art, such as the limitation of existing piezoelectric accelerometers disclosed in the background section above, which states that "the core limitation of existing piezoelectric accelerometers lies in the high-temperature resistance of piezoelectric materials. Conventional piezoelectric ceramic materials, such as lead zirconate titanate, have a Curie temperature of only 386℃, and their operating temperature is difficult to exceed 300℃, which cannot meet the requirements of high-temperature scenarios. Although domestically developed 482℃ series sensors have been developed, their sensitivity stability and service life are still insufficient for extreme environments of 530℃~550℃, and the core ceramic material formula has not yet achieved a breakthrough in domestic production, resulting in a large reliance on imports for high-temperature sensor products." In practical terms, this problem is clearly a real and difficult-to-solve issue. Therefore, to solve this technical problem, a high-temperature resistant piezoelectric accelerometer is provided.

[0019] Example 1 like Figure 1-3 As shown in the figure; Preparation of piezoelectric ceramic materials: Prepare the raw materials according to the following mass percentages: 82% bismuth neodymium titanate, 10% gallium oxide, 5% yttrium oxide, and 3% zirconium oxide. All raw materials have a purity of ≥99.9%.

[0020] The raw materials were placed in a ball mill, using zirconia balls as the grinding medium and anhydrous ethanol as the dispersant. The mixture was milled for 12 hours until the particle size was ≤1μm. Then, it was dried at 80℃ to obtain a mixed powder.

[0021] The mixed powder is placed in a mold and pre-pressed under a pressure of 20 MPa to obtain a ceramic green body. The ceramic green body is then placed in a sintering furnace and sintered at 1250℃ for 4 hours. After natural cooling, a piezoelectric ceramic substrate is obtained.

[0022] The ceramic substrate was subjected to polarization treatment at a polarization temperature of 150℃, a polarization electric field of 5kV / mm, and a polarization time of 30 minutes to obtain a piezoelectric ceramic sheet with piezoelectric properties.

[0023] Sensor assembly: The outer shell is made of Inconel 625 high-temperature alloy, and the inner wall of the outer shell is coated with a high-temperature resistant ceramic coating as a heat insulation buffer layer with a coating thickness of 0.8mm.

[0024] The piezoelectric ceramic component consists of three piezoelectric ceramic sheets stacked together, with platinum electrode sheets placed between adjacent ceramic sheets. The stacked components are fixed together as one unit through a high-temperature sintering process to form the piezoelectric ceramic component 1.

[0025] Mass block 2 is made of tungsten alloy material and weighs 5g. Mass block 2 is fixed to the upper end face of piezoelectric ceramic component 1 by high temperature ceramic adhesive.

[0026] The elastic element 3 is made of Inconel 718 alloy spring. One end of the elastic element 3 is connected to the mass block 2, and the other end is fixed to the top inner wall of the outer shell 4 to ensure that the elastic element 3 is in a pre-compressed state and provides a stable pre-tightening force.

[0027] The electrode lead 5 is made of platinum-iridium alloy wire with a diameter of 0.3 mm. One end of the electrode lead 5 is welded to the platinum electrode sheet of the piezoelectric ceramic component 1, and the other end is led out through the ceramic insulating sleeve 6 on the side wall of the outer shell 4. The ceramic insulating sleeve 6 and the outer shell 4 are sealed with high-temperature sealant.

[0028] After assembly, the sensor undergoes an overall sealing test to ensure no leakage under high temperature and high pressure conditions, followed by temperature calibration and sensitivity calibration.

[0029] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature resistant piezoelectric accelerometer, characterized in that, The sensor includes a housing (4), a piezoelectric ceramic component (1), a mass block (2), an elastic element (3), and electrode leads (5). The piezoelectric ceramic component (1) adopts a bismuth layered perovskite system formulation. The sensor can work stably in an environment of 530℃~550℃.

2. The high-temperature resistant piezoelectric accelerometer sensor according to claim 1, characterized in that, The material formulation of the piezoelectric ceramic component (1) by mass percentage includes: 80%~85% bismuth neodymium titanate, 8%~12% gallium oxide, 3%~6% yttrium oxide, and 2%~4% zirconium oxide.

3. The high-temperature resistant piezoelectric accelerometer sensor according to claim 1, characterized in that, The outer shell (4) is made of Inconel 625 high-temperature alloy, and the inner wall is provided with a heat insulation buffer layer. The heat insulation buffer layer is a high-temperature resistant ceramic coating with a thickness of 0.5mm~1.0mm.

4. A high-temperature resistant piezoelectric accelerometer according to claim 1, characterized in that, The piezoelectric ceramic component (1) has a stacked structure, consisting of 2 to 4 piezoelectric ceramic sheets and platinum electrode sheets stacked alternately, and fixed by a high-temperature sintering process.

5. A high-temperature resistant piezoelectric accelerometer according to claim 1, characterized in that, The electrode lead (5) is a platinum-iridium alloy wire, and is covered with a ceramic insulating sleeve (6). The ceramic insulating sleeve (6) and the outer shell (4) are sealed with high-temperature sealant.

6. A high-temperature resistant piezoelectric accelerometer according to claim 1, characterized in that, The elastic element (3) is an Inconel 718 alloy spring, the mass block (2) is made of tungsten alloy, and the mass block (2) is fixedly connected to the piezoelectric ceramic assembly (1) by a high-temperature ceramic adhesive.

7. A high-temperature resistant piezoelectric accelerometer according to any one of claims 1 to 6, characterized in that, The piezoelectric ceramic component (1) has a Curie temperature ≥600℃, a piezoelectric constant d33 ≥55pC / N, and a dielectric loss ≤0.03 in an environment of 530℃~550℃.

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