Wireless passive / temperature strain two-parameter sensing element based on precursor polymer ferroelectric composite ceramic film and preparation method of wireless passive / temperature strain two-parameter sensing element

Abstract

The invention relates to the technical field of temperature detection and strain testing, and discloses a wireless passive / temperature strain two-parameter sensing element based on a precursor polymer ferroelectric composite ceramic film and a preparation method of the wireless passive / temperature strain two-parameter sensing element. The composite dielectric coating comprises a substrate, an insulating layer and a composite dielectric layer from bottom to top, and the composite dielectric layer is prepared by mixing a precursor ceramic polymer with ferroelectric ceramic powder through high-temperature pyrolysis; the temperature sensitive structure and the strain sensitive structure are both comb tooth structures and are matched with the internal inductor and the external inductor to form an independent LC resonant circuit, the dielectric constant or the polar plate distance is changed through the environment temperature and deformation, the LC resonant frequency is changed, the temperature and the strain are effectively measured, and the working state of a measured structural part can be visually reflected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature detection and strain testing, and particularly relates to a wireless passive / temperature strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic film and a preparation method thereof. BACKGROUND

[0002] The rise of Internet of Things technology promotes the development of wireless sensor networks, which requires sensors to be independent of wired power supply and capable of transmitting data wirelessly, thus stimulating the research and application of passive sensors and wireless communication technology. In industrial production processes, temperature and strain need to be monitored in real time to ensure production safety and production quality. In order to obtain the working state of each object more accurately, multiple physical parameters need to be obtained, and the existing technology focuses on the acquisition of a single strain parameter. Therefore, the demand for wireless passive strain-temperature sensors is gradually increasing, which also promotes the research and development of related technologies. In view of the testing requirements of temperature and strain parameters and the development trend of sensor miniaturization, integration, and multifunctionalization, wireless passive integrated multi-parameter sensors based on LC resonance principle have become a new direction for future research. At the same time, in the field of thin film strain / temperature sensing, the preparation process of sensing films is not mature enough, and there is room for further improvement in the aspects of corrosion-resistant mechanism of protective layer, impact resistance, high-temperature solder production, and temperature compensation. SUMMARY

[0003] The present application relates to the technical field of temperature detection and strain testing, and particularly relates to a wireless passive / temperature strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic film and a preparation method thereof.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted is as follows: In a first aspect, the present application provides a wireless passive temperature / strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic film, characterized in that it comprises a composite dielectric coating, a comb-shaped electrode and an inductor coil; the composite dielectric coating comprises, from bottom to top, a substrate, an insulating layer, a metal lead layer and a composite dielectric layer, the composite dielectric layer is prepared by pyrolysis of a precursor ceramic polymer mixed with ferroelectric ceramic powder; the comb-shaped electrode and the inductor coil form a temperature-sensitive structure and a strain-sensitive structure, wherein the temperature-sensitive structure is a structure in which the comb-shaped electrode is attached to the layered ferroelectric ceramic / precursor ceramic dielectric coating, and the strain-sensitive structure is a comb-shaped structure; the inductor coil comprises an inner inductor and an outer inductor, the inner inductor is used to read the capacitance change of the interdigital electrode strain structure, and the outer inductor is used to read the capacitance change of the interdigital electrode medium temperature sensing structure; the plates of the interdigital capacitor are respectively connected to the two ends of the outer coil of the inductor coil to form an LC resonance circuit.

[0005] Further, the substrate is a metal substrate or an insulating substrate.

[0006] Further, the insulating layer is prepared by using a doctor blade process on the substrate and is formed by high-temperature sintering.

[0007] Further, the ferroelectric ceramic powder comprises at least one perovskite powder selected from PZT, BaTiO3 and BaSrTiO3.

[0008] Further, the average particle size of the composite dielectric coating is 20 nm to 100 μm.

[0009] Further, the adhesion strength between the substrate and the insulating layer, between the insulating layer and the metal electrode layer, and between the metal electrode layer and the composite dielectric layer is greater than 6.22 Mpa.

[0010] Further, the thickness of the composite dielectric layer is 10 to 50 μm, and the thickness of the insulating layer is 10 to 1000 μm.

[0011] Further, the inductor coil comprises an inner inductor coil and an outer inductor coil, the inner inductor coil is arranged in the outer inductor coil; the temperature-sensitive structure is connected to the outer inductor through a temperature reading wire, and the strain-sensitive structure is connected to the inner inductor through a strain reading wire.

[0012] Further, the interdigital capacitor is formed by comb-shaped staggered arrangement between the two electrode plates.

[0013] Further, the substrate is a ceramic substrate, the ceramic substrate is treated by oxygen plasma, and upper and lower through holes are formed by laser drilling technology, and the through holes are filled with silver paste to realize metallization to connect the upper and lower surfaces.

[0014] In a second aspect, the application provides a method for preparing a wireless passive temperature / strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic film as described above, comprising the following steps: (1) cleaning the substrate: sequentially placing the substrate in alcohol, acetone and deionized water for ultrasonic cleaning and then drying; (2) preparing an insulating layer: coating an insulating layer material on the substrate, and then sintering at high temperature to obtain the insulating layer; (3) preparing a metal electrode layer: using silver-palladium high-temperature paste on the surface of the insulating layer, and preparing a comb-shaped electrode and an inductor coil through a flexible mask and brushing process; (4) preparing a precursor polymer ferroelectric ceramic solution: uniformly mixing the precursor polymer ceramic solution and the ferroelectric ceramic powder in a certain proportion to obtain a composite dielectric film precursor solution; (5) preparing a composite dielectric coating: coating the composite dielectric film precursor solution on the surface of the metal electrode layer, solidifying first, and then heat treating at a high temperature of 800℃ or above in air to form a composite dielectric film, thereby completing the preparation of the composite dielectric coating.

[0015] Further, in step (4), the mass fraction of the ferroelectric ceramic powder in the composite dielectric film precursor solution is 12.5-82.5wt%.

[0016] Further, in step (5), the solidification temperature is 120-200℃, and the solidification time is 60-120min.

[0017] Further, in step (2), the high-temperature sintering process is the same as the high-temperature heat treatment process in step (5), specifically: the temperature rising speed is 3-14℃ / min, the temperature is raised to 600-1000℃, and the temperature is kept for 1-6h.

[0018] Further, in step (3), the comb-shaped electrode uses platinum metal as the material and is patterned by laser processing; and in step (5), the composite dielectric film precursor solution is coated on the surface of the comb-shaped electrode through a flexible mask process The application has the following beneficial effects: The temperature / strain sensing element comprises a temperature / strain sensing element and an inductance coil for acquiring sensor information; the temperature / strain sensing element comprises a temperature sensitive structure and a strain sensitive structure; the temperature sensitive structure is a layered PZT / PDC medium coating structure of a comb tooth motor attached to ferroelectric material, for improving sensitivity; the strain sensitive structure is a comb tooth structure; the inductance coil comprises a strain reading coil and a temperature reading coil; the strain reading coil is used for reading the change amount of the interdigital electrode strain structure capacitor, and the temperature reading coil is used for reading the change amount of the interdigital electrode medium temperature sensing structure capacitor; the two plates of the interdigital capacitor are connected with the two ends of the inductance coil outside coil to form an LC resonance loop; and the two plates of the interdigital capacitor are connected with the inductance coil inside coil. The wireless passive temperature / strain sensing element based on the PDC / ferroelectric material system film can detect the change amount parameters of the temperature and strain of an object at the same time, and can more directly express the working state of the object. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A perspective view of a wireless passive temperature / strain dual parameter sensing element based on a PDC / ferroelectric composite ceramic film according to an embodiment of the present application is shown.

[0020] Figure 2 An upper view of a wireless passive temperature / strain dual parameter sensing element based on a PDC / ferroelectric composite ceramic film according to an embodiment of the present application is shown.

[0021] Figure 3 A temperature / strain sensing element according to an embodiment of the present application is shown.

[0022] Figure 4 An inductance coil according to an embodiment of the present application is shown.

[0023] Figure 5 A wireless passive temperature calibration result diagram according to an embodiment of the present application is shown.

[0024] Figure 6 A wireless passive strain calibration result diagram according to an embodiment of the present application is shown.

[0025] REFERENCE NUMERALS: 1 - temperature / strain sensing element; 2 - temperature sensitive structure; 3 - strain sensitive structure; 4 - medium coating layer; 5 - ceramic base; 6 - internal inductance; 7 - external inductance; 8 - strain reading coil; 9 - temperature reading coil. DETAILED DESCRIPTION

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0028] Example 1: This invention provides a wireless passive temperature / strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic thin film, the three-dimensional structure of which is shown below. Figure 1 As shown, the top view structure is as follows Figure 2 As shown. The sensing element includes a composite dielectric coating, comb-tooth electrodes, and an inductor coil, with the specific structure as follows: The composite dielectric coating consists of a substrate 5, an insulating layer, a metal lead layer, and a composite dielectric layer 4 from bottom to top. The composite dielectric layer 4 is prepared by high-temperature pyrolysis of a precursor ceramic polymer (such as polycarbosilane) mixed with ferroelectric ceramic powder (such as PZT). The high-temperature pyrolysis process can transform the precursor polymer into a ceramic phase, forming a stable composite structure with the ferroelectric ceramic powder.

[0029] like Figure 3 As shown, the comb-tooth electrodes and the inductor coil constitute the temperature-sensitive structure 2 and the strain-sensitive structure 3. The temperature-sensitive structure 2 is a structure in which a layered PZT / PDC dielectric coating is attached to the comb-tooth electrodes, and the strain-sensitive structure 3 is a comb-tooth structure. The interdigital capacitor 10 is formed by the electrode plates being arranged in a comb-tooth pattern between each other.

[0030] like Figure 4 As shown, the inductor coil includes an internal inductor 6 and an external inductor 7. The internal inductor 6 is used to read the capacitance change of the interdigital electrode strain structure, and the external inductor 7 is used to read the capacitance change of the interdigital electrode dielectric temperature sensing structure. The plate capacitors are connected to the two ends of the outer coil of the inductor coil to form an LC resonant circuit, and the two plates of the interdigital capacitor 10 are connected to the inner coil of the inductor coil.

[0031] When the ambient temperature changes, the dielectric constant of the composite dielectric layer 4 in the temperature sensitive structure 2 changes with the temperature, resulting in a change in the corresponding capacitance value, and further changing the LC resonance frequency of the external inductor 7 and the capacitor; when the deformation exists in the outside world, the distance between the comb electrodes of the strain sensitive structure 3 changes, so that the capacitance value of the interdigital capacitor 10 changes, and further changes the LC resonance frequency of the internal inductor 6 and the capacitor. By detecting the changes of the two resonance frequencies, the dual-parameter measurement of temperature and strain can be realized.

[0032] The device integrates the temperature and strain sensitive units in the same element, uses two independent LC resonance circuits to realize parameter distinction, can accurately measure temperature and strain at the same time, and solves the problem that the traditional single parameter sensor cannot synchronously obtain multiple physical quantities.

[0033] In some embodiments, the substrate 5 is limited. The substrate 5 can be selected from a metal substrate (such as stainless steel) or an insulating substrate (such as alumina ceramic). When applied to the surface of a metal member (such as a pipeline or a mechanical arm), the use of a metal substrate can improve the adhesion of the sensing element to the measured member and reduce installation errors; when applied to the surface of an insulating material (such as a ceramic insulator), the use of an insulating substrate can avoid the interference of the metal substrate on the electrical properties of the measured member.

[0034] The flexible selection of the substrate type in the embodiment makes the sensing element adaptable to measured structural members of different materials, thereby expanding the application range.

[0035] In some embodiments, the insulating layer is prepared by using a doctor blade coating process on the substrate 5 and is formed by high temperature sintering. For example, the doctor blade coating process can uniformly coat the insulating paste (such as alumina paste) on the surface of the substrate by using a doctor blade to control the thickness of the coating; high temperature sintering (such as 600°C for 2h) can densify the insulating paste to form a ceramic layer with excellent insulating properties.

[0036] The doctor blade coating process is simple and low in cost, and the combination of high temperature sintering can make the insulating layer have good insulating properties and mechanical strength, thereby avoiding the problem of electric leakage between the metal lead layer and the substrate.

[0037] In some embodiments, the ferroelectric ceramic powder is limited. The ferroelectric ceramic powder is selected from a perovskite type powder, and can be specifically selected from: PZT (lead zirconate titanate): high dielectric constant and piezoelectric coefficient, good temperature sensitivity; BaTiO3 (barium titanate): the dielectric constant changes significantly near the Curie point, suitable for measuring in a low temperature range; BaSrTiO3 (barium strontium titanate): the Curie point can be adjusted by adjusting the Sr / Ba ratio to adapt to different temperature ranges.

[0038] The selection of different ferroelectric ceramic powders can make the sensing element adapt to different temperature measurement ranges and sensitivity requirements, and improve the design flexibility of the element.

[0039] In some embodiments, the average particle size of the composite dielectric coating is limited to 20 nm to 100 μm. For example, when it is necessary to improve the density of the coating, ferroelectric ceramic powder with a particle size of 20 nm to 500 nm is selected to reduce the internal pores of the coating; when it is necessary to reduce the difficulty of coating preparation, ferroelectric ceramic powder with a particle size of 1 μm to 100 μm is selected to facilitate mixing and coating.

[0040] In this embodiment, the particle size range of the composite dielectric coating can balance the mechanical properties and dielectric properties of the coating, and ensure that the coating is not prone to cracking under the action of temperature change and deformation.

[0041] In some embodiments, the adhesion strength between each layer is greater than 6.22 Mpa. For example, the adhesion strength between each layer can be ensured by the following methods: ultrasonic cleaning is used to clean the substrate to remove oil stains and impurities and improve the surface activity; the substrate is subjected to plasma treatment before the insulating layer is coated to increase the surface roughness; the metal electrode layer is subjected to annealing treatment before the composite dielectric layer is coated to reduce the interfacial stress.

[0042] High adhesion strength can ensure that the sensing element does not have interlayer peeling under the action of long-term temperature cycling and deformation, and improve the reliability and service life of the element.

[0043] In some embodiments, the thickness of the composite dielectric layer 4 is limited to 10 to 50 μm, and the thickness of the insulating layer is limited to 10 to 1000 μm. For example, the composite dielectric layer 4 has a thickness of 30 μm, which can ensure that the change in dielectric constant caused by temperature can be effectively detected, and will not cause the response speed to be slow due to excessive thickness; the insulating layer has a thickness of 100 μm, which can meet the insulation requirements in a high-temperature environment, while avoiding excessive thickness to increase the overall size of the element. Reasonable thickness design can ensure detection sensitivity while taking into account element miniaturization and response speed.

[0044] In some embodiments, as shown in Figure 2 The temperature-sensitive structure 2 is connected to the external inductor 7 through the temperature reading wire 9, and the strain-sensitive structure 3 is connected to the internal inductor 6 through the strain reading wire 8. The design of the 14-turn inductor coil can ensure sufficient inductance, so that the LC resonance frequency is in the range (500 kHz to 6 MHz) that is easy to detect; the nested layout of the internal inductor and the external inductor can reduce the electromagnetic interference between the two loops and improve the measurement accuracy.

[0045] This coil design can realize independent reading of temperature and strain signals, and reduce cross interference, such asFigure 5 and Figure 6 As shown in the figure, the temperature and strain calibration curves both present good linear relationship, proving the effectiveness of the structure.

[0046] In some embodiments, the structure of the interdigital capacitor 10 is further optimized. The interdigital capacitor 10 is formed by the comb-shaped staggered arrangement between each two electrode plates, and the electrode material is selected to be platinum metal, which has the characteristics of high temperature resistance and good chemical stability. The comb tooth spacing is 50-200 μm, and the tooth number is 10-20 pairs, which can be adjusted according to the strain measurement range: the smaller the spacing, the higher the strain sensitivity; the more the tooth number, the larger the capacitance value, and the stronger the resonance signal. The comb-shaped staggered interdigital capacitor can sensitively reflect the strain by changing the spacing, and the platinum metal electrode ensures that the element can still work stably in a high temperature environment (such as 600℃).

[0047] In some embodiments, the surface of the ceramic substrate 5 is treated by oxygen plasma to introduce polar groups such as hydroxyl groups, thereby enhancing the atomic adhesion between the substrate surface and the thin film; laser drilling technology is used to manufacture upper and lower through holes with a diameter of 100-500 μm on the ceramic substrate 5, silver paste is injected and sintered to metalize the through holes, and the electrical connection 17 between the upper and lower surfaces of the substrate is realized. Oxygen plasma treatment improves the adhesion between the substrate and the coating, and the through hole metallization realizes the interlayer connection of the inductor coil, providing a basis for the miniaturization and integration of the element.

[0048] Embodiment 2: The embodiment of the present application provides a preparation method of a wireless passive temperature / strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic film, which comprises the following steps: Step 1, cleaning the substrate: the ceramic substrate 5 is sequentially placed in alcohol, acetone and deionized water for ultrasonic cleaning for 30 min, and then dried in an 80℃ oven to remove surface oil stains and impurities.

[0049] Step 2, preparing an insulating layer: alumina paste is scraped on the substrate 5 to form an insulating layer, and then placed in a muffle furnace, which is heated to 800℃ at a rate of 5℃ / min and kept for 2h to complete high temperature sintering.

[0050] Step 3, preparing a metal electrode layer: a silver-palladium high-temperature paste is used on the surface of the insulating layer to prepare comb electrodes and inductor coils through a flexible mask and brushing process, and then sintered at 600℃ for 30 min to solidify.

[0051] Step 4, preparing a precursor polymer ferroelectric ceramic solution: polycarbosilane solution (precursor polymer ceramic solution) and PZT powder are mixed in a mass ratio of 1:1, ball milled in a ball mill for 2h to obtain a composite dielectric film precursor solution.

[0052] In this embodiment, the mass fraction of ferroelectric ceramic powder in the composite dielectric film precursor solution is 12.5-82.5wt%. When it is necessary to improve the temperature sensitivity, 82.5wt% of PZT powder is selected to increase the proportion of ferroelectric phase; when it is necessary to improve the flexibility of the coating layer, 12.5wt% of PZT powder is selected to increase the proportion of the precursor polymer. Adjusting the mass fraction of ferroelectric ceramic powder can realize the regulation of the performance of the composite dielectric layer, and meet the needs of different application scenarios.

[0053] Step 5, preparation of a composite dielectric coating layer: the composite dielectric film precursor solution is coated on the surface of the metal electrode layer, and is cured in a 150℃ oven for 90min, and then is placed in a muffle furnace, and is heated to 900℃ at a temperature rising rate of 10℃ / min in air, and is kept for 3h for high-temperature heat treatment, to generate a composite dielectric film 4, and the preparation is completed.

[0054] In this embodiment, the curing temperature is 120-200℃, and the time is 60-120min. For example, for the precursor solution with high viscosity, 200℃ is adopted for curing for 60min, which can quickly remove the solvent and preliminarily crosslink; for the precursor solution with low viscosity, 120℃ is adopted for curing for 120min, which can avoid cracking of the coating layer. Reasonable curing parameters can ensure that the precursor solution is fully cured, and lay a foundation for forming a stable ceramic structure in subsequent high-temperature pyrolysis.

[0055] It should be noted that the high-temperature sintering in step 2 and the high-temperature heat treatment in step 5 have the same process: the temperature rising rate is 3-14℃ / min, the temperature is raised to 600-1000℃, and the temperature is kept for 1-6h. For example, when the insulating layer and the composite dielectric layer are prepared, the temperature is raised to 800℃ at a temperature rising rate of 10℃ / min, and the temperature is kept for 2h, which can reduce the cracking of the coating layer caused by thermal stress. The unified heat treatment process simplifies the preparation process, and at the same time ensures the structural stability of the insulating layer and the composite dielectric layer.

[0056] In step 3, the interdigital electrode adopts platinum metal as the material, and is patterned by laser processing, the laser power is set to 50W, and the scanning speed is set to 10mm / s, so that an interdigital structure with neat edges can be obtained; in step 5, the composite dielectric film precursor solution is coated on the surface of the interdigital electrode by a flexible mask process, and the flexible mask can closely fit the surface of the electrode, so as to ensure the precision of the coating pattern. Laser processing improves the precision of the electrode pattern, and the flexible mask process ensures the accurate alignment of the composite dielectric layer and the electrode, and further improves the performance stability of the sensing element.

[0057] The sensing element prepared by the above method is calibrated, and the results are shown in Figure 5 and Figure 6 The overall process improves the structural precision of the element, so that Figure 5 and Figure 6The calibration results of the sensor element have higher linearity and sensitivity, and further verify the reliability of the preparation method. Therefore, the sensor element with complete structure and stable performance can be prepared through the above steps, and the cooperation of various process parameters ensures the good combination of the coating and the electrode and the stability of the dielectric performance.

[0058] The above embodiments are only used to illustrate the present application, but not to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions belong to the scope of the present application, and the patent protection scope of the present application should be defined by the claims.

Claims

1. A wireless passive temperature / strain dual-parameter sensing element based on a precursor polymer ferroelectric composite ceramic thin film, characterized in that, The composite dielectric coating, the comb-shaped electrode and the inductor coil; the composite dielectric coating comprises a substrate, an insulating layer, a metal lead layer and a composite dielectric layer from bottom to top; the composite dielectric layer is prepared by pyrolysis of a precursor ceramic polymer mixed with ferroelectric ceramic powder; the comb-shaped electrode and the inductor coil form a temperature sensitive structure and a strain sensitive structure; the temperature sensitive structure is a structure in which the comb-shaped electrode is attached to a layered ferroelectric ceramic / precursor ceramic dielectric coating; the strain sensitive structure is a comb-shaped structure; the inductor coil comprises an inner inductor and an outer inductor; the inner inductor is used to read the capacitance change of the interdigital electrode strain structure; the outer inductor is used to read the capacitance change of the interdigital electrode medium temperature sensing structure; the plates of the capacitor are connected to the two ends of the outer inductor coil to form an LC resonance circuit; the two plates of the interdigital capacitor are connected to the inner inductor coil.

2. The sensing element of claim 1, wherein, The substrate is a metal substrate or an insulating substrate.

3. The sensing element of claim 1, wherein, The insulating layer is prepared by using a doctor blade process on the substrate and is formed by high temperature sintering.

4. The sensing element of claim 1, wherein, The ferroelectric ceramic powder comprises at least one perovskite type powder selected from PZT, BaTiO3 and BaSrTiO3.

5. The sensing element of claim 1, wherein, The average particle size of the composite dielectric coating is 20 nm to 100 μm.

6. The sensing element of claim 1, wherein, The adhesion strength between the substrate and the insulating layer, between the insulating layer and the metal electrode layer, and between the metal electrode layer and the composite dielectric layer is greater than 6.22 Mpa.

7. The sensing element of claim 1, wherein, The thickness of the composite dielectric layer is 10 to 50 μm, and the thickness of the insulating layer is 10 to 1000 μm.

8. The sensing element of claim 1, wherein, The inductor coil comprises an inner inductor coil and an outer inductor coil; the inner inductor coil is arranged in the outer inductor coil; The temperature sensitive structure is connected to the outer inductor through a temperature reading wire, and the strain sensitive structure is connected to the inner inductor through a strain reading wire.

9. The sensing element of claim 1, wherein, The interdigital capacitor is formed by comb-shaped interlaced arrangement between the electrode plates.

10. The sensing element of claim 1, wherein, The substrate is a ceramic substrate; the ceramic substrate is treated by oxygen plasma; upper and lower through holes are formed by laser drilling technology; silver paste is injected into the through holes to realize metallization to connect the upper and lower surfaces.

11. A method for producing a wireless passive temperature / strain dual-parameter sensor element based on a precursor polymer ferroelectric composite ceramic thin film as claimed in any one of claims 1 to 10, characterized by, The method comprises the following steps: (1) cleaning the substrate: the substrate is sequentially placed in alcohol, acetone and deionized water for ultrasonic cleaning and then dried; (2) preparing the insulating layer: the insulating layer material is doctor-bladed on the substrate, and then the insulating layer is prepared by high temperature sintering; (3) preparing the metal electrode layer: the silver-palladium high temperature paste is used on the surface of the insulating layer, and the comb-shaped electrode and the inductor coil are prepared by flexible mask and brushing process; (4) preparing the precursor polymer ferroelectric ceramic solution: the precursor polymer ceramic solution and the ferroelectric ceramic powder are uniformly mixed in proportion to obtain a composite dielectric thin film precursor solution; (5) preparing the composite dielectric coating: the composite dielectric thin film precursor solution is coated on the surface of the metal electrode layer, solidified first, and then heat treated at a temperature above 800℃ in air to form a composite dielectric thin film, thereby completing the preparation of the composite dielectric coating.

12. The method of claim 11, wherein, In step (4), the mass fraction of the ferroelectric ceramic powder in the composite dielectric thin film precursor solution is 12.5 to 82.5 wt%.

13. The preparation method according to claim 11, characterized in that, In step (5), the solidification temperature is 120 to 200℃, and the solidification time is 60 to 120 min.

14. The method of claim 11, wherein, In step (2), the high-temperature sintering process is the same as the high-temperature heat treatment process in step (5), specifically: the temperature rising speed is 3-14 ℃ / min, the temperature is raised to 600-1000 ℃, and the temperature is kept for 1-6 h.

15. The preparation method according to claim 11, characterized in that, In step (3), the interdigital electrode adopts platinum metal as the material and is patterned by laser processing; in step (5), the composite dielectric film precursor solution is coated on the surface of the interdigital electrode by a flexible mask process.

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