Flexible piezoelectric ceramic film material and preparation method thereof

Abstract

The invention relates to a piezoelectric sensing composite material, and discloses a flexible piezoelectric ceramic film material and a preparation method thereof. The flexible piezoelectric ceramic film material is prepared from the following raw materials in parts by weight through blending and hot pressing: 100 parts of lead-free piezoelectric ceramic powder, 120-200 parts of flexible high-molecular polymer and 5-20 parts of conductive nano powder. The flexible high-molecular polymer and the conductive nano powder are added into the lead-free piezoelectric ceramic material to serve as main raw materials, and the flexible piezoelectric ceramic thin film material with high flexibility and high piezoelectric characteristics can be obtained by regulating and controlling the component proportion and hot pressing process parameters; and meanwhile, the flexible piezoelectric ceramic film material has the characteristics of lightness, thinness and large bending strain, and is very suitable for being adhered and compounded with various materials to capture and convert piezoelectric signals.

Description

Technical Field

[0001] This invention relates to piezoelectric sensing composite materials, and more particularly to a flexible piezoelectric ceramic thin film material and its preparation method. Background Technology

[0002] With the rapid development of smart devices and the Internet of Things (IoT), flexible wearable piezoelectric sensors are attracting increasing attention. Currently, wearable portable electronic devices are gaining popularity due to their flexibility and small size. Among numerous smart materials, piezoelectric materials are the most widely used, possessing characteristics such as fast electromechanical response and high precision, and have become a research hotspot in recent years. Piezoelectric ceramic materials can directly sense stress and strain to generate electrical signals. Their fabrication process is flexible and controllable, and the resulting materials are economical, efficient, and highly sensitive, making them a potential material for solving the energy source problem of wearable electronic devices.

[0003] However, piezoelectric ceramics suffer from problems such as high brittleness, poor ductility, and poor deformability. On the one hand, their machinability is poor, making it difficult to process them into products of different shapes (such as thin-film piezoelectric ceramic materials); on the other hand, if they are used in flexible wearable electronic devices (such as flexible piezoelectric ceramic materials), they are prone to breakage under external forces. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a flexible piezoelectric ceramic thin film material and its preparation method. This invention uses a flexible polymer and conductive nanoparticles added to a lead-free piezoelectric ceramic material as the main raw materials. By adjusting the component ratios and hot-pressing process parameters, a flexible piezoelectric ceramic thin film material with both high flexibility and high piezoelectric properties can be obtained. Furthermore, this flexible piezoelectric ceramic thin film material is lightweight, thin, and has large bending strain, making it highly suitable for bonding and composite with various materials for capturing and converting piezoelectric signals.

[0005] The specific technical solution of this invention is as follows:

[0006] First, the present invention provides a flexible piezoelectric ceramic thin film material, which is formed by blending and hot pressing the following raw materials in parts by weight: 100 parts of lead-free piezoelectric ceramic powder, 120-200 parts of flexible polymer, and 5-20 parts of conductive nanoparticles.

[0007] In response to the drawbacks of lead oxide in traditional piezoelectric ceramics such as lead zirconate titanate (PZT) which has toxic side effects on the human body, this invention uses lead-free piezoelectric ceramic materials, which are greener and healthier.

[0008] To address the problems of high brittleness, poor ductility, and poor deformability of piezoelectric ceramics, this invention incorporates appropriate amounts of flexible polymers and conductive nanoparticles into lead-free piezoelectric ceramic materials, which are characterized by high brittleness and poor ductility. The introduction of the flexible polymer not only compensates for the poor toughness of lead-free piezoelectric ceramic materials but also improves processability, allowing them to be manufactured into various sizes and shapes (e.g., thin films). The introduction of appropriate amounts of conductive nanoparticles significantly enhances the conductivity of the piezoelectric ceramic thin film material, thereby improving its piezoelectric properties.

[0009] Furthermore, it is important to emphasize that the amount of flexible polymer and conductive nanoparticles introduced has a significant impact on the performance of piezoelectric ceramic thin film materials. Ultimately, this invention found that within the aforementioned range, the obtained flexible piezoelectric ceramic thin film material exhibits superior overall performance, including flexibility and piezoelectric properties.

[0010] Furthermore, the thickness of the flexible piezoelectric ceramic thin film material is 0.20–0.40 mm, and the basis weight is 5–20 g / m³. 2 Flexibility ≥ 6mm (0.22mm).

[0011] Furthermore, the lead-free piezoelectric ceramic powder is selected from one or more of barium strontium niobate (BSN)-based lead-free piezoelectric ceramics, sodium barium niobate (BNN)-based lead-free piezoelectric ceramics, sodium potassium niobate (KNN)-based lead-free piezoelectric ceramics, sodium bismuth titanate (BNT)-based lead-free piezoelectric ceramics, and barium titanate (BT)-based lead-free piezoelectric ceramics.

[0012] Furthermore, the particle size of the lead-free piezoelectric ceramic powder is 20nm-80μm.

[0013] Furthermore, the flexible polymer is selected from one or more of polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polybutylene terephthalate (PBT), polyamide 11 (PA11), and polyamide 1111 (PA1111).

[0014] Furthermore, the conductive nanopowder is selected from one or more of nickel, chromium, tungsten, silver, aluminum, gold, carbon nanotubes, carbon black, graphene, tourmaline, and antimony-doped tin oxide (ATO).

[0015] Secondly, this invention provides a method for preparing the above-mentioned flexible piezoelectric ceramic thin film material, the steps of which are as follows:

[0016] S1. Preparation of lead-free piezoelectric ceramic powder: First, the lead-free piezoelectric ceramic pre-sintered material is sintered at high temperature, and then air jet milling is performed to obtain lead-free piezoelectric ceramic powder.

[0017] S2. Add conductive nanopowder and flexible polymer: Add conductive nanopowder and flexible polymer to the lead-free piezoelectric ceramic powder obtained in step S1 and stir to obtain a mixed powder.

[0018] S3. Homogenization treatment: Homogenize the mixed powder obtained in S2.

[0019] S4. Kneading and crushing: After kneading the mixed powder obtained in S3, crush and sieve it to obtain hot-pressed pre-formed powder.

[0020] S5. Hot-pressed film: The hot-pressed pre-powder obtained in step S4 is dried and hot-pressed. The resulting film is sealed after humidity equilibration at room temperature to obtain a flexible piezoelectric ceramic thin film material.

[0021] Furthermore, in S3, a high-speed disperser is used for homogenization, with a dispersion shaft speed of 1000-1450 r / min and a lifting stroke of 1800-2800 mm.

[0022] Furthermore, in S4, the mesh size of the sieve is 60 to 200 mesh.

[0023] Furthermore, in S5, the hot pressing process is as follows: heating temperature 120-330℃, hot pressing time 1-3 min / t, cooling time 3-5 min / t, pressure 4-45 MPa, and 2-4 cycles.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The present invention uses flexible polymer and conductive nanoparticles added to lead-free piezoelectric ceramic materials as the main raw materials. By adjusting the composition ratio and hot pressing process parameters, a flexible piezoelectric ceramic film material with both high flexibility and high piezoelectric properties can be obtained.

[0026] (2) The present invention combines lead-free piezoelectric ceramics with highly flexible polymer materials, which can be manufactured into various sizes and shapes, and has the characteristics of being thin and light with large bending strain. It is very suitable for bonding and bonding with various materials to capture and convert piezoelectric signals, and is suitable for bonding to various working surfaces including curved surfaces.

[0027] (3) This invention uses lead-free piezoelectric ceramic materials, which are greener and healthier.

[0028] (4) Flexible piezoelectric ceramic thin film materials prepared by simple blending-hot pressing technology have high industrial production economics and have extremely high application value in the field of flexible wearable electronic devices. Attached Figure Description

[0029] Figure 1The image shows the scanning electron microscope (SEM) morphology of the lead-free piezoelectric ceramic powder used. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, so as to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] First, the present invention provides a flexible piezoelectric ceramic thin film material, which is formed by blending and hot pressing the following raw materials in parts by weight: 100 parts of lead-free piezoelectric ceramic powder, 120-200 parts of flexible polymer, and 5-20 parts of conductive nanoparticles.

[0032] Furthermore, the thickness of the flexible piezoelectric ceramic thin film material is 0.20–0.40 mm, and the basis weight is 5–20 g / m³. 2 Flexibility ≥ 6mm (0.22mm).

[0033] Further, the lead-free piezoelectric ceramic powder is selected from one or more of barium strontium niobate (BSN)-based lead-free piezoelectric ceramics, sodium barium niobate (BNN)-based lead-free piezoelectric ceramics, sodium potassium niobate (KNN)-based lead-free piezoelectric ceramics, sodium bismuth titanate (BNT)-based lead-free piezoelectric ceramics, and barium titanate (BT)-based lead-free piezoelectric ceramics; the particle size of the lead-free piezoelectric ceramic powder is 20nm-80μm. The flexible polymer is selected from one or more of polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polybutylene terephthalate (PBT), polyamide 11 (PA11), and polyamide 1111 (PA1111). The conductive nanopowder is selected from one or more of nickel, chromium, tungsten, silver, aluminum, gold, carbon nanotubes, carbon black, graphene, tourmaline, and antimony-doped tin oxide (ATO).

[0034] Secondly, this invention provides a method for preparing the above-mentioned flexible piezoelectric ceramic thin film material, the steps of which are as follows:

[0035] S1. Preparation of lead-free piezoelectric ceramic powder: First, the lead-free piezoelectric ceramic pre-sintered material is sintered at high temperature, and then air jet milling is performed to obtain lead-free piezoelectric ceramic powder.

[0036] S2. Add conductive nanopowder and flexible polymer: Add conductive nanopowder and flexible polymer to the lead-free piezoelectric ceramic powder obtained in step S1 and stir to obtain a mixed powder.

[0037] S3. Homogenization treatment: Homogenize the mixed powder obtained in S2.

[0038] Furthermore, in S3, a high-speed disperser is used for homogenization, with a dispersion shaft speed of 1000-1450 r / min and a lifting stroke of 1800-2800 mm.

[0039] S4. Kneading and crushing: After kneading the mixed powder obtained in S3, crush and sieve it to obtain hot-pressed pre-formed powder.

[0040] Furthermore, in S4, the mesh size of the sieve is 60 to 200 mesh.

[0041] S5. Hot-pressed film: The hot-pressed pre-powder obtained in step S4 is dried and hot-pressed. The resulting film is sealed after humidity equilibration at room temperature to obtain a flexible piezoelectric ceramic thin film material.

[0042] Furthermore, in S5, the hot pressing process is as follows: heating temperature 120-330℃, hot pressing time 1-3 min / t, cooling time 3-5 min / t, pressure 4-45 MPa, and 2-4 cycles.

[0043] Example 1

[0044] A method for preparing a flexible piezoelectric ceramic thin film material, comprising the following specific steps:

[0045] 1. Preparation of lead-free piezoelectric ceramic powder: Lead-free barium strontium niobate (BSN) pre-sintered material was sintered at high temperature and then ground using an air jet mill to obtain lead-free piezoelectric ceramic powder with a particle size of 60 nm. Figure 1 This is a scanning electron microscope (SEM) image of the lead-free piezoelectric ceramic powder.

[0046] 2. Add conductive nanopowder and polymer materials: Add 5% by weight of graphene and tourmaline conductive nanopowder (mass ratio of 1:1) and 120% by weight of polyamide 1111 (PA1111) to the lead-free piezoelectric ceramic powder obtained in step S1 and stir to obtain a mixed powder.

[0047] 3. Homogenization: The above mixed powder is homogenized using a high-speed disperser. The equipment parameters are: dispersion shaft speed 1100 (r / min) and lifting stroke 1800 (mm) to obtain powder for further processing.

[0048] 4. Kneading and crushing: After kneading the mixed powder obtained in S3 using a vacuum kneader, crush it using a high-speed mechanical pulverizer and sieve it through a 120-mesh sieve to obtain hot-pressed pre-formed powder.

[0049] 5. Hot-pressed film: The hot-pressed pre-formed powder obtained in step S4 is dried, and a fixed process is used: heating temperature 220℃, hot-pressing time 2 min / t, cooling time 3 min / t, pressure 20 MPa, and hot-pressing cycle 3 times. After the film reaches humidity equilibrium at room temperature, it becomes a flexible piezoelectric ceramic thin film material with a thickness of 0.30 mm and a basis weight of 11 g / m³. 2 Flexibility ≥ 10.7 mm (0.30 mm).

[0050] Example 2

[0051] A method for preparing a flexible piezoelectric ceramic thin film material, comprising the following specific steps:

[0052] 1. Preparation of lead-free piezoelectric ceramic powder: Lead-free piezoelectric ceramic potassium sodium niobate (KNN) pre-sintered material was sintered at high temperature and then ground using an air jet mill to obtain lead-free piezoelectric ceramic powder with a particle size of 60 μm.

[0053] 2. Add conductive nanopowder and polymer materials: Add 5% by weight of graphene and tourmaline conductive nanopowder (mass ratio of 1:1) and 120% by weight of polyamide 1111 (PA1111) to the lead-free piezoelectric ceramic powder obtained in step S1 and stir to obtain a mixed powder.

[0054] 3. Homogenization: The above mixed powder is homogenized using a high-speed disperser. The equipment parameters are: dispersion shaft speed 1100 (r / min) and lifting stroke 2000 (mm) to obtain powder for further processing.

[0055] 4. Kneading and crushing: After kneading the mixed powder obtained in S3 using a vacuum kneader, crush it using a high-speed mechanical pulverizer and sieve it through a 90-mesh screen to obtain hot-pressed pre-formed powder.

[0056] 5. Hot-pressed film: The hot-pressed pre-formed powder obtained in step S4 is dried, and a fixed process is used: heating temperature 220℃, hot-pressing time 2 min / t, cooling time 1 min / t, pressure 5 MPa, and hot-pressing cycle 3 times. After the film reaches humidity equilibrium at room temperature, it becomes a flexible piezoelectric ceramic thin film material with a thickness of 0.22 mm and a basis weight of 12 g / m³. 2 Flexibility ≥ 9.0 mm (0.22 mm).

[0057] Example 3

[0058] 1. Preparation of lead-free piezoelectric ceramic powder: Lead-free piezoelectric ceramic barium sodium niobate (BNN) pre-sintered material is sintered at high temperature and then ground using an air jet mill to obtain lead-free piezoelectric ceramic powder with a particle size of 5 μm.

[0059] 2. Add conductive nanopowder and polymer materials: Add 11% carbon nanotubes (by weight of lead-free piezoelectric ceramic powder) and 155% polyamide 11 (PA11) (by weight of lead-free piezoelectric ceramic powder) to the lead-free piezoelectric ceramic powder obtained in step S1 and stir to obtain a mixed powder.

[0060] 3. Homogenization: The above-mentioned mixed powder is homogenized using a high-speed disperser. The equipment parameters are: dispersion shaft speed 1450 (r / min) and lifting stroke 1800 (mm) to obtain powder for further processing.

[0061] 4. Kneading and crushing: After kneading the mixed powder obtained in S3 using a vacuum kneader, crush it using a high-speed mechanical pulverizer and sieve it through an 80-mesh screen to obtain hot-pressed pre-formed powder.

[0062] 5. Hot-pressed film: The hot-pressed pre-formed powder obtained in step S4 is dried, and a fixed process is used: heating temperature 300℃, hot-pressing time 2min / t, cooling time 1min / t, pressure 25MPa, and hot-pressing cycle 3 times. After the film reaches humidity equilibrium at room temperature, it becomes a flexible piezoelectric ceramic thin film material with a thickness of 0.28mm and a basis weight of 15g / m³. 2 Flexibility ≥ 16.7 mm (0.28 mm).

Claims

1. A flexible piezoelectric ceramic thin film material, characterized in that: It is made by blending and hot pressing the following raw materials in parts by weight: 100 parts of lead-free piezoelectric ceramic powder 120-200 parts of flexible polymer 5-20 parts of conductive nanoparticles.

2. The flexible piezoelectric ceramic thin film material according to claim 1, characterized in that: The flexible piezoelectric ceramic thin film material has a thickness of 0.20–0.40 mm and a basis weight of 5–20 g / m³. 2 Flexibility ≥ 6mm (0.22mm).

3. The flexible piezoelectric ceramic thin film material according to claim 1, characterized in that: The lead-free piezoelectric ceramic powder is selected from one or more of the following: barium strontium niobate-based lead-free piezoelectric ceramics, sodium barium niobate-based lead-free piezoelectric ceramics, sodium potassium niobate-based lead-free piezoelectric ceramics, sodium bismuth titanate-based lead-free piezoelectric ceramics, and barium titanate-based lead-free piezoelectric ceramics.

4. The flexible piezoelectric ceramic thin film material according to claim 1 or 3, characterized in that: The particle size of the lead-free piezoelectric ceramic powder is 20nm-80μm.

5. The flexible piezoelectric ceramic thin film material according to claim 1, characterized in that: The flexible polymer is selected from one or more of polypropylene, polyethylene terephthalate, polyvinylidene fluoride, polybutylene terephthalate, polyamide 11, and polyamide 1111.

6. The flexible piezoelectric ceramic thin film material according to claim 1, characterized in that: The conductive nanopowder is selected from one or more of nickel, chromium, tungsten, silver, aluminum, gold, carbon nanotubes, carbon black, graphene, tourmaline, and antimony-doped tin oxide.

7. A method for preparing a flexible piezoelectric ceramic thin film material as described in any one of claims 1-6, characterized in that... The steps are as follows: S1. Preparation of lead-free piezoelectric ceramic powder: First, the lead-free piezoelectric ceramic pre-sintered material is sintered at high temperature, and then air jet milling is performed to obtain lead-free piezoelectric ceramic powder. S2. Add conductive nanopowder and flexible polymer: Add conductive nanopowder and flexible polymer material to the lead-free piezoelectric ceramic powder obtained in step S1 and stir to obtain a mixed powder. S3. Homogenization treatment: Homogenize the mixed powder obtained in S2; S4. Kneading and crushing: After kneading the mixed powder obtained in S3, crush and sieve it to obtain hot-pressed pre-formed powder. S5. Hot-pressed film: The hot-pressed pre-powder obtained in step S4 is dried and hot-pressed. The resulting film is sealed after humidity equilibration at room temperature to obtain a flexible piezoelectric ceramic thin film material.

8. The preparation method according to claim 7, characterized in that: In S3, a high-speed disperser is used for homogenization, with a dispersion shaft speed of 1000-1450 r / min and a lifting stroke of 1800-2800 mm.

9. The preparation method according to claim 7, characterized in that: In S4, the mesh size of the sieve is 60 to 200 mesh.

10. The preparation method according to claim 7, characterized in that: In S5, the hot pressing process is as follows: heating temperature 120-330℃, hot pressing time 1-3 min / t, cooling time 3-5 min / t, pressure 4-45 MPa, and 2-4 cycles.

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