A method for preparing lead-free piezoelectric ceramic materials

Abstract

This invention discloses a method for preparing a lead-free piezoelectric ceramic material, the method comprising: providing a lead-free piezoelectric ceramic substrate; magnetron sputtering deposition of a first lead-free piezoelectric ceramic layer on the lead-free piezoelectric ceramic substrate; magnetron sputtering deposition of a second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer; and magnetron sputtering deposition of a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer; wherein the lead-free piezoelectric ceramic substrate, the first lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer, and the third lead-free piezoelectric ceramic layer all have the chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3‑0.16x F 0.32x Where 0.2≤x≤1, the third lead-free piezoelectric ceramic layer has more fluorine than the second lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer has more fluorine than the first lead-free piezoelectric ceramic layer, and the first lead-free piezoelectric ceramic layer has more fluorine than the lead-free piezoelectric ceramic substrate.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to a method for preparing a lead-free piezoelectric ceramic material. Background Technology

[0002] Piezoelectric ceramics are widely used in frequency control devices such as resonators and filters, making them a very important functional material. Currently, piezoelectric ceramics can be divided into lead-free and lead-containing piezoelectric ceramics. Because lead itself is highly harmful to the environment, much research has focused on improving the performance of lead-free piezoelectric ceramics.

[0003] More recent research findings can be found in Chinese Patent CN116573936A, which discloses anion-modified lead-free piezoelectric ceramics and their preparation method. An innovation of this prior art lies in replacing ZrO2 with ZrF4, thereby obtaining a lead-free piezoelectric ceramic with an ultra-high piezoelectric constant. The ceramic material proposed in this prior art is still prepared using traditional steps such as ball milling-cold pressing-sintering. Our research group has found that if this prior art ceramic material is used as a base, supplemented by more advanced preparation techniques, lead-free piezoelectric ceramic materials with further improved performance can be obtained. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a method for preparing lead-free piezoelectric ceramic materials, characterized in that the method includes:

[0005] Provide lead-free piezoelectric ceramic substrates;

[0006] A first lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on a lead-free piezoelectric ceramic substrate;

[0007] A second lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the first lead-free piezoelectric ceramic layer;

[0008] A third lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the second lead-free piezoelectric ceramic layer;

[0009] Among them, the lead-free piezoelectric ceramic substrate, the first lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer, and the third lead-free piezoelectric ceramic layer all have the chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x F 0.32x Where 0.2≤x≤1, the third lead-free piezoelectric ceramic layer has more fluorine than the second lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer has more fluorine than the first lead-free piezoelectric ceramic layer, and the first lead-free piezoelectric ceramic layer has more fluorine than the lead-free piezoelectric ceramic substrate.

[0010] In a preferred embodiment, the lead-free piezoelectric ceramic substrate has the general chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where 0.2≤x1≤0.3;

[0011] The chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where 0.4≤x2≤0.5.

[0012] In a preferred embodiment, the chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where 0.6 ≤ x3 ≤ 0.8;

[0013] The chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where 0.9≤x4≤1.

[0014] In a preferred embodiment, the thickness of the lead-free piezoelectric ceramic substrate is 100-120 micrometers, the thickness of the first lead-free piezoelectric ceramic layer is 10-15 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 10-15 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 10-15 micrometers.

[0015] In a preferred embodiment, the specific process for magnetron sputtering deposition of the first lead-free piezoelectric ceramic layer on a lead-free piezoelectric ceramic substrate is as follows:

[0016] The sputtering power supply is an RF power supply with a sputtering voltage of 150-200V, a sputtering power of 200-300W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm.

[0017] In a preferred embodiment, the specific process for magnetron sputtering deposition of the second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows:

[0018] The sputtering power supply is an RF power supply with a sputtering voltage of 200-250V, a sputtering power of 200-300W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm.

[0019] In a preferred embodiment, the specific process for magnetron sputtering deposition of the third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows:

[0020] The sputtering power supply is an RF power supply with a sputtering voltage of 150-200V, a sputtering power of 400-450W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm.

[0021] This invention provides a lead-free piezoelectric ceramic material, characterized in that the lead-free piezoelectric ceramic material is prepared by the following method:

[0022] Provide lead-free piezoelectric ceramic substrates;

[0023] A first lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on a lead-free piezoelectric ceramic substrate;

[0024] A second lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the first lead-free piezoelectric ceramic layer;

[0025] A third lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the second lead-free piezoelectric ceramic layer;

[0026] Among them, the lead-free piezoelectric ceramic substrate, the first lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer, and the third lead-free piezoelectric ceramic layer all have the chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x F 0.32x Where 0.2≤x≤1, the third lead-free piezoelectric ceramic layer has more fluorine than the second lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer has more fluorine than the first lead-free piezoelectric ceramic layer, and the first lead-free piezoelectric ceramic layer has more fluorine than the lead-free piezoelectric ceramic substrate.

[0027] In a preferred embodiment, the lead-free piezoelectric ceramic substrate has the general chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where 0.2≤x1≤0.3;

[0028] The chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where 0.4≤x2≤0.5.

[0029] In a preferred embodiment, the chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where 0.6 ≤ x3 ≤ 0.8;

[0030] The chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where 0.9≤x4≤1.

[0031] Compared with existing technologies, the present invention has the following advantages: It is a lead-free piezoelectric ceramic material, which is environmentally friendly and uses abundant raw materials. Furthermore, compared with existing technologies, the dielectric constant and piezoelectric constant of the material obtained by the present invention are both improved to a certain extent. Attached Figure Description

[0032] Figure 1 This is a flowchart of a method according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of a lead-free piezoelectric ceramic material according to an embodiment of the present invention. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0035] Figure 1 This is a flowchart of a method according to an embodiment of the present invention. As shown in the figure, the method of the present invention includes the following steps:

[0036] Step 1: Provide a lead-free piezoelectric ceramic substrate;

[0037] Step 2: Deposit the first lead-free piezoelectric ceramic layer on the lead-free piezoelectric ceramic substrate by magnetron sputtering;

[0038] Step 3: Deposit a second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer by magnetron sputtering;

[0039] Step 4: Deposit a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer by magnetron sputtering;

[0040] Among them, the lead-free piezoelectric ceramic substrate, the first lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer, and the third lead-free piezoelectric ceramic layer all have the chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x F 0.32x Where 0.2≤x≤1, the third lead-free piezoelectric ceramic layer has more fluorine than the second lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer has more fluorine than the first lead-free piezoelectric ceramic layer, and the first lead-free piezoelectric ceramic layer has more fluorine than the lead-free piezoelectric ceramic substrate. Figure 1 A schematic diagram of the structure of the lead-free piezoelectric ceramic material prepared by the method shown can be found in [reference needed]. Figure 2 It is important to note that Figure 2 To clearly show the location of each layer, they are shown as having the same thickness, that is, in Figure 2 The thickness relationship between the layers is not shown in the text.

[0041] In a preferred embodiment, the lead-free piezoelectric ceramic substrate has the general chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where 0.2≤x1≤0.3; In one example, the lead-free piezoelectric ceramic substrate can be prepared by the following method: First, Ba is prepared according to the method proposed in prior art CN116573936A. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 The ceramic body is then mechanically cut to obtain ceramic sheet. The ceramic sheet can then be thinned again by polishing with high-grit sandpaper or by ion thinning to obtain the lead-free piezoelectric ceramic substrate to be used in this invention. The ceramic body can be manufactured by a processing company.

[0042] The chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2Where 0.4 ≤ x² ≤ 0.5. Those skilled in the art should understand that, since the first lead-free piezoelectric ceramic layer is formed by magnetron sputtering, Ba... 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 This refers to using Ba 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 The first lead-free piezoelectric ceramic layer is sputtered using a target material. In the field of magnetron sputtering, the chemical formula of the sputtered film is characterized by the sputtering target material. Ba 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 The target material can still be prepared using the method proposed in the existing technology CN116573936A. The ceramic body prepared using this existing technology can be used as a sputtering target material itself, and the target material can still be outsourced to a processing company for production.

[0043] In a preferred embodiment, the chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where 0.6 ≤ x3 ≤ 0.8;

[0044] The chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where 0.9≤x4≤1.

[0045] In a preferred embodiment, the thickness of the lead-free piezoelectric ceramic substrate is 100-120 micrometers, the thickness of the first lead-free piezoelectric ceramic layer is 10-15 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 10-15 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 10-15 micrometers.

[0046] In a preferred embodiment, the specific process for magnetron sputtering deposition of the first lead-free piezoelectric ceramic layer on a lead-free piezoelectric ceramic substrate is as follows:

[0047] The sputtering power supply is an RF power supply with a sputtering voltage of 150-200V, a sputtering power of 200-300W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm. Those skilled in the art should understand that in current magnetron sputtering equipment, the temperature sensor is placed near the substrate; therefore, the sputtering temperature in this invention refers to the temperature near the substrate.

[0048] In a preferred embodiment, the specific process for magnetron sputtering deposition of the second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows:

[0049] The sputtering power supply was an RF power supply, with a sputtering voltage of 200-250V, a sputtering power of 200-300W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm. Our research group discovered that, during the sputtering of the second lead-free piezoelectric ceramic layer, due to the composition of the second lead-free piezoelectric ceramic layer itself, appropriately increasing the sputtering voltage helps to form a film with a better morphology (the film morphology is reflected in the final performance test results).

[0050] In a preferred embodiment, the specific process for magnetron sputtering deposition of the third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows:

[0051] The sputtering power source was an RF power supply with a sputtering voltage of 150-200V, a sputtering power of 400-450W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm. Our research group discovered that, during the sputtering of the third lead-free piezoelectric ceramic layer, due to the composition of the third lead-free piezoelectric ceramic layer itself, appropriately increasing the sputtering power helps to form a film with a better morphology (the film morphology is reflected in the final performance test results). Example 1

[0052] Lead-free piezoelectric ceramic materials are prepared by the following method: providing a lead-free piezoelectric ceramic substrate; magnetron sputtering depositing a first lead-free piezoelectric ceramic layer on the lead-free piezoelectric ceramic substrate; magnetron sputtering depositing a second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer; magnetron sputtering depositing a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer; the general chemical formula of the lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where x1 = 0.2; the chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F0.32x2 Where x2 = 0.4. The chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where x3 = 0.6; the chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where x4 = 0.9, the thickness of the lead-free piezoelectric ceramic substrate is 100 micrometers, the thickness of the first lead-free piezoelectric ceramic layer is 10 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 10 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 10 micrometers.

[0053] The specific process for magnetron sputtering deposition of the first lead-free piezoelectric ceramic layer on a lead-free piezoelectric ceramic substrate is as follows: the sputtering power source is an RF power source, the sputtering voltage is 150V, the sputtering power is 200W, the sputtering temperature is 150℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30sccm.

[0054] The specific process for magnetron sputtering deposition of the second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 200V, the sputtering power is 200W, the sputtering temperature is 150℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30sccm.

[0055] The specific process for magnetron sputtering deposition of a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 150V, the sputtering power is 400W, the sputtering temperature is 150℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30 sccm. Subsequently, the surface of the prepared ceramic material is silver-plated and polarized in a silicone oil bath at 3kV for 20 minutes (this step refers to the prior art CN116573936A). For comparability of results, the test method also refers to CN116573936A. Example 1 of the present invention... 33 The dielectric constant is 3368 (1000-1060 pC / N at room temperature and 100 kHz). Considering that the main body of Embodiment 1 of this invention is still consistent with Embodiment 2 of the prior art CN116573936A, a comparison of the two reveals that the d of Embodiment 1 of this invention... 33Compared with existing technologies, the value represents a certain improvement. Our research group explains this phenomenon by stating that the piezoelectric effect is essentially a reflection of the polarization phenomenon inside the material, which is related to the crystal field. The crystal field itself depends on the crystal lattice structure. This invention fundamentally changes the crystal field of the material by stacking multiple layers of piezoelectric ceramic materials with different lattice parameters, thereby changing the degree of polarization inside the material, ultimately resulting in an improvement in the piezoelectric effect. Example 2

[0056] Lead-free piezoelectric ceramic materials are prepared by the following method: providing a lead-free piezoelectric ceramic substrate; magnetron sputtering depositing a first lead-free piezoelectric ceramic layer on the lead-free piezoelectric ceramic substrate; magnetron sputtering depositing a second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer; magnetron sputtering depositing a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer; the general chemical formula of the lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where x1 = 0.3; the chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where x2 = 0.5. The chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where x3 = 0.8; the chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where x4=1, the thickness of the lead-free piezoelectric ceramic substrate is 120 micrometers, the thickness of the first lead-free piezoelectric ceramic layer is 15 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 15 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 15 micrometers.

[0057] The specific process for magnetron sputtering deposition of the first lead-free piezoelectric ceramic layer on a lead-free piezoelectric ceramic substrate is as follows: the sputtering power source is an RF power source, the sputtering voltage is 200V, the sputtering power is 300W, the sputtering temperature is 200℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30sccm.

[0058] The specific process for magnetron sputtering deposition of the second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 250V, the sputtering power is 300W, the sputtering temperature is 200℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30sccm.

[0059] The specific process for magnetron sputtering deposition of a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 200V, the sputtering power is 450W, the sputtering temperature is 200℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30 sccm. Example 2's d 33 It has a strength of 1160-1290 pC / N and a dielectric constant of 3880 (at room temperature and 100 kHz). Example 3

[0060] Lead-free piezoelectric ceramic materials are prepared by the following method: providing a lead-free piezoelectric ceramic substrate; magnetron sputtering depositing a first lead-free piezoelectric ceramic layer on the lead-free piezoelectric ceramic substrate; magnetron sputtering depositing a second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer; magnetron sputtering depositing a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer; the general chemical formula of the lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where x1 = 0.25; the chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where x2 = 0.45. The chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where x3 = 0.7; the chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where x4 = 0.95, the thickness of the lead-free piezoelectric ceramic substrate is 110 micrometers, the thickness of the first lead-free piezoelectric ceramic layer is 12 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 12 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 12 micrometers.

[0061] The specific process for magnetron sputtering deposition of the first lead-free piezoelectric ceramic layer on a lead-free piezoelectric ceramic substrate is as follows: the sputtering power source is an RF power source, the sputtering voltage is 170V, the sputtering power is 250W, the sputtering temperature is 170℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30sccm.

[0062] The specific process for magnetron sputtering deposition of the second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 220V, the sputtering power is 250W, the sputtering temperature is 180℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30sccm.

[0063] The specific process for magnetron sputtering deposition of a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 170V, the sputtering power is 420W, the sputtering temperature is 170℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30 sccm. Example 3's d 33 It has a strength of 1030-1150 pC / N and a dielectric constant of 3576 (at room temperature and 100 kHz).

[0064] Comparative Example 1

[0065] The general chemical formula of lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where x1 = 0.4; the chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where x2 = 0.4. The chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where x3 = 0.4; the chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where x4 = 0.4, the sputtering process is as follows: sputtering power supply is RF power supply, sputtering voltage is 200V, sputtering power is 200W, sputtering temperature is 150℃, sputtering atmosphere is argon atmosphere, argon flow rate is 30sccm, and other parameters are the same as in Example 1. Comparative Example 1's d33 The dielectric constant is 3760, with a value of 1090-1220 pC / N. The results of Comparative Example 1 are similar to those of Example 4 in the prior art CN116573936A, indicating that simply sputtering multiple layers of the same composition onto a lead-free piezoelectric ceramic substrate by magnetron sputtering does not improve material properties.

[0066] Comparative Example 2

[0067] The general chemical formula of lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where x1 = 0.2; the chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where x2 = 0.4. The second and third lead-free piezoelectric ceramic layers are not sputtered. The thickness of the first lead-free piezoelectric ceramic layer is 30 micrometers, and the remaining parameters are the same as in Example 1. Comparative Example 2's d 33 It has a strength of 970-1040 pC / N and a dielectric constant of 3290.

[0068] Comparative Example 3

[0069] The thickness of the first lead-free piezoelectric ceramic layer is 20 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 20 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 20 micrometers. All other parameters are the same as in Example 1. (d in Comparative Example 3) 33 The dielectric constant is 3376 (1000-1070 pC / N at room temperature and 100 kHz). It is evident that continuously increasing the thickness of the lead-free piezoelectric ceramic layer does not indefinitely improve material performance. On the contrary, the greater the thickness of the coating, the more difficult it is to control the quality of the coating. Therefore, increasing the coating thickness is not a reasonable solution.

[0070] Comparative Example 4

[0071] The specific process for magnetron sputtering deposition of a second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 100V, the sputtering power is 300W, the sputtering temperature is 150℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30 sccm. Other parameters are the same as in Example 1. (Comparative Example 4's d...) 33The dielectric constant is 3210, with a value of 960-1010 pC / N. The performance of Comparative Example 4 is basically similar to that of Example 2 in CN116573936A. This may be due to the poor sputtering quality of the second lead-free piezoelectric ceramic layer, which prevents the second and third lead-free piezoelectric ceramic layers from performing their intended functions.

[0072] Comparative Example 5

[0073] The specific process for magnetron sputtering deposition of a third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows: the sputtering power source is an RF power source, the sputtering voltage is 100V, the sputtering power is 200W, the sputtering temperature is 150℃, the sputtering atmosphere is an argon atmosphere, and the argon flow rate is 30 sccm. Other parameters are the same as in Example 1. (Comparative Example 5 d) 33 The dielectric constant is 3280, with a value of 980-1040 pC / N. The performance of Comparative Example 5 is basically similar to that of Example 2 in CN116573936A, which may be due to the poor sputtering quality of the third lead-free piezoelectric ceramic layer.

[0074] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a lead-free piezoelectric ceramic material, characterized in that, The method includes: Provide lead-free piezoelectric ceramic substrates; A first lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the lead-free piezoelectric ceramic substrate; A second lead-free piezoelectric ceramic layer is deposited on the first lead-free piezoelectric ceramic layer by magnetron sputtering. A third lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the second lead-free piezoelectric ceramic layer; The lead-free piezoelectric ceramic substrate, the first lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer, and the third lead-free piezoelectric ceramic layer all have the chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x F 0.32x Wherein, 0.2≤x≤1, and the third lead-free piezoelectric ceramic layer has more fluorine than the second lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer has more fluorine than the first lead-free piezoelectric ceramic layer, and the first lead-free piezoelectric ceramic layer has more fluorine than the lead-free piezoelectric ceramic substrate.

2. The method as described in claim 1, wherein, The chemical formula of the lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where 0.2≤x1≤0.3; The chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where 0.4≤x2≤0.

5.

3. The method as described in claim 2, wherein, The chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where 0.6 ≤ x3 ≤ 0.8; The chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where 0.9≤x4≤1.

4. The method of claim 3, wherein, The thickness of the lead-free piezoelectric ceramic substrate is 100-120 micrometers, the thickness of the first lead-free piezoelectric ceramic layer is 10-15 micrometers, the thickness of the second lead-free piezoelectric ceramic layer is 10-15 micrometers, and the thickness of the third lead-free piezoelectric ceramic layer is 10-15 micrometers.

5. The method of claim 4, wherein, The specific process for magnetron sputtering deposition of the first lead-free piezoelectric ceramic layer on the lead-free piezoelectric ceramic substrate is as follows: The sputtering power supply is an RF power supply with a sputtering voltage of 150-200V, a sputtering power of 200-300W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm.

6. The method of claim 5, wherein, The specific process for magnetron sputtering deposition of the second lead-free piezoelectric ceramic layer on the first lead-free piezoelectric ceramic layer is as follows: The sputtering power supply is an RF power supply with a sputtering voltage of 200-250V, a sputtering power of 200-300W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm.

7. The method of claim 6, wherein, The specific process for magnetron sputtering deposition of the third lead-free piezoelectric ceramic layer on the second lead-free piezoelectric ceramic layer is as follows: The sputtering power supply is an RF power supply with a sputtering voltage of 150-200V, a sputtering power of 400-450W, a sputtering temperature of 150-200℃, and an argon atmosphere with an argon flow rate of 30-40 sccm.

8. A lead-free piezoelectric ceramic material, characterized in that, The lead-free piezoelectric ceramic material is prepared by the following method: Provide lead-free piezoelectric ceramic substrates; A first lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the lead-free piezoelectric ceramic substrate; A second lead-free piezoelectric ceramic layer is deposited on the first lead-free piezoelectric ceramic layer by magnetron sputtering. A third lead-free piezoelectric ceramic layer is deposited by magnetron sputtering on the second lead-free piezoelectric ceramic layer; The lead-free piezoelectric ceramic substrate, the first lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer, and the third lead-free piezoelectric ceramic layer all have the chemical formula Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x F 0.32x Wherein, 0.2≤x≤1, and the third lead-free piezoelectric ceramic layer has more fluorine than the second lead-free piezoelectric ceramic layer, the second lead-free piezoelectric ceramic layer has more fluorine than the first lead-free piezoelectric ceramic layer, and the first lead-free piezoelectric ceramic layer has more fluorine than the lead-free piezoelectric ceramic substrate.

9. The lead-free piezoelectric ceramic material as described in claim 8, wherein, The chemical formula of the lead-free piezoelectric ceramic substrate is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x1 F 0.32x1 Where 0.2≤x1≤0.3; The chemical formula of the first lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x2 F 0.32x2 Where 0.4≤x2≤0.

5.

10. The lead-free piezoelectric ceramic material as described in claim 9, wherein, The chemical formula of the second lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x3 F 0.32x3 Where 0.6 ≤ x3 ≤ 0.8; The chemical formula of the third lead-free piezoelectric ceramic layer is Ba. 0.86 Sr 0.14 Ti 0.92 Zr 0.08 O 3-0.16x4 F 0.32x4 Where 0.9≤x4≤1.

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