High-hardness wear-resistant piezoelectric sensor and preparation method thereof

Abstract

The application belongs to the field of aero-engine sensors, and particularly relates to a high-hardness wear-resistant piezoelectric sensor and a preparation method thereof. The piezoelectric sensor comprises a substrate, and a Cr bonding layer, a CrN metal ceramic transition layer, a CrN / ZnN nanometer multi-layer blending layer and a CrN / ZnO multi-layer piezoelectric functional layer are sequentially deposited on the substrate. The high-hardness wear-resistant piezoelectric sensor can greatly reduce the internal stress of the piezoelectric coating, avoid peeling of the piezoelectric coating, and has good adhesion to various steel substrates, so that good adhesion can be obtained on various steel substrates.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aero-engine sensors, and particularly relates to a high-hardness wear-resistant piezoelectric sensor and a preparation method thereof. BACKGROUND

[0002] Piezoelectric material is a semiconductor material that is widely used at present. Its principle is that if pressure is applied to the piezoelectric material, it will generate a potential difference, and vice versa, mechanical stress is generated. If the pressure is a high-frequency vibration, a high-frequency current is generated. When a high-frequency electrical signal is applied to the piezoelectric ceramic, a high-frequency acoustic signal is generated. This inherent mechanical-electrical coupling effect makes piezoelectric materials widely used in engineering. At present, piezoelectric materials are divided into piezoelectric crystals and piezoelectric ceramics. Piezoelectric crystal generally refers to piezoelectric single crystal; piezoelectric ceramic refers to piezoelectric polycrystal. Piezoelectric ceramic is prepared by sintering method, and is a polycrystal obtained by irregular collection of microcrystalline grains through solid phase reaction and sintering process between powder particles. Common piezoelectric ceramics are barium titanate, lead zirconate titanate and lead barium lithium niobate, etc. The development of such materials promotes the improvement and enhancement of the performance of various piezoelectric devices such as acoustic transducers and piezoelectric sensors.

[0003] Piezoelectric ceramic has strong piezoelectricity, high dielectric constant and can be processed into any shape, but has low mechanical quality factor, large electrical loss and poor stability, so it is suitable for high-power transducers and wide-band filters, etc., but is not ideal for high-frequency and high-stability applications. Quartz and other piezoelectric single crystals have weak piezoelectricity, very low dielectric constant, size limitation due to cutting type limitation, but have high stability and high mechanical quality factor, and are often used as standard frequency control oscillators, high-selectivity filters and high-frequency, high-temperature ultrasonic transducers, etc. Piezoelectric thin film material is a piezoelectric material prepared by forming a piezoelectric material into a thin film on the surface of another material. It has the characteristics of easy orientation control and uniform thickness. In the acoustic surface wave period, piezoelectric sensors and other aspects have obtained a large number of applications. However, due to the preparation of piezoelectric materials generally using ceramic target for radio frequency sputtering or metal target for reactive sputtering, the deposition speed is slow and the adhesion is poor. It is not conducive to the preparation of highly preferred orientation coating on the surface of various metal matrix materials. Therefore, the development of new piezoelectric ceramic coating preparation technology and materials has important value.

[0004] Therefore, it is desirable to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. SUMMARY

[0005] The purpose of the present application is to provide a high-hardness wear-resistant piezoelectric sensor and a preparation method thereof to solve at least one problem existing in the prior art.

[0006] The technical solution of the present application is:

[0007] The first aspect of the present application provides a high-hardness wear-resistant piezoelectric sensor, comprising:

[0008] a substrate, a Cr bonding layer, a CrN cermet transition layer, a CrN / ZnN nanolayer blend layer, and a CrN / ZnO multilayer piezoelectric functional layer are sequentially deposited on the substrate.

[0009] In at least one embodiment of the present application, the total thickness of the coating on the substrate is 1.73-14.250 microns.

[0010] In at least one embodiment of the present application, the thickness of the Cr bonding layer is 10-100 nanometers.

[0011] In at least one embodiment of the present application, the thickness of the CrN cermet transition layer is 200-800 nanometers.

[0012] In at least one embodiment of the present application, the CrN / ZnN nanolayer blend layer comprises CrN layers and ZnN layers arranged alternately, the total thickness of the CrN / ZnN nanolayer blend layer is 600-3000 nanometers, the single-layer thickness of the CrN layer is 4-20 nanometers, and the single-layer thickness of the ZnN layer is 2-10 nanometers.

[0013] In at least one embodiment of the present application, the CrN / ZnO multilayer piezoelectric functional layer comprises CrN layers and ZnO layers arranged alternately, the single-layer thickness of the CrN layer is 20-50 nanometers, and the single-layer thickness of the ZnO layer is 500-2000 nanometers.

[0014] The second aspect of the present application provides a high-hardness wear-resistant piezoelectric sensor preparation method, which is used for preparing the high-hardness wear-resistant piezoelectric sensor as described above, comprising:

[0015] mounting the substrate in a high-hardness wear-resistant piezoelectric sensor preparation tool;

[0016] performing plasma etching on the substrate in an argon and hydrogen environment at 300-500°C;

[0017] after the etching is completed, performing ion bombardment on the substrate under the conditions of 0.05-0.1 Pa and 600-800 V;

[0018] after the bombardment is completed, depositing a Cr bonding layer with a thickness of 10-100 nanometers on the substrate under the conditions of 0.5-1 Pa and 50-150 V;

[0019] depositing a CrN cermet transition layer with a thickness of 200-800 nanometers on the Cr bonding layer under the conditions of 1-2 Pa and 100-150 V;

[0020] Depositing 600-3000 nanometer thickness CrN / ZnN nanometer multi-layer blend layer on the CrN metal ceramic transition layer under the condition of 2-5 Pa, 50-150 V, wherein the single layer thickness of CrN layer is 4-20 nanometer, the single layer thickness of ZnN layer is 2-10 nanometer, and the modulation period is 6-30 nanometer;

[0021] Depositing CrN / ZnO multi-layer piezoelectric functional layer on the CrN / ZnN nanometer multi-layer blend layer under the condition of 2-5 Pa, 50-150 V, wherein the single layer thickness of CrN layer is 20-50 nanometer, the single layer thickness of ZnO layer is 500-2000 nanometer, and the total thickness of the coating is controlled in 1.73-14.250 micrometer;

[0022] After the coating deposition, the coating is naturally cooled.

[0023] In at least one embodiment of the present application, the high-hardness wear-resistant piezoelectric sensor preparation tool comprises:

[0024] A vacuum chamber, wherein an exhaust port is arranged on the side wall of the vacuum chamber;

[0025] A heater arranged inside the vacuum chamber;

[0026] A thermocouple arranged inside the vacuum chamber;

[0027] An arc target comprising an etched Cr target, a plated Cr target, and a plated Zn target, which are respectively installed on the side wall of the vacuum chamber;

[0028] A workpiece holder arranged inside the vacuum chamber, which is used for mounting the substrate.

[0029] In at least one embodiment of the present application, the vacuum chamber is a cube with a size of 600x600x600mm.

[0030] In at least one embodiment of the present application, the heater comprises four groups, which are respectively arranged at four corners inside the vacuum chamber, and the heating power of each heater is 10-30 kilowatts.

[0031] The present application has at least the following beneficial technical effects:

[0032] The high-hardness wear-resistant piezoelectric sensor of the present application adopts a gradient structure for the coating structure, which can greatly reduce the internal stress of the piezoelectric coating and avoid peeling, and CrN is used as the composite object, which has good adhesion with the substrate of various steels and can obtain good adhesion effect on various steels. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1This is a schematic diagram of a high-hardness, wear-resistant piezoelectric sensor according to one embodiment of this application;

[0034] Fig. 2 This is a schematic diagram of a tooling for fabricating a high-hardness, wear-resistant piezoelectric sensor according to one embodiment of this application.

[0035] in:

[0036] 1-Substrate; 2-Cr bonding layer; 3-CrN cermet transition layer; 4-CrN / ZnN nano-multilayer blend layer; 5-CrN / ZnO multilayer piezoelectric functional layer; 6-Etched Cr target; 7-Heater; 8-Coated Zn target; 9-Ejector port; 10-Coated Cr target; 11-Workpiece holder; 12-Thermocouple. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0038] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this application.

[0039] The following is in conjunction with the appendix Figs. 1-2 This application will be described in further detail.

[0040] The first aspect of this application provides a high-hardness, wear-resistant piezoelectric sensor, such as... Fig. 1 As shown, it includes: a substrate 1, and a Cr bonding layer 2, a CrN cermet transition layer 3, a CrN / ZnN nano-multilayer blend layer 4, and a CrN / ZnO multilayer piezoelectric functional layer 5 sequentially deposited on the substrate 1.

[0041] The high-hardness wear-resistant piezoelectric sensor of the present application, the piezoelectric coating adopts a gradient layer structure, which is composed of a bonding layer, a transition layer, an alternating multi-layer blending layer, and a multi-layer piezoelectric functional layer. The bonding layer is a pure metal Cr layer, the transition layer is a CrN transition ceramic layer, the alternating multi-layer blending layer serves as a support layer and is a CrN / ZnN multi-layer film structure, and the multi-layer piezoelectric functional layer is a multi-layer structure composed of a CrN / ZnO piezoelectric composite coating material.

[0042] In the preferred embodiment of the present application, the coating thickness parameters are set according to the following manner: the total thickness of the coating deposited on the substrate 1 is preferably 1.73-14.250 microns. Among them, the thickness of the Cr bonding layer 2 is preferably 10-100 nanometers; the thickness of the CrN cermet transition layer 3 is preferably 200-800 nanometers; the CrN / ZnN nanometer multi-layer blending layer 4 includes alternating CrN layers and ZnN layers, the total thickness of the CrN / ZnN nanometer multi-layer blending layer 4 is preferably 600-3000 nanometers, the single-layer thickness of the CrN layer is preferably 4-20 nanometers, and the single-layer thickness of the ZnN layer is preferably 2-10 nanometers; the CrN / ZnO multi-layer piezoelectric functional layer 5 includes alternating CrN layers and ZnO layers, the single-layer thickness of the CrN layer is preferably 20-50 nanometers, the single-layer thickness of the ZnO layer is preferably 500-2000 nanometers, and the thickness of the CrN / ZnO multi-layer piezoelectric functional layer 5 is controlled based on the total thickness of the coating.

[0043] Based on the high-hardness wear-resistant piezoelectric sensor described above, the second aspect of the present application provides a high-hardness wear-resistant piezoelectric sensor preparation method, which comprises:

[0044] The substrate 1 is installed in a high-hardness wear-resistant piezoelectric sensor preparation tool;

[0045] The substrate 1 is subjected to plasma etching in an argon and hydrogen environment at 300-500°C;

[0046] After etching, the substrate 1 is subjected to ion bombardment under the conditions of 0.05-0.1 Pa and 600-800 V;

[0047] After bombardment, a 10-100 nanometer thick Cr bonding layer 2 is deposited on the substrate 1 under the conditions of 0.5-1 Pa and 50-150 V;

[0048] A 200-800 nanometer thick CrN cermet transition layer 3 is deposited on the Cr bonding layer 2 under the conditions of 1-2 Pa and 100-150 V;

[0049] Depositing a 600-3000 nanometer thick CrN / ZnN nanometer multi-layer blend layer 4 on the CrN metal ceramic transition layer 3 under the condition of 2-5 Pa, 50-150 V, wherein the single layer thickness of the CrN layer is 4-20 nanometers, the single layer thickness of the ZnN layer is 2-10 nanometers, and the modulation period is 6-30 nanometers;

[0050] Depositing a CrN / ZnO multi-layer piezoelectric functional layer 5 on the CrN / ZnN nanometer multi-layer blend layer 4 under the condition of 2-5 Pa, 50-150 V, wherein the single layer thickness of the CrN layer is 20-50 nanometers, the single layer thickness of the ZnO layer is 500-2000 nanometers, and the total thickness of the coating is controlled to be 1.73-14.250 micrometers;

[0051] After the coating deposition, the coating is naturally cooled.

[0052] In the preferred embodiment of the present application, as shown in Fig. 2 The high-hardness wear-resistant piezoelectric sensor preparation tool includes a vacuum chamber, a plurality of heaters 7, a thermocouple 12, three arc targets, and a plurality of workpiece racks 11. Specifically, the vacuum chamber is surrounded by a furnace wall, and an air exhaust port 9 is arranged on the side wall of the vacuum chamber. A vacuum pumping unit performs vacuum pumping on the vacuum chamber through the air exhaust port 9. The heater 7 and the thermocouple 12 are arranged inside the vacuum chamber. The three arc targets include an etched Cr target 6, a coated Cr target 10, and a coated Zn target 8, which are respectively installed on the side wall of the vacuum chamber. The workpiece rack 11 is arranged inside the vacuum chamber and is used for mounting the substrate 1. This layout greatly increases the plasma density in the vacuum chamber, and the workpiece is completely immersed in the plasma. The coating deposition rate, hardness, and adhesion are greatly improved. Due to the optimization of the target structure, the magnetic field distribution is more uniform, the arc burns uniformly on the target surface, and the uniformity of the coating is improved.

[0053] In the preferred embodiment of the present application, the vacuum chamber is a cube with a size of 600x600x600mm. In this embodiment, the heater 7 includes four groups, which are respectively arranged at the four corners inside the vacuum chamber. The heating power of each heater 7 is 10-30 kW, which improves the heating efficiency.

[0054] The high-hardness wear-resistant piezoelectric sensor preparation method of the application overcomes the shortcomings of magnetron sputtering technology, uses the high ionization rate of arc ion plating to prepare a ZnO piezoelectric composite coating, and simultaneously, in order to reduce the stress of the ZnO layer, the ZnO layer is compounded with a CrN layer. In order to improve the adhesion of the coating and the substrate 1, in the preparation method, firstly, a composite plasma of argon ions and hydrogen ions generated by an arc discharge ion source is used to clean the surface of the substrate, and the purpose of the plasma etching is to remove the oxides and adsorbed gas on the surface. This process has a relatively obvious effect on improving the adhesion of the coating, and if there are oxides on the surface of the substrate 1, the adhesion of the coating and the substrate 1 is generally poor. The plasma etching cleaning is generally carried out under a negative bias voltage of 50-150 V, and the cleaning time can be selected in the range of 30-60. The voltage is generally increased gradually from low to high, so as to avoid causing a spark when it is added to the position at one time. After the plasma etching cleaning is completed, the surface of the substrate 1 material is relatively clean, and the requirement of the coating is achieved. Subsequently, under the conditions of 0.05-0.1 Pa and 600-800 V, the Cr metal is evaporated from the etched Cr target 6 through high-temperature evaporation and moves towards the surface of the substrate, when the Cr ions move to the vicinity of the substrate 1 material, under the attraction of the negative voltage on the surface of the substrate 1, the high-speed movement to the surface of the substrate 1 can further remove the oxides that are not completely removed in the plasma etching process. The bombardment process will generate high temperature, and the Cr metal will form a diffusion layer with the substrate 1, providing a good bonding interface for the subsequent coating. Subsequently, the bias voltage is reduced, and the Cr bonding layer 2 is deposited on the die casting mold. Then, nitrogen gas is introduced to react with Cr to form a CrN metal ceramic transition layer 3. On the basis of the CrN layer, the CrN / ZnN nanometer multilayer blending layer 4 is gradually deposited by opening the plating Zn target 8. The purpose of combining the two is mainly to consider that the direct transition from the CrN layer to the ZnO layer will form a non-coherent interface, and the adhesion is poor. While the CrN and ZnN are both nitrides, the stress of the multilayer film is small, and as a transition layer, it will form a buffer between the CrN and ZnO, which is beneficial to the preparation of the subsequent ZnO. After the deposition of the CrN / ZnN nanometer multilayer blending layer 4 is completed, the nitrogen gas is closed, the plating Cr target 10 is closed, and the oxygen gas is introduced, and then the ZnO layer can be prepared. If the thickness of the ZnO coating is too thick, the coating is prone to peeling. Therefore, after the ZnO layer is prepared to a certain thickness, the oxygen gas is closed, the nitrogen gas is introduced, and the plating Cr target 10 is opened, and then the CrN layer can be prepared. The above process is repeatedly performed, and then the multilayer CrN / ZnO multilayer piezoelectric functional layer 5 can be obtained, and finally natural cooling is performed to complete the entire preparation process.

[0055] The high-hardness wear-resistant piezoelectric sensor and the preparation method thereof of the present application combine the hard CrN material and the piezoelectric material ZnO, so that the piezoelectric material ZnO has better toughness and wear resistance than the conventional piezoelectric coating; the nano multi-layer composite and the gradient composite coating technology are fully utilized to form the gradually changed structure and composition, the coating and the substrate are metallurgically combined, and have good adhesion; compared with the conventional piezoelectric material ZnO, the growth of the columnar crystal is inhibited by using the multi-layer structure technology, and the compactness of the coating ZnO is improved, which not only improves the wear resistance of the coating, but also greatly improves the corrosion resistance; the CrN / ZnN nano multi-layer blend layer 4 is used as the transition between the coating CrN and the coating ZnO, so that the composite piezoelectric coating CrN / ZnO of the surface layer and the CrN of the bottom have good combination performance. The arc ion plating technology is used in the preparation of the coating ZnO, so that the deposition rate is fast, and the crystallization and the combination performance are better, which will greatly improve the adaptability of the piezoelectric coating material ZnO on various different materials, and expand the application field thereof.

[0056] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A high-hardness, wear-resistant piezoelectric sensor, characterized in that, include: The substrate (1) is provided with a Cr bonding layer (2), a CrN metal ceramic transition layer (3), a CrN / ZnN nano multilayer blend layer (4), and a CrN / ZnO multilayer piezoelectric functional layer (5) deposited sequentially on the substrate (1). The CrN / ZnN nano-multilayer blend layer (4) includes alternating CrN layers and ZnN layers. The total thickness of the CrN / ZnN nano-multilayer blend layer (4) is 600-3000 nanometers, the thickness of a single CrN layer is 4-20 nanometers, and the thickness of a single ZnN layer is 2-10 nanometers. The CrN / ZnO multilayer piezoelectric functional layer (5) includes alternating CrN layers and ZnO layers, wherein the thickness of a single CrN layer is 20-50 nanometers and the thickness of a single ZnO layer is 500-2000 nanometers.

2. The high-hardness, wear-resistant piezoelectric sensor according to claim 1, characterized in that, The total thickness of the coating on the substrate (1) is 1.73 to 14.250 micrometers.

3. The high-hardness, wear-resistant piezoelectric sensor according to claim 2, characterized in that, The thickness of the Cr bonding layer (2) is 10 to 100 nanometers.

4. The high-hardness, wear-resistant piezoelectric sensor according to claim 3, characterized in that, The thickness of the CrN metal-ceramic transition layer (3) is 200–800 nanometers.

5. A method for fabricating a high-hardness, wear-resistant piezoelectric sensor, used to fabricate the high-hardness, wear-resistant piezoelectric sensor as described in any one of claims 1 to 4, characterized in that, include: The substrate (1) is installed in a high-hardness, wear-resistant piezoelectric sensor fabrication fixture; Plasma etching was performed on the substrate (1) in an argon and hydrogen atmosphere at 300–500 °C. After etching, the substrate (1) was subjected to ion bombardment under conditions of 0.05-0.1 Pa and 600-800 V; After the bombardment, a Cr bonding layer (2) with a thickness of 10-100 nanometers was deposited on the substrate (1) under the conditions of 0.5-1 Pa and 50-150 V. Under conditions of 1–2 Pa and 100–150 V, a CrN cermet transition layer (3) with a thickness of 200–800 nm was deposited on the Cr bonding layer (2); Under conditions of 2–5 Pa and 50–150 V, a CrN / ZnN nano-multilayer blend layer (4) with a thickness of 600–3000 nm is deposited on the CrN cermet transition layer (3), wherein the thickness of a single CrN layer is 4–20 nm, the thickness of a single ZnN layer is 2–10 nm, and the modulation period is 6–30 nm. Under conditions of 2–5 Pa and 50–150 V, a CrN / ZnO multilayer piezoelectric functional layer (5) was deposited on a CrN / ZnN nanolayer blend layer (4), wherein the thickness of a single CrN layer was 20–50 nm and the thickness of a single ZnO layer was 500–2000 nm, and the total coating thickness was controlled to be 1.73–14.250 μm. After the coating deposition is completed, it is allowed to cool naturally.

6. The method for preparing a high-hardness, wear-resistant piezoelectric sensor according to claim 5, characterized in that, The tooling for fabricating the high-hardness, wear-resistant piezoelectric sensor includes: A vacuum chamber, wherein an air extraction port (9) is provided on the side wall of the vacuum chamber; Heater (7), said heater (7) being arranged inside the vacuum chamber; Thermocouple (12), said thermocouple (12) being arranged inside the vacuum chamber; An arc target, comprising an etched Cr target (6), a coated Cr target (10), and a coated Zn target (8), is respectively mounted on the side wall of the vacuum chamber; A workpiece holder (11) is arranged inside the vacuum chamber and is used for mounting the substrate (1).

7. The method for preparing a high-hardness, wear-resistant piezoelectric sensor according to claim 6, characterized in that, The vacuum chamber is cubic in shape, with dimensions of 600×600×600mm.

8. The method for preparing a high-hardness, wear-resistant piezoelectric sensor according to claim 7, characterized in that, The heater (7) comprises four groups, which are respectively located at the four corners inside the vacuum chamber, and the heating power of each heater (7) is 10 to 30 kilowatts.

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