Ceramic-based nanometer thin film pressure core and manufacturing method thereof

Abstract

The application discloses a ceramic-based nanometer thin film pressure core and a manufacturing method thereof, and belongs to the technical field of ceramic piezoresistive sensor cores. The ceramic-based nanometer thin film pressure core comprises, from bottom to top, a ceramic substrate, an interface transition layer, a composite nanometer film layer, a gold layer and a doped silicon dioxide protective layer. The composite nanometer film layer comprises, from bottom to top, a nickel-chromium alloy layer and a nickel-copper alloy layer. The interface transition layer is a titanium-aluminum alloy layer deposited on the surface of the ceramic substrate by magnetron sputtering. The doped silicon dioxide protective layer contains 1-3 wt% BN, 0.5-2.0 wt% Ga2O3 and the balance of SiO2. The application improves the compatibility of the ceramic and the metal alloy nanometer thin film layer through the interface transition layer, and improves the insulation performance of the core through the doped silicon dioxide protective layer. The application solves the problems of low precision, large temperature drift and poor insulation of traditional cores, and is suitable for harsh scenes such as high-voltage power systems.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic piezoresistive sensor cores, and particularly relates to a ceramic-based nanometer film pressure core and a manufacturing method thereof. BACKGROUND

[0002] In a high-voltage power system, from a large generator at a power generation end, to a transformer, a high-voltage switch cabinet in a power transmission network, and to various high-voltage devices at a power consumption end, all are accompanied by high voltage and strong electric field during operation. Taking a 110kV and above power transmission line as an example, its operating voltage is much higher than that of ordinary electrical equipment, which requires the sensor to not only accurately measure current, voltage, temperature and other parameters, but also to have extremely high insulation strength to prevent breakdown in a high-voltage environment. Once the sensor insulation fails, it may cause serious faults such as line short circuit and tripping, leading to large-area power outage accidents and causing great losses to social production and life.

[0003] A traditional ceramic piezoresistive sensor is based on a ceramic piezoresistive core formed by a printed circuit layer on the ceramic, which has the disadvantage of low measurement accuracy. The circuit layer is a printed film layer, which leads to the fact that the core accuracy has reached the limit of 0.5%FS, and the temperature drift performance is poor. In addition, under the condition of complex stress and uneven electric field distribution, stress concentration phenomenon is prone to occur at the connection parts of the pressure sensitive element, the insulating layer and the electrode. SUMMARY

[0004] The application provides a ceramic-based nanometer film pressure core and a manufacturing method thereof to overcome the above technical problems. The application improves the compatibility of the ceramic and the metal alloy nanometer film layer through an interface transition layer, and improves the insulation performance of the core through a doped silicon dioxide protective layer. The problems of low accuracy, large temperature drift and poor insulation of the traditional core are solved, and the application is suitable for harsh scenes such as high-voltage power systems.

[0005] The application solves the above technical problems through the following technical scheme.

[0006] A ceramic-based nanometer film pressure core comprises, from bottom to top, a ceramic substrate, an interface transition layer, a composite nanometer film layer, a gold layer and a doped silicon dioxide protective layer.

[0007] The composite nanometer film layer comprises, from bottom to top, a nickel-chromium alloy layer and a nickel-copper alloy layer.

[0008] The interface transition layer is a titanium-aluminum alloy layer deposited on the surface of the ceramic substrate by magnetron sputtering.

[0009] The doped silicon dioxide protective layer contains 1-3wt% BN, 0.5-2.0wt% Ga2O3 and the balance of SiO2.

[0010] According to some embodiments of the present application, the raw materials for preparing the ceramic substrate are 0.05-0.2wt% CaO, 0.1-0.3wt% MgO, 3-7wt% Y2O3, 0.2-2.0wt% La2O3, and ZrO2 in balance; preferably, the raw materials for preparing the ceramic substrate are 0.08-0.2wt% CaO, 0.15-0.25wt% MgO, 4-6wt% Y2O3, 0.5-1.5wt% La2O3, and ZrO2 in balance.

[0011] In some preferred embodiments, the doped silicon dioxide protective layer contains 1-2.5wt% BN, 0.8-1.5wt% Ga2O3, and SiO2 in balance.

[0012] According to some embodiments of the present application, the mass ratio of titanium to aluminum in the interface transition layer is 65:35-80:20, preferably 70:30-75:25.

[0013] According to some embodiments of the present application, the mass ratio of nickel to chromium in the nickel-chromium alloy layer is 80:20-86:14, preferably 82:18-84:16.

[0014] According to some embodiments of the present application, the mass ratio of nickel to copper in the nickel-copper alloy layer is 60:40-75:25, preferably 65:35-70:30.

[0015] According to some embodiments of the present application, the bonding strength between the interface transition layer and the ceramic substrate is ≥60N / cm 2 , preferably 60-80 N / cm 2 .

[0016] According to some embodiments of the present application, the bonding strength between the interface transition layer and the upper nickel-chromium alloy layer is ≥55N / cm 2 , preferably 55-75 N / cm 2 .

[0017] According to some embodiments of the present application, the thickness of the interface transition layer is 60-200nm, preferably 80-150nm;

[0018] According to some embodiments of the present application, the thickness of the composite nanometer film layer is 80-150nm.

[0019] According to some embodiments of the present application, the thickness of the gold layer is 1.5-2.5μm.

[0020] According to some embodiments of the present application, the thickness of the doped silicon dioxide protective layer is 0.8-1.5μm.

[0021] The application further discloses a manufacturing method of the ceramic-based nanometer thin film pressure core.

[0022] S1. raw materials of a ceramic substrate are subjected to compression molding, sintering and polishing to obtain the ceramic substrate;

[0023] S2. an interface transition layer and a composite nanometer film layer are sequentially deposited on the surface of the ceramic substrate by magnetron sputtering; and a sol precursor of a doped silicon dioxide protective layer is coated on the surface of the composite nanometer film layer to complete film plating;

[0024] S3. a Wheatstone full bridge is prepared on the surface of the film by photoetching;

[0025] S4. the core after etching in S3 is subjected to stabilization treatment, and the ceramic-based nanometer thin film pressure core is obtained.

[0026] In S1, the raw materials of the ceramic substrate are pre-processed to obtain raw material powder, i.e. the raw material powder is wet-milled and then a binder is added to obtain slurry, and the slurry is spray dried;

[0027] In S1, the compression molding is performed at 25-35 MPa, and the pressure maintaining time is 4-6 min to obtain a green body;

[0028] In S1, the sintering is performed at a rate of 5-8 ℃ / min to 600-700 ℃, and the temperature is maintained for 2-3 h to remove the binder; then the temperature is raised to 1580-1620 ℃ at a rate of 3-5 ℃ / min, and the temperature is maintained for 5-7 h for sintering; finally, the temperature is lowered to room temperature at a rate of 2-4 ℃ / min.

[0029] In S1, the polishing is rough polishing and fine polishing; the rough polishing is performed by diamond sand disc polishing, and the fine polishing is performed by polishing pad polishing.

[0030] Further in S1, the inlet air temperature of the spray drying is 200-220 ℃, and the outlet air temperature is 80-90 ℃;

[0031] Further in S1, the diamond sand disc polishing is performed by using 200-250 mesh diamond sand discs, 400-500 mesh diamond sand discs and 700-900 mesh diamond sand discs in sequence, and the polishing is performed at 300-500 rpm, 3-5 N / cm 2 pressure for 3-7 min, at 400-500 rpm, 3-5 N / cm 2 pressure for 3-7 min, and at 700-800 rpm, 1-3 N / cm 2 pressure for 1-3 min.

[0032] Further in S1, the rough polishing makes the surface roughness Ra≤0.2 μm.

[0033] Further in S1, the fine polishing adopts diamond suspension, and the polishing pad is made of polyurethane material.

[0034] Further in S1, the fine polishing has a rotation speed of 900-1100 rpm and a pressure of 1-2 N / cm. 2 The polishing is performed under pressure for 5-15 min.

[0035] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25.

[0036] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25.

[0037] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25.

[0038] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25.

[0039] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25.

[0040] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25.

[0041] In S2, the interface transition layer is prepared by magnetron sputtering using a titanium-aluminum alloy target, and the mass ratio of Ti:Al in the titanium-aluminum alloy target is 65:35-80:20, preferably 70:30-75:25. -4 ~8×10 -3 Pa.

[0042] In S2, the sample table is rotated at a rotation rate of 5-8 rpm during the magnetron sputtering process to ensure that the thickness uniformity deviation of the film layer is ≤±3%.

[0043] In S2, the preparation of the sol precursor is to add boron nitride dispersion liquid and gallium oxide solution into the silica sol, stir at 30-40°C for 2-3 h, and then add a photoinitiator and continue to stir for 30-40 min.

[0044] Further in S2, the mass fraction of silicon dioxide in the silica sol is 25-35%.

[0045] Further in S2, the pH of the silica sol is 2-4.

[0046] Further in S2, the average particle size of the silicon dioxide in the silica sol is 10-15 nm.

[0047] Further in S2, the gallium oxide solution is a 5-15 wt% gallium oxide nitric acid solution, and the pH of the gallium oxide solution is 3.

[0048] Further in S2, the boron nitride dispersion liquid is prepared by ultrasonic dispersion of 5-15 wt% boron nitride nanoparticles in ethanol, and then adding 1-3 wt% silane coupling agent, and stirring at 60-70°C for 1-1.5 h.

[0049] In S2, the coating is performed by using a film applicator to coat the sol precursor on the surface of the composite nanometer film layer, first at 2500-3500 rpm for 10-15 s, and then at 8000-10000 rpm for 30-40 s to form a wet film, which is solidified after curing.

[0050] Further in S2, the solidification is first pre-baking at 80-90°C for 15-20 min, then curing by irradiation with 80-100 mW / cm 2 of power, 254 nm wavelength ultraviolet light for 10-15 min, and finally heat curing at 150-180°C for 2-3 h.

[0051] In S3, the photoetching development is pre-baking after spraying the photoresist, then exposure treatment, and then hardening treatment after removing the residual agent.

[0052] In S3, the pre-baking temperature is 85-120°C, and the pre-baking time is 30-60 s.

[0053] In S3, the exposure treatment temperature is 20-30°C.

[0054] In S3, the hardening treatment temperature is 100-130°C.

[0055] In S4, the stabilization treatment is first aging treatment, and then 4-7 times of high-low temperature impact treatment.

[0056] In S4, the aging treatment is heat preservation at 330-360°C for 4.5-5.5 h, and nitrogen is introduced during the heat preservation process at a flow rate of 10-15 L / min.

[0057] In S4, each high-low temperature impact treatment is heat preservation at -55 to -45°C for 4.5-5.5 h, and then heat preservation at 155-165°C after heating, with a heat preservation time of 4.5-5.5 h, and the heating rate and the cooling rate are both controlled at 2-3°C / min. The stabilization treatment is to eliminate the stress in the film layer by annealing, and to promote the interface diffusion of the film layer and the substrate after high-low temperature impact, so as to form a stable interface bonding.

[0058] On the basis of common knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily, i.e. to obtain each preferred embodiment of the present application.

[0059] Compared with the prior art, the present application has the following beneficial effects:

[0060] 1. The ceramic piezoresistive sensor usually adopts alumina ceramic, zirconia ceramic and silicon nitride ceramic, etc. The present application considers that the thermal expansion coefficient of zirconia ceramic is close to that of metal, and therefore adopts zirconia ceramic as the substrate, and the hardness is higher. The zirconia ceramic obtained by doping rare earth oxides has high strength and impact resistance, and because the thermal expansion coefficient is close to that of the metal film layer, the temperature drift can be greatly reduced.

[0061] 2. To solve the compatibility of the ceramic substrate and the composite nano thin film, the interface transition layer of the present application forms Ti-O-Zr bond with the ceramic substrate, and forms Ti-Al-Ni intermetallic compound with the nickel-chromium layer, solving the problem of insufficient bonding strength of the transition layer with the substrate / function layer.

[0062] 3. Compared with the silicon dioxide protective layer, the protective layer of the present application introduces boron nitride nano-lubricating components, and introduces gallium oxide to strengthen the lattice, which makes the doped silicon dioxide protective layer not only have high wear resistance, but also have good insulation performance.

[0063] 4. The prior art only uses single high-temperature aging, which cannot completely eliminate the stress in the film layer. The present application promotes the interface diffusion of the film layer and the substrate by high-low temperature impact, forming a stable transition zone. Finally, the sensor has a zero point drift ≤0.0080FS% at 200℃, and in some preferred embodiments, the zero point drift is ≤0.007FS%, for example, 0.003~0.007FS%.

[0064] 5. For the high insulation and wide temperature range requirements of high-voltage power systems, the core insulation strength of the present application is ≥2000VAC, and the working temperature range is -40~300℃, which can be stably applied to the pressure monitoring of devices such as generators and high-voltage switch cabinets. Compared with the existing sensor, the applicable scene is wider, and the reliability is higher. BRIEF DESCRIPTION OF DRAWINGS

[0065] In order to facilitate the understanding of those skilled in the art, the present application will be further described below in conjunction with the drawings.

[0066] Figure 1 It is an appearance view of the ceramic-based nano thin film pressure core of the present application.

[0067] Figure 2 It is an assembly view of the ceramic-based nano thin film pressure core of the present application.

[0068] Figure 3Figure of ceramic-based nanometer thin film pressure sensor of the present application.

[0069] Reference numerals:

[0070] 11, ceramic substrate; 12, interface transition layer; 13, composite nanometer film layer; 14, gold layer; 15, doped silica protective layer;

[0071] 10, ceramic-based nanometer thin film pressure core; 20, pressure introduction nozzle; 30, ED sealing ring; 40, packaging cover; 50, conductive elastic needle; 60, air pipe; 70, riveting sealing. DETAILED DESCRIPTION

[0072] In order to facilitate the understanding of the present application, the following will make a more comprehensive and detailed description of the present application in combination with the preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0073] Unless otherwise defined, all the professional terms used in the following have the same meaning as that generally understood by the person skilled in the art. The professional terms used in the present text are only for the purpose of describing the specific embodiments and are not intended to limit the protection scope of the present application.

[0074] In combination Figure 1 and Figure 2 , the structure of the ceramic-based nanometer thin film pressure core of the present application is, from bottom to top, ceramic substrate (11), interface transition layer (12), composite nanometer film layer (13), gold layer (14), and doped silica protective layer (15); the composite nanometer film layer is composed of lower layer nickel-chromium alloy layer (121) and upper layer nickel-copper alloy layer (122).

[0075] Example 1

[0076] The preparation process of the ceramic-based nanometer thin film pressure core of the present embodiment is as follows:

[0077] S1. Preparation of ceramic substrate:

[0078] The raw materials for the preparation of the ceramic substrate are 0.1wt% CaO, 0.2wt% MgO, 5.7wt% Y2O3, 1.3wt% La2O3, and ZrO2 in the balance;

[0079] The preparation process of the ceramic substrate is as follows: after wet grinding the above preparation raw materials for 5h, polyvinyl alcohol (PVA) is added and stirred uniformly to obtain a slurry; the slurry is dried by a spray drying device, the inlet air temperature of the spray drying granulation is set to 210℃, and the outlet air temperature is 85℃, to obtain dry raw material powder. The dry raw material powder is placed in a mold and pressed into a green body under a pressure of 30MPa for 5min. The green body is placed in a high-temperature sintering furnace, heated to 650℃ at a rate of 6℃ / min, and kept for 2.5h to remove the binder. Then, it is heated to 1600℃ at a rate of 4℃ / min, and kept for 6h for sintering; finally, it is cooled to room temperature at a rate of 3℃ / min.

[0080] First, rough polishing is performed using a diamond sand disc. A 240-mesh diamond sand disc is used in turn, and polished at 300rpm, 5N / cm 2 pressure for 5min; then, a 400-mesh diamond sand disc is used, and polished at 500rpm, 3N / cm 2 pressure for 3min; finally, an 800-mesh diamond sand disc is used, and polished at 800rpm, 2N / cm 2 pressure for 2min, so that the surface roughness Ra≤0.2μm. Subsequently, fine polishing is performed using a polishing pad made of polyurethane (purchased from Hemi Semiconductor Co., Ltd.) and a diamond suspension (purchased from Guangdong Chuili Chip Semiconductor Technology Co., Ltd.), and polished at 1000rpm, 1N / cm 2 pressure for 10min to obtain a ceramic substrate with a smooth surface.

[0081] S2. Magnetron sputtering deposition:

[0082] The ceramic substrate is placed in the vacuum chamber of the magnetron sputtering device, and the vacuum degree is pumped to 5×10 -3Pa, a titanium-aluminum alloy target with a mass ratio of Ti:Al of 72:28 was used, the sputtering power was set to 100 W, the sputtering time was 10 min, the argon flow rate was 20 sccm, and an 80-nm interface transition layer was deposited on the surface of the ceramic substrate; after the interface transition layer was deposited, a nickel-chromium alloy target with a mass ratio of Ni:Cr of 83:17 was used, the sputtering power was adjusted to 150 W, the argon flow rate was 25 sccm, the sputtering time was 20 min, and a nickel-chromium alloy layer was deposited; then, a nickel-copper alloy target with a mass ratio of Ni:Cu of 68:32 was used, the magnetron sputtering power was set to 110 W, the argon flow rate was 23 sccm, the sputtering time was 12 min, and a nickel-copper alloy layer was deposited, thereby completing the preparation of a 100-nm composite nanometer film layer; a high-purity gold target was used, the magnetron sputtering power was set to 130 W, the argon flow rate was 25 sccm, the sputtering time was 30 min, and a 2.0-μm gold layer was deposited. During the entire magnetron sputtering process, the temperature of the ceramic substrate was 200℃, and the sample table was rotated at a rotation rate of 6 rpm to ensure that the film layer thickness uniformity deviation was ≤±3%.

[0083] S2. Preparation of the doped silicon dioxide protective layer:

[0084] 10wt% boron nitride nanoparticles (average particle size 50 nm) were added to ethanol and ultrasonically dispersed for 30 min, and then silane coupling agent KH-560 was added, and stirring was performed at 65℃ for 1.2 h to obtain a boron nitride dispersion liquid. 8wt% gallium oxide (average particle size 40 nm) was dissolved in a nitric acid solution to obtain a gallium oxide solution. The boron nitride dispersion liquid and the gallium oxide solution were added to a silica sol, and stirring was performed at 35℃ for 2.5 h, and then a photoinitiator 651 was added and stirring was continued for 35 min to obtain a sol precursor;

[0085] The sol precursor was coated on the surface of the nickel-copper alloy layer using a film applicator, first at 3000 rpm for 12 s, and then at 9000 rpm for 35 s to form a wet film; first pre-baking was performed at 80-90℃ for 15-20 min, then ultraviolet light irradiation curing was performed at a power of 80-100 mW / cm 2 , a wavelength of 254 nm for 10-15 min, and finally thermal curing was performed at 150-180℃ for 2-3 h; after the curing treatment, a 1.2-μm doped silicon dioxide protective layer was obtained; the doped silicon dioxide protective layer contained 1.8wt% BN, 1.2wt% Ga2O3, and the balance SiO2.

[0086] S3. Photolithography film plating: photoresist was sprayed on the film plating surface, and then pre-baking was performed at 100℃ for 45 s. Exposure treatment was performed at 25℃, and then residual agent was removed, and then hardening treatment was performed at 115℃, thereby preparing a Wheatstone full bridge through photolithography etching. The photoresist was purchased from Shanghai Tongcheng Electronic Materials Co., Ltd. RAE BP212-37S.

[0087] S4. Stabilization treatment:

[0088] The etched core was first aged at 345℃ for 5h, and nitrogen was introduced during the process at a flow rate of 12L / min. Subsequently, it was subjected to 5 times of high-low temperature impact treatment, each at -50℃ for 5h, and then heated to 160℃ at a rate of 2.5℃ / min and kept for 5h.

[0089] The GB / T 5270-2005 uses grid method (grid spacing 1mm, grid blade spacing 1mm) or pull-off method to test the interface transition layer and ceramic substrate bonding strength of 72N / cm 2 , the interface transition layer and nickel-chromium layer bonding strength of 68N / cm 2 .

[0090] Example 2

[0091] The difference between this embodiment and Example 1 is that:

[0092] The content of Y2O3 in the ceramic substrate is adjusted to 4.1wt%;

[0093] The other raw materials, steps and parameters are the same as those in Example 1.

[0094] The interface transition layer and ceramic substrate bonding strength is 70N / cm 2 , the interface transition layer and nickel-chromium layer bonding strength is 66N / cm 2 .

[0095] Example 3

[0096] The difference between this embodiment and Example 1 is that:

[0097] In the preparation of the interface transition layer, the Ti:Al mass ratio of the titanium-aluminum alloy target is adjusted to 80:20;

[0098] The interface transition layer and ceramic substrate bonding strength is 62N / cm 2 , the interface transition layer and nickel-chromium layer bonding strength is 58N / cm 2 .

[0099] The other raw materials, steps and parameters are the same as those in Example 1.

[0100] Example 4

[0101] The difference between this embodiment and Example 1 is that:

[0102] The content of boron nitride nanoparticles in the doped silicon dioxide protective layer is increased to 2.0wt%;

[0103] The other raw materials, steps and parameters are the same as those in Example 1.

[0104] Example 5

[0105] The difference between this comparative example and Example 1 is that:

[0106] No high-low temperature impact treatment was performed during the stabilization treatment, only aging treatment was performed;

[0107] The other raw materials, steps and parameters were the same as in Example 1.

[0108] The bonding strength between the interface transition layer and the ceramic substrate was 65 N / cm 2 , and the bonding strength between the interface transition layer and the nickel-chromium layer was 61 N / cm 2 .

[0109] Example 6

[0110] The difference between this example and Example 1 is that:

[0111] The titanium-aluminum alloy target with a mass ratio of Ti:Al of 60:40 was used to deposit the interface transition layer in this example;

[0112] The other raw materials, steps and parameters were the same as in Example 1.

[0113] The bonding strength between the interface transition layer and the ceramic substrate was 55 N / cm 2 , and the bonding strength between the interface transition layer and the nickel-chromium layer was 51 N / cm 2 .

[0114] Comparative Example 1

[0115] The difference between this comparative example and Example 1 is that:

[0116] The yttrium oxide was not contained in the preparation raw material of the ceramic substrate in this comparative example;

[0117] The other raw materials, steps and parameters were the same as in Example 1.

[0118] The bonding strength between the interface transition layer and the ceramic substrate was 52 N / cm 2 , and the bonding strength between the interface transition layer and the nickel-chromium layer was 48 N / cm 2 .

[0119] Comparative Example 2

[0120] The difference between this comparative example and Example 1 is that:

[0121] No Ga2O3 was added in the doped silicon dioxide protective layer, so no gallium oxide solution was added in the preparation process of the S2 sol precursor;

[0122] The other raw materials, steps and parameters were the same as in Example 1.

[0123] Application Example

[0124] The ceramic-based nanometer thin film pressure core made in the above examples and comparative examples is assembled into a sensor respectively, and the sensor structure is shown in Figure 3 ; the sensor comprises the following structure:

[0125] A pressure introduction nozzle (20) is connected with an external pressure source through threads, and is responsible for introducing the measured pressure into the sensor;

[0126] A ceramic-based nanometer thin film pressure core (10) is installed on the upper part of the pressure introduction nozzle (20), and is used for sensing pressure and converting it into an electrical signal;

[0127] An ED sealing ring (30) is located between the ceramic-based nanometer thin film pressure core (10) and the pressure introduction nozzle (20);

[0128] A packaging cover (40) is covered on the ceramic-based nanometer thin film pressure core (10);

[0129] A conductive elastic needle (50) is installed on the packaging cover (40), and the lower end is in contact with the electrode of the ceramic-based nanometer thin film pressure core (10);

[0130] An air pipe (60) penetrates through the packaging cover (40), and is used for realizing air pressure balance between the inside of the sensor and the outside (if it is an absolute pressure sensor, it can also be used for vacuum sealing and other related functions);

[0131] A riveting sealing (70) is used for riveting the top of the packaging cover (40), and is used for fixing the air pipe (60), the conductive elastic needle (50) and other components on the packaging cover (40).

[0132] Test Example

[0133] (1) Insulation performance test: a ZC75 insulation resistance tester (Zhongce Instrument) is used, the positive electrode of the tester is connected with the conductive elastic needle, the negative electrode of the tester is connected with the pressure introduction nozzle shell, an alternating voltage of 2000VAC and a frequency of 50Hz are applied for 1min, and whether breakdown or flashover phenomenon occurs is observed;

[0134] (2) Temperature drift test: after the above insulation performance test, the zero point drift of the sensor is tested according to the standard JJG860-2015 at 25℃ and 200℃ respectively, and the test pressure range is 0~4MPa;

[0135] Zero point drift refers to the phenomenon that the output signal (in mV in this test) of the pressure sensor changes with the change of the ambient temperature under the condition that the pressure remains constant (usually 0% of the full scale, i.e. no pressure input); zero point drift (%FS / ℃)=(zero point value at 200℃-zero point value at 25℃) / [(full point value at 25℃-zero point value at 25℃)×(200℃-25℃)]×100%;

[0136] The test results are shown in Table 1 Sensor Test Data Table, and the data in the table are the average values of three measurements under 10VDC power supply.

[0137]

[0138] It should be noted in connection with the data in Table 1 that:

[0139] In Example 5, only aging without high-low temperature impact, the internal stress of the film layer is not completely eliminated, the interface bonding strength is reduced, the residual stress is released when the temperature changes, resulting in a large temperature drift;

[0140] In Example 6, the interface transition layer has slightly lower bonding strength with the ceramic substrate, and there are small gaps in the interface, resulting in slight fluctuations in the insulation value;

[0141] The ceramic substrate of Comparative Example 1 does not contain Y2O3, resulting in unstable substrate crystal form, low interface bonding strength, easy local peeling of the interface transition layer, and serious temperature influence on the piezoresistive characteristics, with a sharp increase in drift;

[0142] In Comparative Example 2, Ga2O3 is not added in the silica protective layer, resulting in many lattice defects in the protective layer, uneven shrinkage / expansion of the protective layer when the temperature changes, random extrusion stress on the composite nanometer film layer, and a sharp fluctuation in the piezoresistive signal, with a maximum drift value.

[0143] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or prepared by existing methods. The above specific examples further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A ceramic-based nanometer thin film pressure core, characterized in that, From bottom to top, the ceramic substrate, the interface transition layer, the composite nanometer film layer, the gold layer and the doped silicon dioxide protective layer are sequentially included; The composite nanometer film layer is sequentially a nickel-chromium alloy layer and a nickel-copper alloy layer from bottom to top; The interface transition layer is a titanium-aluminum alloy layer deposited on the surface of the ceramic substrate by magnetron sputtering; The doped silicon dioxide protective layer contains 1-3wt% BN, 0.5-2.0wt% Ga2O3 and the balance SiO2.

2. The ceramic-based nanometer thin film pressure capsule of claim 1, wherein, The preparation raw material of the ceramic substrate is 0.05-0.2wt% CaO, 0.1-0.3wt% MgO, 3-7wt% Y2O3, 0.2-2.0wt% La2O3 and the balance ZrO2. And / or, the doped silicon dioxide protective layer contains 1-2.5wt% BN, 0.8-1.5wt% Ga2O3 and the balance SiO2.

3. The ceramic-based nanometer thin film pressure capsule of claim 1, wherein, At least one of the following conditions a-e is met: a. The mass ratio of titanium to aluminum in the interface transition layer is 65:35-80:20; b. The mass ratio of nickel to chromium in the nickel-chromium alloy layer is 80:20-86:14; c. The mass ratio of nickel to copper in the nickel-copper alloy layer is 60:40-75:25; d. the interface transition layer has a bonding strength to the ceramic substrate of > 60 N / cm 2 ; e. the interface transition layer has a bonding strength with the upper layer of nickel-chromium alloy layer ≥ 55 N / cm 2 .

4. The ceramic-based nanometer thin film pressure capsule of claim 1, wherein, At least one of the following conditions a-d is met: a. The thickness of the interface transition layer is 60-200nm; b. The thickness of the composite nanometer film layer is 80-150nm; c. The thickness of the gold layer is 1.5-2.5μm; d. The thickness of the doped silicon dioxide protective layer is 0.8-1.5μm.

5. The method of claim 1 to 4, wherein the ceramic nanomembrane pressure capsule is manufactured by the steps of: The following steps are included: ​ S1. The raw material of the ceramic substrate is pressed, sintered and polished to obtain the ceramic substrate; S2. The interface transition layer and the composite nanometer film layer are sequentially deposited on the surface of the ceramic substrate by magnetron sputtering, and then the sol precursor of the doped silicon dioxide protective layer is coated on the surface of the composite nanometer film layer to complete the film plating; S3. The Wheatstone full bridge is prepared by photoetching on the surface of the film plating; S4. The core body after S3 etching is stabilized, and the ceramic-based nanometer film pressure core body is obtained.

6. The method for manufacturing a ceramic-based nanofilm pressure core as described in claim 5, characterized in that, At least one of the following conditions a-d is met: a. The raw material powder is obtained after pretreatment of the preparation raw material of the ceramic substrate, that is, the raw material powder is wet-milled, a binder is added to obtain slurry, and the slurry is spray dried; b. The pressing is performed at 25-35MPa, and the pressure holding time is 4-6min to form a green body; c. The sintering is performed at a rate of 5-8℃ / min to 600-700℃, and the binder is removed after 2-3h of heat preservation; then sintering is performed at a rate of 3-5℃ / min to 1580-1620℃, and heat preservation is performed for 5-7h; finally, the temperature is lowered to room temperature at a rate of 2-4℃ / min; d. The polishing is rough polishing and fine polishing; the rough polishing adopts diamond sand disc polishing, and the fine polishing adopts polishing pad polishing.

7. The method of claim 6, wherein the ceramic-based nanomembrane pressure core is manufactured by the steps of: forming a ceramic-based nanomembrane pressure core by the method of claim 1; and coating the ceramic-based nanomembrane pressure core with a metal layer. At least one of the following conditions a-e is met: a. The inlet air temperature of the spray drying is 200-220℃, and the outlet air temperature is 80-90℃; b. The diamond disc polishing is sequentially performed using a 200-250 mesh diamond disc at 300-500 rpm, 3-5 N / cm 2 pressure for 3-7 min; using a 400-500 mesh diamond disc at 400-500 rpm, 3-5 N / cm 2 pressure for 3-7 min; using a 700-900 mesh diamond disc at 700-800 rpm, 1-3 N / cm 2 pressure for 1-3 min c. The rough polishing makes the surface roughness Ra≤0.2μm; d. The fine polishing adopts diamond suspension, and the polishing pad is made of polyurethane material; e. The fine polishing rotation speed is 900-1100 rpm, 1-2 N / cm 2 Polish under pressure for 5-15 min.

8. The method of claim 5, wherein the ceramic-based nanomembrane pressure core is manufactured by the steps of: forming a ceramic-based nanomembrane pressure core by the method of claim 1; and coating the ceramic-based nanomembrane pressure core with a metal layer. At least one of the following conditions a-i is met: a. the sputtering power of the interface transition layer is 80-120 W, the sputtering time is 8-12 min, and the argon flow rate is 15-25 sccm; b. the magnetron sputtering alloy target of the nickel-chromium alloy layer adopts a nickel-chromium alloy target, and the mass ratio of Ni:Cr in the nickel-chromium alloy target is 80:20-86:14; c. the sputtering power of the nickel-chromium alloy layer is 130-170 W, the argon flow rate is 20-30 sccm, and the sputtering time is 18-22 min; d. the magnetron sputtering alloy target of the nickel-copper alloy layer is a nickel-copper alloy target, and the mass ratio of Ni:Cu in the nickel-copper alloy target is 60:40-75:25; e. the magnetron sputtering power of the nickel-copper alloy layer is 90-130 W, the argon flow rate is 18-28 sccm, and the sputtering time is 10-14 min; f. The vacuum degree of the magnetron sputtering is 3 x 10 -4 8 x 10 -3 Pa; g. during the magnetron sputtering process, the sample table adopts a rotating mode, the rotating rate is 5-8 rpm, and the film layer thickness uniformity deviation is ensured to be ≤±3%; h. the preparation of the sol precursor is to add boron nitride dispersion liquid and gallium oxide solution into silica sol, stir at 30-40℃ for 2-3h, and then add a photoinitiator and continue to stir for 30-40 min; i. the coating adopts a spin coater to coat the sol precursor on the surface of the composite nanometer film layer, first coats at 2500-3500 rpm for 10-15 s, then coats at 8000-10000 rpm for 30-40 s to form a wet film, and solidifies after curing.

9. The method of claim 5, wherein the ceramic-based nanomembrane pressure core is manufactured by the steps of: forming a ceramic-based nanomembrane pressure core by the method of claim 1; and coating the ceramic-based nanomembrane pressure core with a metal layer. The photoetching and developing is to perform pre-baking after spraying photoresist, then perform exposure treatment, remove residual agent, and then perform hardening treatment; and / or, the pre-baking temperature is 85-120℃, and the pre-baking time is 30-60 s; and / or, the exposure treatment temperature is 20-30℃; and / or, the hardening treatment temperature is 100-130℃.

10. The method of claim 5, wherein the ceramic-based nanomembrane pressure core is manufactured by the steps of: The stabilization treatment is to perform aging treatment first, and then perform 4-7 times of high-low temperature impact treatment; ​ and / or, the aging treatment is to heat at 330-360℃ for 4.5-5.5 h, and nitrogen is introduced during the heat preservation process, and the flow rate is 10-15 L / min; and / or, each high-low temperature impact treatment is to heat at -55--45℃ for 4.5-5.5 h, then heat to 155-165℃ for 4.5-5.5 h, and the heating rate and the cooling rate are both controlled at 2-3℃ / min.

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