Dual diaphragm sputter film core and application thereof

Abstract

The application discloses a double diaphragm sputtering thin film core and application, relates to the technical field of sensor core, and comprises a pressure sensing diaphragm and a wheatstone bridge diaphragm; the pressure sensing diaphragm and the wheatstone bridge diaphragm are connected through a force transmission rod; the wheatstone bridge diaphragm is provided with a protective layer; the protective layer comprises a transition bottom layer, a protective intermediate layer and a closed outer layer from bottom to top in sequence; the protective intermediate layer is composed of the following mass fraction of preparation raw materials: 10-25% nanometer alumina, 3-9% nanometer zirconia, 0.5-3.0% boron nitride nanotube and the balance nanometer silicon dioxide; the closed outer layer is composed of the following mass fraction of preparation raw materials: 1-5% FDTS, 5-15% nanometer titanium oxide, 0.5-3% fluorinated graphite, 10-20% DMF and the balance electronic-grade epoxy resin.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensor core, in particular to a double diaphragm sputtering thin film core and application thereof. BACKGROUND

[0002] In the fields of industrial production, energy development, and biomedical, as a core detection element, pressure sensors need to work stably in extreme medium environments such as high viscosity, strong corrosion, and easy crystallization for a long time, for example, sulfur-containing crude oil in oil and gas exploration, acid and alkali solution in chemical industry, high-impurity wastewater in wastewater treatment, and body fluid detection in biomedical. However, the existing pressure sensor core has the problems of poor measurement stability and short service life under the above working conditions. The core problems are concentrated in two aspects of medium erosion and structural design defects, which seriously restrict the application range and reliability of the sensor.

[0003] From the perspective of medium erosion, the traditional pressure sensor's Wheatstone bridge diaphragm adopts single-layer protective film or simple organic coating (such as PI protective film, multi-layer composite CPP protective film) for protection. Among them, the PI protective film can prevent short circuit of current for a short time, but it has poor chemical corrosion resistance and is easy to swell and crack in strong acid and alkali medium, resulting in direct exposure and erosion of the resistance strain layer; the multi-layer composite CPP protective film combines barrier layer and adhesive layer through co-extrusion technology, which can improve the protection ability to a certain extent, but the temperature resistance and durability of organic materials are limited, and under the long-term attachment and erosion of high-viscosity medium (such as crude oil, syrup), the coating is easy to peel off, thereby causing the failure of the sensor. Even though some special sensors (such as Weika DSS22T diaphragm sealed pressure sensor) isolate the erosive medium through a diaphragm sealing system, the composition of the diaphragm is not disclosed, and the pressure conduction lag problem caused by the complex structure has not been solved, and the high production cost limits its large-scale application.

[0004] From the perspective of structural design defects, the existing sensor core generally relies on a pressure guide hole to realize the contact between the medium and the pressure sensing element, and this structure is prone to cause hole blockage in high-viscosity and easy-crystallization media. For example, when detecting the pressure of fruit beverage in the food processing field, fruit particles or colloidal particles are easy to accumulate in the pressure guide hole; when measuring the pressure of a solution containing solute in chemical production, the solute is easy to crystallize on the inner wall of the hole, not only causing the interruption of pressure conduction, but also requiring frequent disassembly and cleaning, increasing the maintenance cost and downtime risk. In addition, the interlayer structure of the sensor core lacks coordination: on the one hand, the difference between the thermal expansion coefficients of the metal substrate and the protective layer is large, which is easy to produce interlayer stress under temperature fluctuation conditions, resulting in cracking of the protective film; on the other hand, the connection mode (such as adhesion, ordinary welding) between the pressure sensing diaphragm and the Wheatstone bridge diaphragm has the problems of insufficient rigidity or stress concentration, and uneven deformation is easy to occur during pressure conduction, which directly affects the measurement accuracy and repeatability.

[0005] Further analysis of the key functional layers of the sensor core shows that there is also room for optimization in the performance of the insulating layer and the resistive strain layer. Traditional insulating layers are mostly made of SiO2 or Al2O3, and the dielectric constant stability of these materials is easily affected by humidity and ion penetration in a strong corrosive environment, leading to zero drift of the Wheatstone bridge. The commonly used resistive strain layer materials, such as constantan and nickel-chromium alloy, have a certain strain sensitivity, but they are easily oxidized in high-temperature and corrosive media, leading to resistance drift and thus reducing the long-term measurement accuracy of the sensor. At the same time, the existing protective layer lacks a coordinated design of protection and conduction: some protective layers excessively pursue high hardness to resist erosion, but ignore toughness and thermal conductivity, leading to the easy generation of micro-cracks in the diaphragm under pressure cycling; some protective layers focus on hydrophobicity, but due to insufficient interfacial bonding strength, interlayer peeling occurs under long-term immersion in the medium, and a sustained and effective protective barrier cannot be formed. SUMMARY

[0006] The present application is to overcome the above technical problems, and therefore provides a double-diaphragm sputtered thin film core and its application.

[0007] The present application solves the above technical problems by the following technical solutions. The core includes a pressure-sensing diaphragm and a Wheatstone bridge diaphragm. The Wheatstone bridge diaphragm is provided with a stainless steel substrate, an insulating layer, a resistive strain layer, and a protective layer including a transition bottom layer, a protective intermediate layer, and a closed outer layer from bottom to top. The pressure-sensing diaphragm is provided with a steel base, an elastic layer, and an oxidation-resistant layer from bottom to top. The core does not contain a pressure-conducting channel, which not only avoids the problem of channel blockage, but also enables the core to measure for a long time in a medium with high viscosity and strong corrosion through the design of the diaphragm structure.

[0008] The double-diaphragm sputtered thin film core includes a pressure-sensing diaphragm and a Wheatstone bridge diaphragm. The Wheatstone bridge diaphragm is provided with a protective layer, which includes a transition bottom layer, a protective intermediate layer, and a closed outer layer from bottom to top.

[0009] The protective intermediate layer is composed of the following mass fractions of raw materials: 10-25% nanometer alumina, 3-9% nanometer zirconia, 0.5-3.0% boron nitride nanotubes, and the balance nanometer silicon dioxide.

[0010] The closed outer layer is composed of the following mass fractions of raw materials: 1-5% FDTS, 5-15% nanometer titanium oxide, 0.5-3% fluorinated graphite, 10-20% DMF (N,N-dimethylformamide), and the balance electronic-grade epoxy resin.

[0011] In some preferred embodiments, the preparation raw materials of the protective intermediate layer include, by mass fraction, 12-23% nanometer alumina, 4-7% nanometer zirconia, 0.6-2.1% boron nitride nanotube, and the balance nanometer silicon dioxide. Among them, the nanometer alumina in the intermediate protective layer provides hardness, the nanometer zirconia provides toughness, and the two together add up to achieve high strength and high toughness; the boron nitride nanotube has good thermal conductivity and strength.

[0012] In some preferred embodiments, the preparation raw materials of the closed outer layer include, by mass fraction, 2-4% FDTS, 7-12% nanometer titanium oxide, 0.5-1.8% fluorinated graphite, 12-17% DMF, and the balance electronic-grade epoxy resin.

[0013] The electronic-grade epoxy resin in the closed outer layer serves as a matrix resin, has excellent adhesion and chemical corrosion resistance; the FDTS as a surface modifier can enhance the hydrophobicity and corrosion resistance of the material surface; the nanometer titanium oxide has excellent oxidation resistance; the fluorinated graphite as a solid lubricant has the characteristics of low surface energy, and has excellent thermal stability and chemical stability.

[0014] In some preferred embodiments, the thickness of the transition bottom layer is 0.1-0.5 μm, preferably 0.2-0.3 μm.

[0015] In some preferred embodiments, the thickness of the protective intermediate layer is 1.5-10 μm, preferably 5-10 μm.

[0016] In some preferred embodiments, the thickness of the closed outer layer is 5-30 μm, preferably 5-10 μm.

[0017] The preparation method of the protective intermediate layer includes mixing the preparation raw materials and then spraying them on the surface of the transition bottom layer by plasma to form the protective intermediate layer.

[0018] The preheating temperature of the plasma spraying is 150-200°C.

[0019] The power of the plasma spraying is 40-60 kW.

[0020] The gas flow of the plasma spraying is 40 L / min Ar and 10 L / min He.

[0021] The powder feeding speed of the plasma spraying is 15-25 g / min.

[0022] The preparation method of the closed outer layer includes mixing the preparation raw materials by ultrasonic assistance to obtain a sealing agent, and then spin-coating the sealing agent on the protective intermediate layer to obtain the protective layer after curing.

[0023] In some preferred embodiments, the rotation speed of the spin coating is 1000-5000 rpm, preferably 3000 rpm.

[0024] In some preferred embodiments, the temperature of the spin coating is 20-30℃, for example 25℃.

[0025] In some preferred embodiments, the transition bottom layer is composed of titanium carbide, preferably Ti x C 1-x , x=0.5-0.8.

[0026] In some preferred embodiments, the preparation method of the transition bottom layer comprises: depositing a titanium carbide layer by magnetron sputtering method with a titanium target and methane.

[0027] In some preferred embodiments, the methane needs to be diluted with argon, and the volume ratio of methane to argon is 1:1-20.

[0028] In some preferred embodiments, the substrate temperature of the magnetron sputtering is 360-420℃, preferably 400℃.

[0029] In some preferred embodiments, the particle size of the nano-aluminum oxide is 30-60 nm, preferably 30-50 nm.

[0030] In some preferred embodiments, the nano-zirconium oxide D50=30-50 nm.

[0031] In some preferred embodiments, the thermal conductivity coefficient of the boron nitride nanotube is 3000 W / m·K.

[0032] In some preferred embodiments, the Young's modulus of the boron nitride nanotube is 1.18 TPa.

[0033] In some preferred embodiments, the D50 of the nano-silicon dioxide is 10-30 nm.

[0034] In some preferred embodiments, the electronic-grade epoxy resin is a mixed epoxy resin of bisphenol A and bisphenol F.

[0035] In some preferred embodiments, the nano-titanium oxide D50=15-30 nm.

[0036] In some preferred embodiments, the D50 of the graphite fluoride is 5-10 μm.

[0037] In the present application, the Wheatstone bridge diaphragm comprises, from bottom to top, a stainless steel substrate, an insulating layer, a resistive strain layer, and a protective layer.

[0038] In some preferred embodiments, the insulating layer is composed of Ta2O5.

[0039] In some preferred embodiments, the thickness of the insulating layer is 1.5-2.5 μm, preferably 1.8-2.2 μm.

[0040] In some preferred embodiments, the composition of the electric resistance strain layer is a Kama alloy, which contains 0.5-1.5% Mn, Si≤0.2%, 19.0-21.5% Cr, 2.7-3.2% Al, 2.0-3.0% Fe and the balance of Ni in terms of mass percentage.

[0041] In some preferred embodiments, the thickness of the electric resistance strain layer is 50-100 nm.

[0042] The composition of the wire-bonding layer is Au.

[0043] The pressure-sensitive diaphragm comprises, from bottom to top, a steel base, an elastic layer and an oxidation-resistant layer.

[0044] In some preferred embodiments, the composition of the elastic layer is Ni 60-75 Si 10-20 B, for example, Ni 68 Si 15 B 17 .

[0045] In some preferred embodiments, the thickness of the elastic layer is 0.5-4 μm, preferably 1-3 μm.

[0046] In some preferred embodiments, the composition of the oxidation-resistant layer is SiO2.

[0047] In some preferred embodiments, the thickness of the oxidation-resistant layer is 0.5-1.5 μm, preferably 0.5-1 μm.

[0048] The aforementioned double-diaphragm sputtering thin-film core is used in the fields of petroleum and natural gas, chemical industry, waste water treatment, biomedicine and food processing.

[0049] On the basis of common general knowledge in the art, the above-mentioned preferred conditions can be combined at will, thus obtaining various preferred embodiments of the present application.

[0050] Compared with the prior art, the present application has the following advantages:

[0051] 1. The protective layer material of the Wheatstone bridge diaphragm of the present application is selected as follows: the composition of the transition bottom layer is titanium carbide, which can effectively solve the thermal expansion mismatch problem of the metal and the protective layer, avoid structural damage caused by the difference in thermal expansion, and improve the reliability and service life of the sensor; the combination of the materials used in the protective intermediate layer enables the protective intermediate layer to have high hardness, high toughness, good thermal conductivity and strength, and can effectively resist the erosion of the sensor by high-viscosity and highly corrosive media; in the preparation of the closed outer layer, the electronic grade epoxy resin as the base resin has excellent adhesion and chemical corrosion resistance; FDTS as a surface modifier enhances the hydrophobicity and corrosion resistance of the material surface; nano titanium oxide has excellent oxidation resistance; and the fluorinated graphite as a solid lubricant has low surface energy, excellent thermal stability and chemical stability.

[0052] 2. From the structural design: the double diaphragm structure of the Wheatstone bridge diaphragm and the pressure sensing diaphragm is separately arranged, the fixed base and the pressure conducting rod are matched to form a pressure transmission path without a pressure guide hole, the pressure sensing diaphragm directly contacts the medium to sense the pressure, and then the pressure is accurately transmitted to the Wheatstone bridge diaphragm by the pressure conducting rod, which fundamentally avoids the problem of blockage of the traditional pressure guide hole by high-viscosity and crystallizable media, and the stress relief groove of the fixed base can effectively release the welding stress and pressure strain to ensure linear pressure transmission; the Wheatstone bridge diaphragm is provided with a stainless steel base, an insulating layer, a resistance strain layer and a protective layer from bottom to top, and the protective layer is further divided into a gradient structure of a transition bottom layer, a protective intermediate layer and a closed outer layer, the transition bottom layer can alleviate the thermal expansion mismatch between the layers to avoid cracking and peeling of the protective layer, and the protective intermediate layer and the closed outer layer cooperate to improve the protection effect and reduce the influence of the external environment on the resistance strain layer; the pressure sensing diaphragm is provided with a steel base, an elastic layer and an oxidation-resistant layer from bottom to top to ensure stable pressure sensing in the medium, and the overall structural design enables the core to accurately measure in high-viscosity and strongly corrosive media for a long time. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to facilitate the understanding of those skilled in the art, the present application will be further described below with reference to the accompanying drawings.

[0054] Figure 1 It is a schematic diagram of the appearance of the double diaphragm sputtering film core.

[0055] Figure 2 It is an exploded view of the double diaphragm sputtering film core.

[0056] Figure 3 It is a sectional view of the double diaphragm sputtering film core.

[0057] Figure 4 It is a schematic diagram of the Wheatstone bridge diaphragm structure.

[0058] Figure 5 It is a schematic diagram of the pressure sensing diaphragm structure.

[0059] BRIEF DESCRIPTION OF DRAWINGS

[0060] 100, strain sensing diaphragm assembly; 110, strain sensing base; 120, Wheatstone bridge diaphragm; 130, force conducting rod;

[0061] 200, connecting fixing seat; 210, fixing seat; 220, stress release groove;

[0062] 300, pressure sensing diaphragm assembly; 310, pressure sensing diaphragm seat body; 320, pressure sensing diaphragm;

[0063] 11, protective layer; 12, soldering wire layer; 13, resistance strain layer; 14, insulating layer; 15, stainless steel substrate;

[0064] 111, closed outer layer; 112, protective intermediate layer; 113, transition bottom layer;

[0065] 31, anti-oxidation layer; 32, elastic layer; 33, steel base. DETAILED DESCRIPTION

[0066] In order to facilitate the understanding of the present application, the following will be a more comprehensive and detailed description of the preferred embodiments of the present application, but the protection scope of the present application is not limited to the following specific embodiments.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0068] Structure of double diaphragm sputtering film core

[0069] The double diaphragm sputtering film core of the present application, the product structure schematic diagram is shown in Figures 1-3 ; wherein, Figure 1 is a schematic diagram of the appearance of the double diaphragm sputtering film core, Figure 2 is an exploded view of the double diaphragm sputtering film core, Figure 3 is a sectional view of the double diaphragm sputtering film core.

[0070] 1. The structure of the double diaphragm sputtering film core of the present application is as follows:

[0071] The strain sensing diaphragm assembly (100) comprises a strain sensing base (110), a Wheatstone bridge diaphragm (120) and a force conducting rod (130); the Wheatstone bridge diaphragm (120) is arranged on the strain sensing base (110), and the force conducting rod (130) is fixedly connected with the Wheatstone bridge diaphragm (120) and used for conducting pressure to the Wheatstone bridge diaphragm (120) so that the resistance value of the piezoresistive strain gauge thereon changes to output a pressure signal;

[0072] The connecting fixing seat (200) comprises a fixing seat (210) and a stress release groove (220); the connecting fixing seat (200) plays a role of intermediate connection, and stably connects the strain sensing diaphragm assembly (100) and the pressure sensing diaphragm assembly (300); the stress release groove (220) can reduce internal stress of the structure, and guarantee stability of connection and the whole structure;

[0073] The pressure sensing diaphragm assembly (300) comprises a pressure sensing diaphragm seat body (310) and a pressure sensing diaphragm (320); the pressure sensing diaphragm seat body (310) is a support base of the pressure sensing diaphragm assembly (300), and an annular mounting groove adapted to the pressure sensing diaphragm (320) is formed in the pressure sensing diaphragm seat body (310); the bottom of the pressure sensing diaphragm (320) is fixed and sealed by laser welding with the mounting groove.

[0074] The strain sensing diaphragm assembly (100), the connecting fixing seat (200) and the pressure sensing diaphragm assembly (300) are fixedly connected by laser welding, so that the pressure sensing diaphragm (320) and the Wheatstone bridge diaphragm (120) are connected by the force transmission rod (130), and force transmission is realized.

[0075] The material of the strain sensing base (110), the force transmission rod (130), the fixing seat (210) and the pressure sensing diaphragm seat body (310) can be stainless steel commonly used in the field, and the present application adopts 17-4 PH stainless steel.

[0076] 2. Wheatstone bridge diaphragm

[0077] The Wheatstone bridge diaphragm structure diagram is shown in Figure 4 ;

[0078] The insulating layer (14) is arranged above the stainless steel base (15), the resistance strain layer (13) is arranged on a part of the surface of the insulating layer (14), the welding wire layer (12) is arranged on another part of the surface of the insulating layer (14), the protective layer (11) is arranged on the surface of the resistance strain layer (13), and the welding wire layer (12) penetrates through the resistance strain layer (13) and the protective layer (11); the stainless steel base (15) is part of the strain sensing base (110);

[0079] The protective layer (11) comprises, from bottom to top, a transition bottom layer (113), a protective intermediate layer (112) and a closed outer layer (111).

[0080] 3. Pressure sensing diaphragm

[0081] The pressure sensing diaphragm structure diagram is shown in Figure 5 ;

[0082] A steel base (33) is provided above an elastic layer (32), and an oxidation-resistant layer (31) is provided on the surface of the elastic layer (32); wherein the steel base (33) is part of a pressure-sensitive film seat body (310).

[0083] An elastic layer with a composition of Ni 68 Si 15 B 17 is deposited on the surface of a stainless steel base by magnetron sputtering using a Ni target, a Si target and a B target, and the thickness of the elastic layer is 2.0 μm; the substrate temperature during magnetron sputtering is 260°C, the target-substrate distance is 5 cm, the sputtering speed is 10 nm / min; the power of the Ni target is 150 W, the power of the Si target is 100 W, and the power of the B target is 80 W.

[0084] An oxidation-resistant layer is then deposited on the surface of the elastic layer by magnetron sputtering, and the deposition thickness is 0.8 μm.

[0085] The raw material information used in the following examples is as follows:

[0086] The boron nitride nanotubes are purchased from GuTesu (Shanghai) Trade Co., Ltd., and have a thermal conductivity of 3000 W / m·K, a Young's modulus of 1.18 TPa, and a thermal expansion coefficient of 1×10 -6 ;

[0087] The nano-aluminum oxide is purchased from Hangzhou Hengna New Material Co., Ltd. HN-L100, 30-50 nm, content ≥99.999%, crystal form is alpha phase.

[0088] The nano-zirconium oxide has a D50=50 nm and a content ≥99.9%, and the crystal phase is monoclinic.

[0089] The nano-silicon oxide has a D50=15 nm and a content ≥99.8%, and a specific surface area of 250±30 m 2 / g.

[0090] FDTS: Chinese name: trichloro(1H,1H,2H,2H-perfluorooctyl) silane, CAS number: 78560-45-9.

[0091] The nano-titanium oxide has a D50=15-25 nm and a content ≥99.9%, and a specific surface area of 100-250 m 2 / g.

[0092] The fluorinated graphite is purchased from Shanghai Fluorine Rui Fine Chemical Co., Ltd. Fluorinated graphite CF500, CAS number: 51311-17-2, D50=5-10 μm, tap density is 0.9 g / cm 3 .

[0093] Electronic grade epoxy resin was purchased from Hunan Sailve New Material Technology Co., Ltd. SAW-1100R bisphenol A and bisphenol F type epoxy resin, epoxy equivalent weight of 160~170g / eq, viscosity (25℃) of 2000~4000cps.

[0094] The composition of Karma alloy is 0.63% Mn, Si≤0.15%, 21% Cr, 3.1% Al, 2.4% Fe and the balance of Ni;

[0095] Including but not limited to the above manufacturers model.

[0096] The Wheatstone bridge diaphragm used in different embodiments and comparative examples is as follows:

[0097] Embodiment 1

[0098] 1. The Wheatstone bridge diaphragm of this embodiment comprises, from bottom to top, a stainless steel substrate, an insulation layer, a resistive strain layer, a bonding wire layer and a protective layer;

[0099] The composition of the insulation layer is Ta2O5, and the thickness of the insulation layer is 2.0μm;

[0100] The composition of the resistive strain layer is Karma alloy, and the thickness of the resistive strain layer is 75nm;

[0101] The composition of the bonding wire layer is Au;

[0102] The protective layer comprises, from bottom to top, a 0.27μm transition bottom layer, an 8μm protective intermediate layer and a 10μm closed outer layer.

[0103] The composition of the transition bottom layer is Ti 0.6 C 0.4 ;

[0104] The raw materials for preparing the protective intermediate layer, by mass fraction, consist of 17.6% nano-alumina, 5.4% nano-zirconia, 1.8% boron nitride nanotubes and the balance of nano-silicon dioxide;

[0105] The raw materials for preparing the closed outer layer, by mass fraction, consist of 3.5% FDTs, 8.4% nano-titanium oxide, 1.6% fluorinated graphite, 13% DMF and the balance of electronic grade epoxy resin.

[0106] 2. The preparation method of the Wheatstone bridge diaphragm of this embodiment is as follows:

[0107] (1) Ta2O5 insulation layer is prepared on the stainless steel substrate by atomic deposition method; specifically, the preparation method is that the temperature of the steel substrate is 250℃, the temperature of the Ta(OC2H5)5 source bottle is 180℃, the nitrogen flow rate is 6sccm, and the deposition rate is 9.3Å / s under 3MPa.

[0108] (2) A layer of Karma alloy is plated on the surface of the insulating layer to prepare a resistance strain layer by magnetron sputtering method. During the magnetron sputtering process, the substrate temperature is 150℃, the vacuum degree is 1×10 -3 Pa, and the resistance change layer is patterned.

[0109] (3) A solder wire layer is deposited by magnetron sputtering method, and the solder wire layer is patterned.

[0110] (4) Preparation of the protective layer:

[0111] a. Preparation of the transition bottom layer: titanium target and methane are deposited to form a titanium carbide layer (Ti 0.6 C 10.4 ) by magnetron sputtering method; the magnetron sputtering power is 200W, the substrate temperature is 400℃, and the volume ratio of methane to argon is 1:20;

[0112] b. Preparation of the protective intermediate layer: the raw materials for preparing the protective intermediate layer are mixed and then sprayed on the surface of the transition bottom layer by plasma spraying to form the protective intermediate layer. The preheating temperature of plasma spraying is 185℃, the power is 60kW, the Ar flow rate is 40L / min, the He flow rate is 10L / min, and the powder feeding speed is 20g / min during the process;

[0113] c. Preparation of the closed outer layer: the raw materials for preparing the closed outer layer are mixed uniformly by ultrasonic assistance to obtain a sealing agent, which is spin-coated on the protective intermediate layer. The spin-coating speed is 3000rpm, and the spin-coating temperature is 25℃. After solidification, the closed outer layer is obtained.

[0114] Example 2

[0115] The difference between this embodiment and Example 1 is only that:

[0116] The raw materials for preparing the protective intermediate layer consist of 21% nanometer alumina, 4.3% nanometer zirconia, 1.9% boron nitride nanotubes, and the balance nanometer silicon dioxide by mass fraction; the other raw materials, steps, and parameters are the same as those in Example 1.

[0117] Example 3

[0118] The difference between this embodiment and Example 1 is that:

[0119] The raw materials for preparing the closed outer layer consist of 2.7% FTS, 7.1% nanometer titanium oxide, 0.7% fluorinated graphite, 17% DMF, and the balance electronic grade epoxy resin by mass fraction; the other raw materials, steps, and parameters are the same as those in Example 1.

[0120] Example 4

[0121] The difference between this embodiment and Example 1 is that:

[0122] The composition of the transition underlayer is Ti 0.52 C 0.48 ;

[0123] The transition underlayer was prepared by magnetron sputtering at a substrate temperature of 360°C and a volume ratio of methane to argon of 1:12; the other raw materials, steps, and parameters were the same as in Example 1.

[0124] Example 5

[0125] The difference between this comparative example and Example 1 is that:

[0126] The raw materials for preparing the protective intermediate layer consist of 20% nanometer alumina, 7% nanometer zirconia, 2.0% boron nitride nanotubes, and the balance nanometer silicon dioxide by mass fraction;

[0127] The other raw materials, steps, and parameters were the same as in Example 1.

[0128] Comparative Example 1

[0129] The difference between this comparative example and Example 1 is that:

[0130] The raw materials for preparing the protective intermediate layer consist of 22% nanometer alumina, 6.3% nanometer zirconia, and the balance nanometer silicon dioxide by mass fraction; the other raw materials, steps, and parameters were the same as in Example 1.

[0131] Comparative Example 2

[0132] The difference between this comparative example and Example 1 is that:

[0133] The raw materials for preparing the protective intermediate layer consist of 18% nanometer alumina, 6.5% nanometer zirconia, 4.0% boron nitride nanotubes, and the balance nanometer silicon dioxide by mass fraction; the other raw materials, steps, and parameters were the same as in Example 1.

[0134] Comparative Example 3

[0135] The difference between this comparative example and Example 1 is that:

[0136] The raw materials for preparing the sealing outer layer consist of 10.6% nanometer titanium oxide, 1.4% graphite fluoride, 15% DMF, and the balance electronic-grade epoxy resin by mass fraction; the other raw materials, steps, and parameters were the same as in Example 1.

[0137] Comparative Example 4

[0138] The difference between this comparative example and Example 1 is that:

[0139] The raw materials for preparing the sealing outer layer consist of 3.7% FDTS, 10.2% nanometer titanium oxide, 15% DMF, and the balance electronic-grade epoxy resin by mass fraction; the other raw materials, steps, and parameters were the same as in Example 1.

[0140] Application performance of double diaphragm sputtering thin film core

[0141] The double diaphragm sputtering thin film core prepared in the above examples and comparative examples was tested for various performances. The test medium was a sulfur-containing crude oil (sulfur content 1.2%, viscosity 500 mPa·s), the test temperature was 85°C, the relative humidity was 50% RH, and the test equipment was a high-temperature and high-pressure simulated wellbore.

[0142] Test steps:

[0143] (1) Initial calibration: In the standard environment (23°C, normal pressure), the zero point calibration and full scale (99 MPa) calibration of all sensors were performed, and the initial sensitivity, linear error and basic error were recorded.

[0144] (2) Medium circulation test: The sensor was immersed in the petroleum medium in the high-temperature and high-pressure simulated wellbore, and the following process was repeated for 10 cycles:

[0145] a. Pressure rising stage: from 0 MPa to 99 MPa in 30 s, and stably maintained for 5 min;

[0146] b. Pressure dropping stage: from 99 MPa to 0 MPa in 30 s, and stably maintained for 5 min;

[0147] c. Medium replacement: new petroleum medium was replaced after each cycle to simulate the medium update under actual working conditions;

[0148] (3) Performance retest: After 10 cycles, the sensor was taken out and the surface was cleaned, and then it was recalibrated at 25°C. The output values of several pressure points (-0.011 MPa, 16.497 MPa, 32.996 MPa, 49.498 MPa, 65.994 MPa, 82.498 MPa, 98.998 MPa) were recorded. The standard device was HB600F1 pressure calibrator with a measurement range of (0~100) MPa, and the test was carried out according to JJG860-2015 "Pressure Sensor (Static)", and the data after processing are shown in Table 1.

[0149]

[0150] According to the above application test results, it can be seen that:

[0151] Comparative Example 1 lacks the high-thermal-conductivity characteristics of boron nitride nanotubes, and the local heat accumulation of the diaphragm causes uneven deformation caused by temperature gradient, resulting in large linear error. At the same time, the interlayer bonding strength decreases, and the diaphragm deformation consistency is poor under pressure loading;

[0152] Comparative Example 2: The content of boron nitride nanotubes is too high, which is easy to form agglomeration in the layer, resulting in uneven internal structure of the diaphragm, stress concentration area during pressure transmission, and significantly higher repeatability error and hysteresis error than Example 1;

[0153] Comparative Example 3: The hydrophobic effect of FDTS is missing, and the high-viscosity medium is easy to adhere to the surface of the closed outer layer, even penetrating into the protective intermediate layer, resulting in the diaphragm being damp or corroded; at the same time, the medium adhesion increases the additional mass of the diaphragm, and the "hysteresis effect" occurs during pressure transmission, with higher hysteresis error and linearity error;

[0154] Comparative Example 4: The lubricating effect of fluorinated graphite is missing, and the frictional resistance between the diaphragm and the medium increases, the diaphragm deformation recovery speed slows down during pressure loading / unloading, and the hysteresis error increases; this comparative example lacks the buffering function of fluorinated graphite, and the impact of the medium on the diaphragm is directly transmitted to the resistance strain layer, resulting in an increase in signal fluctuation, higher repeatability error than Example 1, and a sensitivity deviation of 0.100%.

[0155] 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. within the spirit and principles of the present application should be included within the scope of protection of the present application.

Claims

1. A dual diaphragm sputter thin film core comprising a pressure sensitive diaphragm and a Wheatstone bridge diaphragm, characterized in that, The Wheatstone bridge membrane is provided with a protective layer, and the protective layer comprises a transition bottom layer, a protective intermediate layer and a closed outer layer from bottom to top. The protective intermediate layer is composed of the following mass fraction of raw materials: 10-25% nano-alumina, 3-9% nano-zirconia, 0.5-3.0% boron nitride nanotubes, and the balance of nano-silicon dioxide. The closed outer layer is composed of the following mass fraction of raw materials: 1-5% FDTS, 5-15% nano-titanium oxide, 0.5-3% fluorinated graphite, 10-20% DMF, and the balance of electronic-grade epoxy resin.

2. The dual diaphragm sputter film core of claim 1, wherein, At least one of the following conditions a-c is met: a. The thickness of the transition bottom layer is 0.1-0.5 μm; b. The thickness of the protective intermediate layer is 1.5-10 μm; c. The thickness of the closed outer layer is 5-30 μm.

3. The dual diaphragm sputter thin film core of claim 1, wherein, At least one of the following conditions a-c is met for the Wheatstone bridge membrane: a. The preparation method of the transition bottom layer comprises: depositing a titanium carbide layer by magnetron sputtering method with titanium target and methane; b. The preparation method of the protective intermediate layer comprises: mixing the raw materials and then spraying on the surface of the transition bottom layer by plasma to form the protective intermediate layer; c. The preparation method of the closed outer layer comprises: mixing the raw materials by ultrasonic assistance to obtain a sealing agent, and then spin coating the sealing agent on the protective intermediate layer and curing.

4. The dual diaphragm sputter-deposited thin film core of claim 3, wherein, At least one of the following conditions a-c is met: a. The preheating temperature of the plasma spraying is 150-200°C; b. The power of the plasma spraying is 40-60 kW; c. The powder feeding speed of the plasma spraying is 15-25 g / min; d. The transition layer has a composition of TixC 1-x , x = 0.5 ~ 0.

8.

5. The dual diaphragm sputter film core of claim 1, wherein, At least one of the following conditions a-c is met: a. The particle size of the nano-alumina is 30-60 nm; b. The nano-zirconia D50=30-50 nm; c. The thermal conductivity coefficient of the boron nitride nanotube is 3000 W / m·K; d. The D50 of the nano-silicon dioxide is 10-30 nm; e. The electronic-grade epoxy resin is a mixed epoxy resin of bisphenol A and bisphenol F; f. The nano-titanium oxide D50=15-30 nm; g. The D50 of the fluorinated graphite is 5-10 μm.

6. The dual diaphragm sputter thin film core of claim 1, wherein, The Wheatstone bridge membrane comprises a stainless steel substrate, an insulating layer, a resistance strain layer and a protective layer from bottom to top.

7. The dual diaphragm sputter-deposited thin film core of claim 6, wherein, At least one of the following conditions a-d is met for the Wheatstone bridge membrane: a. The composition of the insulating layer is Ta2O5; b. The thickness of the insulating layer is 1.5-2.5 μm; c. The composition of the resistance strain layer is Karma alloy; d. The thickness of the resistance strain layer is 50-100 nm.

8. The dual diaphragm sputter-deposited thin film core of claim 1, wherein, The pressure sensing membrane comprises a steel base, an elastic layer and an oxidation-resistant layer from bottom to top.

9. The dual diaphragm sputter-deposited thin film core of claim 8, wherein, At least one of the following conditions a-c is met for the pressure sensing membrane: a. the elastic layer has a composition of N 60-75 Si 10-20 B; b. The thickness of the elastic layer is 0.5-4 μm; c. The composition of the oxidation-resistant layer is SiO2; d. The thickness of the oxidation-resistant layer is 0.5-1.5 μm.

10. The application of the double-membrane sputtering thin film core in the fields of petroleum and natural gas, chemical industry, wastewater treatment, biomedicine and food processing according to any one of claims 1-9.

Images