A high temperature and pressure in-situ composite measurement sensor, preparation and use method

Abstract

The present invention belongs to the field of testing, and proposes a high-temperature temperature and pressure in-situ composite measurement sensor, preparation and use method, including a sensitive element, a ceramic base and a high-temperature resistant lead; the sensitive element is an elastic diaphragm provided with a high-temperature electrode, which includes five platinum metal electrodes and four indium tin oxide varistors. Four indium tin oxide varistors with equal resistance values ​​are connected to form a Wheatstone bridge. The sensor integrates a sub-micron-thick platinum film thermistor and an indium tin oxide varistor to achieve in-situ simultaneous measurement of temperature-pressure parameters. The sensing element adopts a flip-chip flush package, and the sensitive elastic diaphragm directly senses the temperature and pressure of the medium, avoiding the influence of the airway lumen effect. The test method has no pressure inlet, and the natural frequency is approximately equal to the natural frequency of the sensitive element, which can achieve high-frequency dynamic measurement.

Description

Technical Field

[0001] The present invention relates to the field of testing, and in particular to a high-temperature temperature and pressure in-situ composite measurement sensor, and a preparation and use method thereof. Background Art

[0002] Key components of power equipment, such as rocket engines, aircraft engines, heavy-duty gas turbines, and coal-fired gas boilers, are exposed to harsh, high-temperature environments, with combustion chamber temperatures exceeding 1300°C. High-temperature sensors can provide real-time monitoring of pressure, temperature, heat flow, and other parameters in key components, such as nozzle combustion chambers, compressors, and blades, improving combustion performance and propulsion efficiency while also assessing component health. Current discrete point measurement methods struggle to accurately reveal the underlying influence of temperature and pressure coupling on equipment performance, and therefore fail to meet the testing requirements of next-generation equipment. The coupling mechanisms and failure patterns under extreme operating conditions remain unclear. Based on simplified physical equations and boundary conditions, computational accuracy is limited, and experimental verification methods are lacking, making a closed-loop data loop impossible. Temperature and pressure coupling testing technology enables in-situ measurements, providing a more intuitive understanding of the relevant principles and supporting the design of high-speed vehicle thermodynamic performance, thermo-mechanical strength verification, and environmental health monitoring for in-service environments.

[0003] At present, room temperature MEMS sensors are mainly based on silicon (Si) sensors. Within the working range of 100℃, commercial Si sensors have mature technology, small size and good performance. However, when used in an environment of 120℃, the internal PN junction will leak, and the sensor performance will degrade or even fail. In addition, Si materials will undergo plastic deformation when the temperature is greater than 500℃, which cannot meet the measurement requirements in high temperature environments. "Zhang Qiuning, Zhang Zhijie, Chen Haoze. Preparation and performance test of a new type of platinum-rhodium thin film thermocouple [J]. Micro-Nano Electronics Technology, 2022, 59(05): 473-479+493. DOI: 10.13250 / j.cnki.wndz.2022.05.013." A fast-response S-type platinum-rhodium thin film thermocouple with platinum-rhodium (PtRh) as the dipole material was developed. Although the developed thin film thermocouple can monitor temperature at 1500℃, it cannot achieve temperature and pressure composite measurement. "Okojie RS, Lukco D, Nguyen V, et al. Demonstration of SiC pressure sensors at 750°C [J]. Additional Papers and Presentations, 2014, 2014 (HITEC): 000028-000032." A fully SiC pressure-sensitive chip was designed. The chip uses 6H-SiC as a substrate, homoepitaxial doping and dry etching to form a PN junction and piezoresistive structure, and a Ti / TaSi / Pt film system to achieve ohmic contact. The chip operates at temperatures up to 750°C. While SiC-based high-temperature sensors maintain good mechanical strength at high temperatures, their operating temperature is limited by the degradation of the piezoresistive effect of the epitaxial 6H-SiC film at high temperatures and the temperature limit of the SiC ohmic contact. Summary of the Invention

[0004] The present invention aims to overcome the above-mentioned drawbacks by proposing a high-temperature, in-situ composite temperature and pressure measurement sensor, as well as its preparation and use methods. This high-temperature, in-situ composite temperature and pressure measurement sensor measures transient heat flux and temperature using a submicron-thick platinum (Pt) thin-film thermal resistor, achieving a response time on the order of microseconds. It converts pressure signals into voltage output using an indium tin oxide (ITO) piezoresistor, and utilizes a high-temperature, flip-chip, leadless MEMS sensitive element packaging process. The sensor features high-temperature resistance up to 1300°C, a wide range, high resolution, and excellent dynamic response. It can simultaneously detect medium pressure with high precision under extreme operating conditions, such as high temperatures and high Mach numbers.

[0005] The technical solution of the present invention is: a high-temperature temperature and pressure in-situ composite measurement sensor, including a sensitive element 1, a ceramic base 2 and a high-temperature resistant lead 3; the sensitive element 1 is an elastic diaphragm provided with a high-temperature resistant electrode, which includes five platinum metal electrodes and four indium tin oxide varistors, all of which are sputtered on the back of the elastic diaphragm; the four indium tin oxide varistors with equal resistance are connected to form a Wheatstone bridge; the ceramic base 2 is provided with a square countersunk hole, a square groove and seven lead through holes; a square groove is arranged in the square countersunk hole, and the square groove is directly opposite to the central area of ​​the sensitive element 1, serving as a deformation space for the elastic diaphragm of the sensitive element; the five lead through holes are The pressure measurement lead holes are arranged on two opposite sides of the square countersunk hole; the remaining two lead holes are metalized temperature measurement lead holes, arranged outside the square countersunk hole. The two temperature measurement lead holes are connected by an arc-shaped platinum thin film thermal resistor. The submicron-thick platinum thin film thermal resistor is formed by magnetron sputtering on the surface of the ceramic base 2. The sensitive element 1 is packaged at high temperature using a flip-chip leadless process. The sensitive element 1 is placed in the square countersunk hole of the ceramic base 2 and aligned. The five platinum metal electrodes on the sensitive element 1 are exposed through the pressure measurement lead holes of the ceramic base 2. A high-temperature repair agent is used to seal the gap between the sensitive element 1 and the ceramic base 2 and then cure it at high temperature.

[0006] The high-temperature-resistant lead 3 is connected to the platinum metal electrode through the pressure-measuring lead through-hole of the ceramic base 2. The two are sintered at high temperature using a high-temperature conductive paste, establishing an electrical connection between the sensitive element signal and the outside world. When the medium pressure acts on the elastic diaphragm of the sensitive element 1, the pressure on the front and back sides of the elastic diaphragm is unequal, and the elastic diaphragm deforms. The two indium tin oxide varistors at the edges of the elastic diaphragm are compressed, and their resistance decreases. The two indium tin oxide varistors at the center of the elastic diaphragm are pulled, and their resistance increases, causing the Wheatstone bridge to lose balance. When a power supply is applied to the Wheatstone bridge, an output voltage proportional to the measured pressure is obtained, thereby measuring the pressure characteristics of the measured structure.

[0007] The platinum thin film thermal resistor is led out through the temperature measurement lead through-hole of the ceramic base using the four-wire method. A constant current is loaded at both ends of the platinum thin film thermal resistor, and a voltage linearly related to the resistance is obtained at both ends. When the temperature changes, the resistance value changes accordingly, and the voltage at both ends of the platinum thin film thermal resistor changes. The change in resistance is measured by measuring the change in voltage. Based on the one-dimensional semi-infinite body heat conduction theory, the transient heat flux density value is calculated using the measured voltage value.

[0008] The platinum metal electrode includes a first platinum metal electrode A, a second platinum metal electrode B, a third platinum metal electrode C, a fourth platinum metal electrode D1 and a fifth platinum metal electrode D2; the indium tin oxide varistor includes a first indium tin oxide varistor E1, a second indium tin oxide varistor E2, a third indium tin oxide varistor E3 and a fourth indium tin oxide varistor E4; the second indium tin oxide varistor E2 and the third indium tin oxide varistor E3 are located in the center of the elastic mold, and the first indium tin oxide varistor E1 and the fourth indium tin oxide varistor E4 are located at the edge of the elastic mold; the first indium tin oxide varistor E1 is respectively connected to one end of the second platinum metal electrode B and one end of the third platinum metal electrode C; the second indium tin oxide varistor E2 is respectively connected to one end of the first platinum metal electrode A and the other end of the third platinum metal electrode C; the third indium tin oxide varistor E3 is respectively connected to the other end of the second platinum metal electrode B and one end of the fourth platinum metal electrode D1; the fourth indium tin oxide varistor E4 is respectively connected to the other end of the first platinum metal electrode A and one end of the fifth platinum metal electrode D2.

[0009] The elastic diaphragm of the sensitive element 1 is one of a single crystal sapphire sheet, an aluminum oxide sheet, and a zirconium oxide sheet.

[0010] The excitation power supply is a constant voltage power supply or a constant current power supply.

[0011] A method for preparing a high-temperature temperature and pressure in-situ composite measurement sensor comprises the following steps:

[0012] Step 1: Use CNC machine tools to process the square countersunk holes, square grooves and seven lead holes of the ceramic base;

[0013] Step 2: Arrange high-temperature resistant leads 3 in the lead through holes on both sides of the ceramic base, so that the high-temperature resistant leads 3 are tightly connected to the lead through hole walls;

[0014] Step 3: Use a metal mask to magnetron sputter a sub-micron-thick platinum thin film thermal resistor on the surface of the ceramic base;

[0015] Step 4: Fill the bottom of the sputtered ceramic base with high-temperature repair agent and solidify it. Connect the high-temperature resistant lead 3 of the temperature measuring lead through hole at the bottom of the ceramic base 2 with a four-wire method and weld it as a whole. Use heat shrink tubing to seal the weld.

[0016] Step 5: Use deionized water ultrasonic cleaning, alkaline cleaning, acid cleaning, and deionized water ultrasonic cleaning to obtain a clean sapphire single crystal negative;

[0017] Step 6: Through the process of photolithography-sputtering-stripping, the platinum metal electrode and indium tin oxide varistor are patterned on the elastic diaphragm of the sensitive element;

[0018] Step 7: Place the sensitive element 1 into the square countersunk hole of the ceramic base and align it so that the five pressure lead holes in the middle of the ceramic base expose the platinum metal electrodes on the sensitive element. The square groove is facing the center area of ​​the sensitive element. Use high-temperature repair agent to seal the gap and cure it at high temperature.

[0019] Step 8: Use high-temperature conductive paste to sinter the high-temperature resistant lead 3 connecting the sensitive element 1 and the pressure measuring lead through-hole, fill the bottom of the ceramic base 2 with high-temperature repair agent and solidify it, and use heat shrink tubing to encapsulate the high-temperature resistant lead 3.

[0020] A method for using a high-temperature temperature and pressure in-situ composite measurement sensor comprises the following steps:

[0021] 1. Pressure test: Each of the five pressure test lead holes is provided with a high-temperature resistant lead 3, for a total of five pressure test leads. The circuit uses a semi-enclosed full-bridge structure to convert the change in resistance into a voltage signal. Point D is led out using two leads, connected to the fourth platinum metal electrode D1 and the fifth platinum metal electrode D2 respectively. When not performing a pressure test, the indium tin oxide resistors are connected in series to measure the resistance value between the electrodes. The specific operation steps are as follows:

[0022] 1.1) Connect the fourth platinum metal electrode D1 and the fifth platinum metal electrode D2 together through the high-temperature resistant lead 3 to form the D electrode;

[0023] 1.2) Connect a constant current source between electrode D and the third platinum metal electrode C, set to I0;

[0024] 1.3) Connect a voltmeter between the first platinum metal electrode A and the second platinum metal electrode B, and measure the voltage output U out =ΔRI0;

[0025] 1.4) Turn on the constant current source, measure the voltage after it stabilizes, and record the voltage data;

[0026] 1.5) Data processing: The voltage-pressure conversion formula is used to convert the voltage signal time history to the measured time history:

[0027] pressure:

[0028] Where: K-coefficient; P-pressure acting on the surface of the sensitive element; A-side length of the square elastic diaphragm of the sensitive element; H-thickness of the square elastic diaphragm of the sensitive element; E-elastic modulus of the material of the square elastic diaphragm of the sensitive element; R P -Indium tin oxide varistor resistance; I0-pressure measurement input constant current source current value; ΔR-resistance change caused by pressure change; ΔR t -Resistance change due to temperature change.

[0029] 2. Temperature test: Use the four-wire method. Set two high-temperature resistant leads 3 in each of the two temperature measurement lead holes, for a total of four temperature measurement leads. The specific steps are as follows:

[0030] 2.1) Connect one of the high-temperature resistant leads 3 through the temperature measurement lead hole to a constant current source and set the current to <5mA;

[0031] 2.2) Connect the other high-temperature resistant lead 3 through the temperature measurement lead hole to the voltmeter;

[0032] 2.3) Turn on the constant current source, measure the voltage after it stabilizes, and record the voltage data;

[0033] 2.4) Data processing: The voltage-temperature conversion formula is used to convert the voltage signal time history to the measured time history:

[0034] The temperature change is measured by measuring the change in the resistance of the platinum thermal resistor film;

[0035] The voltage-temperature conversion formula is used to convert the voltage signal time history to the temperature time history:

[0036] temperature:

[0037] Where: T1-temperature before temperature change; T2-temperature after temperature change; U1-voltage across the platinum thin film thermal resistor before temperature change; U2-voltage across the platinum thin film thermal resistor after temperature change; α R -Resistance temperature coefficient of platinum thin film thermal resistor;

[0038] The voltage-heat flow conversion formula is used to convert the voltage signal time history to the heat flow density time history:

[0039] Heat flow:

[0040] Where: q(t)-heat flow; E0-initial voltage across the platinum thin film thermal resistor; E(t)-voltage across the platinum thin film thermal resistor at time t; α R -Resistance temperature coefficient of platinum thin film thermal resistor; -Comprehensive thermal properties of the substrate material.

[0041] The ceramic base is an alumina ceramic base.

[0042] The beneficial effects of the present invention are as follows: The purpose of the present invention is to provide a high-temperature temperature and pressure in-situ composite measurement sensor that can measure temperature, transient heat flux density and pressure in extreme environments of ultra-high temperature and high Mach number. Its advantages are:

[0043] (1) This high-temperature temperature and pressure in-situ composite measurement sensor integrates a platinum (Pt) thin film thermistor and an indium tin oxide (ITO) varistor to achieve in-situ simultaneous measurement of temperature, transient heat flux density, and pressure.

[0044] (2) This high-temperature temperature and pressure in-situ composite measurement sensor uses platinum (Pt) as the material for the thin film thermistor. Platinum (Pt) has a large and stable temperature coefficient of resistance, a good linear relationship between resistance and temperature, high resistivity, small specific heat capacity, fast response speed, good reproducibility and processability, and good high temperature resistance and oxidation resistance.

[0045] (3) This high-temperature temperature and pressure in-situ composite measurement sensor uses indium tin oxide (ITO) varistors as the sensitive element for pressure testing. As a ceramic material, ITO can be used in temperatures above 1400°C and in harsh environments. ITO itself is an oxide, so long-term exposure to oxygen at high temperatures has little effect on it, and no phase change occurs during the heating process. Varistors made of ITO have the characteristics of high gauge factor (GF) and good stability.

[0046] (4) The sensitive element is packaged in a flip-chip, flush package, and the elastic diaphragm directly senses the temperature and pressure of the medium, avoiding the influence of the airway lumen effect. This test method does not introduce an airway, and the natural frequency is approximately equal to the natural frequency of the sensitive element, which can achieve high-frequency dynamic measurement.

[0047] (5) Due to the mismatch in the coefficient of thermal expansion (CTE) between different materials, large temperature changes can cause thermomechanical stress within the sensor structure. Thermomechanical stress can cause stress release and abnormal reactions in devices under extreme operating conditions, causing permanent mechanical damage to the connection structure. This test method uses glass powder and high-temperature conductive paste as bonding materials. It is made of alumina ceramic, sapphire single crystal, and indium tin oxide (ITO) ceramic materials with similar thermal expansion coefficients. It can effectively control thermomechanical stress and can be used at temperatures up to 1300°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a structural diagram of a high-temperature temperature and pressure in-situ composite measurement sensor;

[0049] Figure 2 This is an exploded diagram of the structure of a high-temperature temperature and pressure in-situ composite measurement sensor;

[0050] Figure 3 This is the structural diagram of the sensitive element;

[0051] Figure 4 Schematic diagram of a four-arm pressure differential bridge supplying power to a constant current source for pressure measurement;

[0052] In the figure: 1-sensitive element; 2-ceramic base; 3-high-temperature lead; A-first platinum metal electrode; B-second platinum metal electrode; C-third platinum metal electrode; D1-fourth platinum metal electrode; D2-fifth platinum metal electrode; E1-first indium tin oxide varistor; E2-second indium tin oxide varistor; E3-third indium tin oxide varistor; E4-fourth indium tin oxide varistor. DETAILED DESCRIPTION

[0053] The embodiments of the present invention are described in detail below in conjunction with the technical solutions and drawings.

[0054] Step 1: Use a CNC machine to process a square countersink, a square slot, and seven lead holes on the alumina ceramic base. The side length of the square countersink is 8250 μm, the side length of the square slot is 5900 μm, and the diameter of the lead hole is 800 μm.

[0055] Step 2: Arrange high-temperature resistant leads Ni20Cr80 in the lead through holes on both sides of the alumina ceramic base, so that the high-temperature resistant leads are tightly connected to the lead through hole walls;

[0056] Step 3: Use a metal mask to magnetron sputter a 500nm thick platinum thin film thermal resistor on the surface of the alumina ceramic base;

[0057] Step 4: Fill the bottom of the sputtered ceramic base with high-temperature repair agent and solidify it. Use the four-wire method to connect the high-temperature resistant leads at the bottom of the ceramic base (one high-temperature resistant lead through-hole uses two red and black leads, a total of four leads) and weld them as a whole. Use heat shrink tubing to encapsulate the lead welding points.

[0058] Step 5: The 100um thick sapphire single crystal film is ultrasonically cleaned with deionized water, then alkaline washed, acid washed, and ultrasonically cleaned with deionized water.

[0059] Step 6: Through the photolithography-sputtering-stripping process, the platinum metal electrode and indium tin oxide varistor are patterned on the elastic diaphragm of the sensitive element;

[0060] Step 7: Place the sensitive element into the square countersunk hole of the alumina ceramic base and align it so that the five pressure measuring lead holes in the middle of the alumina ceramic base expose the high-temperature electrodes on the sensitive element. The square groove faces the center area of ​​the sensitive element. Use high-temperature repair agent to seal the gap and cure it at high temperature.

[0061] Step 8: Use high-temperature conductive paste to sinter and connect the sensitive element and the high-temperature resistant lead wire Ni20Cr80. Fill the bottom of the ceramic base with high-temperature repair agent and solidify it. Use heat shrink tube to encapsulate the lead.

[0062] The method of using the high temperature and pressure in-situ composite measurement sensor is:

[0063] (1) There are five pressure test leads, namely A, B, C, D1, and D2. The circuit uses a semi-enclosed full bridge to convert the change in resistance into a voltage signal. Point D is led out using two leads. When not in use, the bridge arms are connected in series to facilitate the measurement of the resistance value between the leads. The specific operation steps are as follows:

[0064] 1) Connect the fourth platinum metal electrode D1 and the fifth platinum metal electrode D2 together through the high-temperature resistant lead 3 to form the D electrode;

[0065] 2) Connect a constant current source between electrode D and the third platinum metal electrode C, set to I0 = 1mA;

[0066] 3) Connect a voltmeter between the first platinum metal electrode A and the second platinum metal electrode B, and measure the voltage output U out =ΔRI0;

[0067] 4) Turn on the constant current source, measure the voltage after it stabilizes, and record the voltage data.

[0068] 5) Data processing: The voltage-pressure conversion formula is used to convert the voltage signal time history to the measured time history:

[0069] pressure:

[0070] Where: P-pressure acting on the surface of the sensitive element; A-side length of the square diaphragm of the sensitive element; H-thickness of the square diaphragm of the sensitive element; E-elastic modulus of the square diaphragm material of the sensitive element; R P -Indium tin oxide varistor resistance; I0-pressure measurement input constant current source current value.

[0071] (2) The temperature test adopts the four-wire method. Two high-temperature resistant leads 3 are set in each of the two temperature measurement lead holes. The specific operation steps are as follows:

[0072] 1) Connect one of the high-temperature resistant leads 3 through the temperature measurement lead hole to a constant current source and set the current to <5mA;

[0073] 2) Connect the other high-temperature resistant lead 3 through the temperature measuring lead hole to the voltmeter;

[0074] 4) Turn on the constant current source, measure the voltage after it stabilizes, and record the voltage data.

[0075] 5) Data processing: The voltage-temperature conversion formula is used to convert the voltage signal time history to the measured time history:

[0076] Since the resistance value and temperature of the platinum thin film thermal resistor are approximately linearly related, the temperature change can be measured by measuring the change in the resistance value of the platinum thin film thermal resistor.

[0077] The voltage-temperature conversion formula is used to convert the voltage signal time history to the temperature time history:

[0078] temperature:

[0079] Where: T1-temperature before temperature change; T2-temperature after temperature change; U1-voltage across the platinum thin film thermal resistor before temperature change; U2-voltage across the platinum thin film thermal resistor after temperature change; α R -Temperature coefficient of resistance of platinum thin film thermal resistors.

[0080] The voltage-heat flow conversion formula is used to convert the voltage signal time history to the heat flow density time history:

[0081] Heat flow:

[0082] Where: q(t)-heat flow; E0-initial voltage across the platinum thin film thermal resistor; E(t)-voltage across the platinum thin film thermal resistor at time t; α R -Resistance temperature coefficient of platinum thin film thermal resistor; -Comprehensive thermal properties of the substrate material.

Claims

1. A high temperature temperature and pressure in-situ composite measurement sensor, characterized in that: The high-temperature temperature and pressure in-situ composite measurement sensor comprises a sensitive element (1), a ceramic base (2) and a high-temperature resistant lead wire (3); the sensitive element (1) is an elastic diaphragm provided with a high-temperature resistant electrode, which comprises five platinum metal electrodes and four indium tin oxide varistors, all of which are sputtered on the back of the elastic diaphragm; the four indium tin oxide varistors with equal resistance values ​​are connected to form a Wheatstone bridge; the ceramic base (2) is provided with a square countersunk hole, a square groove and seven lead through holes; a square groove is arranged in the square countersunk hole, and the square groove faces the central area of ​​the sensitive element (1) as a deformation space of the elastic diaphragm of the sensitive element; the five lead through holes are pressure measurement lead through holes, which are arranged at The square countersunk hole is on two opposite sides; the remaining two lead through holes are metallized temperature measurement lead through holes, which are arranged outside the square countersunk hole, and the two temperature measurement lead through holes are connected by an arc-shaped platinum thin film thermal resistor, and the sub-micron-level thick platinum thin film thermal resistor is formed on the surface of the ceramic base (2) by magnetron sputtering; the sensitive element (1) is packaged at high temperature using a flip-chip leadless process, the sensitive element (1) is placed in the square countersunk hole of the ceramic base (2) and aligned, and the five platinum metal electrodes on the sensitive element (1) are exposed through the pressure measurement lead through holes of the ceramic base (2); a high-temperature repair agent is used to seal the gap between the sensitive element (1) and the ceramic base (2) and cure at high temperature; The high temperature resistant lead wire (3) is connected to the platinum metal electrode through the pressure measuring lead through hole of the ceramic base (2), and the two are sintered at high temperature using a high temperature conductive paste to achieve electrical connection between the sensitive element signal and the outside world; when the medium pressure acts on the elastic diaphragm of the sensitive element (1), the pressure on the front and back sides of the elastic diaphragm is unequal, and the elastic diaphragm is deformed; The two indium tin oxide varistors at the edge of the elastic diaphragm are compressed, and their resistance decreases; the two indium tin oxide varistors at the center of the elastic diaphragm are pulled, and their resistance increases, causing the Wheatstone bridge to lose balance; an excitation power supply is applied to the Wheatstone bridge to obtain an output voltage proportional to the measured pressure, thereby measuring the pressure characteristics of the measured structure; The platinum thin film thermal resistor is led out through the temperature measurement lead through-hole of the ceramic base using the four-wire method. A constant current is loaded at both ends of the platinum thin film thermal resistor, and a voltage that is linearly related to the resistance is obtained at both ends. When the temperature changes, the resistance value changes accordingly, and the voltage at both ends of the platinum thin film thermal resistor changes. The change in resistance is measured by measuring the change in voltage. Based on the one-dimensional semi-infinite body heat conduction theory, the transient heat flux density value is calculated using the measured voltage value.

2. The high-temperature temperature and pressure in-situ composite measurement sensor according to claim 1, characterized in that: The platinum metal electrode includes a first platinum metal electrode (A), a second platinum metal electrode (B), a third platinum metal electrode (C), a fourth platinum metal electrode (D1) and a fifth platinum metal electrode (D2); the indium tin oxide varistor includes a first indium tin oxide varistor (E1), a second indium tin oxide varistor (E2), a third indium tin oxide varistor (E3) and a fourth indium tin oxide varistor (E4); the second indium tin oxide varistor (E2) and the third indium tin oxide varistor (E3) are located at the center of the elastic mold, and the first indium tin oxide varistor (E1), the fourth indium tin oxide varistor (E4) are located at the center of the elastic mold. The varistor (E4) is located at the edge of the elastic mold; the first indium tin oxide varistor (E1) is respectively connected to one end of the second platinum metal electrode (B) and one end of the third platinum metal electrode (C); the second indium tin oxide varistor (E2) is respectively connected to one end of the first platinum metal electrode (A) and the other end of the third platinum metal electrode (C); the third indium tin oxide varistor (E3) is respectively connected to the other end of the second platinum metal electrode (B) and one end of the fourth platinum metal electrode (D1); the fourth indium tin oxide varistor (E4) is respectively connected to the other end of the first platinum metal electrode (A) and one end of the fifth platinum metal electrode (D2).

3. The high temperature and pressure in-situ composite measurement sensor according to claim 1 or 2, characterized in that: The elastic diaphragm of the sensitive element (1) is one of a single crystal sapphire sheet, an aluminum oxide sheet, and a zirconium oxide sheet.

4. The high-temperature temperature and pressure in-situ composite measurement sensor according to claim 3, characterized in that: The excitation power supply is a constant voltage power supply or a constant current power supply.

5. A method for preparing a high-temperature temperature and pressure in-situ composite measurement sensor, characterized in that: The steps include: Step 1: Use CNC machine tools to process the square countersunk holes, square grooves and seven lead holes of the ceramic base; Step 2: arranging high temperature resistant leads (3) in the lead through holes on both sides of the ceramic base, so that the high temperature resistant leads (3) are tightly connected to the wall of the lead through hole; Step 3: Use a metal mask to magnetron sputter a layer of sub-micron-thick platinum thin film thermal resistor on the surface of the ceramic base; Step 4: Fill the bottom of the sputtered ceramic base with a high-temperature repair agent and solidify it, connect the high-temperature resistant lead (3) of the temperature measuring lead through hole at the bottom of the ceramic base (2) with a four-wire method and weld it as a whole, and use a heat shrink tube to seal the welding point; Step 5: Use deionized water ultrasonic cleaning, alkali cleaning, acid cleaning, and deionized water ultrasonic cleaning to obtain a clean sapphire single crystal film; Step 6: Through the process of photolithography-sputtering-stripping, the platinum metal electrode and indium tin oxide varistor are patterned on the elastic membrane of the sensitive element; Step 7: Place the sensitive element (1) into the square countersunk hole of the ceramic base and align it so that the five pressure measuring lead through holes in the middle of the ceramic base expose the platinum metal electrodes on the sensitive element, and the square groove faces the center area of ​​the sensitive element. Use a high-temperature repair agent to seal the gap and cure it at high temperature. Step 8: Use high temperature conductive paste to sinter the high temperature resistant lead (3) in the pressure measuring lead through hole, fill the bottom of the ceramic base (2) with high temperature repair agent and solidify it, and use heat shrink tube to encapsulate the high temperature resistant lead (3).

6. A method for using a high-temperature temperature and pressure in-situ composite measurement sensor, characterized in that: The steps include:

1. Pressure test; each of the five pressure measuring lead through holes is provided with a high temperature resistant lead (3), for a total of five pressure measuring leads; the circuit adopts a semi-enclosed full bridge form to convert the change of resistance into a voltage signal, and point D is led out using two leads, which are respectively connected to the fourth platinum metal electrode (D1) and the fifth platinum metal electrode (D2); when the pressure test is not performed, the indium tin oxide resistors are connected in series to measure the resistance value between the electrodes; the specific operation steps are as follows: 1.1) Connecting the fourth platinum metal electrode (D1) and the fifth platinum metal electrode (D2) together through a high temperature resistant lead wire (3) to form a D electrode; 1.2) Connect a constant current source between the D electrode and the third platinum metal electrode (C) and set it to I0; 1.3) Connect a voltmeter between the first platinum metal electrode (A) and the second platinum metal electrode (B) to measure the voltage output Y. out =ΔRI0; 1.4) Turn on the constant current source, measure the voltage after it stabilizes, and record the voltage data; 1.5) Data processing: The voltage-pressure conversion formula is used to convert the voltage signal time history to the measured time history: pressure: Where: K-factor; P-pressure acting on the surface of the sensitive element; A-side length of the square elastic diaphragm of the sensitive element; H-thickness of the square elastic diaphragm of the sensitive element; E- elastic modulus of the square elastic diaphragm material of the sensitive element; R P -Indium Tin Oxide Varistor Resistance; I0-current value of constant current source for pressure measurement input; ΔR-resistance change caused by pressure change; 2. Temperature test: Using the four-wire method, two high-temperature resistant leads (3) are set in each of the two temperature measuring lead holes, for a total of four temperature measuring leads. The specific operation steps are as follows: 2.1) Connect one of the high temperature resistant leads (3) through the temperature measuring lead hole to a constant current source and set the current to <5mA; 2.2) Connect another high temperature resistant lead (3) through the temperature measuring lead hole to the voltmeter; 2.3) Turn on the constant current source, measure the voltage after it stabilizes, and record the voltage data; 2.4) Data processing: The voltage-temperature conversion formula is used to convert the voltage signal time history to the measured time history: The temperature change is measured by measuring the change in resistance of platinum thin film thermal resistor; The voltage-temperature conversion formula is used to convert the voltage signal time history to the temperature time history: temperature: Where: T1-temperature before temperature change; T2-temperature after temperature change; U1- voltage across the platinum film thermal resistor before temperature changes; U2- voltage across the platinum film thermal resistor after temperature changes; α R -Resistance temperature coefficient of platinum thin film thermal resistor; The voltage-heat flow conversion formula is used to convert the voltage signal time history to the heat flow density time history: Heat flow: Where: q(t)-heat flow; E0-initial voltage across the platinum thin film thermal resistor; E(t)-the voltage across the platinum thin film thermal resistor at time t; α R -Resistance temperature coefficient of platinum thin film thermal resistor; -Comprehensive thermal characteristic parameters of the substrate material.

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