Application of polymer precursor ceramic temperature sensor in low-temperature environment

Abstract

The invention discloses application of a polymer precursor ceramic temperature sensor in a low-temperature environment, and some specific types of polymer precursor ceramics have good low-temperature temperature-resistance characteristics, so that the sensor can realize signal conversion in the low-temperature environment; the polymer precursor ceramic temperature sensors show good low-temperature corrosion resistance, repeatability and stability, and can be suitable for temperature monitoring in low-temperature extreme environments such as aerospace, national defense, lunar probes and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of temperature sensors, and particularly relates to the application of a polymer precursor ceramic temperature sensor in a low-temperature environment. Background Art

[0002] With the development of science and technology, the detection technology for low-temperature environments has been continuously expanded in applications such as national defense, deep space exploration, biology, medicine, and energy, and the demand for low-temperature sensors has also been increasing day by day. Especially in the field of deep space exploration, along with the extreme environments of low temperature, electromagnetic interference, and strong radiation, temperature sensors are required to have better low-temperature environmental weather resistance and anti-interference capabilities. Therefore, it is of great significance to develop low-temperature temperature sensors with good low-temperature weather resistance, strong anti-interference ability, and fast response speed.

[0003] Currently, the existing low-temperature sensors include three categories: metal-based, ceramic-based, and fiber-optic types. However, metal-based components usually have a large volume and a long response time, and cannot maintain the sensitivity of dynamic monitoring. They are not suitable for small spaces, real-time temperature changes, and temperature measurements below 20K. For example, it is known that below approximately 20K, the resistance of a metal resistance temperature sensor only remains the residual resistance, and has little relationship with temperature and cannot be used to measure temperature; the sensitivity of a platinum resistance temperature sensor drops very quickly at 20K (refer to Document 1: Wu Hao, Zhang Huabiao, Xu Lingshun, et al. Application Progress of Low-Temperature Sensors [J]. Cryogenics and Superconductivity, 2013, 41(12): 10-14+58. DOI: 10.16711 / j.1001-7100.2013.12.003). Ceramic-based sensors have strong corrosion resistance and radiation resistance, but their preparation process is complex and the production cost is high. For example, Chinese Patent Application CN202211341527.1 discloses a highly sensitive low-temperature sensor based on zinc oxide micro-rods and its preparation method, which has a complex preparation process, high preparation difficulty, and poor weather resistance when encapsulated with epoxy resin. Fiber-optic sensors have poor anti-bending performance, are easily affected by external environmental factors, have complex temperature decoupling, and the equipment for cooperating with decoupling has a large volume. For example, Chinese Patent Application CN200780031576.2 discloses a grating temperature sensor, which requires multiple complex systems such as an optical frequency difference adjustment unit, a light source system, a spectrum measurement unit, a temperature calculation unit, and a correction unit, as well as decoupling equipment and components, and is not suitable for temperature measurement in scenarios such as aerospace. Due to their respective disadvantages, these three types of existing sensors are not suitable for use in extreme low-temperature environments such as deep space exploration. Therefore, it is of great significance to research and develop new sensors that can meet the strategic needs of the country's future deep space exploration and are suitable for extreme low-temperature environments. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide the application of a polymer precursor ceramic low-temperature temperature sensor in an extreme low-temperature environment.

[0005] The technical solution adopted by the present invention is as follows:

[0006] Application of a polymer precursor ceramic temperature sensor in a low-temperature environment, where the low-temperature environment ranges from 1.25 K to 300 K.

[0007] The polymer precursor ceramic temperature sensor includes a probe and an electrode, and the electrode is connected to the probe.

[0008] The material of the probe is polymer precursor ceramic.

[0009] The polymer precursor ceramic is one of SiCN, SiBCN, SiAlBCN, and SiAlCN polymer precursor ceramics.

[0010] The electrode is one of gold wire, silver wire, copper wire, or carbon fiber.

[0011] The electrode and the probe are connected by an adhesive, brazing, or one-step sintering method.

[0012] When connected by an adhesive, the adhesive is nano silver paste, metal conductive silica gel, or graphite gel; when connected by brazing, the brazing solder is metal indium.

[0013] The preparation steps of the polymer precursor ceramic temperature sensor include:

[0014] 1) Under the protection of inert gas, mix the liquid ceramic precursor with the curing agent and heat it up to dissolve into a precursor solution;

[0015] 2) Pour the precursor solution obtained in 1) into a mold, and demold after curing;

[0016] 3) Under the protection of inert gas, pyrolyze the cured product obtained in step 2) at high temperature to obtain a polymer precursor ceramic probe;

[0017] 4) Connect the probe and the electrode to obtain the polymer precursor ceramic temperature sensor.

[0018] Polymer precursor ceramic is a new type of ceramic formed by pyrolytic conversion of polymer precursors into ceramics. Compared with traditional ceramics, polymer precursor ceramics have excellent properties, such as high-temperature thermal stability, high-temperature semiconductor characteristics, high creep resistance, and large piezoresistive characteristics. Polymer precursor ceramic temperature sensors have been widely used in the field of high-temperature environment sensors due to their excellent high-temperature stability. However, the application of polymer precursor ceramics in low-temperature environments is still unknown.

[0019] When researching polymer precursor ceramics temperature sensors, the inventors of the present invention found that some polymer precursor ceramics exhibit good temperature-resistance characteristics in a low-temperature environment (1.25K - 300K), ensuring that the sensor can achieve signal conversion at low temperatures. In addition, the polymer precursor ceramics temperature sensor in the present invention has the characteristics of small size, high precision, fast response, long life, good stability, etc., and can be suitable for temperature monitoring in low-temperature extreme environments such as aerospace, national defense, and lunar probes. In addition, due to the liquid characteristics of the polymer precursor in the present invention, forming methods such as microfabrication, casting, 3D printing, etc. can be used to efficiently, quickly, and low-cost prepare sensors with specific shapes and sizes that can meet the needs of different scenarios. Description of the Drawings

[0020] Figure 1 It is a graph showing the relationship between the output voltage and temperature of the SiCN temperature sensor.

[0021] Figure 2 It is a graph showing the relationship between the output voltage and temperature of the SiBCN temperature sensor.

[0022] Figure 3 It is a graph showing the relationship between the output voltage and temperature of the SiAlCN temperature sensor.

[0023] Figure 4 It is a graph showing the relationship between the output voltage and temperature of the SiAlBCN temperature sensor.

[0024] Figure 5 It is a comparison graph of the response speed of the output voltage of the SiBCN temperature sensor and the T-type thermocouple.

[0025] Figure 6 It is a voltage-temperature cycle response graph of the SiBCN temperature sensor.

[0026] Figure 7 It is a stability graph of the SiBCN temperature sensor at 250K.

[0027] Figure 8 It is a stability graph of the SiBCN temperature sensor at 230K.

[0028] Figure 9 It is a stability graph of the SiBCN temperature sensor at 80K.

[0029] Figure 10 It is a temperature curve of the SiBCN temperature sensor in the temperature range of 1.25 - 300K.

[0030] Figure 11 It is a temperature-resistance cycle response curve of the SiBCN temperature sensor in the temperature range of 5 - 20K.

[0031] Figure 12It is the stability diagram of the SiBCN temperature sensor at 20K, 50K, 100K, 150K, 200K, 250K, and 300K.

[0032] The following examples are used to illustrate the specific implementation manners of the present invention. However, the following examples are only used to illustrate the present invention in detail and do not limit the scope of the present invention in any way.

[0033] The T-type thermocouple used in the following examples is Kepsen, KPS-T-T-24-3*30*100-LK.

[0034] Example 1:

[0035] A SiBCN polymer precursor ceramic temperature sensor includes a probe and an electrode. The electrode is connected to the probe by indium solder, and the electrode is a copper wire. The preparation method is as follows:

[0036] The preparation method of the SiBCN polymer precursor ceramic temperature sensor includes the following steps: (1) Pour 1 g of organic polyborosilazane (PSNB) into a mold, place it in a vacuum drying oven, and carry out polymerization and cross-linking reactions at 120 °C for 4 h to obtain a green body of the probe; (2) Under argon protection, pyrolyze the green body of the probe at 1400 °C for 4 h (heating rate 0.5 °C / min) to obtain the probe; (3) Connect the copper wire to the probe with indium solder to obtain the SiBCN polymer precursor ceramic temperature sensor.

[0037] Example 2

[0038] A SiCN polymer precursor ceramic temperature sensor includes a probe and an electrode. The electrode is connected to the probe by a binder, and the electrode is a carbon fiber. The probe is made of the following raw materials by mass: 4.775 g of organic polysilazane (PSN), 0.225 g of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819).

[0039] The preparation method of the SiCN polymer precursor ceramic temperature sensor includes the following steps: (1) Add organic polysilazane and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819) to a brown scintillation vial, then place the scintillation vial in an oil bath and heat it to 90 °C, and carry out magnetic stirring for 60 min under nitrogen protection to obtain a mixture; (2) Pour the mixture obtained in step (1) into a mold fixed with carbon fiber, and then carry out polymerization and cross-linking reactions under 400 nm UV light irradiation for 10 min to obtain a green body of the probe with a carbon fiber electrode inserted; (3) Bury the green body of the probe in carbon powder and pyrolyze it at 1000 °C for 4 h (heating rate 0.5 °C / min) under nitrogen protection to obtain the SiCN polymer precursor ceramic temperature sensor.

[0040] Example 3

[0041] A SiAlBCN polymer precursor ceramic temperature sensor, comprising a probe and an electrode. The electrode is connected to the probe by a metal conductive silica gel, the electrode is a gold wire, and the probe is made of raw materials with the following masses: 4.65 g of organopolysilazane (PSNB), 0.1 g of dicumyl peroxide, and 0.25 g of aluminum isopropoxide.

[0042] A preparation method of a SiAlBCN polymer precursor ceramic temperature sensor, comprising the following steps: (1) Add organopolysilazane, aluminum isopropoxide, and dicumyl peroxide into a round-bottom flask equipped with a magnetic stir bar, then place the flask in an oil bath and heat it to 90 °C, and carry out magnetic stirring for 120 min under nitrogen protection; (2) Pour the mixture obtained in step (1) into a mold in an oxygen-isolated environment in a glove box, and place it on a heating platform to carry out polymerization and cross-linking reactions at 140 °C for 4 h to obtain a green body of the probe; (3) Drill two holes in the green body of the probe; (4) Pyrolyze the green body of the probe at 1300 °C for 4 h (heating rate 0.5 °C / min) under argon protection to obtain the probe; (5) Connect a gold wire to the probe using a metal conductive silica gel to obtain a SiAlBCN polymer precursor ceramic temperature sensor.

[0043] Example 4

[0044] A SiAlCN polymer precursor ceramic temperature sensor, comprising a probe and an electrode. The electrode is connected to the probe by a metal conductive silica gel, the electrode is a gold wire, and the probe is made of raw materials with the following masses: 4.65 g of organopolysilazane (PSN), 0.1 g of dicumyl peroxide, and 0.25 g of aluminum isopropoxide.

[0045] A preparation method of a SiAlCN polymer precursor ceramic temperature sensor, comprising the following steps: (1) Add organopolysilazane, aluminum isopropoxide, and dicumyl peroxide into a round-bottom flask equipped with a magnetic stir bar, then place the flask in an oil bath and heat it to 90 °C, and carry out magnetic stirring for 120 min under nitrogen protection; (2) Pour the mixture obtained in step (1) into a mold in an oxygen-isolated environment in a glove box, and place it on a heating platform to carry out polymerization and cross-linking reactions at 140 °C for 4 h to obtain a green body of the probe; (3) Drill two holes in the green body of the probe; (4) Pyrolyze the green body of the probe at 1300 °C for 4 h (heating rate 0.5 °C / min) under argon protection to obtain the probe; (5) Connect a gold wire to the probe using a metal conductive silica gel to obtain a SiAlCN polymer precursor ceramic temperature sensor.

[0046] Effect Experiment 1:

[0047] In this experiment, a Labview system was used to collect the temperature signals output by the circuit, and a digital multimeter was used to collect the output voltage or resistance signals. Among them, the Labview system mainly consists of a DAQ system for signal acquisition and an acquisition module. At the same time, a Wheatstone bridge was used to connect the sensor to improve the sensitivity during measurement. The thermocouple for real-time temperature monitoring is a Type T thermocouple, and the acquisition rate of temperature and voltage is once per second.

[0048] The response relationship between voltage and temperature of the polymer precursor ceramic temperature sensors obtained in Examples 1-4 is as follows Figures 1-4 . From Figures 1-4 it can be seen that as the temperature of the sensor increases, the output voltage gradually decreases, indicating that the temperature sensors of Examples 1-4 exhibit good temperature-resistance effects at low temperatures.

[0049] Effect Experiment Two:

[0050] The comparison chart of the response rates obtained when the SiBCN polymer precursor ceramic temperature sensor obtained in Example 1 and a traditional Type T thermocouple were inserted into liquid nitrogen at the same time is as Figure 5 shown. From Figure 5 it can be seen that at the beginning, as the temperature decreases, the response rate of the Type T thermocouple to temperature is relatively slow, and the output voltage of the sensor in Example 1 increases rapidly and reaches a stable value; this shows that the response rate of the temperature sensor prepared in Example 1 is higher than that of the Type T thermocouple, and the real-time temperature monitoring is faster.

[0051] Effect Experiment Three:

[0052] The SiBCN polymer precursor ceramic temperature sensor obtained in Example 1 was subjected to a voltage-temperature cycle experiment, and the response curve obtained is as Figure 6 shown. From Figure 6 it can be seen that after the temperature sensor has experienced multiple temperature cycles, the output voltage cycle can still maintain the same change trend, indicating that the temperature sensor has good repeatability.

[0053] Effect Experiment Four:

[0054] The SiBCN polymer precursor ceramic temperature sensor obtained in Example 1 was subjected to a stability experiment at different temperatures, and the response curve obtained is as Figures 7-9 shown. From Figures 7-9 it can be seen that the sensor was kept warm and continuously monitored for several hours at 250K, 230K, and 80K respectively, and the output voltage remained basically unchanged, and Figures 7-9 all the collected data came from a single sensor sample, indicating that the sensor can maintain stability for a long time and work properly at different low temperatures, indicating that the sensor has good low-temperature stability.

[0055] Effect Experiment Five:

[0056] Figure 10 The curve of the resistance change with temperature of the SiBCN polymer precursor ceramic temperature sensor obtained in Example 1 within the temperature range of 1.25 to 300 K is shown. Figure 10 It can be seen that its resistance increases steadily with the increase of temperature, indicating that the SiBCN polymer precursor ceramic temperature sensor of Example 1 exhibits good temperature-resistance effect at ultra-low temperature and wide temperature range.

[0057] Effect Experiment Six

[0058] The SiBCN polymer precursor ceramic temperature sensor obtained in Example 1 was subjected to an ultra-low temperature temperature-resistance cycle experiment, and the obtained response curve is as Figure 11 shown. Figure 11 It can be seen that within the temperature range of 5 - 20 K, the resistance of the sensor changes highly consistently with temperature during 10 cycles, indicating that the temperature sensor has excellent repeatability at ultra-low temperature.

[0059] Effect Experiment Seven

[0060] The SiBCN polymer precursor ceramic temperature sensor of Example 1 was subjected to a stability experiment at different temperatures, and the obtained response curve is as Figure 12 shown. Figure 12 It can be seen that when the sensor is kept warm and continuously monitored for a period of time at 20 K, 50 K, 100 K, 150 K, 200 K, 250 K, and 300 K respectively, the output resistance remains basically unchanged, indicating that the sensor can maintain stability for a long time at different low temperatures and can work normally, indicating that the sensor has good low-temperature stability.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention shall be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims

1. Application of polymer precursor ceramic temperature sensor in low temperature environment, characterized by: The low temperature environment ranges from 1.25K to 300K.

2. The use according to claim 1, characterized in that: The polymer precursor ceramic temperature sensor comprises a probe and an electrode, wherein the electrode is connected to the probe.

3. The use according to claim 2, characterized in that: The material of the probe is polymer precursor ceramic.

4. The use according to claim 2, characterized in that: The electrode is one of gold wire, silver wire, copper wire or carbon fiber.

5. The use according to claim 2, characterized in that: The electrode and the probe are connected by using an adhesive, brazing or a one-step sintering method.

6. The use according to claim 5, characterized in that: When an adhesive is used for connection, the adhesive is nano silver paste, metal conductive silicone or graphite glue; when brazing is used for connection, the brazing solder is metal indium.

7. The use according to claim 1 or 2, characterized in that: The preparation steps of the polymer precursor ceramic temperature sensor include: 1) Under the protection of an inert gas, a liquid ceramic precursor and a curing agent are mixed to prepare a precursor solution; 2) pouring the precursor solution obtained in 1) into a mold, and demoulding after curing; 3) Under the protection of inert gas, the solidified product obtained in step 2) is pyrolyzed at high temperature to obtain a polymer precursor ceramic probe; 4) Connect the probe to the electrode to obtain the polymer precursor ceramic temperature sensor.

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