Thin film temperature sensor, preparation method thereof and temperature field measurement method

Abstract

The invention relates to a thin film temperature sensor, a preparation method thereof and a temperature field measurement method, and belongs to the technical field of temperature sensors. The thin film temperature sensor comprises SiBCN ceramic and a filler. The thin film temperature sensor provided by the invention is high in density, good in surface quality, strong in bonding capacity with a substrate and not easy to fall off, has obvious semiconductor characteristics in the range of 0-800 DEG C, and can meet the temperature field measurement requirements of the surfaces of workpieces which are made of different materials and are of plane, curved surface and special-shaped structures under high-temperature working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature sensors, and in particular to a thin film temperature sensor and a preparation method thereof and a temperature field measurement method. Background Art

[0002] Aircraft engines, large gas turbines, hypersonic vehicles, rocket thrusters and other equipment that often work in "extreme environments" such as high temperature, high corrosion, high airflow impact, and high loads have abnormally high temperatures on the surface of high-temperature hot-end components, which can easily cause irreversible damage to the equipment. Therefore, it is of great significance to monitor the surface temperature field distribution of high-temperature hot-end components.

[0003] However, traditional temperature sensors often require drilling holes in the workpiece surface when used, which not only causes irreversible intrusion damage to its structure, but also makes it difficult to fit perfectly with the workpiece surface, resulting in low temperature measurement accuracy; more importantly, traditional temperature sensors can only achieve one-dimensional point temperature measurement, and cannot achieve temperature field distribution measurement at levels higher than two dimensions.

[0004] Therefore, there is an urgent need to provide a temperature sensor that can measure the surface temperature field of a high-temperature hot end. Summary of the invention

[0005] In response to one or more technical problems existing in the prior art, the present invention provides a thin film temperature sensor, a preparation method thereof, and a temperature field measurement method. The thin film temperature sensor provided by the present invention has high density, good surface quality, strong bonding ability with the substrate, is not easy to fall off, and has obvious semiconductor properties in the range of 0 to 800°C. It can meet the temperature field measurement requirements of the surfaces of workpieces with flat surfaces, curved surfaces, and special-shaped structures of different materials under high temperature conditions.

[0006] In a first aspect, the present invention provides a thin film temperature sensor, which has semiconductor characteristics; the thin film temperature sensor comprises SiBCN ceramics and filler.

[0007] In a second aspect, the present invention provides a method for preparing the thin film temperature sensor according to the first aspect, the method comprising:

[0008] S1. mixing polyborosilazane, a filler and an organic solvent to obtain a film slurry;

[0009] S2. Spraying the thin film slurry onto the preheated substrate, and obtaining a thin film temperature sensor through solidification and cracking.

[0010] Preferably, based on the total weight of the polyborosilazane and the filler, the polyborosilazane accounts for 50 to 70 wt %, and the active filler accounts for 30 to 50 wt %.

[0011] Preferably, the organic solvent accounts for 40-60% of the total mass of the polyborosilazane and filler.

[0012] Preferably, the filler is selected from at least one of an active filler and an inert filler; the active filler is preferably at least one of Al, B, Cr, W, Nb, Mo, Si, Ti, V, CrSi2, MoSi2, TiSi2, TiB2; the inert filler is preferably at least one of SiO2, Al2O3, Zr2O3, Y2O3, SiC, B4C, Si3N4, BN; and / or

[0013] The organic solvent is xylene.

[0014] Preferably, the preheating temperature is 80-100°C.

[0015] Preferably, the curing is carried out in a flowing argon atmosphere at a curing temperature of 300 to 400° C.; and / or

[0016] The cracking is carried out under a flowing argon atmosphere at a cracking temperature of 1000-1200°C.

[0017] The present invention provides a temperature field measurement method in a third aspect, which is implemented by the thin film temperature sensor described in the first aspect and comprises the following steps:

[0018] A thin film temperature sensor is prepared on the surface of the workpiece to be measured, and a plurality of electrodes are connected at the boundary position of the thin film temperature sensor to obtain a voltage distribution at the boundary of the thin film temperature sensor under a preset current;

[0019] Based on the voltage distribution at the boundary of the thin film temperature sensor under the preset current, the resistance distribution of each area of ​​the thin film temperature sensor is obtained;

[0020] Based on the resistance distribution of each area of ​​the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained.

[0021] Preferably, based on the voltage distribution at the boundary of the thin film temperature sensor under a preset current, the resistance distribution of each area of ​​the thin film temperature sensor is obtained, including:

[0022] Based on the voltage distribution at the boundary of the thin film temperature sensor under the preset current, the voltage distribution of each area of ​​the thin film temperature sensor is obtained;

[0023] Based on the voltage distribution of each area of ​​the thin film temperature sensor, the resistance distribution of each area of ​​the thin film temperature sensor is obtained.

[0024] Preferably, based on the resistance distribution of each area of ​​the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained, including:

[0025] Based on the resistance distribution of each area of ​​the thin film temperature sensor and the reference resistance of the thin film temperature sensor, and combined with the RT characteristic curve of the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained; the reference resistance is the resistance of the thin film temperature sensor at the reference temperature.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects:

[0027] The thin film temperature sensor provided by the present invention has high density, good surface quality, strong ability to combine with the substrate, is not easy to fall off, and has obvious semiconductor characteristics within the range of 0 to 800°C.

[0028] The present invention can suppress and compensate for the volume shrinkage of the ceramic precursor during the cracking process by adding fillers to the ceramic precursor polyborosilazane, thereby greatly improving the density and surface quality of the material. The substrate is preheated and heat-insulated before spraying the slurry, so that the slurry can be quickly attached to the surface of the substrate after spraying, the solvent evaporates quickly, and the thin film precursor can be quickly and firmly combined with the heterogeneous substrate. After curing and cracking, a high-quality thin film temperature sensor is obtained, which solves the problem of weak bonding and cracking at the interface due to the difference between the film and the substrate.

[0029] The present invention first prepares a thin film temperature sensor on the surface of the workpiece to be measured, and by connecting multiple electrodes in different areas of the surface of the thin film temperature sensor, the voltage distribution of different areas of the surface of the thin film temperature sensor is obtained under a preset current, and then the resistance distribution of different areas of the surface of the thin film temperature sensor is obtained. Finally, in combination with the semiconductor characteristics of the thin film temperature sensor, according to the RT characteristic curve of the thin film temperature sensor, the temperature distribution of different areas of the surface of the thin film temperature sensor can be obtained, and then the temperature field distribution of the surface of the workpiece to be measured can be obtained. The temperature field measurement method provided by the present invention is based on the semiconductor characteristics of the thin film temperature sensor, and there is no requirement for the material and shape of the workpiece. It only needs to prepare the thin film temperature sensor on the surface of the workpiece to be measured to measure the temperature field distribution (surface temperature measurement) of the surface of the workpiece to be measured in real time, which can meet the temperature field measurement requirements of the surface of the workpiece of different materials, planes, curved surfaces, and special-shaped structures under high temperature conditions, and provides a means and method with great application potential for in-situ online monitoring of the temperature field of high-temperature hot end components such as aircraft engines, large gas turbines, hypersonic aircraft, and rocket thrusters. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 is a physical diagram of a thin film temperature sensor provided in Example 1 of the present invention;

[0032] Figure 2 is an XRD diagram of the thin film temperature sensor provided in Example 1 of the present invention;

[0033] Figure 3 is a curve diagram showing the change in resistance of the thin film temperature sensor provided in Example 1 of the present invention with respect to temperature;

[0034] Figure 4 This is a physical diagram of the distribution of electrodes on the surface of a thin film temperature sensor provided by the present invention;

[0035] Figure 5 It is a test diagram of the distribution of electrodes on the surface of a thin film temperature sensor and the output voltage between the electrodes provided by the present invention;

[0036] Figure 6 is a distribution diagram of output voltages of the thin film temperature sensor provided in Example 1 of the present invention at different temperatures;

[0037] Figure 7 is a resistance distribution cloud diagram of the thin film temperature sensor provided in Example 1 of the present invention at different temperatures;

[0038] Figure 8 This is a microscopic picture of a thin film temperature sensor made of a SiBCN ceramic matrix according to the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] In a first aspect, the present invention provides a thin film temperature sensor, which has semiconductor characteristics; the thin film temperature sensor comprises SiBCN ceramics and filler.

[0041] The thin film temperature sensor provided by the present invention has high density, good surface quality, strong ability to combine with the substrate, is not easy to fall off, and has obvious semiconductor characteristics within the range of 0 to 800°C.

[0042] In a second aspect, the present invention provides a method for preparing the thin film temperature sensor according to the first aspect, the method comprising:

[0043] S1. mixing polyborosilazane, a filler and an organic solvent to obtain a film slurry;

[0044] S2. Spraying the thin film slurry onto the preheated substrate, and obtaining a thin film temperature sensor through solidification and cracking.

[0045] The present invention can suppress and compensate for the volume shrinkage of the ceramic precursor during the cracking process by adding fillers to the ceramic precursor polyborosilazane, thereby greatly improving the density and surface quality of the material. The substrate is preheated and heat-insulated before spraying the slurry, so that the slurry can be quickly attached to the surface of the substrate after spraying, the solvent evaporates quickly, and the thin film precursor can be quickly and firmly combined with the heterogeneous substrate. After curing and cracking, a high-quality thin film temperature sensor is obtained, which solves the problem of weak bonding and cracking at the interface due to the difference between the film and the substrate. Furthermore, the inventors found that if active fillers are not added, the obtained film is prone to cracking during the cracking process. At the same time, because the initial resistance of the material is too large, there is no response when the current is passed, and the temperature measurement requirements cannot be met.

[0046] According to some preferred embodiments, based on the total mass of the polyborosilazane and the filler, the polyborosilazane accounts for 50-70wt% (for example, 50wt%, 55wt%, 60wt%, 65wt% or 70wt%), and the active filler accounts for 30-50wt% (for example, 30wt%, 35wt%, 40wt%, 45wt% or 50wt%).

[0047] According to some preferred embodiments, the organic solvent accounts for 40-60% (eg, 40%, 45%, 50%, 55% or 60%) of the total mass of the polyborosilazane and the filler.

[0048] The inventors found that if the amount of active filler is too small, the viscosity of the slurry is too low, and it cannot form effective adhesion on the surface of the substrate after spraying; if the amount of active filler is too high, it will cause uneven dispersion of the filler and easy clogging of the nozzle. Even if it can be sprayed out, due to the excessive amount of filler, some small particles will exist on the surface of the film after curing, becoming a crack initiation source and causing the film to crack and peel off. In addition, too little organic solvent will cause uneven dispersion of the filler and excessive viscosity of the slurry, making it difficult to spray; too much organic solvent will cause the slurry to be too thin and the viscosity to be too low, making it difficult to form a dense film. Therefore, the present invention controls the amount of polyborosilazane, active filler and organic solvent within the above range to ensure that a thin film sensor with excellent performance is obtained.

[0049] According to some preferred embodiments, the filler is selected from at least one of an active filler and an inert filler; the active filler is preferably at least one of Al, B, Cr, W, Nb, Mo, Si, Ti, V, CrSi2, MoSi2, TiSi2, and TiB2; the inert filler is preferably at least one of SiO2, Al2O3, Zr2O3, Y2O3, SiC, B4C, Si3N4, and BN. The present invention can select the type of filler according to the needs.

[0050] According to some preferred embodiments, the organic solvent is xylene.

[0051] According to some preferred embodiments, the temperature of the preheat treatment is 80-100°C (for example, it can be 80°C, 85°C, 90°C, 95°C or 100°C). The present invention performs preheating and heat preservation treatment on the substrate before spraying, so that the slurry can be quickly attached to the surface of the substrate after spraying, the solvent evaporates quickly, and the film obtained after curing and cracking is of good quality and not prone to cracking. The inventors found that when the substrate at room temperature (the substrate that has not been preheated) is directly sprayed, the film obviously falls off after cracking. It can be seen that the process of preheating and heat-insulating the substrate before spraying can effectively overcome the problem of poor interface bonding between heterogeneous surfaces of the film / substrate.

[0052] According to some preferred embodiments, the curing is carried out under a flowing argon atmosphere at a curing temperature of 300 to 400° C.; and / or

[0053] According to some preferred embodiments, the pyrolysis is performed under a flowing argon atmosphere, and the pyrolysis temperature is 1000-1200°C (for example, 800°C, 850°C, 900°C, 950°C or 1000°C). The present invention can select the pyrolysis temperature according to the initial resistance value requirement to obtain the SiBCN ceramic film; the lower the pyrolysis temperature, the greater the initial resistance value of the obtained film.

[0054] In a second aspect, the present invention provides a temperature field measurement method, which is implemented by the thin film temperature sensor described in the first aspect and comprises the following steps:

[0055] A thin film temperature sensor is prepared on the surface of the workpiece to be measured, and a plurality of electrodes are connected at the boundary position of the thin film temperature sensor to obtain the voltage distribution of the boundary of the thin film temperature sensor under a preset current; specifically: a thin film temperature sensor is first prepared on the surface of the workpiece to be measured, and then a plurality of electrodes are set at the boundary position of the thin film temperature sensor according to the shape of the workpiece to be measured, and the ERT technology is adopted, based on the measurement mode of adjacent excitation-relative measurement, a preset constant current is passed, and the output voltage data between the two electrodes are obtained respectively, that is, the voltage distribution of the boundary of the thin film temperature sensor under the preset current is obtained. It should be noted that the boundary position of the thin film temperature sensor refers to the edge position of the thin film temperature sensor. If the workpiece to be measured is a plane structure (for example, a square, a circle, other polygons, etc.), the boundary position of the thin film temperature sensor is the boundary position (edge ​​position) of the plane structure. If the thin film temperature sensor is a curved surface structure (for example, a hemispherical surface, other special-shaped curved surfaces, etc.), the boundary position of the thin film temperature sensor is the boundary position (edge ​​position) of the curved surface structure.

[0056] Based on the voltage distribution of the thin film temperature sensor boundary under a preset current, the resistance distribution of each region of the thin film temperature sensor is obtained; including: (1) Based on the voltage distribution of the thin film temperature sensor boundary under a preset current, the voltage distribution of each region of the thin film temperature sensor is obtained; specifically: based on the voltage distribution data of the thin film temperature sensor boundary under a preset current, the voltage distribution in the middle of the thin film temperature sensor can be obtained, and then the voltage distribution of each region of the thin film temperature sensor can be obtained. (2) Based on the voltage distribution of each region of the thin film temperature sensor, the resistance distribution of each region of the thin film temperature sensor is obtained; specifically: based on the relationship between the preset constant current, voltage and resistance, the resistance distribution of each region of the thin film temperature sensor can be obtained from the voltage distribution of each region of the thin film temperature sensor.

[0057] It should be noted that for the workpiece to be tested with a curved surface structure, the geometric structure of the bonding interface between the thin film temperature sensor and the curved surface structure is mapped into a two-dimensional plane. The voltage distribution (voltage data) of the boundary of the thin film temperature sensor under the preset current is obtained, and the resistance tomography algorithm is used to realize the reconstruction of the resistance distribution after the curved surface interface is mapped to the two-dimensional plane. The reconstructed resistance distribution is mapped back to the curved surface structure again to obtain the resistance distribution of each area of ​​the thin film temperature sensor on the surface of the curved structure.

[0058] Based on the resistance distribution of each area of ​​the thin film temperature sensor, the temperature field distribution of the surface of the workpiece to be measured is obtained; including: based on the resistance distribution of each area of ​​the thin film temperature sensor and the reference resistance of the thin film temperature sensor, and in combination with the RT characteristic curve of the thin film temperature sensor, the temperature field distribution of the surface of the workpiece to be measured is obtained; the reference resistance is the resistance of the thin film temperature sensor at the reference temperature, and the reference temperature is preferably 100°C. Because the thin film temperature sensor has semiconductor characteristics, according to the RT characteristic curve of the thin film temperature sensor, the relationship between resistance and temperature is obtained, and the temperature of different areas of the thin film temperature sensor can be obtained from the resistance value of different areas of the thin film temperature sensor, and then the temperature distribution of each area of ​​the thin film temperature sensor is obtained, and the temperature field distribution of the surface of the workpiece to be measured can be obtained.

[0059] The temperature field measurement method provided by the present invention is realized based on the semiconductor characteristics of the thin film temperature sensor. There is no requirement for the material and shape of the workpiece. It only needs to prepare the thin film temperature sensor on the surface of the workpiece to be measured to measure the temperature field distribution (surface temperature measurement) of the surface of the workpiece to be measured in real time. It can meet the temperature field measurement requirements of the surface of the workpiece with planes, curved surfaces, and special-shaped structures of different materials under high temperature conditions, and provides a means and method with great application potential for in-situ online monitoring of the temperature field of high-temperature hot end components such as aircraft engines, large gas turbines, hypersonic aircraft, and rocket thrusters. Through the real-time measurement of the temperature field distribution, it can be located in time when the local temperature is abnormal, and corresponding countermeasures can be taken. In addition, the temperature field measurement method can also be applied to the research and development design stage of the high-temperature hot end component to perform structural design according to the temperature field distribution on the surface of the high-temperature hot end component to avoid the phenomenon of local temperature abnormalities; or it can be used to verify the rationality of the component structure design.

[0060] In order to more clearly illustrate the technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the examples. The present invention does not specifically limit the sources of the reagents used in the examples and comparative examples, and the reagents can be directly purchased or synthesized by themselves.

[0061] Example 1

[0062] S1. The polyborosilazane precursor liquid, the active filler TiB2, and the organic solvent (xylene) were mixed in a mass ratio of 3:2:3 and stirred for 90 minutes using a magnetic stirrer to obtain a thin film slurry;

[0063] S2. The substrate (Al2O3 substrate) was preheated at 100°C for 3 minutes, and then the thin film slurry was sprayed on the preheated substrate using a spray gun of an electronically controlled air pump. After spraying, it was cured at 350°C for 2 hours, and finally pyrolyzed at 1000°C for 6 hours. Both curing and pyrolysis were carried out under a flowing argon atmosphere to obtain a high-quality thin film temperature sensor.

[0064] Example 2

[0065] S1. The polyborosilazane precursor liquid, the active filler TiB2, and the organic solvent (xylene) were mixed in a mass ratio of 1:1:1, and stirred for 90 minutes using a magnetic stirrer to obtain a thin film slurry;

[0066] S2. The substrate (Al2O3 substrate) was preheated at 80°C for 6 minutes, and then the thin film slurry was sprayed on the preheated substrate using a spray gun of an electronically controlled air pump. After spraying, it was cured at 350°C for 2 hours and finally pyrolyzed at 1100°C for 6 hours. Both curing and pyrolysis were carried out under a flowing argon atmosphere to obtain a high-quality thin film temperature sensor.

[0067] Example 3

[0068] S1. The polyborosilazane precursor liquid, active filler TiB2, and organic solvent (xylene) were mixed in a mass ratio of 7:3:4 and stirred for 90 minutes using a magnetic stirrer to obtain a film slurry;

[0069] S2. The substrate (Al2O3 substrate) was preheated at 90°C for 4 minutes, and then the thin film slurry was sprayed on the preheated substrate using a spray gun of an electronically controlled air pump. After spraying, it was cured at 350°C for 2 hours and finally pyrolyzed at 1200°C for 6 hours. Both curing and pyrolysis were carried out under a flowing argon atmosphere to obtain a high-quality thin film temperature sensor.

[0070] It should be noted that the thin film temperature sensors prepared in Examples 1-3 of the present invention are similar in substance and performance, and will not be described one by one here. The technical solution of the present invention will be further described below by taking Example 1 as an example.

[0071] The actual picture of the thin film temperature sensor prepared in Example 1 of the present invention is as follows Figure 1 As shown, the thin film temperature sensor has a flat surface and uniform thickness. It should be noted that the present invention also uses the above method to prepare a thin film temperature sensor on the curved surface of an Al2O3 ceramic cylinder, and a high-quality thin film temperature sensor can also be obtained.

[0072] The XRD spectrum of the thin film temperature sensor prepared in Example 1 of the present invention is as follows: Figure 2 As shown, the SiBCN ceramic film without adding active filler TiB2 is a typical amorphous SiBCN ceramic, and the TiB2 in the thin film temperature sensor prepared by the present invention exists in the film in a crystalline state.

[0073] The present invention explores the relationship between the resistance of the thin film temperature sensor obtained in Example 1 and the temperature change, and finds that the resistance of the thin film temperature sensor decreases with the increase of the ambient temperature, and has semiconductor characteristics. Its RT characteristic curve is as follows: Figure 3 shown.

[0074] The present invention utilizes the large area and high temperature semiconductor characteristics of the prepared thin film temperature sensor, and the characteristics of different resistivity of the thin film temperature sensor at different temperatures (100°C, 200°C, 300°C). The ERT method is used to arrange electrodes at the geometric boundaries of the prepared thin film temperature sensor, apply current excitation at the electrodes, and measure the corresponding voltage signal. At the same time, the optimization method is used to reconstruct the resistance distribution, thereby measuring the relative numerical value of the resistance of each area on the surface of the film (resistance distribution). It should be noted that the electrode (platinum wire or nickel wire) on the surface of the thin film temperature sensor can be bonded to the surface of the film using the slurry used to prepare the thin film temperature sensor as an adhesive after the film is solidified, and cracked together with the film. Alternatively, after the thin film temperature sensor is prepared, the electrode (platinum wire or nickel wire) is bonded to the surface of the film, and the bonding material used for bonding the electrode is selected according to the test temperature. The bonding material can be graphite conductive glue or high temperature resistant tape. The test method for the resistance distribution of each area of ​​the thin film temperature sensor at each temperature (100℃, 200℃, 300℃) is as follows: the ERT method of arranging 16 electrodes at the boundary position of the thin film temperature sensor is used to obtain the wire layout that can be used for ERT inversion of the temperature field (the actual diagram of the electrode distribution is shown in Figure 2). Figure 4 ). Select the adjacent excitation-relative measurement mode: In the first group of operations, press Figure 5 In the method shown, a constant direct current I (0.1 mA) is applied to the object under test through adjacent electrodes 1 and 2, and electrode 2 inputs current, while electrode 1 outputs current and is grounded. The voltage data between electrode 3 and electrode 4, electrode 3 and electrode 5, ..., electrode 3 and electrode 16 (U3-4, U3-5, U3-6, U3-7, U3-8, U3-9, U3-10, U3-11, U3-12, U3-13, U3-14, U3-15, U3-16) are collected respectively, for a total of 13 data. In the second group of operations, the same constant DC current I as in the first group is applied to the object under test through the adjacent electrodes 2 and 3. The current is input to the electrode 3, and the current is output to the electrode 2 and grounded. 13 data are measured in a sequence similar to the first group of operations. Finally, 13*16=208 groups of output voltage data are obtained by traversing the 16 electrodes. The output voltage distribution of the thin film temperature sensor at different temperatures (100℃, 200℃, 300℃) is shown in the figure. Figure 6 As shown. Figure 6It can be seen that at different constant temperatures, the output voltage distribution diagrams (shapes) of each region are similar, and the only difference is the size of the voltage value. This means that if the output voltage distribution diagram of a certain region changes for the same thin film temperature sensor, it can be considered that the change is caused by the temperature of the region, and it can be known that the temperature of the region is abnormal compared to other regions. Furthermore, the resistance distribution of each region of the thin film temperature sensor can be obtained based on the output voltage data and the constant DC current, forming a resistance distribution cloud diagram (such as Figure 7 , where (a) corresponds to 100°C, (b) corresponds to 200°C, and (c) corresponds to 300°C). Figure 7 It can be seen that the color of the middle area of ​​the thin film temperature sensor is close and relatively uniform, that is, the resistance value of the middle area of ​​the thin film temperature sensor is not much different, indicating that the thin film temperature sensor prepared by the present invention has good uniformity. It should be noted that Figure 7 The color at the middle edge is much different from that in the center area. The reason for the large difference in resistance is that the electrodes are arranged at the boundary of the thin-film temperature sensor, and the electrodes arranged at the boundary are easily affected by the "contact resistance", as well as the technical limitations of the ERT method itself. The resistance image at the boundary where the electrodes are connected fluctuates more seriously. It is generally believed that the error in the boundary part is large and is usually not considered.

[0075] The present invention uses the prepared thin film temperature sensor to measure the surface temperature field of the workpiece to be measured, and includes the following steps:

[0076] (1) First, a thin film temperature sensor is prepared on the surface of the workpiece to be measured, and then a plurality of electrodes are arranged at the boundary position of the thin film temperature sensor according to the shape of the workpiece to be measured, and then a constant current is passed to obtain the output voltage data between the electrodes respectively, that is, the voltage distribution of the boundary of the thin film temperature sensor under the preset current is obtained;

[0077] (2) based on the voltage distribution at the boundary of the thin film temperature sensor under a preset current, obtaining the voltage distribution of each region of the thin film temperature sensor; based on the voltage distribution of each region of the thin film temperature sensor, obtaining the resistance distribution of each region of the thin film temperature sensor;

[0078] (3) Based on the resistance distribution of each area of ​​the thin film temperature sensor and the reference resistance of the thin film temperature sensor, and in combination with the RT characteristic curve of the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained; the reference resistance is the resistance of the thin film temperature sensor at the reference temperature.

[0079] The present invention also prepares a thin film temperature sensor on a SiBCN ceramic substrate (homogeneous substrate). The preparation method is the same as that in Example 1, and a high-quality thin film temperature sensor is obtained. Figure 8 As shown. Figure 8As can be seen in (a), many small particles can be observed on the surface of the SiBCN ceramic matrix under an optical microscope. The surface of the material actually has many tiny cracks and holes, which indicates that the surface quality of the SiBCN ceramic matrix after pyrolysis is not very good. Figure 8 As can be seen in (b), the surface of the thin film temperature sensor prepared by curing and pyrolysis after thin film slurry spraying is relatively uniform without cracking, and the uneven surface and excessive granularity of the material have been greatly improved, which preliminarily verifies that the prepared film has good density.

[0080] In summary, the preparation method of the thin film temperature sensor provided by the present invention can prepare high-quality thin film temperature sensors on both homogeneous substrates and heterogeneous substrates. The thin film temperature sensor provided by the present invention can realize temperature field measurement on the surface of workpieces of different materials under high temperature conditions, meeting the use requirements of temperature field measurement in different fields.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thin film temperature sensor, characterized in that: The thin film temperature sensor has semiconductor characteristics; the thin film temperature sensor comprises SiBCN ceramics and fillers.

2. A method for preparing the thin film temperature sensor according to claim 1, characterized in that: The preparation method comprises: S1. mixing polyborosilazane, a filler and an organic solvent to obtain a film slurry; S2. Spraying the thin film slurry onto the preheated substrate, and obtaining a thin film temperature sensor through solidification and cracking.

3. The preparation method according to claim 2, characterized in that: Based on the total weight of the polyborosilazane and the filler, the polyborosilazane accounts for 50 to 70 wt %, and the filler accounts for 30 to 50 wt %.

4. The preparation method according to claim 3, characterized in that: The organic solvent accounts for 40-60% of the total mass of the polyborosilazane and the filler.

5. The preparation method according to claim 2, characterized in that: The filler is selected from at least one of active fillers and inert fillers; the active filler is preferably at least one of Al, B, Cr, W, Nb, Mo, Si, Ti, V, CrSi2, MoSi2, TiSi2, TiB2; the inert filler is preferably at least one of SiO2, Al2O3, Zr2O3, Y2O3, SiC, B4C, Si3N4, BN; and / or The organic solvent is xylene.

6. The preparation method according to claim 2, characterized in that: The temperature of the preheating treatment is 80-100°C.

7. The preparation method according to claim 2, characterized in that: The curing is carried out in a flowing argon atmosphere at a curing temperature of 300 to 400° C.; and / or The cracking is carried out under a flowing argon atmosphere at a cracking temperature of 1000-1200°C.

8. A temperature field measurement method, characterized in that: The thin film temperature sensor according to claim 1 comprises the following steps: A thin film temperature sensor is prepared on the surface of the workpiece to be measured, and a plurality of electrodes are connected at the boundary position of the thin film temperature sensor to obtain a voltage distribution at the boundary of the thin film temperature sensor under a preset current; Based on the voltage distribution at the boundary of the thin film temperature sensor under the preset current, the resistance distribution of each area of ​​the thin film temperature sensor is obtained; Based on the resistance distribution of each area of ​​the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained.

9. The temperature measurement method according to claim 8, characterized in that: Based on the voltage distribution at the boundary of the thin film temperature sensor under the preset current, the resistance distribution of each area of ​​the thin film temperature sensor is obtained, including: Based on the voltage distribution at the boundary of the thin film temperature sensor under the preset current, the voltage distribution of each area of ​​the thin film temperature sensor is obtained; Based on the voltage distribution of each area of ​​the thin film temperature sensor, the resistance distribution of each area of ​​the thin film temperature sensor is obtained.

10. The temperature measurement method according to claim 8, characterized in that: Based on the resistance distribution of each area of ​​the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained, including: Based on the resistance distribution of each area of ​​the thin film temperature sensor and the reference resistance of the thin film temperature sensor, and combined with the RT characteristic curve of the thin film temperature sensor, the temperature field distribution on the surface of the workpiece to be measured is obtained; the reference resistance is the resistance of the thin film temperature sensor at the reference temperature.

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