Preparation method of high-temperature-resistant film temperature sensor based on laser manufacturing

Abstract

The invention discloses a method for preparing a high-temperature-resistant film temperature sensor based on laser manufacturing, which comprises the following steps of: firstly, coating a precursor film of polymer precursor ceramic on a substrate, heating to 180 DEG C or naturally placing and curing, scanning the precursor film by adopting a fiber laser according to a certain mode, and removing unnecessary parts, so as to obtain the high-temperature-resistant film temperature sensor. The left pattern part is the polymer precursor ceramic sensing film with patterning and pyrolysis completed synchronously. By adopting the technical scheme provided by the invention, the problems of relatively wide pattern, low preparation efficiency and high cost of the current polymer precursor ceramic film are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thin film sensors, and in particular relates to a method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing. Background Art

[0002] With the increasing demand for high-temperature measurements, research on polymer precursor ceramic thin film sensors is growing. The main challenges faced in the fabrication of high-temperature resistant PDC thin film sensors include low fabrication efficiency and difficulty in achieving fine patterning. Lasers are used to locally pyrolyze polymer precursors, rapidly converting them into ceramics. This method significantly improves fabrication efficiency due to the high speed of laser pyrolysis and the ability to precisely control the pyrolysis area, reducing unnecessary material waste.

[0003] However, traditional laser manufacturing requires patterning first and then pyrolysis. However, there has also been the use of high-precision femtosecond lasers to directly pattern on polymer precursor films, which can achieve fine patterns with a minimum line width of 30 microns. This method has high resolution and high precision, but the equipment cost is high, and further pyrolysis is required afterwards. In addition, the polymer precursor is treated by rapid thermal treatment to complete ceramicization in a short time. This method can complete the process that traditional thermal treatment takes several hours in a few seconds to a few minutes, greatly improving efficiency. However, this method has high requirements for equipment and needs to be completed in an inert atmosphere and requires a current of up to tens of amperes. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing, so as to solve the current problems of wide patterns, low preparation efficiency and high cost for polymer precursor ceramic films.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing, comprising:

[0007] Step S1, adding 10-20% by mass of titanium diboride nanopowder, 10-20% by mass of zirconium diboride nanopowder, and 10-20% by mass of silicon carbide nanopowder to a liquid precursor such as polysilazane, polysiloxane, or polycarbosilane, and adding 60-80% by mass of titanium diboride nanopowder to a liquid precursor such as polysilazane, polysiloxane, or polycarbosilane, and obtaining precursor slurries of PDC sensor film and solder joint respectively after magnetic stirring for 1-2 hours;

[0008] Step S2, ultrasonically cleaning the aluminum oxide substrate and drying it, and printing a layer of sensitive layer precursor film on the treated aluminum oxide substrate using flexible screen printing;

[0009] Step S3: Scanning the PDC sensor film precursor along a certain path using a fiber laser to remove unnecessary parts, leaving the patterned part as the pyrolyzed and patterned PDC sensor film;

[0010] Step S4: Apply a PDC solder precursor solution to the pins of the PDC sensor film. Place a PDC lead connector and press it with a pressure block. Then, place the PDC lead connector in a tube furnace and heat it to 800-1000°C in a low vacuum atmosphere for 1-4 hours to obtain a PDC thin film temperature sensor. Preferably, the titanium diboride powder has a particle size of 40 nanometers.

[0011] Preferably, the particle size of powders such as titanium diboride, zirconium diboride, and silicon carbide is 10 to 90 nanometers.

[0012] Preferably, the precursor liquids of the polymer precursor ceramics SiCN, SiCO and SiC are polysilazane PSN, polysiloxane PSO and polycarbosilane PCS respectively; and the alumina substrate is a flat alumina substrate or a curved alumina substrate.

[0013] Preferably, the spot diameter of the fiber laser is 20 to 150 microns, the scanning speed is 20 to 1000 mm / s, the power is 3 to 30 W, the wavelength is 1.064 μm, the frequency is 20 kHz, and the scanning path is S-shaped, gradually moving away from the target line; the line width of the PDC sensor film obtained by scanning is 10 to 2000 microns.

[0014] Preferably, the pressed block is an alumina block, and the heat treatment atmosphere is a low vacuum with a vacuum degree of 1 Pa to 700 Pa.

[0015] The present invention adopts a laser removal method to quickly obtain a polymer precursor ceramic sensing film with fine line width. A specific scanning path is adopted to remove excess film while pyrolyzing the unremoved part, thereby achieving simultaneous completion of patterning and pyrolysis, and can obtain a PDC sensing film with a minimum line width of 10 microns. Based on this, a thin film temperature sensor is prepared, and resistance temperature tests from room temperature to 1000°C are carried out, and the stability is tested. The thin film sensor prepared by the method of the present invention can withstand a temperature of 900°C and has good repeatability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0017] Figure 1 This is a flow chart of a method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing according to an embodiment of the present invention;

[0018] Figure 2 This is an optical micrograph of the prepared PDC sensing film with a line width of approximately 10 μm.

[0019] Figure 3 Optical images of PDC sensing films with different designed line widths prepared by laser removal method; Figure 3 (a)-(f) are optical images of the actual films with designed thicknesses of 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, and 500 μm, respectively. The black lines are PDC sensing films.

[0020] Figure 4 The relationship between the actual line width and the designed line width of the PDC sensing film prepared by the laser removal method;

[0021] Figure 5 Schematic diagram of the principle of laser removal of PDC film to achieve patterning and pyrolysis, where: Figure 5 (a)-(d) represent the removal effects when the power is insufficient, slightly higher, appropriate, and excessive, respectively;

[0022] Figure 6 Optical micrographs of various fine line width PDC films prepared by laser removal method; among them, Figure 6 (a) is an optical picture of the heat flux meter pattern with different line widths. Figure 6 (b) to 6(d) Figure 6 Optical micrographs of heat flux meter patterns with different line widths in (a). Figure 6 (e) is an optical picture of grating patterns with different line widths. Figure 6 (f)~6(h) Figure 6 (e) Optical micrographs of grating patterns with different line widths. Figure 6 (i) is an optical image of a grid pattern on an alumina sphere. Figure 6 (j) Figure 6 (i) Optical micrograph of the grating pattern, Figure 6 (k) is an optical image of the heat flux meter pattern on the alumina sphere. Figure 6 (l) Figure 6 (k) Optical micrograph of the heat flux meter pattern, Figure 6 (m) is an optical image of a five-pointed star pattern on an alumina sphere. Figure 6 (n) and Figure 6 (o) Figure 6 Optical micrograph of the five-pointed star pattern in (m);

[0023] Figure 7 (a) is an optical image of a thin film temperature sensor prepared using the patented method. Figure 7 (b) is a microscopic optical image of the sensing film of the prepared thin film temperature sensor. Figure 7 (c) is the test curve of the thin film temperature sensor from room temperature to 900℃ for 6 rounds. Figure 7 (d) is the 6-round temperature-resistance curve of the thin film sensor. Figure 7 (e) is the change of resistance and temperature of the thin film sensor over time, Figure 7 (f) is the test curve of the thin film sensor kept at 900℃ for 2 hours. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 efforts are within the scope of protection of the present invention.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1:

[0027] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing, comprising:

[0028] Step S1, adding 20% ​​by mass of titanium diboride nanopowder, 20% by mass of zirconium diboride nanopowder, and 10% by mass of silicon carbide nanopowder to a polysilazane PSN liquid precursor, and adding 70% by mass of titanium diboride nanopowder to the polysilazane PSN liquid precursor, and obtaining precursor slurries for PDC sensing film and solder joints respectively after magnetic stirring for 1 hour;

[0029] Step S2: ultrasonically clean the aluminum oxide substrate and then dry it, and then print a layer of sensitive layer precursor film on the treated aluminum oxide substrate using flexible screen printing; wherein the aluminum oxide substrate has a size parameter of 15 mm × 15 mm × 1 mm;

[0030] Step S3: Scanning the PDC sensor film precursor using a fiber laser to remove unwanted portions, leaving the patterned portion as the patterned and pyrolyzed sensor film; wherein the parameters of the fiber laser are: scanning speed 160 mm / s, power 18 W, wavelength 1.064 μm, frequency 20 kHz, and spot diameter 50 μm;

[0031] Step S4: Apply PDC solder point precursor liquid to the pins of the PDC sensor film, place the PDC lead connector and press, then place it in a tube furnace, heat it to 1000°C in a 60Pa vacuum atmosphere, and keep it warm for 1 hour to obtain a PDC film temperature sensor.

[0032] Figure 2 The PDC sensing film with a line width of about 10 microns was obtained by laser scanning. The laser parameters were: scanning speed 160 mm / s, power 18 W, wavelength 1.064 μm, frequency 20 kHz, spot diameter 50 μm, and the gap without removal was 10 microns.

[0033] Generally speaking, the film design width is positively correlated with the actual line width. Figure 3 The PDC sensing films with different line widths prepared by the laser removal method are shown in Figure 2. It can be seen that as the designed line width increases, the actual line width of the prepared film also increases. The designed line widths are 50μm, 100μm, 200μm, 300μm, 400μm and 500μm, while the actual line widths obtained are 61.9μm, 123.7μm, 221.6μm, 314.4μm, 412.4μm and 567.0μm, respectively. Figure 4 The relationship between the actual line width and the designed line width of the PDC sensor film prepared by the laser removal method is shown. It can be seen that the actual line width and the designed line width are almost linearly related, which provides a process reference for preparing sensor films with different line widths.

[0034] Based on the above parameter studies, the principle of laser removal to achieve PDC film patterning can be summarized, such as Figure 5 The figure shows the principle of laser removal of PDC film to achieve patterning and pyrolysis. At a certain scanning speed, when the laser power is lower than a certain value, the laser acts on the PDC precursor film, and the energy obtained by the PDC precursor film is not enough to vaporize the PDC precursor film. However, due to the laser acting on the PDC precursor film, the temperature exceeds the pyrolysis temperature, and the film near the laser scanning is pyrolyzed into a PDC sensing film, as shown in FIG. Figure 5 As shown in a. When the laser power exceeds a certain value, the surface of the PDC precursor film begins to vaporize, and the PDC precursor film near the laser scanning is pyrolyzed into a PDC sensing film. After the PDC precursor film vaporizes, it condenses into PDC residue in the nearby air. Figure 5 As shown in b. As the laser power increases, the surface and interior are completely vaporized, and the film at a certain distance on both sides of the laser scanning path is pyrolyzed into a PDC sensing film, as shown in Figure 5 c. When the power reaches a certain level, the PDC precursor film scanned by the laser is completely vaporized, and even part of the substrate is vaporized, as shown in Figure 5Therefore, according to the set scanning path, the speed and power are adjusted. The area where the laser scans is the area where the unwanted film is removed, the area near the laser scan is the pyrolysis area, and the remaining PDC sensing film is the desired sensing film after patterning and pyrolysis.

[0035] According to the above mechanism and parameter optimization, PDC sensing film patterns with different line widths and shapes were prepared, such as Figure 6 The laser parameters used are: scanning speed 160mm / s, power 18W, frequency 20kHz. Figure 2 It can be seen that by using this method, a PDC sensor film with a line width of about 10 microns can be prepared, which is smaller than the line width prepared by femtosecond laser. In addition, the method of the embodiment of the present invention can be used to prepare various patterns and sensor films on curved surfaces, such as Figure 6 i-6o show the PDC sensing patterns prepared on the sphere.

[0036] The thin film temperature sensor was prepared by the method of the embodiment of the present invention. The prepared sample is as follows: Figure 7 As shown in a, Figure 7 b is a microscopic image of the PDC sensor film. The temperature resistance test was performed on the sample. Figure 7 c is the test curve of the prepared thin film temperature sensor from room temperature to 900℃ for 6 rounds. Figure 7 d is the 6-round temperature-resistance curve of the thin film sensor, which shows good repeatability. Figure 7 e is the change of resistance and temperature of the thin film sensor over time. It can be seen that the resistance stability at each temperature point is good. Figure 7 Figure f shows the test curve of the thin film sensor after being held at 900°C for 2 hours. The resistance change rate over 2 hours is only -2.4%, indicating good resistance stability. Therefore, the thin film sensor prepared using the method of the present embodiment has excellent stability and repeatability, and can withstand temperatures up to 900°C. Thin film sensors prepared using the method of the present embodiment and thin film sensors prepared using other methods have similar stability and repeatability.

[0037] The present invention uses a low-cost fiber laser for simultaneous depatterning and pyrolysis, achieving fine-grained patterning of PDC sensor films. The relationship between the actual and designed PDC linewidths was studied. The mechanism of laser depatterning of PDC sensor films was revealed. The fabrication of fine-grained PDC films on flat and curved substrates was achieved, with a minimum linewidth of 10 microns, at low equipment cost. PDC thin film sensors were fabricated and tested, verifying that the present invention's methods can be used to fabricate thin-film sensors with fine linewidths.

[0038] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing, characterized in that: include: Step S1, adding 10-20% by mass of titanium diboride nanopowder, 10-20% by mass of zirconium diboride nanopowder, and 10-20% by mass of silicon carbide nanopowder to a liquid precursor such as polysilazane, polysiloxane, or polycarbosilane, and adding 60-80% by mass of titanium diboride nanopowder to a liquid precursor such as polysilazane, polysiloxane, or polycarbosilane, and obtaining precursor slurries of PDC sensor film and solder joint respectively after magnetic stirring for 1-2 hours; Step S2, ultrasonically cleaning the aluminum oxide substrate and drying it, and printing a layer of sensitive layer precursor film on the treated aluminum oxide substrate using flexible screen printing; Step S3: Scanning the PDC sensor film precursor along a certain path using a fiber laser to remove unnecessary parts, leaving the patterned part as the pyrolyzed and patterned PDC sensor film; Step S4: Apply PDC solder point precursor liquid to the pins of the PDC sensor film, place the PDC lead connector and press it with a pressing block, then place it in a tube furnace, heat it to 800-1000°C in a vacuum atmosphere, and keep it warm for 1-4 hours to obtain a PDC film temperature sensor.

2. The method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing according to claim 1, characterized in that: The particle size of powders such as titanium diboride, zirconium diboride, and silicon carbide is 10 to 90 nanometers.

3. The method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing according to claim 2, characterized in that: The precursor liquids of polymer precursor ceramics SiCN, SiCO and SiC are polysilazane PSN, polysiloxane PSO and polycarbosilane PCS respectively; the alumina substrate is a flat alumina substrate or a curved alumina substrate.

4. The method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing according to claim 3, characterized in that: The spot diameter of the fiber laser is 20 to 150 microns, the scanning speed is 20 to 1000 mm / s, the power is 3 to 30 W, the wavelength is 1.064 μm, the frequency is 20 kHz, and the scanning path is S-shaped, gradually moving away from the target line; the line width of the PDC sensor film obtained by scanning is 10 to 2000 microns.

5. The method for preparing a high-temperature resistant thin film temperature sensor based on laser manufacturing according to claim 4, characterized in that: The pressed block is an alumina block, and the heat treatment atmosphere is a low vacuum with a vacuum degree of 1Pa to 700Pa.

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