Method for preparing vanadium dioxide flexible intelligent thermal control device through thermal treatment of vanadium nitride

Abstract

The invention relates to a method for preparing a vanadium dioxide flexible intelligent thermal control device through thermal treatment of vanadium nitride. The preparation method comprises the steps that magnetron sputtering and low-temperature heat treatment oxidation are adopted, a vanadium nitride thin film is sputtered on the surface of a substrate made of a polymer thin film, a silicon wafer and other materials, then the vanadium nitride thin film is transferred into a low-pressure oxygen-containing atmosphere cavity for heating oxidation treatment, the vanadium nitride thin film is converted into a vanadium dioxide thin film, and the intelligent thermal control device is formed. The core of the method is a technology for preparing the vanadium dioxide film through heat treatment of the vanadium nitride film, and the method has the advantages that the temperature adopted in the whole preparation period of an intelligent thermal control device is not higher than 400 DEG C, so that the vanadium dioxide can be prepared on the surface of the polymer substrate through the method, and the heat treatment condition for converting vanadium nitride into vanadium dioxide is simple and easy to control. The method is suitable for preparing the vanadium dioxide flexible intelligent thermal control device.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal control coatings for spacecraft, and specifically relates to a method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride. Background Art

[0002] Spacecraft face an extremely complex thermal environment in space. As the spacecraft switches between the sun-facing state and the sun-facing state, the heat energy it receives from the sun and the earth is constantly changing. Therefore, the spacecraft needs to be equipped with an active thermal control system to adjust the internal temperature of the spacecraft according to the satellite thermal environment to ensure the normal operation of the instruments and personnel in the cabin. At present, active thermal control systems of spacecraft, such as mechanical shutters and heat pipes, usually include temperature sensors, brake components, etc., which increase the manufacturing cost of the spacecraft, the energy consumption on orbit, and reduce the payload. Intelligent thermal control devices have good prospects for aerospace applications. They are coated on the surface of the spacecraft and can spontaneously adjust the emissivity as the satellite thermal environment changes to achieve temperature regulation in the spacecraft cabin. Based on the property that vanadium dioxide (VO2) undergoes a reversible "insulator-metal" phase transition at 341K, causing its infrared emissivity to change, VO2 intelligent thermal control devices can spontaneously change their own thermal radiation characteristics according to the ambient temperature to adjust the heat exchange between the spacecraft and the space environment, thereby achieving spontaneous control of the temperature inside the spacecraft. Therefore, this type of thermal control device is characterized by light weight, zero energy consumption, low cost and intelligent regulation, and is one of the key directions of spacecraft thermal control technology development.

[0003] The VO2 core layer in the intelligent thermal control devices reported in current literature and patents is generally prepared by vapor deposition methods, including magnetron sputtering (CN108866483A, CN114059032A, CN111139432A), vapor phase chemical deposition (CN110331366A, CN104805411A), pulsed laser deposition (CN107190235A, CN103556218A), atomic layer deposition (CN116219397A, CN110699670A), etc. However, at present, the following two problems still restrict the application of VO2 in the field of intelligent thermal control: (1) Due to the multi-chemical valence of vanadium (V 5+ 、V 4+ 、V 3+ 、V 2+ ), the above methods have harsh process conditions and require strict control of parameters such as atmosphere composition, gas partial pressure, gas flow rate, and vacuum degree in the vapor deposition environment for preparing VO2; (2) In order to ensure the growth of dense and highly crystalline VO2, the above preparation techniques require that the VO2 growth substrate be in a high temperature state (usually above 400°C), which is much higher than the melting point of most thermal control device materials currently used in aerospace (such as polyimide films widely used in aerospace). This poses a challenge to the existing thermal control device preparation technology and limits the application of VO2 in the field of intelligent thermal control of spacecraft. Summary of the invention

[0004] In order to solve the problem that the existing vapor deposition method for preparing VO2 intelligent thermal control devices has harsh process conditions and is difficult to grow on the surfaces of most thermal control device materials currently used in aerospace (especially the surface of polyimide films), the present invention proposes a method for preparing VO2 flexible intelligent thermal control devices by heat treating vanadium nitride, in order to meet the actual application needs of VO2 in the field of intelligent thermal control of spacecraft. Conventional methods cannot achieve the preparation of high-quality VO2 films on the surface of the polyimide film of the present invention. Other preparation methods, such as atomic layer deposition, have complex technical processes for preparing VO2, and it is difficult to prepare large-area VO2.

[0005] The purpose of the present invention can be achieved by the following scheme:

[0006] The present invention provides a method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride, the method comprising the following steps:

[0007] S1. Deposition of vanadium nitride layer

[0008] Depositing a vanadium nitride layer on the surface of the substrate to obtain a vanadium nitride / substrate composite component;

[0009] S2. Preparation of VO2 by heat treatment of vanadium nitride

[0010] The vanadium nitride / substrate composite component is heated and heat-insulated under oxygen conditions to convert the vanadium nitride into VO2 to form a VO2 / substrate composite component;

[0011] A protective layer is deposited on the surface of S3 and VO2.

[0012] A protective layer is deposited on the VO2 surface of the VO2 / substrate composite component to obtain the vanadium dioxide flexible intelligent thermal control device.

[0013] The present invention can prepare VO2 under low temperature conditions (≤400° C.), while other VO2 preparation methods are not easy to prepare high-quality films under low temperature conditions, especially on the surface of a polyimide film.

[0014] As an embodiment of the present invention, in step S1, the substrate is one of a gold film, a silver film, a titanium film, an aluminum film, a polyimide film, a gold-plated polyimide film, a silver-plated polyimide film, a titanium-plated polyimide film, an aluminum-plated polyimide film, a silicon wafer, a quartz wafer, a sapphire wafer, and a glass wafer.

[0015] As an embodiment of the present invention, in step S1, the thickness of the substrate is 5 to 35 μm.

[0016] As an embodiment of the present invention, in step S1, the substrate is pretreated. The pretreatment step is: ultrasonically cleaning the substrate with acetone, methanol, and acetone in sequence for 15 to 30 minutes, and then drying the substrate with a nitrogen air gun.

[0017] As an embodiment of the present invention, in step S1, the vanadium nitride layer is deposited by magnetron sputtering, preferably radio frequency magnetron sputtering. The heating temperature of the substrate for magnetron sputtering is 100-300° C., preferably 200-300° C. The atmosphere for magnetron sputtering is argon and nitrogen.

[0018] Preferably, the steps of magnetron sputtering are: evacuating and exhausting the cavity of the magnetron sputtering device, heating the substrate, introducing a mixture of argon and nitrogen and maintaining a certain vacuum degree, using vanadium nitride as a target material, and performing magnetron sputtering.

[0019] Preferably, the vacuum degree of the vacuum exhaust is 1×10 -5 ~1×10 -6 Torr.

[0020] Preferably, the deposition parameters of magnetron sputtering are: the flow rate of argon is preferably 10-30 sccm, the flow rate of nitrogen is preferably 1-5 sccm, the vacuum degree (pressure in the chamber) is 0.1-50 mTorr, the power is 100-300 W, and the vanadium nitride deposition rate is 0.2-2 nm / s. Vanadium nitride is used as the target material, and the purity of the vanadium nitride target material is 99.95%.

[0021] The present invention places a substrate into a cavity of a radio frequency magnetron sputtering device and fixes it on a sputtering sample carrier. After the cavity is evacuated, the substrate is heated to a certain temperature. Then, a mixed gas of argon and nitrogen is introduced into the cavity and a certain vacuum degree is maintained. Vanadium nitride is used as a target material and sputtering is performed at a certain power for a specified time to deposit a vanadium nitride material layer with a certain thickness on the surface of the substrate to obtain a vanadium nitride / substrate composite component.

[0022] As an embodiment of the present invention, in step S1, the thickness of the vanadium nitride layer is 50 to 1000 nm.

[0023] As an embodiment of the present invention, in step S2, the aerobic condition refers to the flow of air or oxygen at a flow rate of 0.5 to 10 sccm and a vacuum degree (pressure in the chamber) of 0.1 to 10 mTorr. Before the air or oxygen is passed, the vacuum is first evacuated to a vacuum degree of 1×10 -5 ~1×10 -6 Torr.

[0024] As an embodiment of the present invention, in step S2, the heating and insulation temperature is 300-400°C, preferably 350-400°C, and the time is 0.5-5h.

[0025] The present invention fixes a vanadium nitride / substrate composite component in a vacuum annealing chamber, introduces a certain flow of air or oxygen after evacuation and maintains the chamber at a certain vacuum degree, then heats the chamber to a heat treatment temperature and maintains it for a certain time to convert the vanadium nitride into VO2, thereby forming a VO2 / substrate composite component.

[0026] As an embodiment of the present invention, in step S3, the protective layer is a hafnium oxide (HfO2) layer, and the deposition is obtained by magnetron sputtering, preferably incident DC sputtering. The temperature of magnetron sputtering is 250-350° C. The atmosphere of magnetron sputtering is argon and oxygen.

[0027] Preferably, the steps of magnetron sputtering are: evacuating and exhausting the cavity of the incident DC sputtering device, heating the substrate, introducing a mixture of argon and oxygen and maintaining a certain vacuum degree, using metal hafnium as a target material, and performing magnetron sputtering.

[0028] Preferably, the vacuum degree of the vacuum exhaust is 1×10 -5 ~1×10 -6 The heating temperature of the substrate is 250-350°C.

[0029] Preferably, the deposition parameters of magnetron sputtering are: the flow rates of argon and oxygen are both 0.1-100 sccm (the flow rate of argon is preferably 40-80 sccm, and the flow rate of oxygen is preferably 4-10 sccm), the vacuum degree (pressure in the chamber) is 0.1-50 mTorr. The power is 20-300 W, and the HfO2 deposition rate is 0.2-2 nm / s. Metal hafnium is used as the target material, and the purity of the metal hafnium target material is 99.95%.

[0030] As an embodiment of the present invention, in step S3, the thickness of the protective layer is 2-50 nm. The thermal control film of the present invention is used in space and faces strong space radiation, which causes performance degradation. The protective layer (hafnium oxide layer) is an effective method to solve the space radiation.

[0031] The present invention places a VO2 / substrate composite component into a cavity of a direct current sputtering device and fixes it on a sputtering sample stage. After the cavity is evacuated, the substrate is heated to a certain temperature, and then a mixture of argon and oxygen is introduced into the cavity and a certain vacuum is maintained. Metal hafnium is used as a target material, and sputtering is performed at a certain power for a specified time. A hafnium oxide (HfO2) material layer with a certain thickness is deposited on the surface of VO2 to obtain a HfO2 / VO2 / substrate composite component, i.e., a VO2 intelligent thermal control device. The VO2 intelligent thermal control device prepared using a polyimide-based film as a substrate has a flexible feature.

[0032] The present invention also provides an application of a vanadium dioxide flexible intelligent thermal control device prepared by the method in the field of aerospace intelligent thermal control. The present invention is a technology that can simply and controllably prepare a vanadium dioxide film on a flexible polymer substrate to form an intelligent thermal control device, so as to promote the application of vanadium dioxide in the field of aerospace intelligent thermal control.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The reported methods of preparing VO2 thin films by magnetron sputtering, vapor chemical deposition, pulsed laser deposition, atomic layer deposition, etc. require strict control of the atmosphere composition, gas partial pressure, gas flow rate, vacuum degree and other parameters in the VO2 deposition environment, and the process parameters have high requirements;

[0035] (2) Compared with the reported methods such as magnetron sputtering, vapor chemical deposition, pulsed laser deposition, atomic layer deposition, etc., the VO2 preparation conditions of the present invention are relatively low in temperature, and the temperature range of the whole cycle of the preparation of the VO2 intelligent thermal control device is 100-400°C. Therefore, the method of the present invention can meet the requirements of preparing thermal control devices with materials with lower melting temperatures as the substrate, and in particular, can realize the preparation of flexible VO2 intelligent thermal control devices with polyimide films widely used in aerospace as the substrate;

[0036] (3) Compared with the reported methods such as magnetron sputtering, vapor chemical deposition, pulsed laser deposition, atomic layer deposition, etc., the process conditions of the method of the present invention are relatively mild and the preparation temperature is low, so the preparation cost is relatively low;

[0037] (4) Product performance characterization proves that the VO2 intelligent thermal control device manufactured by the method described in the present invention has good ambient temperature response, wide infrared emissivity adjustment and good proton irradiation resistance, which meets the low-energy consumption and lightweight thermal control requirements of spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0039] Figure 1 The VO2 intelligent thermal control device structure of the present invention;

[0040] Figure 2 This is a photo of the VO2 intelligent thermal control device based on polyimide;

[0041] Figure 3 XRD pattern of VO2 layer in VO2 intelligent thermal control device based on polyimide;

[0042] Figure 4 HfO in polyimide-based VO2 intelligent thermal control devices x / VO2 film cross-section SEM image;

[0043] Figure 5 This is the transmittance adjustment diagram of the VO2 intelligent thermal control device based on polyimide;

[0044] Figure 6 This is a real photo of the VO2 intelligent thermal control device based on silicon wafer;

[0045] Figure 7 This is the transmittance adjustment diagram of the VO2 intelligent thermal control device based on silicon wafer;

[0046] Figure 8 This is the transmittance adjustment diagram of the VO2 intelligent thermal control device (annealing temperature 360°C) of Comparative Example 1;

[0047] Fig. 9 This is the transmittance adjustment diagram of the VO2 intelligent thermal control device of comparative example 1 (annealing temperature 460°C). DETAILED DESCRIPTION

[0048] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following examples are implemented on the premise of the technical solution of the present invention, provide detailed implementation methods and specific operation processes, and will help those skilled in the art to further understand the present invention. It should be pointed out that the protection scope of the present invention is not limited to the following embodiments, and several adjustments and improvements made under the premise of the concept of the present invention all belong to the protection scope of the present invention.

[0049] The structure of the VO2 intelligent thermal control device of the present invention is as follows: Figure 1 As shown, (1) is a HfO2 protective layer, (2) is a VO2 layer, and (3) is a base layer. The base layer (3) is one of a gold film, a silver film, a titanium film, an aluminum film, a polyimide film, a gold-plated polyimide film, a silver-plated polyimide film, a titanium-plated polyimide film, an aluminum-plated polyimide film, and a silicon wafer. The VO2 layer (2) is obtained by using a vanadium nitride layer prepared by heat-treatment magnetron sputtering, and the HfO2 protective layer (1) is prepared by sputtering on the surface of the VO2 layer by magnetron sputtering.

[0050] Example 1

[0051] The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride in this embodiment is carried out according to the following steps:

[0052] Step 1: Deposit a vanadium nitride layer on the surface of the polyimide film substrate using a radio frequency magnetron sputtering device

[0053] Acetone, methanol, and acetone were used to ultrasonically clean the 25 μm thick polyimide film substrate for 30 min respectively. Then, the substrate was dried with a nitrogen air gun. The polyimide film was placed in the cavity of the radio frequency magnetron sputtering device and fixed on the sputtering sample stage. The cavity was evacuated to 2×10 -6 After the substrate was heated to 250° C. at 1000 ℃, a mixed gas of argon (17.9 sccm) and nitrogen (1.79 sccm) was introduced into the chamber and the vacuum degree in the chamber was maintained at 2 mTorr. A vanadium nitride layer with a thickness of 50 nm was deposited on the surface of the substrate by sputtering at a power of 300 W using 99.95% vanadium nitride as a target, thereby obtaining a vanadium nitride / polyimide component.

[0054] Step 2: Heat treatment of vanadium nitride to prepare VO2

[0055] The vanadium nitride / substrate composite component is fixed in a vacuum annealing chamber and evacuated to 2×10 -6 After 2000 rpm, oxygen gas was introduced at a flow rate of 2 sccm and the chamber was kept at a vacuum degree of 1 mTorr. The chamber was then heated to an annealing temperature of 400°C and maintained for 0.5 h to convert vanadium nitride into VO2 to form a VO2 / polyimide component.

[0056] Step 3: Deposition of hafnium oxide (HfO2) protective layer on the VO2 surface

[0057] The VO2 / substrate composite component was placed in the cavity of the direct current sputtering device and fixed on the sputtering sample stage. The cavity was evacuated to 2×10 -6 Torr, then heat the substrate to 300°C, then introduce a mixture of argon (60sccm) and oxygen (6sccm) into the chamber and maintain a vacuum of 2mTorr, use metal hafnium as a target, sputter at 300W power, and reactively deposit an 8nm thick hafnium oxide layer on the substrate surface to obtain a HfO2 / VO2 / polyimide composite component, namely a VO2 intelligent thermal control device. The VO2 intelligent thermal control device prepared by deposition on a non-silicon wafer substrate has flexible characteristics.

[0058] The test results of the VO2 intelligent thermal control device prepared in this implementation case are as follows:

[0059] (1) Appearance: The film is uniform and dark brown ( Figure 2 );

[0060] (2) VO2 crystal phase is monoclinic phase ( Figure 3 );

[0061] (3) The thickness of HfO2 / VO2 film is 82.5nm ( Figure 4 );

[0062] (4) The flexible VO2 intelligent thermal control device has good infrared optical adjustment before and after phase change. In the 1-2.2 μm band, the average transmittance adjustment value is 0.47; Figure 5 )

[0063] (5) After simulating one year of proton radiation dose in space under 90 keV proton irradiation conditions, the average transmittance adjustment value in the 1-2.2 μm band is 0.42.

[0064] Example 2

[0065] The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride in this embodiment is carried out according to the following steps:

[0066] Step 1: Deposit a vanadium nitride layer on the surface of the silicon wafer substrate using a radio frequency magnetron sputtering device

[0067] Acetone, methanol, and acetone were used to ultrasonically clean the 100 μm thick silicon wafer substrate for 30 min respectively. After the substrate was dried with a nitrogen air gun, the crystalline silicon wafer was placed in the cavity of the RF magnetron sputtering device and fixed on the sputtering sample stage. The cavity was evacuated to 2×10 -6 After the substrate is heated to 300° C. at 400° C., a mixed gas of argon (30 sccm) and nitrogen (1.79 sccm) is introduced into the chamber and the vacuum degree in the chamber is maintained at 4 m Torr. A vanadium nitride layer with a thickness of 100 nm is deposited on the surface of the substrate at a power of 300 W for a specified time using 99.95% vanadium nitride as a target, and sputtering is performed at a power of 300 W for a specified time to obtain a vanadium nitride / silicon wafer component.

[0068] Step 2: Heat treatment of vanadium nitride to prepare VO2

[0069] The vanadium nitride / silicon wafer composite component is fixed in a vacuum annealing chamber and evacuated to 2×10 -6 After 2000 rpm, oxygen gas with a flow rate of 5 sccm is introduced into the chamber and the vacuum degree of the chamber is maintained at 2 mTorr. The chamber is then heated to an annealing temperature of 360°C and maintained for 2 hours to convert vanadium nitride into VO2 to form a VO2 / silicon wafer component.

[0070] Step 3: Deposition of hafnium oxide (HfO2) protective layer on the VO2 surface

[0071] The VO2 / silicon wafer component was placed in the cavity of the direct current sputtering device and fixed on the sputtering sample stage. The cavity was evacuated to 2×10 -6Torr and then heat the substrate to 300°C. Then, a mixed gas of argon (60sccm) and oxygen (6sccm) is introduced into the chamber and the vacuum degree is maintained at 2mTorr. Metal hafnium is used as a target and sputtered at 300W for 20min. A 25nm thick amorphous hafnium oxide layer is reactively deposited on the surface of the substrate to obtain a HfO2 / VO2 / silicon wafer composite component, namely a VO2 intelligent thermal control device.

[0072] The test results of the VO2 intelligent thermal control device prepared in this implementation case are as follows:

[0073] (1) Appearance: The film is uniform and dark brown ( Figure 6 );

[0074] (2) VO2 crystal phase is monoclinic phase;

[0075] (3) The thickness of HfO2 / VO2 film is 185nm;

[0076] (4) In the 1-2.2 μm band, the emissivity adjustment value is 0.39 ( Figure 7 );

[0077] (5) After simulating one year of proton radiation dose in space under 90 keV proton irradiation conditions, the average transmittance adjustment value in the 1-2.2 μm band is 0.32.

[0078] Comparative Example 1

[0079] In this comparative example, a HfO2 / VO2 / silicon wafer composite component is prepared by directly sputtering a vanadium dioxide layer by magnetron sputtering, and the steps are as follows (other steps are the same as those in Example 2):

[0080] In a vacuum reaction chamber, vanadium dioxide is used as a sputtering target, and a 100nm thick vanadium dioxide layer is deposited on the substrate surface by radio frequency magnetron sputtering (substrate temperature is 300°C; argon flow rate is 0.8sccm; oxygen flow rate into the reaction chamber is 40sccm; and the gas pressure in the reaction chamber is 0.8Pa) to obtain a vanadium dioxide / silicon wafer component. However, the vanadium dioxide film obtained by direct magnetron sputtering under low temperature conditions has low crystallinity and poor performance, and further high-temperature annealing treatment is required.

[0081] The obtained vanadium dioxide / silicon wafer component is then subjected to in-situ annealing treatment (temperature 360° C. and 460° C., time 2 h) to obtain an annealed vanadium dioxide / silicon wafer component.

[0082] A hafnium oxide (HfO2) protective layer is further deposited to produce a HfO2 / VO2 / silicon wafer composite component, namely a VO2 intelligent thermal control device.

[0083] The HfO2 / VO2 / silicon wafer composite intelligent thermal control device was obtained with the VO2 layer annealing temperature at 360°C. The test results are as follows:

[0084] (1) Appearance: The film is uniform and dark brown;

[0085] (2) VO2 crystal phase is monoclinic phase;

[0086] (3) The thickness of HfO2 / VO2 film is 180nm;

[0087] (4) In the 1-2.2 μm band, the emissivity adjustment value is 0.24 ( Figure 8 );

[0088] (5) After simulating one year of proton radiation dose in space under 90 keV proton irradiation conditions, the average transmittance adjustment value in the 1-2.2 μm band is 0.2.

[0089] The HfO2 / VO2 / silicon wafer composite intelligent thermal control device was obtained with the VO2 layer annealing temperature at 460°C. The test results are as follows:

[0090] (1) Appearance: The film is uniform and dark brown;

[0091] (2) VO2 crystal phase is monoclinic phase;

[0092] (3) The thickness of HfO2 / VO2 film is 187nm;

[0093] (4) In the 1-2.2 μm band, the emissivity adjustment value is 0.30 ( Fig. 9 );

[0094] (5) After simulating one year of proton radiation dose in space under 90 keV proton irradiation conditions, the average transmittance adjustment value in the 1-2.2 μm band is 0.22.

[0095] in conclusion:

[0096] (1) In the HfO2 / VO2 / silicon wafer composite component, under the same heat treatment temperature condition (360°C), the emissivity adjustment value of the thermal control device using the directly sputtered VO2 film is 0.24, which is much lower than the emissivity adjustment value (0.34) of the thermal control device using the VO2 film obtained by conversion from vanadium nitride. This shows that the technology of preparing vanadium dioxide from vanadium nitride described in the present invention is advanced in performance.

[0097] (2) The emissivity adjustment value (0.28) of the thermal control device using directly sputtered VO2 film is still lower than the emissivity adjustment value (0.34) of the thermal control device using VO2 film obtained by vanadium nitride conversion, even when using VO2 film with improved crystallinity (460°C). This further illustrates that the technology of preparing vanadium dioxide from vanadium nitride described in the present invention is advanced in performance.

[0098] Comparative Example 2

[0099] The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride in this comparative example is carried out according to the following steps:

[0100] Step 1: Deposit a vanadium nitride layer on the surface of the polyimide film substrate using a radio frequency magnetron sputtering device

[0101] Acetone, methanol, and acetone were used to ultrasonically clean the 25 μm thick polyimide film substrate for 30 min respectively. Then, the substrate was dried with a nitrogen air gun. The polyimide film was placed in the cavity of the radio frequency magnetron sputtering device and fixed on the sputtering sample stage. The cavity was evacuated to 2×10 -6 After the substrate was heated to 250° C. at 1000 ℃, a mixed gas of argon (17.9 sccm) and nitrogen (1.79 sccm) was introduced into the chamber and the vacuum degree in the chamber was maintained at 2 mTorr. A vanadium nitride layer with a thickness of 50 nm was deposited on the surface of the substrate by sputtering at a power of 300 W using 99.95% vanadium nitride as a target, thereby obtaining a vanadium nitride / polyimide component.

[0102] Step 2: Heat treatment of vanadium nitride to prepare VO2

[0103] The vanadium nitride / substrate composite component is fixed in a vacuum annealing chamber and evacuated to 2×10 -6 After 2000 rpm, oxygen gas was introduced at a flow rate of 2 sccm and the chamber was kept at a vacuum degree of 1 mTorr. The chamber was then heated to an annealing temperature of 400°C and maintained for 0.5 h to convert vanadium nitride into VO2 to form a VO2 / polyimide component.

[0104] The test results of the VO2 intelligent thermal control device prepared in this implementation case are as follows:

[0105] (1) Appearance: The film is uniform and dark brown;

[0106] (2) VO2 crystal phase is monoclinic phase;

[0107] (3) VO2 film thickness is 50.3nm;

[0108] (4) The flexible VO2 intelligent thermal control device has good infrared optical adjustment before and after phase change. In the 1-2.2 μm band, the average transmittance adjustment value is 0.41;

[0109] (5) After simulating one year of proton radiation dose in space under 90 keV proton irradiation conditions, the average transmittance adjustment value in the 1-2.2 μm band is 0.29.

[0110] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride, characterized in that: The method comprises the following steps: S1. Deposition of vanadium nitride layer Depositing a vanadium nitride layer on the surface of the substrate to obtain a vanadium nitride / substrate composite component; S2. Preparation of VO2 by heat treatment of vanadium nitride The vanadium nitride / substrate composite component is heated and heat-insulated under oxygen conditions to convert the vanadium nitride into VO2 to form a VO2 / substrate composite component; S3, VO2 surface deposition protective layer A protective layer is deposited on the VO2 surface of the VO2 / substrate composite component to obtain the vanadium dioxide flexible intelligent thermal control device.

2. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 1, characterized in that: In step S1, the substrate is one of a gold film, a silver film, a titanium film, an aluminum film, a polyimide film, a gold-plated polyimide film, a silver-plated polyimide film, a titanium-plated polyimide film, an aluminum-plated polyimide film, a silicon wafer, a quartz wafer, a sapphire wafer, and a glass wafer.

3. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 1, characterized in that: In step S1, the vanadium nitride layer is obtained by magnetron sputtering; the temperature of the magnetron sputtering is 100-300°C.

4. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 3, characterized in that: The steps of magnetron sputtering are: evacuate and exhaust the cavity of the magnetron sputtering device, heat the substrate, introduce a mixture of argon and nitrogen and maintain a certain vacuum degree, use vanadium nitride as a target material, and perform magnetron sputtering.

5. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 1, characterized in that: In step S1, the thickness of the vanadium nitride layer is 50-1000 nm.

6. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 1, characterized in that: In step S2, the aerobic condition refers to the passage of air or oxygen at a flow rate of 0.5 to 10 sccm; And / or, in step S2, the heating and insulation temperature is 300-400°C and the time is 0.5-5h.

7. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 1, characterized in that: In step S3, the protective layer is a hafnium oxide layer, and the deposition is obtained by magnetron sputtering; the temperature of the magnetron sputtering is 250-350°C.

8. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 7, characterized in that: The steps of magnetron sputtering are: evacuate and exhaust the cavity of the incident DC sputtering device, heat the substrate, introduce a mixture of argon and oxygen and maintain a certain vacuum degree, use metal hafnium as a target material, and perform magnetron sputtering.

9. The method for preparing a vanadium dioxide flexible intelligent thermal control device by heat treating vanadium nitride according to claim 1, characterized in that: In step S3, the thickness of the protective layer is 2-50 nm.

10. Application of the vanadium dioxide flexible intelligent thermal control device prepared by the method according to claim 1 in the field of aerospace intelligent thermal control.

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