Preparation method of infrared wavelength selective emitter and infrared wavelength selective emitter

Abstract

The invention provides a preparation method of an infrared wavelength selective emitter and the infrared wavelength selective emitter, and the method can comprise the steps: a beryllium oxide layer preparation step: preparing a beryllium oxide layer with a first specified thickness on a substrate, and obtaining a current multi-layer thin film; a first all-dielectric layer preparation step: preparing a first all-dielectric layer on the current multi-layer thin film to obtain an updated current multi-layer thin film; a second all-dielectric layer preparation step: preparing a second all-dielectric layer on the current multi-layer thin film to obtain an updated current multi-layer thin film; and repeating the first all-dielectric layer preparation step and the second all-dielectric layer preparation step to form the first all-dielectric layer and the second all-dielectric layer which are alternately stacked until the thickness of the current multi-layer thin film reaches the set thickness, and obtaining the target infrared wavelength selective emitter. By means of the method, infrared selection can be achieved under the condition that the high-temperature-resistant and oxidation-resistant capacity is high.

Description

Technical Field

[0001] This application relates to the technical field of lens manufacturing. Specifically, it relates to a preparation method of an infrared wavelength selective emitter and an infrared wavelength selective emitter. Background Art

[0002] Infrared selective radiation devices are devices that adjust infrared radiation characteristics based on the principle of impedance matching. Currently, multi-layer structure infrared selective radiation devices all face problems such as low upper limit of operating temperature, poor high-temperature stability, and poor oxidation resistance. Summary of the Invention

[0003] The purpose of this application is to provide a preparation method of an infrared wavelength selective emitter and an infrared wavelength selective emitter, which can achieve infrared selection while meeting the requirements of high temperature resistance and high oxidation resistance.

[0004] In a first aspect, the present invention provides a preparation method of an infrared wavelength selective emitter, including: a beryllium oxide layer preparation step: preparing a beryllium oxide layer with a first specified thickness on a substrate to obtain a current multi-layer thin film; a first all-dielectric layer preparation step: preparing a first all-dielectric layer on the current multi-layer thin film to obtain an updated current multi-layer thin film; wherein, the material of the first all-dielectric layer is an oxide; a second all-dielectric layer preparation step: preparing a second all-dielectric layer on the current multi-layer thin film to obtain an updated current multi-layer thin film; wherein, the material of the second all-dielectric layer is an oxide or a fluoride; repeating the above first all-dielectric layer preparation step and second all-dielectric layer preparation step to form the alternately stacked first all-dielectric layer and the second all-dielectric layer until the thickness of the current multi-layer thin film reaches a set thickness, obtaining a target infrared wavelength selective emitter.

[0005] In the above implementation, when designing and manufacturing an infrared wavelength selective emitter, all-dielectric materials have an application temperature exceeding 1200 °C and have characteristics such as high temperature resistance, oxidation resistance, and stable high-temperature physical and chemical properties. Based on these characteristics, an infrared wavelength selective emitter is designed. Based on the stacking of multi-layer all-dielectric layers, it is possible to achieve high temperature resistance and oxidation resistance, and to select infrared wavelengths.

[0006] In an optional implementation, the step of preparing a beryllium oxide layer with a first specified thickness on the substrate includes: using a beryllium metal target with a first specified purity as a sputtering target, and depositing a beryllium oxide layer on the substrate by radio frequency reactive sputtering under the conditions of a first specified flow ratio of oxygen and argon, a first specified sputtering gas pressure, a first specified sputtering power, a first specified sputtering temperature, and a first specified sputtering speed.

[0007] In an alternative embodiment, a beryllium metal target with a first specified purity is used as a sputtering target, and a beryllium oxide layer is deposited on the substrate by a radio frequency reactive sputtering method under the conditions of a first specified flow ratio of oxygen and argon, a first specified sputtering gas pressure, a first specified sputtering power, a first specified sputtering temperature, and a first specified sputtering speed, including: using a beryllium metal target with a first specified purity of not less than 99.99 wt% as a sputtering target, under the conditions that the first specified flow ratio is in the range of 2 sccm:(36 - 60) sccm for the flow ratio of oxygen and argon, the first specified sputtering gas pressure is in the range of 0.2 - 0.6 Pa, the first specified sputtering power is in the range of 300 - 500 W, the first specified sputtering temperature is in the range of 500 - 800 °C, and the first specified sputtering speed is in the range of 6.5 nm / min to 8 nm / min, a beryllium oxide layer is deposited on the substrate by a radio frequency reactive sputtering method.

[0008] In the above implementation, the production of the beryllium oxide layer under defined conditions can better control the thickness and uniformity of the layer.

[0009] In an alternative embodiment, the material of the first all-dielectric layer includes strontium titanate; the preparation of the first all-dielectric layer on the current multi-layer thin film includes: using strontium titanate with a second specified purity as a sputtering target, and depositing a strontium titanate layer on the current multi-layer thin film by a radio frequency sputtering method under the conditions of a second specified flow ratio of oxygen and argon, a second specified sputtering gas pressure, a second specified sputtering power, a second specified sputtering temperature, and a second specified sputtering speed.

[0010] In an alternative embodiment, using strontium titanate with a second specified purity as a sputtering target, and depositing a strontium titanate layer on the current multi-layer thin film by a radio frequency sputtering method under the conditions of a second specified flow ratio of oxygen and argon, a second specified sputtering gas pressure, a second specified sputtering power, and a second specified sputtering temperature, includes: using a strontium titanate ceramic target with a second specified purity of not less than 99.99 wt% as a sputtering target, under the conditions that the second specified flow ratio is in the range of 20:(10 - 20) sccm for the flow ratio of oxygen and argon, the second specified sputtering gas pressure is in the range of 0.2 - 0.6 Pa, the second specified sputtering power is in the range of 300 - 500 W, the second specified sputtering temperature is in the range of 500 - 800 °C, and the second specified sputtering speed is in the range of 2.3 nm / min - 3 nm / min, a strontium titanate layer is deposited on the current multi-layer thin film by a radio frequency sputtering method.

[0011] In the above implementation, the processing parameters for depositing the first all-dielectric layer are adaptively designed. In the case where multiple first all-dielectric layers are required, the thicknesses of different first all-dielectric layers can be adjusted more flexibly, so that the determined infrared wavelength selective emitter can accurately achieve the selection of infrared wavelengths.

[0012] In an alternative embodiment, the material of the second all-dielectric layer includes magnesium fluoride; preparing the second all-dielectric layer on the current multi-layer thin film includes: using magnesium fluoride particles with a third specified purity as an evaporation source, in an environment with a specified vacuum degree and a specified temperature, at a specified deposition rate and under specified electron beam current conditions, using an electron beam vacuum coating method to deposit the second all-dielectric layer on the current multi-layer thin film.

[0013] In an alternative embodiment, using magnesium fluoride particles with a third specified purity as an evaporation source, in an environment with a specified vacuum degree and a specified temperature, at a specified deposition rate and under specified electron beam current conditions, using an electron beam vacuum coating method to deposit the second all-dielectric layer on the current multi-layer thin film includes: using magnesium fluoride particles with a third specified purity of not less than 99.99 wt% as an evaporation source, in an environment with a specified vacuum degree in the range of 10-4 to 10-5 Pa and a specified deposition temperature in the range of 200 to 500 °C, at a specified deposition rate in the range of 0.2 nm / s to 1.5 nm / s and a specified electron beam current in the range of 80 to 120 mA, using an electron beam vacuum coating method to deposit a magnesium fluoride layer.

[0014] In the above implementation, the processing parameters for depositing the first all-dielectric layer are adaptively designed. In the case where multiple second all-dielectric layers are required, the thicknesses of different first all-dielectric layers can be adjusted more flexibly, so that the determined infrared wavelength selective emitter can accurately achieve the selection of infrared wavelengths.

[0015] In a second aspect, the present invention provides an infrared wavelength selective emitter, including: a substrate, a beryllium oxide layer, a first all-dielectric layer, and a second all-dielectric layer; wherein, the number of the first all-dielectric layers is multiple; the number of the second all-dielectric layers is multiple; the first all-dielectric layer and the second all-dielectric layer are alternately stacked; the substrate and one of the first all-dielectric layers are distributed on both sides of the beryllium oxide layer.

[0016] In an alternative embodiment, the number of the first all-dielectric layers is three; the number of the second all-dielectric layers is two; the thicknesses of the three first all-dielectric layers are respectively in the range of 280 nm to 340 nm, 340 mm to 420 nm, and 290 nm to 350 nm; the thicknesses of the two second all-dielectric layers are respectively in the range of 620 nm to 760 nm and 540 nm to 660 nm.

[0017] In an alternative embodiment, the material of the first all-dielectric layer is strontium titanate or titanium oxide; the material of the second all-dielectric layer is magnesium fluoride or silicon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a flowchart of the preparation method of the infrared wavelength-selective emitter provided by the embodiment of the present application;

[0020] Figure 2 It is a schematic structural diagram of the infrared wavelength-selective emitter provided by the embodiment of the present application;

[0021] Figure 3 It is a schematic diagram of the curves of wavelength and reflectivity before and after annealing at 1000 °C for 8 h for the embodiment, Comparative Example 1, and Comparative Example 2 provided by the embodiment of the present application;

[0022] Figure 4 It is a schematic diagram of the high-temperature infrared imaging test results for the embodiment, Comparative Example 1, and Comparative Example 2 provided by the embodiment of the present application;

[0023] Figure 5a It is a schematic diagram of the relationship between the measured temperature, radiation temperature, and radiation intensity data for the embodiment, Comparative Example 1, and Comparative Example 2 provided by the embodiment of the present application;

[0024] Figure 5b It is another schematic diagram of the relationship between the measured temperature, radiation temperature, and radiation intensity data for the embodiment, Comparative Example 1, and Comparative Example 2 provided by the embodiment of the present application.

[0025] Reference Signs: 210 - beryllium oxide layer; 220 - first all-dielectric layer; 230 - second all-dielectric layer; 240 - substrate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0027] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0028] In the description of this application, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of this application.

[0029] In the description of this application, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] An infrared selective radiation device is a device that adjusts infrared radiation characteristics based on the impedance matching principle. Among them, the multi-layer structure infrared selective radiation device has many advantages such as simple structure, stable performance, batch production, and large-area processing. With the rapid development of advanced networking and three-dimensional detection technologies based on modern optics and electronics, the all-round infrared camouflage performance including the rearward direction has become a typical feature and important ability of the new generation of fighter jets. In the aerospace field, the problem of high-temperature infrared radiation management of hot-end parts mainly including high-speed mobile platform windows, radomes, and tail nozzles is particularly prominent.

[0031] Currently, the material systems adopted in the field of high-temperature resistant infrared camouflage mainly include organic materials, semiconductor materials, and metal materials. In the prior art, there is an infrared stealth coating prepared by using an organic resin and nano-metal powder to achieve an infrared camouflage effect with an emissivity of 0.12 in the infrared wavelength range of 3μm to 5μm during a 10-minute thermal test at 1000°C. There is also an infrared microwave compatible stealth coating prepared by using a high-temperature resistant composite ceramic and a metal Ag film layer to achieve an infrared camouflage effect with emissivities of 0.25 and 0.24 in the infrared wavelength ranges of 3μm to 5μm and 8 - 14μm respectively at 900°C. The organic materials, semiconductor materials, and metal materials adopted in the above-mentioned prior art in high-temperature infrared stealth applications all face problems such as low upper limit of use temperature, poor high-temperature stability, and poor oxidation resistance.

[0032] Considering all-dielectric materials such as Al2O3, beryllium oxide, MgF2, etc., the application temperature exceeds 1200 °C, and it is resistant to high temperature and oxidation, and the high-temperature physical and chemical properties are stable. Based on this research, the present application provides a preparation method and an infrared wavelength-selective emitter of an infrared wavelength-selective emitter, which can solve the problem of poor high-temperature resistance and oxidation resistance of the infrared-selective radiation material of the infrared wavelength-selective emitter, and there is an urgent need to develop a new type of high-temperature-resistant all-dielectric multilayer structure infrared wavelength-selective emitter. The preparation method and the infrared wavelength-selective emitter provided by the present application will be described below with reference to some embodiments.

[0033] Figure 1 The flowchart of the preparation method of the infrared wavelength-selective emitter provided by the embodiment of the present application. As Figure 1 shown, the preparation method of the infrared wavelength-selective emitter may include:

[0034] Step 110, preparing a beryllium oxide layer with a first specified thickness on a substrate to obtain a current multilayer thin film.

[0035] This step 110 is used as the preparation step of the beryllium oxide layer 210 (BeO) to realize the preparation of the beryllium oxide layer 210.

[0036] Optionally, each layer of all-dielectric multilayer thin film required for the infrared wavelength-selective emitter can be sequentially deposited on the substrate 240 by methods such as evaporation and sputtering. The substrate 240 can be a single-crystal sapphire substrate 240. In one example, the size of the single-crystal sapphire substrate 240 can be 20 mm × 20 mm × 1 mm, and the crystal orientation is C-0001. Of course, based on the different requirements of the infrared wavelength-selective emitter to be fabricated according to actual needs, the size of the single-crystal sapphire substrate 240 can also be different.

[0037] Optionally, the first specified thickness can be in the range of 1600 nm to 2000 nm. For example, the first specified thickness can be 1600 nm, 1620 nm, 1650 nm, 1700 nm, 1750 nm, 1800 nm, 1850 nm, 1900 nm, 1950 nm, 2000 nm and other thicknesses.

[0038] Step 120, preparing a first all-dielectric layer on the current multilayer thin film to obtain an updated current multilayer thin film.

[0039] Among them, the material of the first all-dielectric layer 220 is an oxide.

[0040] This step 120 is used as the preparation step of the first all-dielectric layer 220 to realize the preparation of the first all-dielectric layer 220. In the case where multiple layers of the first all-dielectric layer 220 need to be prepared, step 120 can be executed multiple times.

[0041] Step 130: Prepare a second all-dielectric layer on the current multi-layer film to obtain an updated current multi-layer film.

[0042] Among them, the material of the second all-dielectric layer 230 is oxide or fluoride.

[0043] This step 130, as the preparation step of the second all-dielectric layer 230, is used to realize the preparation of the second all-dielectric layer 230. In the case where multiple second all-dielectric layers 230 need to be prepared, step 130 can be executed multiple times.

[0044] Repeat the above preparation steps of the first all-dielectric layer 220 and the second all-dielectric layer 230 to form an alternately stacked first all-dielectric layer and second all-dielectric layer 230 until the thickness of the current multi-layer film reaches the set thickness, and obtain a target infrared wavelength selective emitter.

[0045] Repeat the above preparation steps of the first all-dielectric layer 220 and the second all-dielectric layer 230 to form an alternately stacked first all-dielectric layer and second all-dielectric layer 230 until the number of layers of the first all-dielectric layer 220 and the number of layers of the second all-dielectric layer 230 both reach the set number of layers, and obtain a target infrared wavelength selective emitter.

[0046] Optionally, the multi-layer structure obtained from the above steps 110 to 130 can also be placed in a heat treatment furnace and annealed for a specified duration at a specified high temperature in an atmospheric atmosphere to obtain a target infrared wavelength selective emitter.

[0047] The above-mentioned specified high temperature is a temperature in the range of 800°C to 1000°C. The specified high temperature can be 800°C, 820°C, 850°C, 880°C, 900°C, 920°C, 950°C, 980°C, 1000°C, etc. Exemplarily, the temperature can also be adjusted based on the real-time annealing state.

[0048] The above-mentioned specified duration can be in the range of 5h to 10h. The specified duration can be 5h, 6h, 7h, 7.5h, 8h, 8.5h, 9h, 10h, etc.

[0049] In this embodiment, the thicknesses of the first all-dielectric layers of different layers can be different, and the thicknesses of each layer of the first all-dielectric layer 220 are controlled based on actual requirements. The thicknesses of the second all-dielectric layers of different layers can be different, and the thicknesses of each layer of the second all-dielectric layer 230 are controlled based on actual requirements.

[0050] For the target infrared wavelength selective emitter obtained in the embodiment of the present application, its infrared wavelength selective radiation effect can include: the emissivity in the range of infrared wavelength from 3μm to 5μm is 0.74, the emissivity in the range of infrared wavelength from 8μm to 14μm is 0.70, and the emissivity of infrared wavelength from 5μm to 8μm is 0.71.

[0051] Under the above-mentioned infrared wavelength selective radiation effect, the target infrared wavelength selective emitter may include three layers of the first all-dielectric layer 220 and two layers of the second all-dielectric layer 230, with a total of six-layer structure. The material of the first all-dielectric layer 220 is strontium titanate, and the material of the second all-dielectric layer 230 is magnesium fluoride. From bottom to top, there are beryllium oxide (BeO) film layer, strontium titanate (SrTiO3) film layer, magnesium fluoride (MgF2) film layer, strontium titanate (SrTiO3) film layer, magnesium fluoride (MgF2) film layer and strontium titanate (SrTiO3) film layer. Among them, the thickness of each thin film from bottom to top is 1800nm, 310nm, 690nm, 380nm, 600nm and 320nm in turn. Of course, based on the differences in the actual infrared wavelength selective radiation effect or the selection of materials for each layer, the thickness of each layer and the number of layers can also be adjusted adaptively.

[0052] For the infrared wavelength selective emitter obtained by the above method, since all-dielectric materials with high temperature resistance are selected to make each layer structure, the obtained infrared wavelength selector can achieve the effects of high temperature resistance and oxidation resistance.

[0053] Optionally, step 110 described above may include: using a beryllium metal target with a first specified purity as a sputtering target, and depositing a beryllium oxide layer 210 on the substrate 240 by a radio frequency reactive sputtering method under the conditions of a first specified flow ratio of oxygen and argon, a first specified sputtering gas pressure, a first specified sputtering power, a first specified sputtering temperature, and a first specified sputtering speed.

[0054] The above-mentioned first specified purity may be a purity not less than 99.99wt%. A beryllium metal target with a purity not less than 99.99wt% can be used as a sputtering target.

[0055] The above-mentioned first specified flow ratio may be within the range of the flow ratio of oxygen and argon from 2sccm:36sccm to 2sccm:60sccm. For example, the flow ratio of oxygen and argon may be in the ratios of 2sccm:36sccm, 2sccm:40sccm, 2sccm:45sccm, 2sccm:50sccm, 2sccm:55sccm, 2sccm:60sccm, etc.

[0056] The above-mentioned first specified sputtering gas pressure may be within the range of 0.2Pa to 0.6Pa. Exemplarily, the first specified sputtering gas pressure may be 0.2Pa, 0.3Pa, 0.4Pa, 0.5Pa, 0.6Pa and other gas pressures, and the sputtering gas pressure can also be adjusted within the range where the first specified sputtering gas pressure is located based on the actual preparation situation.

[0057] The above-mentioned first specified sputtering power can be a value within the range of 300W to 500W. Exemplarily, the first specified sputtering power can be values such as 300W, 350W, 400W, 450W, 500W, etc.

[0058] The above-mentioned first specified sputtering temperature can be a value within the range of 500°C to 800°C. The specified sputtering temperature can be values such as 500°C, 600°C, 700°C, 800°C, 550°C, 650°C, 750°C, etc. Optionally, the first specified sputtering temperature can also be adjusted within this range based on the sputtering situation.

[0059] The above-mentioned first specified sputtering rate is a value within the range of 6.5nm / min to 8nm / min. In one example, the first specified sputtering rate can be 7.5nm / min. The first specified sputtering rate can also be values such as 6.5nm / min, 6.8nm / min, 7nm / min, 7.5nm / min, 7.7nm / min, 8nm / min, etc.

[0060] In this embodiment, the time for preparing the beryllium oxide layer 210 can be determined based on the required thickness of the beryllium oxide layer 210 and the first specified sputtering rate.

[0061] In one embodiment, the material of the first all-dielectric layer 220 can include strontium titanate (SrTiO3).

[0062] The above-mentioned step 120 can include: using strontium titanate with a second specified purity as the sputtering target, and depositing a strontium titanate layer on the current multi-layer thin film by means of radio frequency sputtering under the conditions of a second specified flow ratio of oxygen and argon, a second specified sputtering pressure, a second specified sputtering power, a second specified sputtering temperature, and a second specified sputtering rate.

[0063] Optionally, the above-mentioned second specified purity can be not less than 99.99wt%. Then, a strontium titanate ceramic target with a purity not less than 99.99wt% can be used as the sputtering target. Optionally, the size of the strontium titanate ceramic target can be 100mm in diameter and 5mm in thickness.

[0064] The above-mentioned second specified flow ratio is within the range of 20sccm:10sccm to 20sccm:20sccm for the flow ratio of oxygen and argon.

[0065] The above-mentioned second specified sputtering pressure is within the range of 0.2Pa to 0.6Pa. Exemplarily, the second specified sputtering pressure can be values such as 0.2Pa, 0.3Pa, 0.4Pa, 0.5Pa, 0.6Pa, etc.

[0066] The above-mentioned second specified sputtering power is within the range of 300W to 500W.

[0067] The above-mentioned second specified sputtering temperature can be in the range of 500°C to 800°C. Exemplarily, the second specified sputtering temperature can be values such as 500°C, 600°C, 700°C, 750°C, 800°C.

[0068] The above-mentioned second specified sputtering speed can be in the range of 2.3 nm / min to 3 nm / min. In one example, the second specified sputtering speed can be 2.66 nm / min. The second specified sputtering speed can also be values such as 2.3 nm / min, 2.5 nm / min, 2.9 nm / min, 3 nm / min.

[0069] In this embodiment, the time for preparing the strontium titanate layer can be calculated based on the currently required thickness of the strontium titanate layer and the second specified sputtering speed.

[0070] In the above example, the target infrared wavelength selection emitter can include a six-layer structure, which is, from bottom to top, a BeO film layer, a SrTiO3 film layer, a MgF2 film layer, a SrTiO3 film layer, a MgF2 film layer, and a SrTiO3 film layer. The target infrared wavelength selection emitter can include three first all-dielectric layers of strontium titanate, and the thicknesses of the three first all-dielectric layers of strontium titanate are 310 nm, 380 nm, and 320 nm in sequence. In this example, the preparation time for each first all-dielectric layer 220 can be determined based on the thickness of the three first all-dielectric layers 220 and the second specified sputtering speed.

[0071] In one implementation, the material of the first all-dielectric layer 220 can include titanium oxide (TiO2).

[0072] Using titanium oxide with a purity of not less than 99.99 wt% as the sputtering target, optionally, the size of the titanium oxide target can be a diameter of 100 mm and a thickness of 5 mm. The titanium oxide first all-dielectric layer 220 can be deposited by radio frequency sputtering under the conditions that the flow ratio of oxygen and argon is 20 sccm:10 sccm to 20 sccm:20 sccm, the sputtering gas pressure is 0.2 Pa to 0.6 Pa, the sputtering power is 300 W to 500 W, and the sputtering temperature is 500°C to 800°C.

[0073] Optionally, the sputtering speed for depositing the first all-dielectric layer of titanium oxide can be a value in the range of 6.5 nm / min to 8 nm / min or 2.3 nm / min to 3 nm / min. For example, the sputtering speed can be 2.66 nm / min.

[0074] In this embodiment, the time for preparing the titanium oxide layer can be calculated based on the currently required thickness of the titanium oxide layer and the sputtering speed used for sputtering the titanium oxide layer.

[0075] In one embodiment, the material of the second all-dielectric layer 230 may include magnesium fluoride (MgF2).

[0076] The above step 130 may include: using magnesium fluoride particles with a third specified purity as an evaporation source, in a specified vacuum and specified temperature environment, at a specified deposition rate and specified electron beam current conditions, preparing the second all-dielectric layer 230 on the current multi-layer film by means of electron beam vacuum coating.

[0077] The above third specified purity is that the purity can be not less than 99.99 wt%, so magnesium fluoride particles with a purity of not less than 99.99 wt% can be used as the evaporation source.

[0078] The above specified vacuum can be in the range of 10 -4 Pa to 10 -5 Pa. The above specified deposition temperature is in the range of 200°C to 500°C. Exemplarily, the specified deposition temperature can be 200°C, 300°C, 350°C, 400°C, 450°C, 500°C and other values.

[0079] The above specified deposition rate is in the range of 0.2 nm / s to 1.5 nm / s. The specified deposition rate can be 0.2 nm / s, 0.5 nm / s, 0.6 nm / s, 0.8 nm / s, 0.9 nm / s, 1 nm / s, 1.3 nm / s, 1.5 nm / s and other values. The specified deposition rate can also be adaptively adjusted within this rate range based on the actual production situation.

[0080] The above specified electron beam current is under the condition of being in the range of 80 mA to 120 mA. The specified electron beam current can be 80 mA, 90 mA, 95 mA, 100 mA, 110 mA, 120 mA and other values.

[0081] In this embodiment, the deposition time of the magnesium fluoride layer can be determined based on the thickness of the currently required magnesium fluoride layer and the above specified deposition rate.

[0082] Taking the above example as an example, the target infrared wavelength selective emitter may include a six-layer structure, which are successively a BeO film layer, a SrTiO3 film layer, a MgF2 film layer, a SrTiO3 film layer, a MgF2 film layer and a SrTiO3 film layer from bottom to top. The target infrared wavelength selective emitter may include two second all-dielectric layers of magnesium fluoride, and the thicknesses of the two second all-dielectric layers of magnesium fluoride are 690 nm and 600 nm respectively. In this example, the preparation time of each second all-dielectric layer of magnesium fluoride can be determined based on the thickness of the two second all-dielectric layers of magnesium fluoride and the above specified deposition rate.

[0083] In one embodiment, the material of the second all-dielectric layer 230 may include silicon dioxide.

[0084] Using Be silicon dioxide with a purity of not less than 99.99 wt% as the sputtering target, the target size is 100 mm in diameter and 5 mm in thickness. Under the conditions that the flow ratio of oxygen to argon is 2 sccm:36 sccm to 2 sccm:60 sccm, the sputtering pressure is 0.2 Pa to 0.6 Pa, the sputtering power is 300 W to 500 W, and the sputtering temperature is 500 °C to 800 °C, the silicon dioxide layer is deposited by radio frequency reactive sputtering.

[0085] The target infrared wavelength selective emitter obtained through the above manufacturing process has the following infrared wavelength selective radiation effects: the emissivity in the range of 3 μm to 5 μm of the infrared wavelength is 0.74, the emissivity in the range of 8 μm to 14 μm of the infrared wavelength is 0.70, and the emissivity in the range of 5 μm to 8 μm is 0.71. On this basis, at a test temperature of 800 °C: the infrared imaging test results in the range of 3 μm to 5 μm show that compared with the SiC substrate, the radiation temperature of the target infrared wavelength selective emitter achieved by the method provided in the embodiment of the present application decreased by 129 °C, and the infrared radiation intensity decreased by 41.4%; the temperature measurement results of the patch-type K-type thermocouple show that compared with the Pt substrate, the actual surface temperature of the target infrared wavelength selective emitter achieved by the method provided in the embodiment of the present application decreased by 34 °C, and the infrared radiation intensity decreased by 12.6%.

[0086] The embodiment of the present application also provides an infrared wavelength selective emitter, as Figure 2 shown, the infrared wavelength selective emitter may include: a substrate 240, a beryllium oxide layer 210, a first all-dielectric layer 220, and a second all-dielectric layer 230.

[0087] Among them, the number of the first all-dielectric layers 220 is multiple; the number of the second all-dielectric layers 230 is multiple; the first all-dielectric layers 220 and the second all-dielectric layers 230 are alternately stacked.

[0088] The substrate 240 and one of the first all-dielectric layers 220 are distributed on both sides of the beryllium oxide layer 210. That is, the beryllium oxide layer 210 may be disposed between the substrate 240 and one of the first all-dielectric layers 220.

[0089] Optionally, as Figure 2 shown, the number of the above first all-dielectric layers is three; the number of the above second all-dielectric layers is two.

[0090] The thicknesses of the three layers of the first all-dielectric layer 220 are respectively in the ranges of 280 nm to 340 nm, 340 nm to 420 nm, and 290 nm to 350 nm. Exemplarily, the thickness of the first layer of the first all-dielectric layer 220 can be values such as 280 nm, 290 nm, 310 nm, 320 nm, 340 nm. The thickness of the second layer of the first all-dielectric layer 220 can be values such as 340 nm, 350 nm, 370 nm, 380 nm, 400 nm, 420 nm. The thickness of the third layer of the first all-dielectric layer 220 can be values such as 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm. For example, the thicknesses of the three layers of the first all-dielectric layer 220 are respectively: 310 nm, 380 nm, 320 nm.

[0091] The thicknesses of the two layers of the second all-dielectric layer 230 are respectively in the ranges of 620 nm to 760 nm and 540 nm to 660 nm. Exemplarily, the thickness of the first layer of the second all-dielectric layer 230 can be values such as 620 nm, 640 nm, 650 nm, 690 nm, 710 nm, 760 nm. The thickness of the second layer of the second all-dielectric layer 230 can be values such as 540 nm, 560 nm, 580 nm, 600 nm, 620 nm, 640 nm, 660 nm. For example, the thicknesses of the two layers of the second all-dielectric layer 230 are respectively 690 nm, 600 nm.

[0092] In one example, from bottom to top are the substrate 240, the beryllium oxide layer 210, the first all-dielectric layer 220, the second all-dielectric layer 230, the first all-dielectric layer 220, the second all-dielectric layer 230, and the first all-dielectric layer 220. The thicknesses of each thin film layer from bottom to top are 1800 nm, 310 nm, 690 nm, 380 nm, 600 nm, and 320 nm in sequence.

[0093] Optionally, the material of the first all-dielectric layer 220 can be strontium titanate, and the material of the second all-dielectric layer 230 can also be titanium oxide.

[0094] Optionally, the material of the second all-dielectric layer 230 can be magnesium fluoride, and the material of the second all-dielectric layer 230 can also be silicon dioxide.

[0095] Taking the material of the first all-dielectric layer 220 as strontium titanate and the material of the second all-dielectric layer 230 as magnesium fluoride, in an example of an infrared wavelength-selective emitter, the six-layer structure from bottom to top is respectively: BeO film layer, SrTiO3 film layer, MgF2 film layer, SrTiO3 film layer, MgF2 film layer, and SrTiO3 film layer. If the substrate 240 structure is added, the infrared wavelength-selective emitter is a seven-layer structure, which are respectively: substrate 240, BeO film layer, SrTiO3 film layer, MgF2 film layer, SrTiO3 film layer, MgF2 film layer, and SrTiO3 film layer.

[0096] The infrared wavelength-selective emitter of this embodiment can be used in hot-end parts such as fighter jet canopies, radomes, and tail nozzles under high-temperature and high-speed working conditions. The infrared wavelength-selective emitter provided by the embodiment of the present application has good high-temperature stability.

[0097] The following combines some examples and comparative examples to analyze the effects of the infrared wavelength-selective emitter obtained in the embodiment of the present application.

[0098] As Figure 3 shown, it shows the schematic diagrams of the curves of wavelength and reflectivity before and after annealing for 8 h at 1000 °C in the example, comparative example 1, and comparative example 2. The test results show that before and after annealing, the example maintains the selective radiation effect with the emissivity less than 0.3 in the infrared wavelength range of 3 μm to 5 μm and the emissivity greater than 0.7 in the infrared wavelength range of 5 μm to 8 μm; before and after annealing, comparative example 1 maintains the infrared low-emission effect with the emissivity less than 0.05 in the infrared wavelength range of 3 μm to 8 μm; before and after annealing, comparative example 2 maintains the infrared high-emission effect with the emissivity greater than 0.9 in the infrared wavelength range of 3 μm to 8 μm.

[0099] In this example, the infrared imaging test of the example and the comparative examples can also be combined with a high-temperature infrared imaging test system. The high-temperature infrared imaging test system mainly includes a 3-5 μm high-temperature infrared imaging camera, a high-temperature-resistant sample stage, and a back-heating flame spray gun. Among them, the high-temperature-resistant sample stage can hold three groups of samples of the example, comparative example 1, and comparative example 2. Further, K-type thermocouple 1 and K-type thermocouple 2 can be respectively arranged on the surfaces of the example and comparative example 1 for accurately measuring the surface temperature.

[0100] Figure 4 shows the schematic diagrams of the high-temperature infrared imaging test results of the example, comparative example 1, and comparative example 2; the infrared imaging temperatures of the example, comparative example 1, and comparative example 2 in the temperature range of 400 °C to 800 °C are marked in the figure; and the thermocouple-measured surface temperatures of the example and comparative example 1.

[0101] Figure 5a and Figure 5bThe figure shows a schematic diagram of the relationship between the measured temperature, radiation temperature and radiation intensity data of the embodiment provided by the present application, Comparative Example 1 and Comparative Example 2. The test results show that among the 5 infrared imaging temperature measurement points, the imaging temperature of Comparative Example 2 with a high emissivity in the infrared wavelength range of 3 μm to 5 μm is 775 °C. Compared with the imaging temperature of the embodiment, which is 636 °C, the imaging temperature drops by 129 °C, and the corresponding radiation intensity decreases by 41.4%; the measured temperature of Comparative Example 1 with a low emissivity in the infrared wavelength range of 5 μm to 8 μm is 762 °C. Compared with the measured temperature of the embodiment, which is 728 °C, the actual temperature drops by 34 °C due to the selected radiative cooling, and the corresponding radiation intensity decreases by 12.6%.

[0102] Based on the test results of the above examples, it shows that the infrared wavelength selective emitter prepared by the method provided in the embodiments of the present application can maintain stable radiation characteristics in the infrared wavelength range of 3 μm to 14 μm after annealing at 1000 °C for 8 h, and exhibits good high-temperature infrared camouflage characteristics in the infrared imaging test in the range of 400 °C to 800 °C.

[0103] The above are only optional embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0104] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, and all should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A preparation method of an infrared wavelength-selective emitter, characterized in that, Including: Step of preparing beryllium oxide layer: A beryllium oxide layer with a first specified thickness is prepared on a substrate to obtain a current multi-layer thin film; Step of preparing the first all-dielectric layer: A first all-dielectric layer is prepared on the current multi-layer thin film to obtain an updated current multi-layer thin film; wherein, the material of the first all-dielectric layer is an oxide; Step of preparing the second all-dielectric layer: A second all-dielectric layer is prepared on the current multi-layer thin film to obtain an updated current multi-layer thin film; wherein, the material of the second all-dielectric layer is an oxide or a fluoride; Repeat the above step of preparing the first all-dielectric layer and the step of preparing the second all-dielectric layer to form the first all-dielectric layer and the second all-dielectric layer stacked alternately until the thickness of the current multi-layer thin film reaches a set thickness, and a target infrared wavelength selective emitter is obtained.

2. The method according to claim 1, wherein The step of preparing a beryllium oxide layer with a first specified thickness on the substrate includes: Using a beryllium metal target with a first specified purity as a sputtering target, depositing a beryllium oxide layer on the substrate by radio frequency reactive sputtering under the conditions of a first specified flow ratio of oxygen and argon, a first specified sputtering pressure, a first specified sputtering power, a first specified sputtering temperature, and a first specified sputtering speed.

3. The method according to claim 2, wherein The step of depositing a beryllium oxide layer on the substrate by radio frequency reactive sputtering under the conditions of using a beryllium metal target with a first specified purity as a sputtering target, a first specified flow ratio of oxygen and argon, a first specified sputtering pressure, a first specified sputtering power, a first specified sputtering temperature, and a first specified sputtering speed includes: Using a beryllium metal target with a first specified purity of not less than 99.99 wt% as a sputtering target, depositing a beryllium oxide layer on the substrate by radio frequency reactive sputtering under the conditions that the flow ratio of oxygen and argon is in the range of 2 sccm:(36 - 60) sccm, the first specified sputtering pressure is in the range of 0.2 - 0.6 Pa, the first specified sputtering power is in the range of 300 - 500 W, the first specified sputtering temperature is in the range of 500 - 800 °C, and the first specified sputtering speed is from 6.5 nm / min to 8 nm / min.

4. The method according to claim 1, characterized in that, The material of the first all-dielectric layer includes strontium titanate; The step of preparing the first all-dielectric layer on the current multi-layer thin film includes: Using strontium titanate with a second specified purity as a sputtering target, depositing a strontium titanate layer on the current multi-layer thin film by radio frequency sputtering under the conditions of a second specified flow ratio of oxygen and argon, a second specified sputtering pressure, a second specified sputtering power, a second specified sputtering temperature, and a second specified sputtering speed.

5. The method according to claim 4, wherein The step of depositing a strontium titanate layer on the current multi-layer thin film by radio frequency sputtering under the conditions of using strontium titanate with a second specified purity as a sputtering target, a second specified flow ratio of oxygen and argon, a second specified sputtering pressure, a second specified sputtering power, and a second specified sputtering temperature includes: Using a strontium titanate ceramic target with the second specified purity of not less than 99.99 wt%, under the conditions that the second specified flow rate ratio is in the range of 20:(10 - 20) sccm for the flow rate ratio of oxygen to argon, the second specified sputtering gas pressure is in the range of 0.2 - 0.6 Pa, the second specified sputtering power is in the range of 300 - 500 W, the second specified sputtering temperature is in the range of 500 - 800 °C, and the second specified sputtering speed is in the range of 2.3 nm / min - 3 nm / min, a strontium titanate layer is deposited on the current multilayer thin film by radio frequency sputtering method.

6. The method according to claim 1, wherein The material of the second all-dielectric layer includes magnesium fluoride; Preparing the second all-dielectric layer on the current multilayer thin film includes: Using magnesium fluoride particles with the third specified purity as the evaporation source, in a specified vacuum degree and specified temperature environment, under the conditions of a specified deposition rate and specified electron beam current, the second all-dielectric layer is prepared on the current multilayer thin film by electron beam vacuum coating method.

7. The method according to claim 6, characterized in that The step of using magnesium fluoride particles with the third specified purity as the evaporation source, in a specified vacuum degree and specified temperature environment, under the conditions of a specified deposition rate and specified electron beam current, and preparing the second all-dielectric layer on the current multilayer thin film by electron beam vacuum coating method includes: Using magnesium fluoride particles with the third specified purity of not less than 99.99 wt% as the evaporation source, in an environment where the specified vacuum degree is in the range of 10-4 - 10-5 Pa and the specified deposition temperature is in the range of 200 - 500 °C, under the conditions that the specified deposition rate is in the range of 0.2 nm / s - 1.5 nm / s and the specified electron beam current is in the range of 80 - 120 mA, a magnesium fluoride layer is deposited by electron beam vacuum coating method.

8. An infrared wavelength-selective emitter, characterized in that, Including: A substrate, a beryllium oxide layer, a first all-dielectric layer, and a second all-dielectric layer; Among them, the number of the first all-dielectric layers is multiple; The number of the second all-dielectric layers is multiple; the first all-dielectric layers and the second all-dielectric layers are alternately stacked; The substrate and one of the first all-dielectric layers are distributed on both sides of the beryllium oxide layer.

9. The infrared wavelength selection emitter according to claim 8, characterized in that, The number of the first all-dielectric layers is three; the number of the second all-dielectric layers is two; The thicknesses of the three first all-dielectric layers are respectively in the range of 280 nm to 340 nm, 340 nm to 420 nm, and 290 nm to 350 nm; The thicknesses of the two second all-dielectric layers are respectively in the range of 620 nm to 760 nm and 540 nm to 660 nm.

10. The infrared wavelength selection emitter according to claim 8, wherein, The material of the first all-dielectric layer is strontium titanate or titanium oxide; The material of the second all-dielectric layer is magnesium fluoride or silicon dioxide.

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