High-temperature-resistant infrared stealth film and preparation method thereof

Abstract

The application provides a high-temperature-resistant infrared stealth film and a preparation method of the high-temperature-resistant infrared stealth film. The high-temperature-resistant infrared stealth film is a nano multilayer film composed of 99-50 wt.% of metal and 1-50 wt.% of oxide. The nano multilayer film has a three-layer or more laminated structure composed of metal layers and oxide layers alternately. The thickness of the metal layer is greater than or equal to 400 nm and less than or equal to 2000 nm, the thickness of the oxide layer is greater than or equal to 200 nm and less than or equal to 600 nm, and the infrared emissivity of the nano multilayer film after being kept at 1000 DEG C or above for at least 25 hours is less than 0.17. The high-temperature-resistant infrared stealth film has the excellent characteristics of high-temperature resistance and low infrared emissivity, and is a high-temperature-resistant infrared stealth nano multilayer film material with wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to a high-temperature-resistant infrared stealth film and a preparation method of the high-temperature-resistant infrared stealth film. BACKGROUND

[0002] With the rapid development of modern military detection technology, stealth technology has become an important research direction in the field of military technology. Infrared stealth is an important aspect of stealth technology, which reduces the intensity of external radiation of the target infrared below the sensitivity of the infrared detector, and reduces the probability of being detected by the infrared detector.

[0003] The infrared radiation intensity is related to the infrared emissivity and the surface temperature of the target. In order to realize infrared stealth, infrared stealth materials can be divided into two categories: controlling emissivity and controlling temperature. The former mainly includes paint and film, and the latter mainly includes thermal insulation materials, heat-absorbing materials and high specific radiation polymers. Among them, low-emissivity film is suitable for mid-infrared and far-infrared wave bands, and its role is to make up for the radiation temperature difference between the target and the environment. Its advantages are very low emissivity and good thermal insulation effect. Metal film is a kind of the simplest and most effective low-emissivity film.

[0004] At present, the low-emissivity film has poor performance in high-temperature resistance and infrared stealth. It can only work for 1-2 hours at most in a high-temperature environment above 1000℃, and cannot work for a long time, which seriously affects the wide application of infrared stealth film. Therefore, with the rapid development of aerospace technology, there is an urgent need for a material that has good high-temperature resistance and low infrared emissivity to meet the application requirements of important key parts in the field of aerospace. SUMMARY

[0005] The purpose of the present application is to provide a high-temperature-resistant infrared stealth film and a preparation method of the high-temperature-resistant infrared stealth film, which solves the problem that the existing infrared stealth material cannot have both high-temperature resistance and low infrared emissivity.

[0006] Other characteristics and advantages of the present application will become apparent from the following detailed description, or will be learned by practice of the present application.

[0007] According to a first aspect of the present application, a high-temperature-resistant infrared stealth film is provided, which is a nanomultilayer film composed of 99-50 wt.% of a metal and 1-50 wt.% of an oxide, the nanomultilayer film having a three-layer or more stacked structure composed of metal layers and oxide layers alternately; wherein the thickness of the metal layer is greater than or equal to 400 nm and less than or equal to 2000 nm, the thickness of the oxide layer is greater than or equal to 200 nm and less than or equal to 600 nm, and the infrared emissivity of the nanomultilayer film after being kept at a temperature above 1000℃ for at least 25 hours is less than 0.17.

[0008] In some embodiments of the present application, based on the foregoing scheme, the outermost layer of the nanomultilayer film is the oxide layer.

[0009] In some embodiments of the present application, based on the foregoing scheme, the infrared emissivity of the nanomultilayer film decreases with an increase in the number of layers of the stacked structure.

[0010] In some embodiments of the present application, based on the foregoing scheme, when the nanomultilayer film has a three-layer stacked structure, the infrared emissivity of the nanomultilayer film in the 3-5 μm wave band is less than 0.17 and the infrared emissivity in the 8-14 μm wave band is less than 0.16 after being kept at a temperature of 1000-1500℃ for 25-50 h; when the nanomultilayer film has a four-layer stacked structure, the infrared emissivity of the nanomultilayer film in the 3-5 μm wave band is less than 0.096 and the infrared emissivity in the 8-14 μm wave band is less than 0.082 after being kept at a temperature of 1000-1500℃ for 25-50 h.

[0011] In some embodiments of the present application, based on the foregoing scheme, the metal is at least one of Pt, Au, Rh, Pd, and Ir; and the oxide is at least one of SiO2, ZrO2, HfO2, Al2O3, Ta2O5, and VO2.

[0012] In some embodiments of the present application, based on the foregoing scheme, the nanomultilayer film is prepared by a magnetron sputtering method, wherein the metal layer is formed by a direct current sputtering method and the oxide layer is formed by a radio frequency sputtering method.

[0013] According to a second aspect of the present application, a preparation method of a high-temperature-resistant infrared stealth film is provided, and has the characteristics that the method comprises the following steps: fixing a cleaned ceramic substrate on a magnetron sputtering deposition platform, installing a metal target and an oxide target, adjusting a target base distance to 10-100 mm, and performing vacuumization on a vacuum chamber to below 8*10-4 Pa; argon gas is introduced to maintain the pressure of the vacuum chamber at 0.1-1 Pa; the metal target and the oxide target are simultaneously used to perform pre-sputtering in an argon atmosphere for 1-5 min; after the pre-sputtering is completed, the metal target and the oxide target are respectively used to perform formal sputtering in an argon atmosphere to form a metal layer and an oxide layer, so as to obtain the nano multi-layer film as described in the above embodiment; wherein the metal target is used to perform the pre-sputtering and the formal sputtering in a direct current sputtering mode, and the oxide target is used to perform the pre-sputtering and the formal sputtering in a radio frequency sputtering mode; the power of the direct current sputtering mode is 20-100 W, and the power of the radio frequency sputtering mode is 100-300 W.

[0014] In some embodiments of the present application, based on the foregoing scheme, the thickness and the component ratio of the metal layer and the oxide layer are regulated by controlling the sputtering time and the sputtering power of the formal sputtering.

[0015] In some embodiments of the present application, based on the foregoing scheme, the preparation method further comprises: alternately sputtering the metal target and the oxide target, and taking the oxide layer as an outermost layer to prepare the nano multi-layer film.

[0016] In some embodiments of the present application, based on the foregoing scheme, the alternately sputtering the metal target and the oxide target, and taking the oxide layer as an outermost layer to prepare the nano multi-layer film comprises: performing radio frequency sputtering on the oxide target to form an inner oxide layer, performing direct current sputtering on the metal target on the inner oxide layer to form a middle metal layer, and continuing to perform radio frequency sputtering on the oxide target on the middle metal layer to form an outer oxide layer, so as to form the nano multi-layer film according to the inner oxide layer, the middle metal layer and the outer oxide layer.

[0017] The high-temperature-resistant infrared stealth film in the present application is a nano multi-layer film composed of metal and oxide, wherein the metal has the characteristics of high conductivity, high-temperature resistance and low infrared emissivity, and the oxide has the characteristics of water and oxygen resistance and high-temperature resistance; by combining the two components in different proportions, the high-temperature resistance, the water and oxygen resistance of the infrared stealth film can be improved, the emissivity of the infrared stealth film in the infrared window band can be reduced, and the infrared stealth film can work at a high temperature of 1000℃ or above for a long time while maintaining a low emissivity, thereby having excellent stealth performance.

[0018] Compared with the prior art, the high-temperature-resistant infrared stealth film and the preparation method of the high-temperature-resistant infrared stealth film have the following advantages:

[0019] 1. The infrared stealth film in the present application is high-temperature-resistant and resistant to water and oxygen, can work for a long time in a high-temperature environment above 1000 DEG C, still has a low infrared emissivity, and has excellent infrared stealth performance.

[0020] 2. The infrared stealth film in the present application is prepared by a magnetron sputtering method, in the preparation process, the stability of the infrared stealth film can be improved by a combination of pre-sputtering and formal sputtering, and the infrared stealth film in the present application has simple components, simple preparation process and low equipment requirement.

[0021] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the present application. DETAILED DESCRIPTION

[0022] Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example embodiments to those skilled in the art.

[0023] In addition, the described features, structures, or characteristics can be combined in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the application can be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known methods, devices, articles, or operations are not shown or described in detail to avoid

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The materials, methods, and examples provided herein are illustrative only and in no way limiting.

[0025] The high-temperature-resistant infrared stealth film disclosed in the embodiments of the present application is a nano multilayer film composed of a metal layer and an oxide layer, has a three-layer or more laminated structure composed of the metal layer and the oxide layer alternately, wherein the metal accounts for 99-50 wt.%, and the oxide accounts for 1-50 wt.%; at the same time, the thickness of the metal layer is greater than or equal to 400 nm and less than or equal to 2000 nm, the thickness of the oxide layer is greater than or equal to 200 nm and less than or equal to 600 nm, and the infrared emissivity of the nano multilayer film is less than 0.17 after being kept at a temperature above 1000 DEG C for at least 25 hours.

[0026] In one embodiment of the present application, when forming the nano-multilayer film of the high-temperature resistant infrared stealth film, the oxide layer is used as the outermost layer, and accordingly, the metal layer and the oxide layer have different structures according to the number of layers, for example, the nano-multilayer film can have an inner oxide layer-middle metal layer-outer oxide layer structure, or an inner metal layer-inner oxide layer-outer metal layer-outer oxide layer structure, and the like.

[0027] In one embodiment of the present application, magnetron sputtering can be used to prepare various materials such as metals, semiconductors, and insulators, and has the advantages of simple equipment, easy control, large film area, and strong adhesion, and the like, and therefore, the nano-multilayer film can be formed by the method of magnetron sputtering, and the infrared emissivity of the nano-multilayer film can be controlled by controlling the thickness of each layer during magnetron sputtering.

[0028] Further, different sputtering methods can be used to form the metal layer and the oxide layer in the nano-composite material. Magnetron sputtering includes direct current sputtering, radio frequency sputtering, and direct current-radio frequency co-sputtering. Direct current sputtering refers to sputtering and film deposition by bombarding the target material with ions generated by direct current glow discharge. Radio frequency sputtering refers to sputtering and film deposition by bombarding the target material with positive ions in the radio frequency discharge plasma, and then depositing the target material atoms on the grounded substrate surface. Direct current-radio frequency co-sputtering is suitable for the case of having double targets. In the present embodiment, the metal layer and the oxide layer need to be prepared, and accordingly, the metal target and the oxide target need to be used. Therefore, the direct current-radio frequency co-sputtering can be used to prepare the metal layer and the oxide layer, and the direct current sputtering method can be used to prepare the metal layer, and the radio frequency sputtering method can be used to prepare the oxide layer. The two sputtering methods can also be set to different powers, so as to obtain films with different properties and thicknesses.

[0029] In one embodiment of the present application, the metal layer in the nano-multilayer film can be prepared by using any noble metal, for example, at least one of Pt, Au, Rh, Pd, and Ir. The oxide can be an oxide material with excellent water-oxygen resistance and high-temperature resistance, for example, at least one of SiO2, ZrO2, HfO2, Al2O3, Ta2O5, and VO2.

[0030] In an embodiment of the present application, the infrared emissivity of the nanometer multilayer film with different component proportions and layer thicknesses is different, but the nanometer multilayer film in the embodiment of the present application still has a low infrared emissivity in the atmospheric infrared window band after being kept at a temperature of 1000℃ for at least 25 hours, and the infrared emissivity decreases with the increase of the number of layers of the nanometer multilayer film. Specifically, when the nanometer multilayer film is a three-layer stacked structure, the infrared emissivity of the nanometer multilayer film in the 3-5 μm band is less than 0.17 and the infrared emissivity in the 8-14 μm band is less than 0.16 after being kept at a temperature of 1000-1500℃ for 25-50 hours; when the nanometer multilayer film is a four-layer stacked structure, the infrared emissivity of the nanometer multilayer film in the 3-5 μm band is less than 0.096 and the infrared emissivity in the 8-14 μm band is less than 0.082 after being kept at a temperature of 1000-1500℃ for 25-50 hours.

[0031] The embodiment of the present application also discloses a preparation method of the high-temperature-resistant infrared stealth film.

[0032] Step 1: fixing a cleaned ceramic substrate on a magnetron sputtering deposition support, installing a metal target and an oxide target, adjusting a target base distance to 10-100 mm, and vacuumizing a vacuum chamber to 8x10 -4 Pa or below;

[0033] Step 2: introducing argon to maintain the air pressure of the vacuum chamber at 0.1-1 Pa;

[0034] Step 3: simultaneously pre-sputtering the metal target and the oxide target in an argon atmosphere for 1-5 min;

[0035] Step 4: after the pre-sputtering, respectively sputtering the metal target and the oxide target in an argon atmosphere to form a metal layer and an oxide layer, so as to prepare the nanometer multilayer film in the above embodiment;

[0036] The metal target is sputtered in a direct current sputtering mode and the oxide target is sputtered in a radio frequency sputtering mode; the power of the direct current sputtering mode is 20-100 W and the power of the radio frequency sputtering mode is 100-300 W;

[0037] The target base distance in step 1 is the distance between the target material and the center of the deposition platform; the purity of the argon used in steps 2-3 is greater than or equal to 99.99%; and the metal target material and the oxide target material are simultaneously pre-sputtered in step 3 to remove contaminants such as oxides on the surface of the deposition platform, so as to prevent the contaminants from entering the nano-multilayer film during the magnetron sputtering process, thereby affecting the high-temperature resistance and infrared stealth performance of the nano-multilayer film.

[0038] In an embodiment of the present application, the nano-multilayer film can be formed by alternately sputtering the oxide target material and the metal target material, and taking the oxide layer as the outermost layer. Specifically, the nano-multilayer film can be a nano-multilayer film having an inner oxide layer-intermediate metal layer-outer oxide layer structure, the inner oxide layer is formed by radio frequency sputtering of the oxide target material, the intermediate metal layer is formed by direct current sputtering of the metal target material on the inner oxide layer, and the outer oxide layer is formed by continuing radio frequency sputtering of the oxide target material on the intermediate metal layer, so as to form the nano-multilayer film according to the inner oxide layer, the intermediate metal layer and the outer oxide layer. The nano-multilayer film can also be a nano-multilayer film having an inner metal layer-inner oxide layer-outer metal layer-outer oxide layer structure from inside to outside. Of course, the nano-multilayer film can also have other structures with the oxide layer as the outermost layer, which will not be described herein again. It is worth noting that the sputtering sequence of the metal target material and the oxide target material in the embodiment of the present application is different according to the number of layers of the nano-multilayer film, and the sputtering preparation method of the nano-multilayer film described above is included but not limited to the embodiment of the present application.

[0039] In an embodiment of the present application, the thickness of the metal layer and the oxide layer and the composition ratio of the metal and the oxide in the nano-multilayer film can be adjusted by controlling the sputtering time and the sputtering power during the magnetron sputtering process.

[0040] Next, the method for preparing the nano-multilayer film and the film performance in the present application will be described through different embodiments. It is worth noting that the content of the metal and the oxide in the embodiment of the present application is in mass percentage.

[0041] Embodiment 1:

[0042] Step 1: Fix the cleaned ceramic substrate on the magnetron sputtering deposition platform, install the Pt target material and the SiO2 target material, adjust the target base distance to 30 mm, and vacuumize the vacuum chamber to 8x10 -4 Pa or below;

[0043] Step 2: Introduce argon to maintain the gas pressure in the vacuum chamber at 0.5 Pa;

[0044] Step 3: Simultaneously pre-sputter the Pt target material and the SiO2 target material in an argon atmosphere for 4 min;

[0045] Step 4: After the pre-sputtering, the Pt target and the SiO2 target are used to perform formal sputtering in an argon atmosphere to form an inner layer of SiO2 layer with a thickness of 250 nm, a middle Pt layer with a thickness of 400 nm and an outer layer of SiO2 layer with a thickness of 250 nm, so as to form a SiO2-Pt-SiO2 nanometer multi-layer film; wherein the direct current sputtering power of the Pt target is 40 W, the radio frequency sputtering power of the SiO2 target is 250 W, the content of Pt is 82%, and the content of SiO2 is 18%.

[0046] The infrared emissivity of the SiO2-Pt-SiO2 nanometer multi-layer film generated by the formal sputtering in the 3-5 μm wave band is 0.167, and the infrared emissivity in the 8-14 μm wave band is 0.137 after the high temperature of 1000℃ for 25 h.

[0047] Example 2:

[0048] Step 1: A clean ceramic substrate is fixed on a magnetron sputtering deposition stage, an Au target and a VO2 target are installed, the target-substrate distance is adjusted to 20 mm, and the vacuum chamber is vacuumed to 8×10 -4 Pa or below;

[0049] Step 2: Argon is introduced to maintain the gas pressure of the vacuum chamber at 0.6 Pa;

[0050] Step 3: The Au target and the VO2 target are used to perform pre-sputtering in an argon atmosphere for 5 min;

[0051] Step 4: After the pre-sputtering, the Au target and the VO2 target are used to perform formal sputtering in an argon atmosphere to form an inner layer of VO2 layer with a thickness of 200 nm, a middle Au layer with a thickness of 600 nm and an outer layer of VO2 layer with a thickness of 200 nm, so as to form a VO2-Au-VO2 nanometer multi-layer film; wherein the direct current sputtering power of the Au target is 60 W, the radio frequency sputtering power of the VO2 target is 150 W, the content of Au is 78%, and the content of VO2 is 22%.

[0052] The infrared emissivity of the VO2-Au-VO2 nanometer multi-layer film generated by the formal sputtering in the 3-5 μm wave band is 0.154, and the infrared emissivity in the 8-14 μm wave band is 0.124 after the high temperature of 1200℃ for 28 h.

[0053] Example 3:

[0054] Step 1: A clean ceramic substrate is fixed on a magnetron sputtering deposition stage, an Rh target and a ZrO2 target are installed, the target-substrate distance is adjusted to 40 mm, and the vacuum chamber is vacuumed to 8×10 -4 Pa or below;

[0055] Step 2: The pressure in the vacuum chamber is maintained at 0.3 Pa by introducing argon;

[0056] Step 3: Pre-sputtering is performed for 3 min in an argon atmosphere using Rh and ZrO2 targets simultaneously;

[0057] Step 4: After pre-sputtering, formal sputtering is performed in an argon atmosphere using Rh and ZrO2 targets to form an inner layer of ZrO2 with a thickness of 400 nm, an intermediate layer of Rh with a thickness of 800 nm, and an outer layer of ZrO2 with a thickness of 400 nm, thereby forming a ZrO2-Rh-ZrO2 nanolayer film, wherein the direct current sputtering power of the Rh target is 50 W, the radio frequency sputtering power of the ZrO2 target is 200 W, the content of Rh is 75%, and the content of ZrO2 is 25%.

[0058] The ZrO2-Rh-ZrO2 nanolayer film generated by formal sputtering has an infrared emissivity of 0.163 in the 3-5 μm wave band and an infrared emissivity of 0.155 in the 8-14 μm wave band after being kept at a high temperature of 1100℃ for 34 h.

[0059] Example 4:

[0060] Step 1: A clean ceramic substrate is fixed on a magnetron sputtering deposition stage, a Pd target and an HfO2 target are installed, the target-substrate distance is adjusted to 35 mm, and the vacuum chamber is vacuumed to below 8×10 -4 Pa;

[0061] Step 2: The pressure in the vacuum chamber is maintained at 0.4 Pa by introducing argon;

[0062] Step 3: Pre-sputtering is performed for 4 min in an argon atmosphere using Pd and HfO2 targets simultaneously;

[0063] Step 4: After pre-sputtering, formal sputtering is performed in an argon atmosphere using Pd and HfO2 targets to form an inner layer of HfO2 with a thickness of 200 nm, an intermediate layer of Pd with a thickness of 600 nm, and an outer layer of HfO2 with a thickness of 200 nm, thereby forming a HfO2-Pd-HfO2 nanolayer film; wherein the direct current sputtering power of the Pd target is 45 W, the radio frequency sputtering power of the HfO2 target is 250 W, the content of Pd is 80%, and the content of HfO2 is 20%.

[0064] The HfO2-Pd-HfO2 nanolayer film generated by formal sputtering has an infrared emissivity of 0.167 in the 3-5 μm wave band and an infrared emissivity of 0.146 in the 8-14 μm wave band after being kept at a high temperature of 1300℃ for 42 h.

[0065] Example 5:

[0066] Step 1: Fix the cleaned ceramic substrate on the magnetron sputtering deposition stage, install Ir target and Al2O3 target, adjust the target-substrate distance to 25 mm, and vacuumize the vacuum chamber to 8x10 -4 Pa or below;

[0067] Step 2: Introduce argon to maintain the pressure of the vacuum chamber at 0.5 Pa;

[0068] Step 3: Pre-sputter for 3 min in argon atmosphere using Ir target and Al2O3 target simultaneously;

[0069] Step 4: After pre-sputtering, perform formal sputtering in argon atmosphere using Ir target and Al2O3 target respectively to form an inner layer of Al2O3 layer with a thickness of 350 nm, an intermediate Ir layer with a thickness of 800 nm, and an outer layer of Al2O3 layer with a thickness of 350 nm, to form an Al2O3-Ir-Al2O3 nano-multilayer film; wherein the direct current sputtering power of the Ir target is 55 W, the radio frequency sputtering power of the Al2O3 target is 200 W, the content of Ir is 80%, and the content of Al2O3 is 20%.

[0070] The infrared emissivity of the Al2O3-Ir-Al2O3 nano-multilayer film generated by formal sputtering in the 3-5 μm wave band is 0.163, and the infrared emissivity in the 8-14 μm wave band is 0.122 after heat preservation at 1400℃ for 38h.

[0071] Example 6:

[0072] Step 1: Fix the cleaned ceramic substrate on the magnetron sputtering deposition stage, install Pt target and SiO2 target, adjust the target-substrate distance to 30 mm, and vacuumize the vacuum chamber to 8x10 -4 Pa or below;

[0073] Step 2: Introduce argon to maintain the pressure of the vacuum chamber at 0.5 Pa;

[0074] Step 3: Pre-sputter for 4 min in argon atmosphere using Pt target and SiO2 target simultaneously;

[0075] Step 4: After pre-sputtering, perform formal sputtering in argon atmosphere using Pt target and SiO2 target respectively to form an inner layer of Pt layer with a thickness of 400 nm, an inner layer of SiO2 layer with a thickness of 250 nm, an outer layer of Pt layer with a thickness of 400 nm, and an outer layer of SiO2 layer with a thickness of 250 nm, to form a Pt-SiO2-Pt-SiO2 nano-multilayer film; wherein the direct current sputtering power of the Pt target is 40 W, the radio frequency sputtering power of the SiO2 target is 250 W, the content of Pd is 74%, and the content of SiO2 is 26%.

[0076] The infrared emissivity of the Pt-SiO2-Pt-SiO2 nanomultilayer film formed by formal sputtering at 1000℃ for 25h is 0.0876 in the 3-5μm wave band and 0.0789 in the 8-14μm wave band.

[0077] Example 7

[0078] Step 1: Fix the cleaned ceramic substrate on the magnetron sputtering deposition stage, install the Au target and the VO2 target, adjust the target-substrate distance to 20mm, and vacuumize the vacuum chamber to 8x10 -4 Pa or below;

[0079] Step 2: Introduce argon to maintain the pressure in the vacuum chamber at 0.6Pa;

[0080] Step 3: Pre-sputter the Au target and the VO2 target simultaneously in argon atmosphere for 5min;

[0081] Step 4: After pre-sputtering, form the 600nm-thick inner layer Au layer, the 200nm-thick inner layer VO2 layer, the 600nm-thick outer layer Au layer and the 200nm-thick outer layer VO2 layer by formal sputtering of the Au target and the VO2 target respectively in argon atmosphere to form the Au-VO2-Au-VO2 nanomultilayer film; wherein the direct current sputtering power of the Au target is 60W, the radio frequency sputtering power of the VO2 target is 150W, the content of Au is 70%, and the content of VO2 is 30%.

[0082] The infrared emissivity of the Au-VO2-Au-VO2 nanomultilayer film formed by formal sputtering at 1200℃ for 36h is 0.0952 in the 3-5μm wave band and 0.0811 in the 8-14μm wave band.

[0083] Example 8

[0084] Step 1: Fix the cleaned ceramic substrate on the magnetron sputtering deposition stage, install the Rh target and the ZrO2 target, adjust the target-substrate distance to 40mm, and vacuumize the vacuum chamber to 8x10 -4 Pa or below;

[0085] Step 2: Introduce argon to maintain the pressure in the vacuum chamber at 0.3Pa;

[0086] Step 3: Pre-sputter the Rh target and the ZrO2 target simultaneously in argon atmosphere for 3min;

[0087] Step 4: After the pre-sputtering, the Rh target and the ZrO2 target are used to perform formal sputtering in an argon atmosphere to form an 800 nm thick inner layer Rh layer, a 400 nm thick inner layer ZrO2 layer, an 800 nm thick outer layer Rh layer and a 400 nm thick outer layer ZrO2 layer, so as to form a Rh-ZrO2-Rh-ZrO2 nano multi-layer film; wherein the direct current sputtering power of the Rh target is 50 W, the radio frequency sputtering power of the ZrO2 target is 200 W, the content of Rh is 68%, and the content of ZrO2 is 32%.

[0088] The Rh-ZrO2-Rh-ZrO2 nano multi-layer film generated by formal sputtering has an infrared emissivity of 0.0873 in the 3-5 μm wave band and an infrared emissivity of 0.0763 in the 8-14 μm wave band after being kept at a high temperature of 1300℃ for 50 h.

[0089] Example 9:

[0090] Step 1: A clean ceramic substrate is fixed on a magnetron sputtering deposition stage, a Pd target, a Rh target, an HfO2 target and a VO2 target are installed, the target-substrate distance is adjusted to 35 mm, and the vacuum chamber is vacuumized to 8×10 -4 Pa below;

[0091] Step 2: Argon is introduced to maintain the gas pressure in the vacuum chamber at 0.4 Pa;

[0092] Step 3: The Pd target, the Rh target, the HfO2 target and the VO2 target are simultaneously pre-sputtered in an argon atmosphere for 4 min;

[0093] Step 4: After the pre-sputtering, the Pd target, the Rh target, the HfO2 target and the VO2 target are respectively used to perform formal sputtering in an argon atmosphere to form an 1800 nm thick inner layer Rh layer, a 600 nm thick inner layer VO2 layer, an 1800 nm thick outer layer Pd layer and a 600 nm thick outer layer HfO2 layer, so as to form a Rh-VO2-Pd-HfO2 nano multi-layer film; wherein the direct current sputtering power of the Pd target and the Rh target is 45 W, the radio frequency sputtering power of the HfO2 target and the VO2 target is 250 W, the content of Pd is 38%, the content of Rh is 38%, the content of HfO2 is 12%, and the content of VO2 is 12%.

[0094] The Rh-VO2-Pd-HfO2 nano multi-layer film generated by formal sputtering has an infrared emissivity of 0.0711 in the 3-5 μm wave band and an infrared emissivity of 0.0634 in the 8-14 μm wave band after being kept at a high temperature of 1400℃ for 50 h.

[0095] Example 10:

[0096] Step 1: Fix the cleaned ceramic substrate on the magnetron sputtering deposition stage, install Ir target, Pt target, Al2O3 target and HfO2 target, adjust the target-substrate distance to 25 mm, and vacuumize the vacuum chamber to 8x10 -4 Pa or below;

[0097] Step 2: Introduce argon to maintain the pressure in the vacuum chamber at 0.5 Pa;

[0098] Step 3: Pre-sputter the Ir target, Pt target, Al2O3 target and HfO2 target in argon atmosphere for 3 min;

[0099] Step 4: After pre-sputtering, use the Ir target, Pt target, Al2O3 target and HfO2 target to respectively perform formal sputtering in argon atmosphere to form a 2000 nm thick inner layer Pt layer, a 550 nm thick inner layer HfO2 layer, a 2000 nm thick outer layer Ir layer and a 550 nm thick outer layer Al2O3 layer, so as to form a Pt-HfO2-Ir-Al2O3 nano-multilayer film; wherein the direct current sputtering power of the Ir target and the Pt target is 55 W, the radio frequency sputtering power of the Al2O3 target and the HfO2 target is 200 W, the content of Ir is 39%, the content of Pt is 39%, the content of Al2O3 is 11%, and the content of HfO2 is 11%.

[0100] The infrared emissivity of the Pt-HfO2-Ir-Al2O3 nano-multilayer film generated by formal sputtering in the 3-5 μm wave band is 0.0745, and the infrared emissivity in the 8-14 μm wave band is 0.0618 after heat preservation at 1500℃ for 45 h.

[0101] The nano-multilayer films in Examples 1-5 are inner layer oxide-intermediate layer metal-outer layer oxide nano-multilayer films, and by adjusting the sputtering parameters and sputtering time, nano-multilayer films with different component ratios and layer thicknesses can be prepared. The inner layer oxide-intermediate layer metal-outer layer oxide nano-multilayer film still has excellent infrared emissivity after heat preservation at a high temperature of 1000℃ or above for 25-50 h, specifically, the infrared emissivity in the 3-5 μm wave band is less than 0.17, and the infrared emissivity in the 8-14 μm wave band is less than 0.16.

[0102] The nanolaminate film in Embodiment 6-Embodiment 8 is an inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film, and nanolaminate films with different component ratios and layer thicknesses can be prepared by adjusting sputtering parameters and sputtering time. The inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film still has excellent infrared emissivity after being kept at a high temperature of 1000℃ or above for 25-50h, specifically, the infrared emissivity in the 3-5μm wave band is less than 0.096, and the infrared emissivity in the 8-14μm wave band is less than 0.082. Compared with the inner layer oxide-intermediate metal-outer layer oxide nanolaminate film in Embodiment 1-Embodiment 5, the inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film has better high-temperature-resistant infrared stealth performance.

[0103] The nanolaminate film in Embodiment 9-Embodiment 10 is an inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film with different components, and nanolaminate films with different component ratios and layer thicknesses can be prepared by adjusting sputtering parameters and sputtering time. The inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film still has excellent infrared emissivity after being kept at a high temperature of 1000℃ or above for 25-50h, specifically, the infrared emissivity in the 3-5μm wave band is less than 0.075, and the infrared emissivity in the 8-14μm wave band is less than 0.064. Compared with the inner layer oxide-intermediate metal-outer layer oxide nanolaminate film in Embodiment 1-Embodiment 5 and the inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film in Embodiment 6-Embodiment 8, the inner layer metal-inner layer oxide-outer layer metal-outer layer oxide nanolaminate film with different components has the best high-temperature-resistant infrared stealth performance, that is, as the number of metal layers and oxide layers in the nanolaminate film increases, the nanolaminate film has better high-temperature-resistant infrared stealth performance.

[0104] In the above embodiments, for the nanolaminate film with multiple metal layers or multiple oxide layers, the thickness of the metal layers is the same or the thickness of the oxide layers is the same, which is only a design for reducing parameters. In actual production and processing, the thickness of each metal layer or the thickness of each oxide layer in the nanolaminate film in the embodiments can be the same or different.

[0105] The application solves the problem that infrared stealth materials are difficult to have high temperature resistance and low infrared emissivity, mainly changes the chemical composition ratio and film thickness of the nano multilayer film by the magnetron sputtering method, uses the strong conductivity and high temperature resistance of the noble metal material, reduces the resistivity of the nano multilayer film, enhances the conductivity, and reduces the infrared emissivity of the nano multilayer film; at the same time, different raw materials are used, the interface characteristics of the metal and the oxide are improved by adjusting the parameters of the magnetron sputtering, the binding force and the acting force between different phases are improved, so that the nano multilayer film not only has good mechanical properties, but also has low emissivity after being used in a high temperature environment above 1000 DEG C for a long time, has excellent stealth effect and application prospect.

[0106] The above are only preferred embodiments of the application, and do not limit the patent scope of the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the patent protection scope of the application.

Claims

1. A high-temperature-resistant infrared stealth film, characterized in that: a nanomultilayer film composed of 99-50 wt.% of a metal and 1-50 wt.% of an oxide, the nanomultilayer film having a three-layer or four-layer stack structure composed of metal layers and oxide layers alternately, and the outermost layer of the nanomultilayer film being the oxide layer; wherein the thickness of the metal layer is greater than or equal to 400 nm and less than or equal to 2000 nm, the thickness of the oxide layer is greater than or equal to 200 nm and less than or equal to 600 nm, and the infrared emissivity of the nanomultilayer film in the 3-5 μm wave band is less than 0.17 after being kept at a temperature above 1000℃ for at least 25 hours; wherein when the nanomultilayer film is a four-layer stack structure, the infrared emissivity of the nanomultilayer film in the 3-5 μm wave band is less than 0.096 and the infrared emissivity in the 8-14 μm wave band is less than 0.082 after being kept at a temperature of 1000-1500℃ for 25-50 hours; the metal is at least one of Pt, Au, Rh, Pd, and Ir; and the oxide is at least one of SiO2, ZrO2, HfO2, Al2O3, Ta2O5, and VO2.

2. The high-temperature-resistant infrared stealth film according to claim 1, characterized in that: the infrared emissivity of the nanomultilayer film decreases with an increase in the number of layers of the stack structure.

3. The high-temperature-resistant infrared stealth film according to claim 2, characterized in that: when the nanomultilayer film is a three-layer stack structure, the infrared emissivity of the nanomultilayer film in the 3-5 μm wave band is less than 0.17 and the infrared emissivity in the 8-14 μm wave band is less than 0.16 after being kept at a temperature of 1000-1500℃ for 25-50 hours.

4. The high-temperature-resistant infrared stealth film according to claim 1, characterized in that: the nanomultilayer film is prepared by a magnetron sputtering method, wherein the metal layer is formed by a direct current sputtering method and the oxide layer is formed by a radio frequency sputtering method. including: introducing argon to maintain the gas pressure of the vacuum chamber at 0.1-1 Pa; simultaneously pre-sputtering the metal target and the oxide target in an argon atmosphere for 1-5 min; after the pre-sputtering is completed, sputtering the metal target and the oxide target in an argon atmosphere respectively to form a metal layer and an oxide layer, thereby preparing the high-temperature-resistant infrared stealth film according to any one of claims 1-4; wherein the metal target is subjected to the pre-sputtering and the formal sputtering in a direct current sputtering mode, and the oxide target is subjected to the pre-sputtering and the formal sputtering in a radio frequency sputtering mode; the power of the direct current sputtering mode is 20-100 W, and the power of the radio frequency sputtering mode is 100-300 W; the thickness and the composition ratio of the metal layer and the oxide layer are regulated by controlling the sputtering time and the sputtering power of the formal sputtering; and the preparation method further includes: ​ ​ ​ ​ ​ ​ ​ 5. A method for preparing a high-temperature resistant infrared stealth film, characterized in that, ​ The cleaned ceramic substrate is fixed on the magnetron sputtering deposition stage, the metal target and the oxide target are installed, the target-substrate distance is adjusted to 10-100 mm, and the vacuum chamber is vacuumized to 8x10 -4 Pa or below; ​ ​ ​ ​ 6. The method for preparing the high-temperature resistant infrared stealth film according to claim 5, characterized in that: ​ 7. The method for preparing the high-temperature resistant infrared stealth film according to claim 5, characterized in that, ​ Alternately sputtering the metal target and the oxide target, and taking the oxide layer as the outermost layer to prepare the nano-multilayer film.

8. The method for preparing a high-temperature resistant infrared stealth film according to claim 7, characterized in that, The alternately sputtering the metal target and the oxide target, and taking the oxide layer as the outermost layer to prepare the nano-multilayer film comprises: RF sputtering the oxide target to form an inner oxide layer, DC sputtering the metal target on the inner oxide layer to form a middle metal layer, and continuing RF sputtering the oxide target on the middle metal layer to form an outer oxide layer, so as to form the nano-multilayer film according to the inner oxide layer, the middle metal layer and the outer oxide layer.