Infrared stealth composite coating as well as preparation method and application thereof

Abstract

The invention relates to an infrared stealth composite coating as well as a preparation method and application thereof, and belongs to the technical field of infrared stealth coatings. The infrared stealth composite coating sequentially comprises a bonding layer, a ceramic layer, an aluminum film layer, a nickel film layer and a platinum film layer, and the material of the bonding layer comprises NiCoCrAlYTa. The bonding layer, the ceramic layer, the aluminum film layer, the nickel film layer and the platinum film layer are sequentially arranged on the surface of the base body to form the infrared stealth composite coating, and the problems that the aluminum film layer is melted at a high temperature, so that the outer film layer is broken, and the stealth effect is reduced can be solved; the composite coating obtained through the structural design has excellent infrared stealth performance, high-temperature oxidation resistance and thermal shock resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of infrared stealth coating, and particularly relates to an infrared stealth composite coating, a preparation method thereof and an application thereof. Background Art

[0002] Stealth technology, namely low detectability technology or target feature control technology, its main purpose is to change the signal difference between the target and the background to make it tend to be consistent, and when the signal difference is smoothed out, it is stealth. With the rapid development of detection technology, the detection technology has been extended from microwave detection to infrared, acoustic wave and other bands. In order to meet the requirements of multi-band detection technology, stealth technology has also put forward high-performance requirements from single-band stealth to multi-band compatible stealth, that is, compatible visible light stealth, infrared stealth, laser stealth, radar microwave stealth and even full-band stealth technology. Infrared detection is based on the principle of thermal imaging, and since the object itself is an infrared light source, infrared detection is relatively easy in the two atmospheric windows of medium wave and long wave, and has the characteristics of strong anti-interference ability and all-weather operation. Therefore, improving infrared stealth technology has received great attention.

[0003] It can be known from the Stefan-Boltzmann law that the magnitude of the target radiation ability is determined by the emissivity and temperature. Therefore, reducing the target surface emissivity and controlling the target surface temperature are the basic ways to achieve infrared stealth. High-temperature infrared stealth coatings generally consist of an infrared radiation attenuation layer and a thermal radiation control layer, which is a typical multi-layer structure. The infrared radiation attenuation layer mainly uses materials with a relatively low infrared emissivity in a specific band, such as metal coating materials, polymer materials, etc., so that this layer has good low infrared emissivity characteristics, can effectively weaken the infrared radiation emitted by the target surface, and enhance the thermal radiation scattering performance of the target surface, thereby reducing the possibility of the target being detected by an infrared detector. The thermal radiation control layer generally uses nano-materials, metal oxides, ceramic materials, etc., which can effectively control the scattering range and scattering intensity of the target surface thermal radiation, as well as the temperature transfer in the coating, and reduce the influence of temperature factors on the magnitude of the infrared radiation amount.

[0004] Patent CN117802500A discloses a high-temperature infrared stealth coating material, a preparation method thereof and an application thereof. The coating includes an adhesive layer, a ceramic layer, an aluminum film layer and a platinum metal layer, and can improve the bonding strength and thermal shock performance on the basis of maintaining good infrared stealth performance of the coating. However, the aluminum film layer in this coating will undergo melting and agglomeration in a vacuum high-temperature environment, and during this process, due to the relatively thin platinum film layer, the downward compressive stress is insufficient and the film layer will rupture. Therefore, it is of great significance to develop an infrared stealth composite coating with excellent high-temperature oxidation resistance and thermal shock resistance. Summary of the Invention

[0005] The object of the present invention is to overcome the problems existing in the above-mentioned prior art, and to provide an infrared stealth composite coating, a preparation method and an application thereof.

[0006] The present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides an infrared stealth composite coating, which sequentially includes an adhesive layer, a ceramic layer, an aluminum film layer, a nickel film layer and a platinum film layer; the material of the adhesive layer includes NiCoCrAlYTa.

[0008] The present invention provides an infrared stealth composite coating with high-temperature oxidation resistance and low infrared emissivity. The adhesive layer material is NiCoCrAlYTa, so that the coating has better high-temperature oxidation resistance and thermal shock resistance. The ceramic layer is used as a thermal barrier coating, and a metal film layer is arranged on its surface, thereby improving the high-temperature oxidation performance and stealth effect of the composite coating. The present invention uses a ceramic layer with excellent high-temperature oxidation resistance and thermal shock resistance as the bottom layer, which can effectively inhibit the increase of instantaneous temperature and the rise of thermal radiation intensity. On the basis of the ceramic layer, an aluminum film layer and a nickel film layer are further prepared as an intermediate layer structure, and a platinum film layer with low infrared emissivity and excellent antioxidant performance is arranged on the outermost layer. The aluminum film layer and the ceramic layer will generate a dense alumina film in a vacuum high-temperature environment, which can not only enhance the bonding strength between the metal layer and the ceramic layer, but also further improve the high-temperature oxidation resistance of the ceramic layer. Since the aluminum film layer will undergo melting and agglomeration phenomena in a vacuum high-temperature environment, which will cause the film layer to rupture, the present invention further arranges a nickel film layer on the surface of the aluminum film layer. The nickel film layer gives the aluminum film layer a large compressive stress, so that the aluminum film layer cannot damage the coating, and the thermal expansion coefficients of nickel and platinum are more matched. The bonding strength between the metal layers will increase due to the diffusion phenomenon, further improving the performance of the infrared stealth composite coating of the present invention.

[0009] Preferably, the thickness of the adhesive layer is 50 μm - 100 μm; further, in the specific embodiment of the present invention, the thickness of the adhesive layer is 60 μm - 90 μm.

[0010] Preferably, the thickness of the ceramic layer is 100 μm - 200 μm.

[0011] Preferably, the material of the ceramic layer includes ZrO 2 -7wt%Y 2 O 3 .

[0012] Preferably, the thickness of the aluminum film layer is 3 μm - 4 μm.

[0013] Preferably, the thickness of the nickel film layer is 1 μm - 3 μm.

[0014] Preferably, the thickness of the platinum film layer is 1 μm - 3 μm.

[0015] In the present invention, the thickness of the aluminum film layer can fully generate an alumina thin film at this thickness, strengthening the bonding strength between its metal film layer and the ceramic layer. The nickel film layer, as an intermediate layer structure, effectively reduces the influence caused by the mismatch of the thermal expansion coefficients between the surface platinum film layer and the bottom layer, and reduces the influence of metal diffusion on the infrared performance. In addition, the present invention reduces the thickness of the ceramic layer, which can greatly reduce the coating weight and, while ensuring its basic performance, reduce the load during application.

[0016] In a second aspect, the present invention provides a method for preparing the infrared stealth composite coating, including the following steps: successively preparing a bonding layer, a ceramic layer, an aluminum film layer, a nickel film layer, and a platinum film layer on the surface of a substrate, and then performing heat treatment to obtain the infrared stealth composite coating.

[0017] The preparation method of the present invention prepares three different metal film layers, namely an aluminum film layer, a nickel film layer, and a platinum film layer, on the surface of the ceramic layer, and then performing heat treatment on them can enable the prepared infrared stealth composite coating to have excellent high-temperature oxidation resistance and thermal shock resistance while ensuring low infrared emissivity in multiple temperature ranges. Heat treatment can make the grains of the metal film layer grow and form and maintain uniformity. The bottom ceramic layer has thermal shock resistance and low infrared emissivity at high temperatures, and the structural design of the metal film layer has the functions of high-temperature oxidation resistance and low infrared emissivity in multiple temperature ranges.

[0018] Preferably, the preparation methods of the bonding layer and the ceramic layer independently include at least one of atmospheric plasma spraying and low-pressure plasma spraying.

[0019] Preferably, the conditions for atmospheric plasma spraying are: argon gas flow rate 40 NLPM - 50 NLPM, hydrogen gas flow rate 5 NLPM - 10 NLPM, current 500 A - 600 A, rotation speed 1 r / min - 3 r / min, spraying distance 100 mm - 120 mm, and gun travel speed 650 mm / s - 750 mm / s.

[0020] Preferably, the conditions for low-pressure plasma spraying are: argon gas flow rate 40 NLPM - 50 NLPM, hydrogen gas flow rate 5 NLPM - 10 NLPM, current 500 A - 600 A, rotation speed 1 r / min - 3 r / min, spraying distance 100 mm - 120 mm, and gun travel speed 650 mm / s - 750 mm / s.

[0021] Preferably, the preparation methods of the aluminum film layer, the nickel film layer, and the platinum film layer include magnetron sputtering.

[0022] Preferably, the conditions for magnetron sputtering are: magnetron target current 2 - 5 A, bias voltage 100 - 180 V, and gas pressure less than 5×10 -3 Pa.

[0023] Preferably, the conditions of the heat treatment are as follows: first, keep the temperature at 650°C - 700°C for 2h - 4h, and then keep the temperature at 900°C - 1100°C for 4h - 8h; during the heat treatment process, the vacuum oxygen partial pressure does not exceed 2×10 -4 Pa.

[0024] More specifically, the heating rate during the heat treatment is 6°C / min - 10°C / min.

[0025] Preferably, the substrate is pretreated; pretreating the substrate can improve the bonding strength between the subsequent composite coating and the substrate. There is no special limitation on the pretreatment method, which can be adjusted according to conventional means in the field. Specifically, in an embodiment of the present invention, the pretreatment is as follows: the substrate is ultrasonically cleaned with gasoline and alcohol in sequence, and then sandblasted with corundum at 0.2MPa - 0.5MPa.

[0026] Preferably, the substrate includes superalloy.

[0027] Specifically, in some embodiments, the superalloy substrate is a nickel-based superalloy.

[0028] In a third aspect, the present invention provides the application of the infrared stealth composite coating or the infrared stealth composite coating prepared by the preparation method of the infrared stealth composite coating in aerospace engines, aerospace vehicles, armored vehicles, and medical devices.

[0029] The infrared stealth composite coating of the present invention has excellent infrared stealth effect and high-temperature oxidation stability, and can be applied in aspects such as aerospace engines, aerospace vehicles, armored vehicles, and medical devices.

[0030] The present invention has the following beneficial effects: The present invention forms an infrared stealth composite coating by sequentially arranging a bonding layer, a ceramic layer, an aluminum film layer, a nickel film layer, and a platinum film layer on the surface of the substrate, which can overcome the problem that the aluminum film layer melts at high temperatures, resulting in the rupture of the outer film layer and the decline of the stealth effect. The composite coating designed by the structure of the present invention has excellent infrared stealth, high-temperature oxidation resistance, and thermal shock resistance. Description of the Drawings

[0031] Figure 1 It is a cross-sectional morphology diagram of the infrared stealth composite coating of Example 1;

[0032] Figure 2 It is a cross-sectional morphology diagram of the platinum film layer, nickel film layer, aluminum film layer, and ceramic layer of the infrared stealth composite coating of Example 1;

[0033] Among them, 1 - substrate; 2 - bonding layer; 3 - ceramic layer; 4 - aluminum film layer; 5 - nickel film layer; 6 - platinum film layer. Detailed implementation manners

[0034] To better illustrate the objectives, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Unless otherwise specified, the test methods used in the embodiments are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0036] The NiCoCrAlYTa is purchased from Oerlikon-Metco Company in Switzerland, and the grade is Amdry TM 997; the NiCoCrAlY is purchased from Höganäs Company, and the grade is AMPERIT 410.001.

[0037] Example 1

[0038] A preparation method of an infrared stealth composite coating, comprising the following steps:

[0039] (1) Using a nickel-based superalloy K4169 as a substrate, it is processed into a specimen, and the specimen is ultrasonically cleaned of oil stains successively with gasoline and alcohol, and the surface of the specimen is sandblasted with 46# corundum grit under a pressure of 0.2 MPa;

[0040] (2) Using low-pressure plasma spraying to prepare a NiCoCrAlYTa bonding layer with a thickness of 60 μm on the sandblasted specimen surface, wherein the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0041] (3) Using atmospheric plasma spraying to prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 150 μm on the bonding layer, wherein the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0042] (4) Using a magnetron target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa, to prepare an aluminum film layer with a thickness of 3 μm on the surface of the ceramic layer;

[0043] (5) Using a magnetron target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10-3 Pa, deposit a nickel film layer with a thickness of 3 μm on the surface of the aluminum film layer;

[0044] (6) Use a magnetron target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa, deposit a platinum film layer with a thickness of 1 μm on the surface of the nickel film layer;

[0045] (7) Keep it at 700 °C for 2 h, 900 °C for 4 h, with a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4 Pa, heat-treat the specimen with the coating, and the infrared stealth composite coating is obtained.

[0046] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this embodiment. After static oxidation at 900 °C, the average oxidation rate is 0.08427 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 52 MPa. The coating does not peel off after 100 water-cooling cycles with 5 minutes of heat preservation at 1000 °C. During the process of heating to 1000 °C at a rate of 200 °C / min, the infrared radiation intensity has no obvious change. The anti-high-temperature oxidation performance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating are good.

[0047] Example 2

[0048] A preparation method of an infrared stealth composite coating, comprising the following steps:

[0049] (1) Using a nickel-based superalloy K4169 as the substrate, it is processed into a specimen by wire cutting. The specimen is ultrasonically cleaned of oil stains with gasoline and alcohol in sequence, and the surface of the specimen is sandblasted with 46# corundum grit at a gas pressure of 0.2 MPa;

[0050] (2) Use low-pressure plasma spraying to deposit a NiCoCrAlYTa bonding layer with a thickness of 70 μm on the sandblasted specimen surface, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0051] (3) Use atmospheric plasma spraying to deposit a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 160 μm on the bonding layer, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0052] (4) Use a magnetron sputtering target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa to deposit an aluminum film layer with a thickness of 3 μm on the surface of the ceramic layer;

[0053] (5) Use a magnetron sputtering target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa to deposit a nickel film layer with a thickness of 2 μm on the surface of the aluminum film layer;

[0054] (6) Use a magnetron sputtering target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa to deposit a platinum film layer with a thickness of 2 μm on the surface of the nickel film layer;

[0055] (7) Heat the specimen with the coating at 700 °C for 2 h, 900 °C for 4 h, with a heating rate of 8 °C / min and a vacuum oxygen partial pressure of 2×10 -4 Pa to obtain the infrared stealth composite coating.

[0056] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this example. After static oxidation at 900 °C, the average oxidation rate is 0.08528 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 49 MPa. The coating does not peel off after 100 water-cooling cycles of heating to 1000 °C and holding for 5 minutes at a heating rate of 200 °C / min. During the process of heating to 1000 °C, the infrared radiation intensity does not change significantly. The anti-high-temperature oxidation performance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating are good.

[0057] Example 3

[0058] A method for preparing an infrared stealth composite coating, comprising the following steps:

[0059] (1) Using a nickel-based superalloy K4169 as the substrate, machining it into a specimen, ultrasonically cleaning the specimen with gasoline and alcohol in sequence, and sandblasting the surface of the specimen with 46# corundum grit at a gas pressure of 0.2 MPa;

[0060] (2) Using low-pressure plasma spraying to deposit a NiCoCrAlYTa bonding layer with a thickness of 80 μm on the sandblasted specimen surface, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0061] (3) Using atmospheric plasma spraying to deposit a ZrO 2 -7wt.Y 2 O3 A ceramic layer, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0062] (4) Using a magnetron target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa, a 3-μm-thick aluminum film layer is prepared on the surface of the ceramic layer;

[0063] (5) Using a magnetron target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa, a 1-μm-thick nickel film layer is prepared on the surface of the aluminum film layer;

[0064] (6) Using a magnetron target current of 3 A, a bias voltage of 170 V, and a gas pressure of 4×10 -3 Pa, a 2-μm-thick platinum film layer is prepared on the surface of the nickel film layer;

[0065] (7) Heat-treating the specimen with the coating at 700 °C for 2 h, 900 °C for 4 h, a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4 Pa, and the infrared stealth composite coating is obtained.

[0066] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this example. After static oxidation at 900 °C, the average oxidation rate is 0.08727 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 53 MPa. The coating does not peel off after 100 water-cooling cycles of holding at 1000 °C for 5 minutes. During the process of heating to 1000 °C at a rate of 250 °C / min, the infrared radiation intensity does not change significantly. The anti-high-temperature oxidation performance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating are good.

[0067] Example 4

[0068] A method for preparing an infrared stealth composite coating, comprising the following steps:

[0069] (1) Using a nickel-based superalloy K4169 as the substrate, machining it into a specimen, ultrasonically cleaning the specimen for oil stains successively with gasoline and alcohol, and sandblasting the surface of the specimen with 46# corundum grit at a gas pressure of 0.2 MPa;

[0070] (2) A NiCoCrAlYTa bond coat with a thickness of 90 μm was prepared on the surface of the sandblasted specimen by low-pressure plasma spraying. The spraying parameters were as follows: argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun travel speed of 700 mm / s;

[0071] (3) An atmospheric plasma spraying was used to prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 180 μm on the bond coat. The spraying parameters were as follows: argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun travel speed of 700 mm / s;

[0072] (4) A 4-μm-thick aluminum film layer was prepared on the surface of the ceramic layer by using a magnetron sputtering target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa;

[0073] (5) A 3-μm-thick nickel film layer was prepared on the surface of the aluminum film layer by using a magnetron sputtering target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa;

[0074] (6) A 1-μm-thick platinum film layer was prepared on the surface of the nickel film layer by using a magnetron sputtering target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa;

[0075] (7) The specimen with the coating was heat-treated at 700 °C for 2 h, 900 °C for 4 h, with a heating rate of 8 °C / min and a vacuum oxygen partial pressure of 2×10 -4 Pa to obtain the infrared stealth composite coating.

[0076] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure was finally formed in this example. After static oxidation at 900 °C, the average oxidation rate was 0.08827 (g / m 2 h), which was at the fully antioxidant level. The bonding strength was 46 MPa. The coating did not peel off after 100 water-cooling cycles of heating to 1000 °C and holding for 5 minutes at a heating rate of 250 °C / min. During the process of heating to 1000 °C, the infrared radiation intensity did not change significantly. The coating had good high-temperature oxidation resistance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating conditions.

[0077] Example 5

[0078] A method for preparing an infrared stealth composite coating, comprising the following steps:

[0079] (1) Using nickel-based superalloy K4169 as the matrix, it is wire-cut into specimens, and the specimens are ultrasonically cleaned of oil stains successively with gasoline and alcohol. The surface of the specimens is sandblasted with No. 46 corundum grit at a gas pressure of 0.2 MPa;

[0080] (2) A NiCoCrAlYTa bonding layer with a thickness of 80 μm is prepared on the sandblasted specimen surface by low-pressure plasma spraying. The spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s;

[0081] (3) An atmospheric plasma spraying is used to prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 170 μm on the bonding layer. The spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s;

[0082] (4) A 3-μm-thick aluminum film layer is prepared on the surface of the ceramic layer with a magnetron target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa;

[0083] (5) A 2-μm-thick nickel film layer is prepared on the surface of the aluminum film layer with a magnetron target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa;

[0084] (6) A 1-μm-thick platinum film layer is prepared on the surface of the nickel film layer with a magnetron target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa;

[0085] (7) Heat-treat the specimens with the coating at 700 °C for 2 h, 900 °C for 4 h, a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4 Pa to obtain the infrared stealth composite coating.

[0086] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this example. After static oxidation at 900 °C, the average oxidation rate is 0.08357 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 47 MPa. After 100 water-cooling cycles of heating to 1000 °C and holding for 5 minutes at a heating rate of 300 °C / min, the coating does not peel off, and there is no obvious change in the infrared radiation intensity during the process of heating to 1000 °C. The high-temperature oxidation resistance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating conditions are good.

[0087] Example 6

[0088] A preparation method of an infrared stealth composite coating, comprising the following steps:

[0089] (1) Using a nickel-based superalloy K4169 as the substrate, it is processed into a specimen by wire cutting. The specimen is ultrasonically cleaned of oil stains successively with gasoline and alcohol, and the surface of the specimen is sandblasted with 46# corundum grit under a gas pressure of 0.2 MPa;

[0090] (2) A NiCoCrAlYTa bonding layer with a thickness of 80 μm is prepared on the sandblasted specimen surface by low-pressure plasma spraying, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0091] (3) Using atmospheric plasma spraying to prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 170 μm on the bonding layer, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0092] (4) Using a magnetron sputtering target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa, an aluminum film layer with a thickness of 3 μm is prepared on the surface of the ceramic layer;

[0093] (5) Using a magnetron sputtering target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa, a nickel film layer with a thickness of 2 μm is prepared on the surface of the aluminum film layer;

[0094] (6) Using a magnetron sputtering target current of 4 A, a bias voltage of 180 V, and a gas pressure of 4×10 -3 Pa, a platinum film layer with a thickness of 3 μm is prepared on the surface of the nickel film layer;

[0095] (7) Heat-treat the specimen with the coating at 700 °C for 2 h, 900 °C for 4 h, a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4 Pa to obtain the infrared stealth composite coating.

[0096] After testing, the final high-temperature infrared stealth composite coating system with a five-layer structure is formed in this example. After static oxidation at 900 °C, the average oxidation rate is 0.08594 (g / m 2h) It is at the complete antioxidant level, with a bonding strength of 54 MPa. After 100 water-cooling cycles with a 5-minute hold at 1000 °C, the coating does not peel off. During the process of heating to 1000 °C at a rate of 300 °C / min, the infrared radiation intensity shows no obvious change. It has good high-temperature oxidation resistance, bonding strength, thermal cycling performance, and infrared stealth performance under instantaneous heating conditions.

[0097] Example 7

[0098] A preparation method of an infrared stealth composite coating, comprising the following steps:

[0099] (1) Using nickel-based superalloy K4169 as the substrate, it is processed into specimens, and the specimens are ultrasonically cleaned of oil stains successively with gasoline and alcohol. The surface of the specimens is sandblasted with 46# corundum grit at a pressure of 0.2 MPa;

[0100] (2) A NiCoCrAlYTa bonding layer with a thickness of 80 μm is prepared on the sandblasted specimen surface by low-pressure plasma spraying, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0101] (3) Using atmospheric plasma spraying to prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 170 μm on the bonding layer, where the spraying parameters are argon gas flow rate of 45 NLPM, hydrogen gas flow rate of 8 NLPM, current of 550 A, rotation speed of 2.0 r / min, spraying distance of 110 mm, and gun traversing speed of 700 mm / s;

[0102] (4) Using a magnetron target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa, an aluminum film layer with a thickness of 3 μm is prepared on the surface of the ceramic layer;

[0103] (5) Using a magnetron target current of 2 A, a bias voltage of 180 V, and a gas pressure of 4×10 -3 Pa, a nickel film layer with a thickness of 3 μm is prepared on the surface of the aluminum film layer;

[0104] (6) Using a magnetron target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa, a platinum film layer with a thickness of 1 μm is prepared on the surface of the nickel film layer;

[0105] (7) Holding at 700 °C for 2 h, holding at 900 °C for 4 h, with a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4Heat-treat the sample with the coating at [Pa] to obtain the infrared stealth composite coating.

[0106] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this example. After static oxidation at 900 °C, the average oxidation rate is 0.08736 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 52 MPa. After 100 water-cooling cycles with a 5-minute hold at 1000 °C, the coating does not peel off. During the process of heating to 1000 °C at a rate of 250 °C / min, the infrared radiation intensity does not change significantly. The anti-high-temperature oxidation performance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating are good.

[0107] Comparative Example 1

[0108] A preparation method of an infrared stealth composite coating includes the following steps:

[0109] (1) Using nickel-based superalloy K4169 as the substrate, wire-cut it into a sample. Ultrasonically clean the sample with gasoline and alcohol in sequence, and sandblast the surface of the sample with 46# corundum grit at a pressure of 0.2 MPa.

[0110] (2) Prepare a NiCoCrAlYTa bonding layer with a thickness of 60 μm on the sandblasted sample surface by low-pressure plasma spraying. The spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s.

[0111] (3) Prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 150 μm on the bonding layer by atmospheric plasma spraying. The spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s.

[0112] (4) Prepare an aluminum film layer with a thickness of 3 μm on the ceramic layer surface with a magnetron target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa.

[0113] (5) Prepare a platinum film layer with a thickness of 1 μm on the aluminum film layer surface with a magnetron target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa.

[0114] (6) Hold at 700 °C for 2 h, hold at 900 °C for 4 h, with a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10-4 The infrared stealth composite coating is obtained by heat-treating the coated sample at [Pa]

[0115] After testing, the high-temperature infrared stealth composite coating system with a four-layer structure is finally formed in this comparative example. After static oxidation at 900 °C, the average oxidation rate is 0.08528 (g / m 2 h), which is a completely antioxidant level. The bonding strength is 40 MPa. After 100 water-cooling cycles with a 5-minute hold at 1000 °C, the coating does not peel off. During the process of heating to 1000 °C at a rate of 200 °C / min, the infrared radiation intensity shows a significant increase compared with Example 1. The high-temperature oxidation resistance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating conditions are all lower than those of Example 1.

[0116] Comparative Example 2

[0117] A preparation method of an infrared stealth composite coating includes the following steps:

[0118] (1) Using a nickel-based superalloy K4169 as the substrate, it is processed into a sample by wire cutting. The sample is ultrasonically cleaned of oil stains successively using gasoline and alcohol, and the surface of the sample is sandblasted with 46# corundum grit at a pressure of 0.2 MPa.

[0119] (2) A NiCoCrAlYTa bonding layer with a thickness of 60 μm is prepared on the sandblasted sample surface by low-pressure plasma spraying, where the spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s;

[0120] (3) A ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 150 μm is prepared on the bonding layer by atmospheric plasma spraying, where the spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s;

[0121] (4) An aluminum film layer with a thickness of 3 μm is prepared on the ceramic layer surface with a magnetron target current of 2 A, a bias voltage of 150 V, and a pressure of 4×10 -3 Pa;

[0122] (5) A chromium film layer with a thickness of 3 μm is prepared on the aluminum film layer surface with a magnetron target current of 3 A, a bias voltage of 160 V, and a pressure of 4×10 -3 Pa.

[0123] (6) Use a magnetron target current of 3 A, a bias voltage of 170 V, and a gas pressure of 4×10 -3 Pa to prepare a platinum film layer with a thickness of 1 μm on the surface of the chromium film layer;

[0124] (7) Keep at 700 °C for 2 h, keep at 900 °C for 4 h, with a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4 Pa to heat-treat the sample with the coating, and the infrared stealth composite coating is obtained.

[0125] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this comparative example. After static oxidation at 900 °C, the average oxidation rate is 0.08727 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 46 MPa. After 100 water-cooling cycles of 5 minutes at 1000 °C, the coating does not peel off. During the process of heating to 1000 °C at a rate of 250 °C / min, the infrared radiation intensity gradually increases. The high-temperature oxidation resistance, bonding strength, thermal cycle performance, and infrared stealth performance under instantaneous heating conditions are all lower than those of Example 1.

[0126] Comparative Example 3

[0127] A preparation method of an infrared stealth composite coating includes the following steps:

[0128] (1) Use a nickel-based superalloy K4169 as the substrate, and process it into a sample by wire cutting. Ultrasonically clean the sample with gasoline and alcohol in sequence, and perform sandblasting on the surface of the sample with 46# corundum grit at a gas pressure of 0.2 MPa;

[0129] (2) Use low-pressure plasma spraying to prepare a NiCoCrAlY bonding layer with a thickness of 60 μm on the surface of the sandblasted sample. The spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s;

[0130] (3) Use atmospheric plasma spraying to prepare a ZrO 2 -7wt.Y 2 O 3 ceramic layer with a thickness of 150 μm on the bonding layer. The spraying parameters are: argon gas flow rate 45 NLPM, hydrogen gas flow rate 8 NLPM, current 550 A, rotation speed 2.0 r / min, spraying distance 110 mm, and gun traversing speed 700 mm / s;

[0131] (4) Use a magnetron target current of 2 A, a bias voltage of 150 V, and a gas pressure of 4×10 -3 Pa to prepare an aluminum film layer with a thickness of 3 μm on the surface of the ceramic layer;

[0132] (5) Use a magnetron target current of 3 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa to deposit a nickel film layer with a thickness of 3 μm on the surface of the aluminum film layer;

[0133] (6) Use a magnetron target current of 2 A, a bias voltage of 160 V, and a gas pressure of 4×10 -3 Pa to deposit a platinum film layer with a thickness of 1 μm on the surface of the nickel film layer;

[0134] (7) Heat-treat the specimen with the coating at 700 °C for 2 h, 900 °C for 4 h, a heating rate of 8 °C / min, and a vacuum oxygen partial pressure of 2×10 -4 Pa to obtain the infrared stealth composite coating.

[0135] After testing, the high-temperature infrared stealth composite coating system with a five-layer structure is finally formed in this embodiment. After static oxidation at 900 °C, the average oxidation rate is 0.08427 (g / m 2 h), which is at the fully antioxidant level. The bonding strength is 49 MPa. After 100 water-cooling cycles with a 5-minute hold at 1000 °C, small-area peeling occurs on the coating. During the process of heating to 1000 °C at a rate of 200 °C / min, the infrared radiation intensity does not change significantly. The anti-high-temperature oxidation performance and infrared stealth performance under instantaneous heating conditions are good, but the bonding strength and thermal cycle performance decrease compared with those in Example 1.

[0136] The cross-sectional morphology of the infrared stealth composite coating in Example 1 is shown as Figure 1 and Figure 2 shown. It can be seen from Figure 1 and Figure 2 that the interfaces of each coating are well-bonded, and the high-temperature antioxidant experiment results at 900 °C show that the infrared stealth composite coating of the present invention has excellent infrared stealth performance and antioxidant performance.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An infrared stealth composite coating, characterized in that: The infrared stealth composite coating comprises a bonding layer, a ceramic layer, an aluminum film layer, a nickel film layer and a platinum film layer in sequence; the material of the bonding layer comprises NiCoCrAlYTa.

2. The infrared stealth composite coating according to claim 1, characterized in that: The thickness of the nickel film layer is 1 μm-3 μm.

3. The infrared stealth composite coating according to claim 1, characterized in that: The thickness of the bonding layer is 50 μm-100 μm.

4. The infrared stealth composite coating according to claim 1, characterized in that: The material of the ceramic layer includes ZrO2-7wt% Y2O3.

5. The infrared stealth composite coating according to claim 1, characterized in that: The thickness of the ceramic layer is 100 μm-200 μm; and / or the thickness of the aluminum film layer is 3 μm-4 μm; and / or the thickness of the platinum film layer is 1 μm-3 μm.

6. A method for preparing the infrared stealth composite coating according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: preparing a bonding layer, a ceramic layer, an aluminum film layer, a nickel film layer and a platinum film layer on the surface of a substrate in sequence, and then performing heat treatment to obtain the infrared stealth composite coating.

7. The method for preparing the infrared stealth composite coating according to claim 6, characterized in that: The heat treatment conditions are: first, keep the temperature at 650℃-700℃ for 2h-4h, then keep the temperature at 900℃-1100℃ for 4h-8h; during the heat treatment, the vacuum oxygen partial pressure does not exceed 2×10 -4 Pa.

8. The method for preparing the infrared stealth composite coating according to claim 6, characterized in that: The preparation methods of the bonding layer and the ceramic layer independently include at least one of atmospheric plasma spraying and low-pressure plasma spraying; and / or, the preparation methods of the aluminum film layer, the nickel film layer and the platinum film layer include magnetron sputtering.

9. The method for preparing the infrared stealth composite coating according to claim 8, characterized in that: The conditions of atmospheric plasma spraying are: argon amount 40NLPM-50NLPM, hydrogen amount 5NLPM-10NLPM, current 500A-600A, rotation speed 1r / min-3r / min, spraying distance 100mm-120mm, and gun travel speed 650mm / s-750mm / s; the conditions of low-pressure plasma spraying are: argon amount 40NLPM-50NLPM, hydrogen amount 5NLPM-10NLPM, current 500A-600A, rotation speed 1r / min-3r / min, spraying distance 100mm-120mm, and gun travel speed 650mm / s-750mm / s; the conditions of magnetron sputtering are: magnetron target current 2-5A, bias voltage 100-180V, gas pressure less than 5×10 -3 Pa.

10. Application of the infrared stealth composite coating according to any one of claims 1 to 5 or the infrared stealth composite coating prepared by the preparation method of the infrared stealth composite coating according to any one of claims 6 to 9 in aerospace engines, aerospace vehicles, armored vehicles, and medical devices.

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