Composite laser protective coating and preparation method thereof

Abstract

The invention belongs to the field of protective coatings, and particularly discloses a composite laser protective coating and a preparation method thereof. The protective coating comprises a high-temperature-resistant oxidation layer, a ceramic heat insulation layer, a ceramic reflection layer and a metal reflection layer which are sequentially arranged on the base body in a stacked mode. The porosity of the ceramic heat insulation layer is not lower than 10%; the material of the high-temperature-resistant oxidation layer comprises at least one of NiCrAlY, CoCrAlY and NiCoCrAlY, and the material of the high-temperature-resistant oxidation layer comprises at least one of NiCrAlY, CoCrAlY and The material of the ceramic thermal insulation layer comprises zirconium oxide and oxide doped in the zirconium oxide; materials of the ceramic reflecting layer comprise zirconium oxide and rare earth elements doped in the zirconium oxide. The protective coating has low heat conductivity, the average temperature of the side, away from the protective coating, of the base body is lower than 150 DEG C after the protective coating is continuously irradiated by laser with the power density being 8050 W.cm <-2 > for 300 s, and the binding force of the coating ranges from 35 MPa to 50 MPa.

Description

Technical Field

[0001] The present invention belongs to the field of protective coatings, and in particular relates to a composite laser protective coating and a preparation method thereof. Background Art

[0002] High-energy laser strike is a type of directed energy weapon that uses the high energy of lasers to destroy targets. It boasts high lethality, low cost, and strong anti-interference capabilities. Intense lasers can increase the surface temperature of materials, severely damaging or even completely destroying their integrity, load-bearing capacity, and functionality. This can occur through burns, cutting, or fracture. Under laser action, the macroscopic manifestation is energy absorption by metals, with surface temperatures rising, melting, vaporization, and spattering. Non-metallic materials experience sublimation, chemical reactions, coking, and erosion. The interaction between lasers and materials primarily involves thermal and impulse coupling effects. Differences in these parameters lead to distinct interaction processes and destructive effects, such as thermal ablation and explosion, shock damage and spallation, and plasma cloud effects. From a microscopic perspective, the interaction between lasers and materials is the effect of high-frequency electromagnetic fields on free or bound electrons in the material. The material's response to laser light is closely related to its electronic band structure, manifesting itself macroscopically as reflection, absorption, and transmission of the laser light.

[0003] Thermal insulation laser protective coatings mainly rely on some low thermal conductivity materials to reduce the longitudinal transmission of laser energy and protect the substrate from ablation and structural damage. Thermal ablation principle Laser protective materials use materials with high effective ablation heat to take away most of the energy during the ablation process, or low thermal conductivity materials to reduce the longitudinal transmission of energy. Composite laser protective coatings refer to the combined use of two or three of the above protection methods, and the design of one or more layers of structure to achieve anti-laser ablation effect. The application field of laser protective coatings requires that they be used under high temperature, high pressure, high load and other conditions. Laser protective coatings are prone to failure in harsh service environments. Among them, oxidation failure of the reflective layer, quality loss of the ablation layer, insufficient effective thermal insulation capacity of the thermal insulation layer, poor fracture toughness, internal stress of the coating, sintering and hardening of the ceramic layer are all the main reasons for the failure of laser protective coatings.

[0004] As laser weapons enter the combat application stage, research on laser protection for various types of unmanned and manned aircraft is urgent. Existing protective coating materials, due to prolonged exposure to high-energy lasers, suffer from oxidation, reduced reflectivity of the metal reflective layer, mass loss of the ablation layer, and insufficient toughness of the thermal insulation layer. Consequently, laser protection coatings quickly fail and fail to meet operational requirements. Summary of the Invention

[0005] To overcome at least one of the technical problems of the aforementioned prior art, one of the objectives of the present invention is to provide a protective coating. This protective coating utilizes the principles of reflection, ablation, and thermal insulation to protect the substrate. By leveraging the intrinsic properties of high-reflectivity materials and the surface reflection of laser irradiation, it achieves both good bonding strength and excellent laser radiation protection, providing excellent substrate protection.

[0006] A second object of the present invention is to provide a method for preparing a protective coating.

[0007] A third object of the present invention is to provide a product comprising the above-mentioned protective coating.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A first aspect of the present invention provides a protective coating comprising a high-temperature oxidation resistant layer, a ceramic heat-insulating layer, a ceramic reflective layer, and a metal reflective layer sequentially stacked on a substrate, wherein the high-temperature oxidation resistant layer and the heat-insulating ceramic layer form a gradient thermal protection, and the ceramic reflective layer comprehensively utilizes its own oxygen vacancy defects, pores, and high interface reflective properties to provide effective protection against laser irradiation;

[0010] The porosity of the ceramic insulation layer is not less than 10%;

[0011] The material of the high temperature oxidation resistant layer includes at least one of NiCrAlY, CoCrAlY, and NiCoCrAlY;

[0012] The material of the ceramic insulation layer includes zirconium oxide and oxides doped in the zirconium oxide; the oxides include at least one of Y2O3, Gd2O3, Yb2O3, TiO2, and Ta2O5;

[0013] The material of the ceramic reflective layer includes zirconium oxide and rare earth elements doped in the zirconium oxide;

[0014] The number of layers of the metal reflective layer is ≥1;

[0015] The material of each metal reflective layer is independently selected from at least one of Al, Cu, Ag, Au, NiCrAlY, CoCrAlY, and NiCoCrAlY.

[0016] In the present invention, a metal reflective layer and a ceramic reflective layer are provided, and a metal-ceramic interface is formed between the two. The reflectivity of the metal reflective layer is not less than 80%. When a high-energy laser is irradiated on the metal reflective layer, the reflectivity of the laser on the coating surface and the metal-ceramic interface can be increased and the longitudinal transfer of laser energy can be reduced. In addition, the ceramic thermal insulation layer in the present invention has a low thermal conductivity, which can avoid the longitudinal transfer of heat. The present invention constructs a unique oxygen vacancy ceramic phase during the preparation of the ceramic reflective layer. During service, the oxygen vacancy defects act as phonon scattering centers to enhance the anharmonicity of the lattice vibration and further enhance the intrinsic scattering between phonons, thereby improving the overall laser protection capability of the coating; at the same time, by controlling the porosity of the ceramic thermal insulation layer, it has a higher porosity, thereby increasing phonon scattering and reducing the thermal conductivity of the coating, thereby reducing the overall ablation and structural damage caused by the laser energy to the substrate.

[0017] In some embodiments of the present invention, the number of the metal reflective layer is 1 to 2 layers.

[0018] In some embodiments of the present invention, the metal reflective layer is a single-layer structure of Al layer, or a double-layer structure of NiCrAlY layer and Al layer.

[0019] In some embodiments of the present invention, the metal reflective layer includes a stacked NiCrAlY layer and an Al layer. The NiCrAlY layer is disposed on the ceramic reflective layer. The melting point of the NiCrAlY alloy is higher than that of Al. When the surface high-reflectivity Al layer is deformed under long-term laser irradiation, the thermal matching between the ceramic layer and the metal layer can be improved, thereby ensuring the safe service of the ceramic protective layer. Al has a low density, a large specific heat capacity, and a high reflectivity. Since the Al metal reflective layer will rapidly oxidize to produce an aluminum oxide film under continuous high-power laser irradiation, resulting in a significant decrease in reflectivity, it is necessary to use the Al metal reflective layer and the ceramic reflective layer at the same time. A metal-ceramic interface will be formed at the contact point between the two, so that the protective coating can greatly enhance the protection time under continuous high-power laser irradiation while having a high reflectivity.

[0020] In some embodiments of the present invention, the metal reflective layer is an Al layer.

[0021] like Figure 1 As shown, the protective principle of the protective coating in the present invention is: a high-temperature anti-oxidation layer, a ceramic heat-insulating layer, a ceramic reflective layer and a metal reflective layer are sequentially arranged on the surface of the substrate, and the reflection, ablation and heat-insulating principles are comprehensively utilized to further improve the material's resistance to laser radiation.

[0022] In some embodiments of the present invention, the substrate is an alloy substrate. In some embodiments of the present invention, the substrate is a titanium alloy substrate or an aluminum alloy substrate. Of course, the present invention may also use other alloys as the substrate, but the present invention preferably uses a titanium alloy substrate or an aluminum alloy substrate as the substrate material, both of which have the advantage of being lightweight.

[0023] In some embodiments of the present invention, the porosity of the ceramic thermal insulation layer is 10-20%; in some specific embodiments of the present invention, the porosity of the ceramic thermal insulation layer is any one of 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or a range formed by any two of the values.

[0024] In some embodiments of the present invention, the material of the ceramic thermal insulation layer is yttria-stabilized zirconia.

[0025] In some embodiments of the present invention, the material of the ceramic thermal insulation layer includes 5-10% by mass of yttrium oxide and 90-95% by mass of zirconium oxide.

[0026] In some embodiments of the present invention, the rare earth element is selected from at least one of ytterbium, gadolinium, and yttrium. In some embodiments of the present invention, the rare earth element is selected from a mixture of ytterbium and gadolinium.

[0027] In some embodiments of the present invention, the mass percentage of rare earth elements in the ceramic reflective layer is 0.5% to 50%. In some specific embodiments of the present invention, the mass percentage of rare earth elements is any one of 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%, or a range formed by any two of these. In some embodiments of the present invention, the rare earth elements are composed of 1% to 10% by mass of ytterbium, 1% to 10% by mass of gadolinium, and 1% to 10% by mass of yttrium.

[0028] In some embodiments of the present invention, the thickness of the high-temperature oxidation resistant layer is 50 to 250 μm; in some embodiments of the present invention, the thickness of the high-temperature oxidation resistant layer is 50 μm, 60 μm, 70 μm, 75 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, any one of the values or a range formed by any two of them.

[0029] In some embodiments of the present invention, the thickness of the ceramic thermal insulation layer is 150-350 μm; in some specific embodiments of the present invention, the thickness of the ceramic thermal insulation layer is 150 μm, 160 μm, 170 μm, 175 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 275 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, any one value or a range formed by any two of them.

[0030] In some embodiments of the present invention, the thickness of the ceramic reflective layer is 150-350 μm; in some specific embodiments of the present invention, the thickness of the ceramic reflective layer is 150 μm, 160 μm, 170 μm, 175 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 275 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, any one value or a range formed by any two of them.

[0031] In some embodiments of the present invention, the thickness of the metal reflective layer is 5 to 50 μm; in some specific embodiments of the present invention, the thickness of the metal reflective layer is any value among 5 μm, 7 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or a range formed by any two of the values.

[0032] In some embodiments of the present invention, the thermal conductivity of the protective coating is ≤1.0W / (m·K); in some embodiments of the present invention, the thermal conductivity of the protective coating is 0.1W / (m·K), 0.2W / (m·K), 0.3W / (m·K), 0.4W / (m·K), 0.5W / (m·K), 0.6W / (m·K), 0.7W / (m·K), 0.8W / (m·K), 0.9W / (m·K), 1W / (m·K) or any value in the range formed by any two of them.

[0033] In some embodiments of the present invention, at a power density of 8050 W·cm -2 After continuous laser irradiation for 300 seconds, the average temperature of the substrate on the side away from the protective coating is lower than 150°C.

[0034] The second aspect of the present invention provides a method for preparing the protective coating according to the first aspect of the present invention, comprising the following steps:

[0035] The high-temperature oxidation resistance layer, the ceramic heat insulation layer, the ceramic reflection layer and the metal reflection layer are sequentially formed on the substrate.

[0036] In some embodiments of the present invention, at least one of the high-temperature oxidation resistant layer, the ceramic heat-insulating layer, the ceramic reflective layer and the metal reflective layer is prepared by spraying.

[0037] In some embodiments of the present invention, the spraying is selected from at least one of supersonic flame spraying, atmospheric plasma spraying, low-pressure plasma spraying, plasma-physical vapor deposition, and magnetron sputtering.

[0038] In some embodiments of the present invention, at least one of the high-temperature oxidation resistant layer, the ceramic heat-insulating layer and the ceramic reflective layer is produced by atmospheric plasma spraying.

[0039] In some embodiments of the present invention, in the atmospheric plasma spraying method, the argon flow rate is 25 to 50 L / min; in some embodiments of the present invention, in the atmospheric plasma spraying method, the argon flow rate is selected from any value of 25 L / min, 27 L / min, 28 L / min, 30 L / min, 32 L / min, 34 L / min, 37 L / min, 40 L / min, 42 L / min, 44 L / min, 46 L / min, 47 L / min, 48 L / min, and 50 L / min, or a range formed by any two of the values.

[0040] In some embodiments of the present invention, in the atmospheric plasma spraying method, the hydrogen flow rate is 5 to 30 L / min; in some embodiments of the present invention, in the atmospheric plasma spraying method, the hydrogen flow rate is 5 L / min, 6 L / min, 7 L / min, 8 L / min, 10 L / min, 12 L / min, 14 L / min, 16 L / min, 17 L / min, 18 L / min, 20 L / min, 22 L / min, 24 L / min, 25 L / min, 26 L / min, 27 L / min, 28 L / min, 30 L / min, any one value or a range formed by any two of them.

[0041] In some embodiments of the present invention, in the atmospheric plasma spraying method, the current is 500-700A; in some embodiments of the present invention, in the atmospheric plasma spraying method, the current is 500A, 510A, 520A, 530A, 540A, 550A, 560A, 570A, 580A, 590A, 600A, 610A, 620A, 630A, 640A, 650A, 660A, 670A, 680A, 690A, and 700A, or a range formed by any two of the values.

[0042] In some embodiments of the present invention, in the atmospheric plasma spraying method, the powder feeding rate is 10 to 30 g / min; in some embodiments of the present invention, in the atmospheric plasma spraying method, the powder feeding rate is any one of 10 g / min, 12 g / min, 14 g / min, 16 g / min, 18 g / min, 20 g / min, 22 g / min, 24 g / min, 26 g / min, 28 g / min, and 30 g / min, or a range formed by any two of the values.

[0043] In some embodiments of the present invention, in the atmospheric plasma spraying method, the spraying distance is 100 to 300 mm; in some embodiments of the present invention, in the atmospheric plasma spraying method, the spraying distance is any one of 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, and 300 mm, or a range formed by any two of the values.

[0044] In some embodiments of the present invention, the high temperature oxidation resistant layer is prepared by atmospheric plasma spraying, and the parameters of the atmospheric plasma spraying method are: argon flow rate 25-50 L / min, hydrogen flow rate 5-30 L / min, current 500-600 A, powder feeding rate 10-20 g / min, spray distance 100-300 mm, coating thickness 50-250 μm; wherein, the argon flow rate is 25-50 L / min, preferably 27 L / min, 37 L / min, 47 L / min; hydrogen flow rate 5-30L / min, preferably 7L / min, 17L / min, and 27L / min; current 500-600A, preferably 500A, 550A, and 600A; powder feeding rate 10-20g / min, preferably 10g / min, 15g / min, and 20g / min; spray distance 100-300mm, preferably 100mm, 200mm, and 300mm; coating thickness 50-250μm, preferably 75μm, 100μm, 150μm, and 200μm.

[0045] In some embodiments of the present invention, the ceramic thermal insulation layer is prepared by atmospheric plasma spraying, and the parameters of the atmospheric plasma spraying method are: argon flow rate 25-50 L / min, hydrogen flow rate 5-30 L / min, current 500-700 A, powder feeding rate 10-30 g / min, spray distance 100-300 mm, coating thickness 150-350 μm; wherein, the argon flow rate is 25-50 L / min, preferably 27 L / min, 30 L / min, 40 L / min; hydrogen flow rate 5- 30L / min, preferably 7L / min, 15L / min, 25L / min; current 500-700A, preferably 570A, 600A, 670A; powder feeding rate 10-30g / min, preferably 10g / min, 20g / min, 30g / min; spray distance 100-300mm, preferably 100mm, 200mm, 300mm; coating thickness is 150-350μm, preferably 175μm, 200μm, 250μm and 275μm.

[0046] In some embodiments of the present invention, the ceramic reflective layer is prepared by atmospheric plasma spraying, and the parameters of the atmospheric plasma spraying method are: argon flow rate 25-50 L / min, hydrogen flow rate 5-30 L / min, current 500-700 A, powder feeding rate 10-30 g / min, spray distance 100-300 mm, and coating thickness 150-350 μm; wherein, the argon flow rate is 25-50 L / min, preferably 27 L / min, 30 L / min, 40 L / min. n; hydrogen flow rate 5-30L / min, preferably 7L / min, 15L / min, and 25L / min; current 500-700A, preferably 570A, 600A, and 670A; powder feeding rate 10-30g / min, preferably 10g / min, 20g / min, and 30g / min; spray distance 100-300mm, preferably 100mm, 200mm, and 300mm; coating thickness is 175μm, 200μm, 250μm, and 275μm.

[0047] In some embodiments of the present invention, the metal reflective layer is produced by magnetron sputtering. This method deposits metal vapor particles onto the surface of the reflective ceramic layer, further enhancing interfacial reflection through the microcrystalline boundaries of the vapor particles. This increases laser reflection loss through interface regulation, effectively reducing longitudinal laser energy transfer.

[0048] In some embodiments of the present invention, in the magnetron sputtering method, the coating temperature is 100°C to 350°C; in some embodiments of the present invention, in the magnetron sputtering method, the coating temperature is any one of 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C, 320°C, and 350°C, or a range formed by any two of the values.

[0049] In some embodiments of the present invention, in the magnetron sputtering method, the vacuum degree is 0.001Pa~0.09Pa; in some embodiments of the present invention, in the magnetron sputtering method, the vacuum degree is any one of 0.001Pa, 0.005Pa, 0.01Pa, 0.02Pa, 0.03Pa, 0.04Pa, 0.05Pa, 0.06Pa, 0.07Pa, 0.08Pa, 0.09Pa or a range formed by any two of them.

[0050] In some embodiments of the present invention, in the magnetron sputtering method, the current is 10A to 100A; in some embodiments of the present invention, in the magnetron sputtering method, the current is any value among 10A, 20A, 30A, 40A, 50A, 60A, 70A, 80A, 90A, 100A or a range formed by any two of them.

[0051] In some embodiments of the present invention, in the magnetron sputtering method, the bias voltage is 50V to 500V; in some embodiments of the present invention, in the magnetron sputtering method, the bias voltage is any one value of 50V, 100V, 150V, 200V, 250V, 300V, 350V, 400V, 450V, 500V, or a range formed by any two of them.

[0052] In some embodiments of the present invention, in the magnetron sputtering method, the gas flow rate is 50 sccm to 500 sccm; in some embodiments of the present invention, in the magnetron sputtering method, the gas flow rate is any one of 50 sccm, 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm, 450 sccm, and 500 sccm, or a range formed by any two of the values.

[0053] In some embodiments of the present invention, the metal oxide layer is prepared by magnetron sputtering, and the parameters of the magnetron sputtering are: coating temperature: 100℃~350℃, preferably 150℃, 250℃, and 300℃; vacuum degree: 0.001Pa~0.09Pa, preferably 0.005Pa and 0.05Pa; current: 10A~100A, preferably 10A, 50A, and 100A; bias voltage: 50V~500V, preferably 150V, 250V, and 350V; gas flow rate: 50sccm~500sccm, preferably 200sccm, 300sccm, and 400sccm; coating thickness is 5~50μm, preferably 7μm, 10μm, 15μm, and 30μm.

[0054] The third aspect of the present invention provides a product comprising the protective coating described in the first aspect of the present invention; the product comprises a drone, an airplane, a protective mask, a fighter jet or a weapon.

[0055] The beneficial effects of the present invention are as follows: the protective coating of the present invention constructs a unique oxygen vacancy ceramic phase in the ceramic reflective layer. During service, the oxygen vacancy defects not only serve as phonon scattering centers, but also enhance the anharmonicity of the lattice vibration, thereby further enhancing the intrinsic scattering between phonons, thereby improving the overall thermal insulation capacity of the coating and improving the laser coating protection capability. The present invention forms a gradient protection for the longitudinal transmission energy of the laser by setting a ceramic thermal insulation layer and a high-temperature oxidation resistant layer, and through interface regulation, it has both excellent bonding strength and excellent anti-laser radiation performance. Specifically, the protective coating of the present invention has a low thermal conductivity, and its thermal conductivity is ≤1.0W / (m·K). At a power density of 8050W·cm -2 After continuous laser irradiation for 300 seconds, the average temperature of the substrate on the side away from the protective coating is lower than 150° C., and the bonding strength of the coating is 35 to 50 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of the laser protection principle of the composite laser protective coating in an embodiment of the present invention.

[0057] Figure 2 This is a physical picture of the composite laser protective coating in Example 1.

[0058] Figure 3 This is a real picture of the composite laser protective coating in Example 2 after laser irradiation. DETAILED DESCRIPTION

[0059] The specific implementation of the present invention will be further described in detail below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are any processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

[0060] The NiCrAlY used in the following examples and comparative examples is a nickel-based high-temperature protective coating material, mainly composed of Ni (nickel), Cr (chromium), Al (aluminum), and Y (yttrium).

[0061] Example 1

[0062] This example provides a composite laser protective coating, which is provided on a skin substrate. The composite laser protective coating is provided with a high-temperature oxidation resistance layer, a ceramic heat insulation layer, a ceramic reflective layer and a metal reflective layer from the inside to the outside.

[0063] The skin matrix is titanium alloy;

[0064] The high temperature oxidation resistant layer is a NiCrAlY layer with a thickness of 100 μm;

[0065] The ceramic heat-insulating layer is a YSZ (yttria-stabilized zirconia) layer having a thickness of 175 μm. The YSZ layer contains 8% by mass of yttria.

[0066] The ceramic reflective layer is a ZrO2 layer doped with Yb (ytterbium), Gd (gadolinium) and Y (yttrium), with a thickness of 175 μm. The coating contains 2.5% by mass of gadolinium, 2.5% by mass of ytterbium, 5% by mass of yttrium, and 90% by mass of zirconium oxide.

[0067] The metal reflective layer is composed of a NiCrAlY layer and an Al layer, wherein the NiCrAlY layer has a thickness of 20 μm and the Al layer has a thickness of 7 μm.

[0068] This example provides a method for preparing a composite laser protective coating, comprising the following steps:

[0069] (1) Titanium alloy is selected as the skin matrix;

[0070] (2) A NiCrAlY high-temperature oxidation resistant layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0071] (3) A ceramic thermal insulation layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 10 g / min.

[0072] (4) A ceramic reflective layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 20 g / min.

[0073] (5) A NiCrAlY layer with a thickness of 20 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0074] (6) A 7 μm thick Al layer was prepared by magnetron sputtering method with the following process parameters: coating temperature 150 °C, vacuum degree 0.05 Pa, current 10 A, bias voltage 150 V, and argon gas flow rate 200 sccm.

[0075] The actual picture of the composite laser protective coating in this example is as follows Figure 2 As shown. The coating adhesion strength measured according to the HB5476 standard is 41 MPa. When the coated substrate is bent 90° according to the ASTM A1122 / A1122M-22 standard, the coating surface shows no peeling, bulging, or cracking. The thermal conductivity of the coating measured according to the Q / AVIC 06019 standard is 0.97 W / (m·K). The porosity of the ceramic insulation layer measured using Image J software is 16.6%. The power density used is 8050 W·cm -2 The composite laser protective coating in this example was continuously irradiated with laser for 300 seconds, and there was no crack or hole damage on the coating surface. After continuous irradiation for 300 seconds, the maximum temperature of the back side of the skin substrate (i.e., the side away from the composite laser protective coating) measured was 147°C, and the average temperature was 84°C.

[0076] Example 2

[0077] This example provides a composite laser protective coating, which is provided on a skin substrate. The composite laser protective coating is provided with a high-temperature oxidation resistance layer, a ceramic heat insulation layer, a ceramic reflective layer and a metal reflective layer from the inside to the outside.

[0078] The skin matrix is aluminum alloy;

[0079] The high temperature oxidation resistant layer is a NiCrAlY layer with a thickness of 100 μm;

[0080] The ceramic heat-insulating layer is a YSZ layer with a thickness of 175 μm; the YSZ layer contains 8% by mass of yttrium oxide.

[0081] The ceramic reflective layer is a ZrO2 layer doped with Yb (ytterbium), Gd (gadolinium), and Y (yttrium), with a thickness of 175 μm. The coating contains 2.5% by mass of gadolinium, 2.5% by mass of ytterbium, 5% by mass of yttrium, and 90% by mass of zirconium oxide.

[0082] The metal reflective layer is an Al layer, and its thickness is 7 μm.

[0083] This example provides a method for preparing a composite laser protective coating, comprising the following steps:

[0084] (1) Aluminum alloy is selected as the skin matrix;

[0085] (2) A NiCrAlY high-temperature oxidation layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0086] (3) A ceramic thermal insulation layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 10 g / min.

[0087] (4) A ceramic reflective layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 20 g / min.

[0088] (5) A 7 μm thick Al metal reflective layer was prepared by magnetron sputtering method. The process parameters were: coating temperature 150 °C, vacuum degree 0.05 Pa, current 10 A, bias voltage 150 V, and argon gas flow rate 200 sccm.

[0089] The composite laser protective coating in this example has a coating adhesion of 38 MPa as measured by the HB5476 standard, and a thermal conductivity of 0.81 W / (m·K) as measured by the Q / AVIC 06019 standard. After bending the coated substrate 90° according to the ASTM A1122 / A1122M-22 standard, the coating surface showed no peeling, bulging, or cracking. The porosity of the ceramic thermal insulation layer, measured using Image J software, was 17.3%. The power density used was 8050 W·cm -2The composite laser protective coating in this example was continuously irradiated with laser for 300s. There was no crack or hole damage on the coating surface. The average temperature of the back of the skin substrate measured after 300s of continuous irradiation was 196℃ at the highest and 139℃ at the average. The actual picture of the coating after 300s of irradiation is as follows: Figure 3 As shown, the surface discoloration is due to the fact that the surface oxygen-unsaturated zirconium oxide is reduced in the atmospheric environment, resulting in a lighter color.

[0090] Comparative Example 1

[0091] This example provides a high-temperature oxidation-resistant coating, including a high-temperature oxidation-resistant layer, which is arranged on a skin substrate; the skin substrate is a titanium alloy; the high-temperature oxidation-resistant layer is a NiCrAlY layer, and its thickness is 100 μm.

[0092] This example provides a method for preparing a high-temperature anti-oxidation coating, comprising the following steps:

[0093] (1) Titanium alloy is selected as the skin matrix.

[0094] (2) A NiCrAlY high-temperature oxidation resistant layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min.

[0095] The coating adhesion of the high-temperature anti-oxidation coating in this example is 47 MPa according to the HB5476 standard test, and the power density is 800 W·cm -2 The laser was continuously irradiated for 3 seconds on the high-temperature anti-oxidation coating in this example. Obvious ablation holes and cracks appeared on the coating surface. The maximum temperature of the back of the skin substrate was measured to be 532°C after irradiation for 3 seconds. The substrate deformed and failed. The reason was that the thermal conductivity of the high-temperature oxidation layer was high, and a large amount of heat was transferred to the back of the skin substrate.

[0096] Comparative Example 2

[0097] This example provides a protective coating, which is provided on a skin substrate. The protective coating is provided with a high-temperature oxidation resistance layer and a ceramic reflective layer from the inside to the outside.

[0098] The skin matrix is titanium alloy;

[0099] The high temperature oxidation resistant layer is a NiCrAlY layer with a thickness of 100 μm;

[0100] The ceramic reflective layer is a ZrO2 layer doped with Yb (ytterbium), Gd (gadolinium) and Y (yttrium), with a thickness of 175 μm. The coating contains 2.5% by mass of gadolinium, 2.5% by mass of ytterbium, 5% by mass of yttrium and 90% by mass of zirconium oxide.

[0101] This example provides a method for preparing a protective coating, comprising the following steps:

[0102] (1) Titanium alloy is selected as the skin matrix;

[0103] (2) A NiCrAlY high-temperature oxidation resistant layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0104] (3) A ceramic reflective layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 20 g / min.

[0105] The protective coating in this example cannot serve reliably because of the large difference in thermodynamic properties between the ceramic reflective layer and the high-temperature oxidation resistant layer, resulting in severe thermal mismatch.

[0106] Comparative Example 3

[0107] This example provides a YSZ ceramic coating, which is provided on a skin substrate. The YSZ ceramic coating is provided with a high-temperature oxidation resistance layer and a ceramic heat insulation layer in sequence from the inside to the outside;

[0108] The skin matrix is titanium alloy;

[0109] The high temperature oxidation resistant layer is a NiCrAlY layer with a thickness of 100 μm;

[0110] The ceramic heat-insulating layer is a YSZ layer with a thickness of 175 μm; the YSZ layer contains 8% by mass of yttrium oxide.

[0111] This example provides a method for preparing a YSZ ceramic coating, comprising the following steps:

[0112] (1) Titanium alloy is selected as the skin matrix.

[0113] (2) A NiCrAlY high-temperature oxidation layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0114] (3) A ceramic thermal insulation layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 10 g / min.

[0115] The coating adhesion of the YSZ ceramic coating in this example was 45 MPa according to the HB5476 standard test, and the porosity of the ceramic thermal insulation layer was 15.8% as measured by Image J software. The power density was 3800 W·cm -2 The YSZ ceramic coating in this example was continuously irradiated with laser for 12 seconds, and obvious ablation holes and cracks appeared on the coating surface. The maximum temperature of the back of the skin substrate measured after 12 seconds of continuous irradiation was 486℃, and the average temperature was 417℃. The substrate deformed and failed. The reason was that the laser obviously ablated the surface of the ceramic layer because the metal reflective layer and the ceramic reflective layer were not constructed.

[0116] Comparative Example 4

[0117] This example provides a laser protective coating, which is provided on a skin substrate. The laser protective coating is provided with a high-temperature oxidation resistance layer, a ceramic heat insulation layer, and a ceramic reflective layer from the inside to the outside.

[0118] The skin matrix is titanium alloy;

[0119] The high temperature oxidation resistant layer is a NiCrAlY layer with a thickness of 100 μm;

[0120] The ceramic heat-insulating layer is a YSZ layer with a thickness of 175 μm; the YSZ layer contains 8% by mass of yttrium oxide;

[0121] The ceramic reflective layer is a ZrO2 layer doped with Yb (ytterbium), Gd (gadolinium) and Y (yttrium) with a thickness of 175μm; the coating contains 2.5% gadolinium by mass, 2.5% ytterbium by mass, 5% yttrium by mass and 90% zirconium oxide by mass.

[0122] This example provides a method for preparing a laser protective coating, comprising the following steps:

[0123] (1) Titanium alloy is selected as the skin matrix.

[0124] (2) A NiCrAlY high-temperature oxidation layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0125] (3) A ceramic thermal insulation layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 10 g / min.

[0126] (4) A ceramic reflective layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 20 g / min.

[0127] The coating adhesion of the laser protective coating in this example is 40 MPa according to the HB5476 standard test, and the power density is 8050 W·cm -2 The laser protective coating in this example was continuously irradiated with laser for 300 seconds. No obvious ablation holes or cracks appeared on the coating surface. However, the average temperature of the back side of the skin substrate measured after 300 seconds of continuous irradiation was 423°C. The reason was that since no surface metal reflective layer was added, the highly concentrated laser energy was not lost through reflection, resulting in excessively high temperature on the back side of the substrate and insufficient protective capability of the coating.

[0128] Comparative Example 5

[0129] This example provides a composite laser protective coating, which is provided on a skin substrate. The composite laser protective coating is provided with a high-temperature oxidation resistance layer, a ceramic heat insulation layer, a ceramic reflective layer and a metal reflective layer from the inside to the outside.

[0130] The skin matrix is titanium alloy;

[0131] The high temperature oxidation resistant layer is a NiCrAlY layer with a thickness of 100 μm;

[0132] The ceramic heat-insulating layer is a YSZ layer with a thickness of 175 μm; the YSZ layer contains 8% by mass of yttrium oxide;

[0133] The ceramic reflective layer is a ZrO2 layer doped with Yb (ytterbium), Gd (gadolinium) and Y (yttrium), with a thickness of 175 μm; the coating contains 2.5% by mass of gadolinium, 2.5% by mass of ytterbium, 5% by mass of yttrium and 90% by mass of zirconium oxide;

[0134] The metal reflective layer is an Al layer, and its thickness is 7 μm.

[0135] This example provides a method for preparing a composite laser protective coating, comprising the following steps:

[0136] (1) Titanium alloy is selected as the skin matrix.

[0137] (2) A NiCrAlY high-temperature oxidation layer with a thickness of 100 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 27 L / min, hydrogen flow rate 7 L / min, current 500 A, and powder feeding rate 10 g / min;

[0138] (3) A ceramic thermal insulation layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 35 L / min, hydrogen flow rate 20 L / min, current 650 A, and powder feeding rate 12.5 g / min;

[0139] (4) A ceramic reflective layer with a thickness of 175 μm was prepared by atmospheric plasma spraying. The spraying parameters were as follows: spraying distance 200 mm, argon flow rate 30 L / min, hydrogen flow rate 15 L / min, current 600 A, and powder feeding rate 20 g / min.

[0140] (5) A 7 μm thick Al metal reflective layer was prepared by magnetron sputtering method. The process parameters were: coating temperature 150 °C, vacuum degree 0.05 Pa, current 10 A, bias voltage 150 V, and argon gas flow rate 200 sccm.

[0141] The coating adhesion of the composite laser protective coating in this example was 47 MPa according to the HB5476 standard, and the thermal conductivity of the coating was 2.4 W / (m·K) according to the Q / AVIC 06019 standard. The porosity of the ceramic thermal insulation layer was 5.8% as measured by Image J software. The power density used was 8050 W·cm -2 The composite laser protective coating in this example was continuously irradiated with laser for 300 seconds, and there was no crack or hole damage on the coating surface. The average temperature of the back side of the skin substrate (i.e., the side away from the composite laser protective coating) measured after continuous irradiation for 300 seconds was 407°C. The reason is that the porosity of the ceramic thermal insulation layer is low and the effect of phonon scattering is poor. The protective performance of the prepared coating is significantly weaker than that of the composite laser protective coating with a high-porosity ceramic thermal insulation layer in the embodiment.

[0142] While the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A protective coating, characterized in that: It includes a high-temperature oxidation resistance layer, a ceramic heat insulation layer, a ceramic reflective layer and a metal reflective layer stacked in sequence on a substrate; The porosity of the ceramic insulation layer is not less than 10%; The material of the high temperature oxidation resistant layer includes at least one of NiCrAlY, CoCrAlY, and NiCoCrAlY; The material of the ceramic insulation layer includes zirconium oxide and oxides doped in the zirconium oxide; the oxides include at least one of Y2O3, Gd2O3, Yb2O3, TiO2, and Ta2O5; The material of the ceramic reflective layer includes zirconium oxide and rare earth elements doped in the zirconium oxide; The number of layers of the metal reflective layer is ≥1; The material of each metal reflective layer is independently selected from at least one of Al, Cu, Ag, Au, NiCrAlY, CoCrAlY, and NiCoCrAlY.

2. The protective coating according to claim 1, characterized in that: The porosity of the ceramic heat insulation layer is 10-20%; And / or, the material of the ceramic thermal insulation layer is yttria-stabilized zirconia.

3. The protective coating according to claim 1, characterized in that: The rare earth element is at least one selected from ytterbium, gadolinium, and yttrium; And / or, the mass percentage of rare earth elements in the ceramic reflective layer is 0.5% to 50%.

4. The protective coating according to claim 1, wherein: The thickness of the high temperature oxidation resistant layer is 50 to 250 μm; and / or, the thickness of the ceramic thermal insulation layer is 150 to 350 μm; and / or, the thickness of the ceramic reflective layer is 150 to 350 μm; And / or, the thickness of the metal reflective layer is 5-50 μm.

5. The protective coating according to claim 1, characterized in that: The thermal conductivity of the protective coating is ≤1.0 W / (m·K); and / or, at a power density of 8050 W cm -2 After continuous laser irradiation for 300 seconds, the average temperature of the substrate on the side away from the protective coating is lower than 150°C.

6. The method for preparing the protective coating according to any one of claims 1 to 5, characterized in that: The following steps are involved: The high-temperature oxidation resistance layer, the ceramic heat insulation layer, the ceramic reflection layer and the metal reflection layer are sequentially formed on the substrate.

7. The method for preparing a protective coating according to claim 6, wherein: At least one of the high-temperature oxidation resistant layer, the ceramic heat-insulating layer, the ceramic reflective layer and the metal reflective layer is prepared by a spraying method, and the spraying is selected from at least one of supersonic flame spraying, atmospheric plasma spraying, low-pressure plasma spraying, magnetron sputtering and plasma-physical vapor deposition.

8. The method for preparing a protective coating according to claim 6, wherein: At least one of the high-temperature oxidation resistant layer, the ceramic heat-insulating layer and the ceramic reflective layer is prepared by atmospheric plasma spraying; The atmospheric plasma spraying method has at least one of the following characteristics: (a1) Argon gas flow rate 25-50 L / min; (a2) Hydrogen flow rate 5 to 30 L / min; (a3) Current 500-700A; (a4) Powder feeding rate 10-30 g / min; (a5) Spraying distance 100~300mm.

9. The method for preparing a protective coating according to claim 6, wherein: The metal reflective layer is produced by magnetron sputtering, and the magnetron sputtering method has at least one of the following characteristics: (b1) Coating temperature: 100℃~350℃; (b2) Vacuum degree: 0.001Pa~0.09Pa; (b3) Current: 10A to 100A; (b4) Bias voltage: 50 V to 500 V; (b5) Gas flow rate: 50 sccm to 500 sccm.

10. A product characterized by: The protective coating comprises any one of claims 1 to 5; the product comprises a drone, an airplane, a protective mask, a fighter jet or a weapon.

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