A high-temperature-resistant waterproof coating for a quartz fiber composite material surface and a preparation method thereof

Abstract

The application provides a quartz fiber composite surface high-temperature-resistant waterproof coating and a preparation method thereof. The coating is ytterbium silicate (YbSiO5) ceramic, is prepared by using a low-pressure plasma spraying process, has a thickness of 0.05-0.30 mm, a porosity of not more than 5%, and a thermal expansion coefficient of less than 4*10 ‑6 / K. A laser etching process is selected for a quartz fiber composite pre-spraying treatment process, X-direction and Y-direction fibers are subjected to roughening and densification treatment, and Z-direction fibers are not treated, so as to form a grid. On the one hand, the grid maintains the integrity of the fiber bundle, and on the other hand, the surface roughness is controllable, so that the coating bonding force can be greatly improved. The coating bonding strength is greater than or equal to 1 MPa, the coating has no cracking or peeling in a prepared state, and the surface has super-hydrophobic effect. The ytterbium silicate coating has good durability, can be stored stably for a long time, does not discolor or age and fall off, is resistant to 1600 DEG C ablation, and has a water immersion weight gain rate of not more than 0.02 g / (cm 2 *h) after ablation.

Description

Technical Field

[0001] This invention belongs to the field of thermal spraying technology, and specifically relates to a high-temperature resistant and waterproof coating for the surface of quartz fiber composites and its preparation method. Background Technology

[0002] Radomes are crucial components of spacecraft, playing a key role in enabling communication, guidance, and telemetry functions. They must possess characteristics such as wave transmission, heat insulation, structural load-bearing capacity, and resistance to complex environmental conditions. Typically, radome materials are composed of ceramic materials with high porosity. Currently, widely used radome materials include alumina ceramics, Mg-Al-Si microcrystalline glass, low-cost phosphates, quartz ceramics, silicon nitride, or boron nitride ceramics. At present, the most promising radome material is orthogonal triaxial quartz fiber reinforced silica composite material, primarily due to its low dielectric constant of 3.1–3.2, minimal change in dielectric properties with temperature, and excellent ablation resistance.

[0003] The main problem with using quartz fiber reinforced silica composites as radome materials is their susceptibility to moisture absorption, which severely affects the electrical performance of the radome. Previous research has focused on waterproof coatings for radomes, primarily using various polymers such as fluoropolymers, silicone resins, and polyphenylene sulfide. While organic radome coatings offer excellent waterproofing, their high-temperature resistance and aging resistance are poor. Furthermore, during spacecraft flight, high-temperature ablation caused by aerodynamic forces can leave residual carbon on the radome surface, reducing its wave transmission performance. Increasing research is pointing towards high-temperature resistant ceramic coatings. Currently, most ceramic materials have a temperature resistance of no more than 1200℃ and are often prepared using a slurry brushing followed by high-temperature heat treatment, resulting in coating thickness uniformity that is difficult to meet the requirements of various product models. Thermal spraying technology is a special processing method applicable to the preparation of ceramic coatings and is currently widely used in aerospace, energy, steel metallurgy, and electronic semiconductor industries, offering the potential to solve the waterproofing / moisture-proofing problems of radome materials.

[0004] To address the waterproofing issue of quartz fiber composites used in radomes, there is an urgent need to find a ceramic material that can withstand temperatures up to 1600℃ and to prepare a high-temperature waterproof coating with uniform structure, dense texture, and excellent performance through a suitable thermal spraying process. Summary of the Invention

[0005] To address the issues of moisture / water absorption and high-temperature ablation in quartz fiber composites used in aerospace radomes, the inventors conducted intensive research and developed a high-temperature resistant waterproof coating for quartz fiber composites and its preparation method. This method utilizes ytterbium silicate (Yb₂SiO₅) ceramic, which is resistant to temperatures up to 1600℃ and has high density, as the waterproof layer. A corresponding low-pressure plasma spraying process was developed for the coating. Addressing the anisotropy of orthogonal triaxial quartz fiber reinforced silica composites, laser etching technology was used for specific surface roughening treatment. The coating exhibits a bonding strength ≥1MPa, good durability, and can be stored stably for a long time without discoloration, aging, or peeling. It is resistant to 1600℃ ablation, and the coating maintains good water-proof properties before and after ablation, meeting the high-temperature and waterproof requirements of radomes.

[0006] The technical solution provided by this invention is as follows:

[0007] Firstly, a high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is provided. The coating has a chemical composition of ytterbium silicate (Yb₂SiO₅), exhibits no phase change within 1600℃, and has a porosity ≤5% and a coefficient of thermal expansion less than 4×10⁻⁶. -6 / K. The coating thickness is 0.05-0.30mm, and the bonding strength between the coating and the orthogonal triaxial quartz fiber reinforced silica composite matrix is ​​≥1MPa.

[0008] Secondly, a method for preparing a high-temperature resistant and waterproof coating on the surface of a quartz fiber composite material includes:

[0009] Remove surface dust from the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean;

[0010] Observe the spatial arrangement of orthogonal triaxial quartz fibers on the substrate coating surface and set the path arrangement for laser etching;

[0011] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fiber, to roughen the coating surface;

[0012] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0013] The high-temperature resistant and waterproof coating for quartz fiber composite materials and its preparation method provided by the present invention have the following beneficial effects:

[0014] (1) The present invention provides a high temperature resistant waterproof coating on the surface of quartz fiber composite and its preparation method. Ytterbium silicate (Yb2SiO5) ceramic, which is resistant to high temperature of 1600℃ and has high density, is used as the waterproof layer. The thermal expansion coefficient of the ytterbium silicate coating is close to that of the quartz fiber composite. The thermal stress is low during coating preparation and ablation cooling.

[0015] (2) The present invention provides a high temperature resistant waterproof coating on the surface of a quartz fiber composite and its preparation method. The quartz fiber composite matrix has anisotropy, and the sprayed surface has Z-direction fibers perpendicular to the surface, as well as X-direction and Y-direction cross-linked fibers parallel to the surface. Before spraying, the X-direction and Y-direction fibers are coarsened and densified by laser etching, while the Z-direction fibers are not treated to form a grid. On the one hand, the integrity of the fiber bundle is maintained, and on the other hand, the surface roughness is controllable, which can greatly improve the coating adhesion.

[0016] (3) The present invention provides a high temperature resistant waterproof coating on the surface of quartz fiber composite material and its preparation method. The coating is prepared by low pressure plasma spraying process. The sprayed particles are completely melted, and the resulting coating is dense with a porosity of ≤5%. It has a superhydrophobic effect, is not easy to seep water, and has a high bonding force with the quartz fiber composite matrix with a bonding strength ≥1MPa.

[0017] (4) The present invention provides a high-temperature resistant and waterproof coating for the surface of quartz fiber composites and its preparation method. The ytterbium silicate coating prepared by this process has good durability, can be stored stably for a long time, does not change color, does not age or peel off, and has both good ablation resistance and waterproof performance. The coating does not peel off or crack when ablated at 1600℃, and the weight gain rate after ablation by water immersion does not exceed 0.02 g / (cm³). 2 *h). Attached Figure Description

[0018] Figure 1 The surface morphology of the matrix of orthogonal triaxial quartz fiber reinforced silica composite material;

[0019] Figure 2 This is a schematic diagram of laser etching path planning;

[0020] Figure 3 Scanning electron microscope (SEM) image of the cross-sectional morphology of a ytterbium silicate coating. Detailed Implementation

[0021] The features and advantages of the present invention will become clearer and more explicit from the following detailed description.

[0022] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0023] This invention provides a high-temperature resistant and waterproof coating for the surface of quartz fiber composites. The coating has the chemical composition of ytterbium silicate (Yb₂SiO₅), exhibits no phase change within 1600℃, and has a porosity of ≤5% and a coefficient of thermal expansion of less than 4×10⁻⁶. -6 / K. The coating thickness is 0.05-0.30mm, and the bonding strength between the coating and the orthogonal triaxial quartz fiber reinforced silica composite matrix is ​​≥1MPa.

[0024] The present invention also provides a high-temperature resistant and waterproof coating for the surface of quartz fiber composites, comprising the following steps:

[0025] Step 1: Remove the surface dust from the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0026] In this step, clean compressed gas, such as compressed air, is used to blow away the surface dust on the orthogonal triaxial quartz fiber reinforced silica composite matrix. Of course, the method of removing dust is not limited to blowing with compressed air; wiping or other methods can also be used, and this is not a limitation here.

[0027] Step 2: Observe the spatial arrangement of orthogonal triaxial quartz fibers on the substrate coating surface using an optical microscope or scanning electron microscope, and set the path arrangement for laser etching.

[0028] In this step, the sprayed surface has Z-direction fibers perpendicular to the sprayed surface, and X-direction and Y-direction cross-linked fibers parallel to the sprayed surface.

[0029] In this step, if the spacing between adjacent Z-direction square cluster fibers on the substrate coating surface is d, then the etching width in the X and Y directions is set to 0.7d-0.9d, the distance between the etching boundary and the Z-direction square cluster fibers is 0.15d-0.05d, and the etching path is set to first move in a serpentine manner in the X direction until the X-direction fibers are completely filled, and then move in a serpentine manner along the Y direction until the Y-direction fibers are completely filled.

[0030] After machining, the surface roughness of the quartz fiber composite is relatively low, requiring surface roughening treatment. Therefore, selective laser etching is performed on the X and Y phase fibers to create a height difference with the Z phase fibers, increasing the surface roughness. Furthermore, the X and Y phase fibers are bonded together with resin, resulting in low bonding strength. In contrast, the Z phase fibers are parallel to the spraying direction, and their inherent strength in this direction is sufficiently high. Laser etching in the X and Y directions allows for bonding between fiber bundles in the same direction, improving the shear resistance of the substrate at the interface.

[0031] Step 3: Use a laser to perform X-axis and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fiber, to achieve the effect of roughening the coating surface.

[0032] The main laser etching process parameters used in this step include: laser power 2-5kW, frequency 25-50kHz, pulse width 80-120ns, spot diameter 30-50μm, laser scanning speed 400-800mm / s, and 1-2 scan passes.

[0033] Step 4: Using a low-pressure plasma spraying process, a ytterbium silicate coating is sprayed onto the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix.

[0034] In this step, the ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0035] Before spraying the ytterbium silicate coating, the substrate must be preheated. The main preheating parameters are: current 500-800A, power 40-60kW, spraying distance 150-200mm, vacuum chamber pressure 400-600mbar, spray gun moving speed 400-600mm / s, step size 6-10mm, and 1-3 preheating passes. Excessive preheating passes under these parameters can cause severe sintering of the X and Y axes, leading to localized fractures and coating cracking. Furthermore, a significant height difference with the Z axis can result in discontinuous coating at the etched line boundaries, reducing waterproofing performance. If preheating is not performed before spraying the ytterbium silicate coating, the substrate temperature will be low, resulting in weak cross-sectional bonding strength between the coating and the substrate, making it prone to detachment.

[0036] In this step, the main process parameters for spraying the ytterbium silicate coating are: current 500-800A, power 40-60kW, spraying distance 150-200mm, vacuum chamber pressure 400-600mbar, powder feeding rate 8-15g / min, spray gun moving speed 400-600mm / s, and step distance 6-10mm.

[0037] In this step, the thickness of the ytterbium silicate coating is 0.05-0.30 mm, which ensures that the coating has a good waterproof effect.

[0038] Example

[0039] Example 1

[0040] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0041] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0042] (2) Laser etching path planning:

[0043] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1As shown in the scanning electron microscope image, the spacing between adjacent Z-axis square cluster fibers on the coated surface is 1 mm. Therefore, the laser etching width in the X and Y directions is set to 0.7 mm, and the distance between the etching boundary and the Z-axis square cluster fiber is 0.15 mm. The etching path is set to first serpentine in the X direction until the X-axis fibers are completely filled, and then serpentine in the Y direction until the Y-axis fibers are completely filled. The simplified path planning diagram is shown below. Figure 2 As shown.

[0044] (3) Laser etching:

[0045] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0046] (4) Spraying a ytterbium silicate coating:

[0047] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0048] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0049] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0050] The main process parameters for spraying ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.05mm.

[0051] The ytterbium silicate coating prepared in this embodiment exhibits no phase change within 1600℃, and has a porosity of approximately 4.3%, with a thermal expansion coefficient of approximately 3.5 × 10⁻⁶ at 1000℃. -6 The bonding strength between the coating and the orthogonal triaxial quartz fiber reinforced silica composite matrix reached 1.5 MPa. The ytterbium silicate coating withstood ablation at 1600℃, and the coating structure remained intact after ablation without peeling; the water immersion weight gain rate after ablation did not exceed 0.02 g / (cm³). 2 *h).

[0052] Example 2

[0053] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0054] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0055] (2) Laser etching path planning:

[0056] For orthogonal triaxial quartz fiber reinforced silica composite material, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1.4 mm. Therefore, the etching width in the X and Y directions of laser etching is set to 1.2 mm, the distance between the etching boundary and the Z-direction square cluster fiber is 0.1 mm, and the etching path is set to first serpentine in the X direction until the X-direction fiber is completely filled, and then serpentine in the Y direction until the Y-direction fiber is completely filled.

[0057] (3) Laser etching:

[0058] A laser is used to perform X-axis and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fiber to achieve a surface roughening effect. The main laser etching process parameters include: laser power 3.5kW, frequency 36kHz, pulse width 100ns, spot diameter 40μm, laser scanning speed 600mm / s, and one scan pass.

[0059] (4) Spraying a ytterbium silicate coating:

[0060] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0061] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0062] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 650A, power 50kW, spraying distance 175mm, vacuum chamber pressure 500mbar, spray gun moving speed 500mm / s, step distance 8mm, and 2 preheating passes.

[0063] The main process parameters for spraying ytterbium silicate coating are: current 650A, power 50kW, spraying distance 175mm, vacuum chamber pressure 500mbar, powder feeding rate 11g / min, spray gun moving speed 500mm / s, step distance 8mm, and coating thickness approximately 0.15mm.

[0064] The SEM image of the cross-sectional microstructure of the ytterbium silicate coating prepared in this embodiment is shown below. Figure 3 As shown, the coating has a porosity of approximately 4%, exhibits no phase change up to 1600℃, and has a thermal expansion coefficient of approximately 3.5 × 10⁻⁶ at 1000℃. -6 The bonding strength between the coating and the orthogonal triaxial quartz fiber reinforced silica composite matrix reached 1.8 MPa. The ytterbium silicate coating withstood ablation at 1600℃, and the coating structure remained intact after ablation without peeling; the water immersion weight gain rate after ablation did not exceed 0.02 g / (cm³). 2 *h).

[0065] Example 3

[0066] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0067] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0068] (2) Laser etching path planning:

[0069] For orthogonal triaxial quartz fiber reinforced silica composite material, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1.5 mm. Therefore, the etching width in the X and Y directions is set to 1.34 mm, the distance between the etching boundary and the Z-direction square cluster fiber is 0.08 mm, and the etching path is set to first serpentine in the X direction until the X-direction fiber is completely filled, and then serpentine in the Y direction until the Y-direction fiber is completely filled.

[0070] (3) Laser etching:

[0071] A laser is used to perform X-axis and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 5kW, frequency 50kHz, pulse width 120ns, spot diameter 50μm, laser scanning speed 800mm / s, and 2 scan passes.

[0072] (4) Spraying a ytterbium silicate coating:

[0073] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0074] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 phase content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0075] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 800A, power 60kW, spraying distance 200mm, vacuum chamber pressure 600mbar, spray gun moving speed 600mm / s, step distance 10mm, and 1 preheating pass.

[0076] The main process parameters for spraying ytterbium silicate coating are: current 800A, power 60kW, spraying distance 200mm, vacuum chamber pressure 600mbar, powder feeding rate 15g / min, spray gun moving speed 600mm / s, step distance 10mm, and coating thickness approximately 0.30mm.

[0077] The ytterbium silicate coating prepared in this embodiment exhibits no phase change within 1600℃, and has a porosity of approximately 4.2%, with a thermal expansion coefficient of approximately 3.5 × 10⁻⁶ at 1000℃. -6 The bonding strength between the coating and the orthogonal triaxial quartz fiber reinforced silica composite matrix reached 1.9 MPa. The ytterbium silicate coating withstood ablation at 1600℃, and the coating structure remained intact after ablation without peeling; the water immersion weight gain rate after ablation did not exceed 0.02 g / (cm³). 2 *h).

[0078] Example 4

[0079] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0080] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0081] (2) Laser etching path planning:

[0082] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1 As shown in the scanning electron microscope image, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1 mm. Therefore, the etching width in the X and Y directions is set to 0.7 mm, the distance between the etching boundary and the Z-direction square cluster fiber is 0.15 mm, and the etching path is set to first serpentine in the X direction until the X-direction fiber is completely filled, and then serpentine in the Y direction until the Y-direction fiber is completely filled.

[0083] (3) Laser etching:

[0084] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0085] (4) Spraying a ytterbium silicate coating:

[0086] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0087] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0088] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0089] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.15mm. Performance results are shown in Table 1.

[0090] Example 5

[0091] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0092] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0093] (2) Laser etching path planning:

[0094] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1 As shown in the scanning electron microscope image, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1 mm. Therefore, the etching width in the X and Y directions is set to 0.7 mm, the distance between the etching boundary and the Z-direction square cluster fiber is 0.15 mm, and the etching path is set to first serpentine in the X direction until the X-direction fiber is completely filled, and then serpentine in the Y direction until the Y-direction fiber is completely filled.

[0095] (3) Laser etching:

[0096] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0097] (4) Spraying a ytterbium silicate coating:

[0098] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0099] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0100] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0101] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.30mm. Performance results are shown in Table 1.

[0102] Comparative Example 1

[0103] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0104] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0105] (2) Laser etching path planning:

[0106] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1As shown in the scanning electron microscope image, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1 mm. Therefore, the etching width in the X and Y directions is set to 0.7 mm, the distance between the etching boundary and the Z-direction square cluster fiber is 0.15 mm, and the etching path is set to first serpentine in the X direction until the X-direction fiber is completely filled, and then serpentine in the Y direction until the Y-direction fiber is completely filled.

[0107] (3) Laser etching:

[0108] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0109] (4) Spraying a ytterbium silicate coating:

[0110] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0111] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0112] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0113] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.02mm. Performance results are shown in Table 1.

[0114] Comparative Example 2

[0115] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0116] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0117] (2) Laser etching path planning:

[0118] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1 As shown in the scanning electron microscope image, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1 mm. Therefore, the etching width in the X and Y directions is set to 0.7 mm, the distance between the etching boundary and the Z-direction square cluster fiber is 0.15 mm, and the etching path is set to first serpentine in the X direction until the X-direction fiber is completely filled, and then serpentine in the Y direction until the Y-direction fiber is completely filled.

[0119] (3) Laser etching:

[0120] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0121] (4) Spraying a ytterbium silicate coating:

[0122] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0123] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0124] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0125] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.40mm. Performance results are shown in Table 1.

[0126] Comparative Example 3

[0127] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0128] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0129] (2) Laser etching path planning:

[0130] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1 As shown in the scanning electron microscope image, laser etching path planning was performed on the entire sprayed surface to ensure uniform etching of the X, Y, and Z phase fibers.

[0131] (3) Laser etching:

[0132] A laser was used to perform micro-etching on the substrate coating surface. The main laser etching process parameters included: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0133] (4) Spraying a ytterbium silicate coating:

[0134] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0135] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0136] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0137] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.05mm. Performance results are shown in Table 2.

[0138] Comparative Example 4

[0139] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0140] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0141] (2) Laser etching path planning:

[0142] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1As shown in the scanning electron microscope image, the spacing between adjacent Z-direction square cluster fibers on the sprayed surface is 1 mm. Therefore, the etching width in the X-direction is set to 0.7 mm, the distance between the etching boundary and the Y-direction and Z-direction fibers is 0.15 mm, and the etching path is set to first move in a serpentine manner in the X-direction until the X-direction fibers are completely filled.

[0143] (3) Laser etching:

[0144] A laser was used to perform X-axis micro-etching on the substrate coating surface, bypassing the Y-axis and Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters included: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0145] (4) Spraying a ytterbium silicate coating:

[0146] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0147] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0148] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 3 preheating passes.

[0149] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.05mm. Performance results are shown in Table 2.

[0150] Comparative Example 5

[0151] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0152] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0153] (2) Laser etching path planning:

[0154] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1 As shown in the scanning electron microscope image, the spacing between adjacent Z-axis square cluster fibers on the coated surface is 1 mm. Therefore, the laser etching width in the X and Y directions is set to 0.7 mm, and the distance between the etching boundary and the Z-axis square cluster fiber is 0.15 mm. The etching path is set to first serpentine in the X direction until the X-axis fibers are completely filled, and then serpentine in the Y direction until the Y-axis fibers are completely filled. The simplified path planning diagram is shown below. Figure 2 As shown.

[0155] (3) Laser etching:

[0156] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0157] (4) Spraying a ytterbium silicate coating:

[0158] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0159] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0160] No preheating treatment is performed on the substrate before spraying the ytterbium silicate coating.

[0161] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.05mm. Performance results are shown in Table 3.

[0162] Comparative Example 6

[0163] A high-temperature resistant and waterproof coating for the surface of a quartz fiber composite material is prepared by the following steps:

[0164] (1) Surface cleaning: Use clean compressed air to remove the floating dust on the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean.

[0165] (2) Laser etching path planning:

[0166] For orthogonal triaxial quartz fiber reinforced silica composites, such as Figure 1As shown in the scanning electron microscope image, the spacing between adjacent Z-axis square cluster fibers on the coated surface is 1 mm. Therefore, the laser etching width in the X and Y directions is set to 0.7 mm, and the distance between the etching boundary and the Z-axis square cluster fiber is 0.15 mm. The etching path is set to first serpentine in the X direction until the X-axis fibers are completely filled, and then serpentine in the Y direction until the Y-axis fibers are completely filled. The simplified path planning diagram is shown below. Figure 2 As shown.

[0167] (3) Laser etching:

[0168] A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fibers to achieve a surface roughening effect. The main laser etching process parameters include: laser power 2kW, frequency 25kHz, pulse width 80ns, spot diameter 30μm, laser scanning speed 400mm / s, and one scan pass.

[0169] (4) Spraying a ytterbium silicate coating:

[0170] Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process.

[0171] The ytterbium silicate powder used for spraying is a spray-granulated spherical powder with a Yb2SiO5 content of not less than 90 wt.% and a particle size of 15-60 μm accounting for ≥90%.

[0172] Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, spray gun moving speed 400mm / s, step distance 6mm, and 4 preheating passes.

[0173] The main process parameters for spraying the ytterbium silicate coating are: current 500A, power 40kW, spraying distance 150mm, vacuum chamber pressure 400mbar, powder feeding rate 8g / min, spray gun moving speed 400mm / s, step distance 6mm, and coating thickness approximately 0.05mm. Performance results are shown in Table 3.

[0174] Performance Results

[0175] Examples 4-5 and Comparative Examples 1-2

[0176] Examples 4-5 and Comparative Examples 1-2 are the same as Example 1, except that the thickness of the ytterbium silicate coating in Examples 4-5 and Comparative Examples 1-2 is 0.15, 0.30, 0.02, and 0.40 mm, respectively.

[0177] The performance of the ytterbium silicate coating was tested, and the results are shown in Table 1 below.

[0178] Table 1. Performance test results of ytterbium silicate coatings in Examples 4-5 and Comparative Examples 1-2

[0179]

[0180] Comparative Examples 3-4

[0181] Comparative Example 3 is the same as Example 1, except that a laser is used to perform micro-etching treatment on the substrate coating surface in the X, Y and Z directions, without bypassing the Z-direction quartz fiber.

[0182] Comparative Example 4 is the same as Example 1, except that a laser is used to perform X-axis micro-etching on the substrate coating surface, bypassing the Y-axis and Z-axis quartz fibers.

[0183] The performance of the ytterbium silicate coating was tested, and the results are shown in Table 2 below.

[0184] Table 2 shows the performance test results of the ytterbium silicate coatings in Comparative Examples 3 and 4.

[0185]

[0186]

[0187] Comparative Examples 5-6

[0188] Comparative Example 5 is the same as Example 1, except that the substrate was not preheated before the ytterbium silicate coating was applied.

[0189] Comparative Example 6 is the same as Example 1, except that the substrate is preheated four times before the ytterbium silicate coating is applied.

[0190] The performance of the ytterbium silicate coating was tested, and the results are shown in Table 3 below.

[0191] Table 3 shows the performance test results of ytterbium silicate coatings in comparative examples 5 and 6.

[0192]

[0193] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0194] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for preparing a high temperature resistant and water repellent coating on the surface of a quartz fiber composite material for an aircraft radome, characterized by, Includes the following steps: Remove surface dust from the orthogonal triaxial quartz fiber reinforced silica composite matrix and keep the working environment dry and clean; Observe the spatial arrangement of orthogonal triaxial quartz fibers on the substrate coating surface and determine the laser etching path arrangement. The coating surface has Z-axis fibers perpendicular to the coating surface, and X-axis and Y-axis cross-shaped fibers parallel to the coating surface. The etching path is set to first serpentine in the X-direction until the X-axis fibers are completely filled, and then serpentine in the Y-direction until the Y-axis fibers are completely filled. If the spacing between adjacent Z-axis square cluster fibers on the substrate coating surface is... d Therefore, the etching width in both the X and Y directions of the laser etching is set to 0.

7. d -0.9 d The distance between the etched boundary and the Z-direction square cluster fiber is 0.

15. d -0.05 d ; A laser is used to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fiber, to roughen the coating surface; Ytterbium silicate coating was applied to the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process. The coating thickness was 0.05-0.30 mm. Before spraying the ytterbium silicate coating, the substrate is preheated. The main preheating process parameters are: current 500-800A, power 40-60kW, spraying distance 150-200mm, vacuum chamber pressure 400-600mbar, spray gun moving speed 400-600mm / s, step distance 6-10mm, and 1-3 preheating passes.

2. The method for preparing a high-temperature resistant and waterproof coating on the surface of a quartz fiber composite material for an aircraft radome according to claim 1, characterized in that, In the step of removing the floating dust from the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix, clean compressed gas is used to blow away the floating dust from the surface of the orthogonal triaxial quartz fiber reinforced silica composite matrix.

3. The method of claim 1, wherein the method further comprises the step of: 3-1) applying a primer layer on the surface of the quartz fiber composite material of the aircraft radome, and 3-2) applying a top coat layer on the primer layer of the quartz fiber composite material of the aircraft radome. In the step of using a laser to perform X- and Y-axis micro-etching on the substrate coating surface, bypassing the Z-axis quartz fiber, and roughening the coating surface, the main process parameters of the etching process include: laser power 2-5kW, frequency 25-50kHz, pulse width 80-120ns, spot diameter 30-50μm, laser scanning speed 400-800mm / s, and 1-2 scan passes.

4. The method of claim 1, wherein the method further comprises the step of applying a surface treatment to the quartz fiber composite surface. In the step of spraying a ytterbium silicate coating onto the surface of an orthogonal triaxial quartz fiber reinforced silica composite matrix using a low-pressure plasma spraying process, the main process parameters for spraying the ytterbium silicate coating are: current 500-800A, power 40-60kW, spraying distance 150-200mm, vacuum chamber pressure 400-600mbar, powder feeding rate 8-15g / min, spray gun moving speed 400-600mm / s, and step distance 6-10mm.

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