A quartz fiber reinforced silica ceramic matrix composite material with sandwich structure and a preparation method thereof

Abstract

The present application relates to a kind of quartz fiber reinforced silica ceramic matrix composite with sandwich structure and its preparation method.The method includes the following steps: using silica sol to impregnate quartz fiber preform, to obtain blank;Surface hydrophobic treatment is carried out using hydrophobic reagent;The surface of blank is irradiated by quartz lamp to remove surface hydrophobic group;Using silica sol to continue to impregnate blank;Blank is sintered, and quartz fiber reinforced silica composite material with sandwich structure is prepared.The method of the present application uses quartz fiber preform, and a new method for preparing quartz fiber reinforced silica ceramic matrix composite with sandwich structure is developed by selective heat treatment and selective impregnation.

Description

TECHNICAL FIELD

[0001] The present application relates to a composite material and a preparation method thereof, in particular to a quartz fiber reinforced silica ceramic matrix composite material with a sandwich structure and a preparation method thereof, and belongs to the technical field of composite materials. BACKGROUND

[0002] The quartz fiber reinforced silica composite material is a domestic application mature ceramic matrix wave-transparent material, which has good high-temperature wave-transparent performance and mechanical properties, and is commonly used in products such as antenna covers and antenna windows, and can also be simply used as a load-bearing thermal insulation structural member.

[0003] Although the quartz fiber reinforced silica composite material with a sandwich structure has a broad application prospect in light-weight thermal insulation and wide-band wave-transparent products, the preparation of such a composite material has always been a problem. At present, the few application examples of the quartz fiber reinforced silica composite material with a sandwich structure are all based on the idea similar to the patent CN 111703142 A: stitching a certain thickness of a preform cloth layer on the upper surface and the lower surface of the quartz fiber reinforced silica aerogel, and then performing composite impregnation. Such a method has the problems of a relatively complicated process, and insufficient interlayer bonding force between the panel and the intermediate layer, which is maintained only by the limited stitching lines.

[0004] Therefore, it is still a challenge to develop a relatively simple method for preparing the quartz fiber reinforced silica composite material with a sandwich structure. SUMMARY

[0005] The main purpose of the present application is to overcome the problems of a complicated preparation process and insufficient interlayer bonding force of the existing quartz fiber reinforced silica composite material with a sandwich structure, which needs to stitch a preform cloth layer during the preparation process. The present application only uses a conventional quartz fiber preform fabric, adopts the idea of removing the surface hydrophobic groups by selective heat treatment after hydrophobizing the composite material blank, and realizes the efficient preparation of the quartz fiber reinforced silica composite material with a sandwich structure after multiple impregnations.

[0006] The first aspect of the present application provides a preparation method of a quartz fiber reinforced silica ceramic matrix composite material with a sandwich structure, which comprises the following steps:

[0007] (1) impregnating a quartz fiber preform with a preform impregnation silica sol, drying, and obtaining a blank;

[0008] (2) hydrophobizing the blank using a hydrophobic reagent, grinding and flattening after drying, and obtaining a hydrophobized blank;

[0009] (3) irradiating the surface of the hydrophobized blank by a quartz lamp to remove the surface layer hydrophobic groups of the hydrophobized blank, to obtain a surface layer hydrophilic and inner hydrophobic blank;

[0010] (4) continuing to impregnate the surface layer hydrophilic and inner hydrophobic blank by using a silica sol for blank impregnation, to obtain a final blank;

[0011] (5) performing a sintering treatment on the final blank, to obtain a quartz fiber reinforced silica composite material with sandwich structure.

[0012] The present application provides, in a second aspect, a quartz fiber reinforced silica ceramic matrix composite material with sandwich structure prepared by the preparation method according to the first aspect of the present application.

[0013] Compared with the prior art, the present application has the following beneficial effects: the quartz fiber reinforced silica composite material with sandwich structure can be prepared by using a conventional fabric, and the density of the material and the thickness of each layer of the sandwich structure can be controlled in a wide range. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The present application provides a process flow chart of the preparation method. DETAILED DESCRIPTION

[0015] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application will be described in more detail in conjunction with the following specific embodiments, but these specific embodiments should not be understood as limiting the scope of the present application.

[0016] As described above, the present application provides, in a first aspect, a preparation method of a quartz fiber reinforced silica ceramic matrix composite material with sandwich structure, which comprises the following steps:

[0017] (1) impregnating a quartz fiber preform by using a silica sol for preform impregnation, and drying to obtain a blank;

[0018] (2) performing hydrophobic treatment on the blank by using a hydrophobic reagent, and grinding after drying to obtain a hydrophobized blank;

[0019] (3) irradiating the surface of the hydrophobized blank by a quartz lamp to remove the surface layer hydrophobic groups of the hydrophobized blank, to obtain a surface layer hydrophilic and inner hydrophobic blank;

[0020] (4) continuing to impregnate the surface layer hydrophilic and inner hydrophobic blank by using a silica sol for blank impregnation, to obtain a final blank;

[0021] (5) performing sintering treatment on the final blank to obtain a quartz fiber reinforced silica composite material with sandwich structure.

[0022] In some preferred embodiments, the quartz fiber preform is one fabric selected from the group consisting of needle-punched fabric, 2.5D fabric, 3D orthogonal fabric, and stitched fabric, or a combination of two or more thereof. The structure and parameters of the quartz fiber preform can be selected according to the strength requirement of the actual product. For products with higher interlaminar performance requirement, 2.5D fabric or 3D orthogonal fabric is preferred.

[0023] Preferably, the quartz fiber preform has a uniform density, and more preferably, the quartz fiber preform has a relatively low density (for example, about 0.4 g / cm 3 The thickness and fiber volume content of the quartz fiber preform are not particularly limited in the present application and can be adjusted as needed.

[0024] In some preferred embodiments, the preform impregnation silica sol and the blank impregnation silica sol are independently commercially available industrial-grade silica sol. The preform impregnation silica sol and the blank impregnation silica sol can be the same or different.

[0025] In some more preferred embodiments, the solid content of the preform impregnation silica sol and the blank impregnation silica sol is independently 20-25 mass% (for example, 20, 21, 22, 23, 24, or 25 mass%).

[0026] In some more preferred embodiments, in step (1), after the first use of the preform impregnation silica sol to impregnate the quartz fiber preform to prepare the blank, the density of the final blank prepared in step (1) is controlled by adjusting the number of times of subsequent use of the preform impregnation silica sol to impregnate the blank.

[0027] The preform is impregnated in the preform impregnation silica sol, and after each time of blank impregnation with the preform impregnation silica sol, a drying treatment is performed in an oven. Preferably, the number of times of blank impregnation is controlled to 1-2 times. If the number of times of impregnation is too high, it is difficult for the blank to continue to gain weight, which is not conducive to the subsequent formation of sandwich structure.

[0028] The hydrophobic agent is not particularly limited in the present application, as long as it can achieve hydrophobization after the treatment. However, in some more preferred embodiments, the hydrophobic agent is a small organic silicon molecule (e.g. trimethylmethoxysilane or hexamethylsilazane, etc.) or an organic silicon resin (e.g. methyl silicone resin). In the hydrophobic treatment, the blank can be soaked in a solution (e.g. an ethanol solution) of the small organic silicon molecule or the organic silicon resin, so as to achieve the conversion of the blank from hydrophilicity to hydrophobicity by hydrophobically modifying the matrix formed by the silica particles in the blank.

[0029] In the removal of the surface layer hydrophobic groups by high-temperature short-time irradiation treatment using a quartz lamp (e.g. a quartz lamp set), a temperature control point can be arranged on the surface of the blank, and the surface temperature is controlled at 500-600°C. The irradiation time can be adjusted according to the thickness of the surface layer from which the hydrophobic groups are to be removed. During the irradiation, the methyl and other hydrophobic organic groups in the blank will be thermally degraded at high temperature, and the short-time irradiation of the surface of the blank by the quartz lamp will thermally decompose the hydrophobic groups in the surface layer, so as to make the surface layer of the blank regain hydrophilicity. The removal thickness of the surface layer hydrophobic groups can be controlled by adjusting the irradiation time. The intermediate layer of the blank maintains hydrophobicity because the surface layer material has a heat insulation effect, and the temperature of the intermediate layer is lower than the thermal decomposition temperature of the hydrophobic organic groups. In addition, in the present application, after the blank is treated by the hydrophobic agent, the surface of the blank can be first subjected to a flattening treatment, so as to achieve better quartz lamp irradiation effect in the subsequent quartz lamp irradiation.

[0030] In some more preferred embodiments, the surface temperature of the hydrophobized blank is controlled at 500-600°C (e.g. 550°C) during the irradiation in step (3). In some embodiments, the irradiation time at the temperature can be 10s to 50s, e.g. 15s, 20s, 25s, 30s, 35s, 40s or 45s, preferably 10s to 30s.

[0031] In some more preferred embodiments, in step (4), the density of the surface layer material of the sandwich structure is adjusted by controlling the number of times of continuing to immerse the surface layer hydrophilic internal hydrophobic blank in the silica sol for blank immersion.

[0032] During the continuing immersion, the intermediate layer of the blank maintains hydrophobicity, and the silica sol for blank immersion cannot enter the interior of the blank due to the water property, but can only enter the hydrophilic surface layer of the blank, so that the density of the surface layer of the blank is continuously increased after multiple immersions, thereby enabling the target density of the surface layer to be controlled by the number of times of continuing to immerse.

[0033] The present application provides, in a second aspect, a quartz fiber reinforced silica ceramic matrix composite material with a sandwich structure prepared by the preparation method according to the first aspect of the present application.

[0034] Embodiment

[0035] The application will be described in more detail below with reference to the drawings and specific examples.

[0036] Embodiment 1

[0037] In this embodiment, a quartz fiber reinforced silica ceramic matrix composite material with sandwich structure is prepared, and the specific preparation process is as follows:

[0038] (1) A needled fabric with a fiber volume density of 0.4 g / cm 3 is used as a preform, the thickness of the fabric is 20 mm, the length is 200 mm, and the width is 200 mm; under vacuum, the preform is impregnated with silica sol (solid content of 20 mass%) to fill a sealed container containing the fabric, the fabric is taken out after impregnation for 12 h, dried in an oven at 80°C for 4 h, then dried at 100°C for 1 h, and finally dried at 150°C for 1 h to obtain a blank.

[0039] (2) The surface of the blank is ground flat, 100 g of trimethylmethoxysilane is added to 2 L of ethanol solvent to prepare an ethanol solution of hydrophobic reagent, and the surface-ground blank is placed in the ethanol solution, taken out and air-dried after room temperature impregnation for 48 h to obtain a hydrophobized blank.

[0040] (3) Quartz lamp heating temperature control points are arranged on the upper surface and the lower surface of the hydrophobized blank, and the surface temperature is controlled at 500°C, the upper surface and the lower surface are irradiated with a quartz lamp for 10 s respectively to obtain a blank with a surface layer of hydrophilic and an inner layer of hydrophobic.

[0041] (4) The preform prepared in step (1) is used as the silica sol for blank impregnation to fill a container containing the blank with a surface layer of hydrophilic and an inner layer of hydrophobic, and after impregnation for 4 h, the blank is taken out and dried according to the drying process of step (1), and then the impregnation process is repeated for 7 times to obtain a final blank.

[0042] (5) The final blank is sintered at 600°C for 1 hour to obtain a final quartz fiber reinforced silica ceramic matrix composite material with sandwich structure.

[0043] (6) The material density is tested every 1 mm in the thickness direction to obtain a composite material with sandwich structure, in which the density of the upper surface and the lower surface of the material is about 1.5 g / cm 3 , and the density of the middle layer is 0.7 g / cm 3 .

[0044] Embodiment 2

[0045] The embodiment prepares a quartz fiber reinforced silica ceramic matrix composite material with sandwich structure, and the specific preparation process is as follows.

[0046] (1) A needle-punched fabric with a fiber volume density of 0.4 g / cm 3 is used as a preform, the thickness of the fabric is 20 mm, the length is 200 mm, and the width is 200 mm; under vacuum, the preform is impregnated with silica sol (solid content 20 mass%) to fill a sealed container containing the fabric, the fabric is taken out after impregnation for 12 h, dried in an oven at 80°C for 4 h, then dried at 100°C for 1 h, and finally dried at 150°C for 1 h to obtain a blank.

[0047] (2) The surface of the blank is ground flat, 100 g of trimethylmethoxysilane is added to 2 L of ethanol solvent to prepare an ethanol solution of hydrophobic reagent, and the surface-ground blank is placed in the ethanol solution, taken out and dried after room temperature impregnation for 48 h to obtain a hydrophobized blank.

[0048] (3) A quartz lamp temperature control point is arranged on the upper surface and the lower surface of the hydrophobized blank, the surface temperature is controlled at 500°C, and the upper surface and the lower surface are irradiated with a quartz lamp for 30 s respectively to obtain a blank with a surface layer of hydrophilic and an inner layer of hydrophobic.

[0049] (4) The preform prepared in step (1) is used to impregnate silica sol as a blank impregnation silica sol to fill a container containing the blank with a surface layer of hydrophilic and an inner layer of hydrophobic, the blank is taken out after impregnation for 4 h, and the blank is dried according to the drying process of step (1), and then the impregnation process is repeated for 7 times to obtain a final blank.

[0050] (5) The final blank is sintered at 600°C for 1 hour to obtain a final quartz fiber reinforced silica ceramic matrix composite material with sandwich structure.

[0051] (6) The material density is tested every 1 mm in the thickness direction to obtain a composite material with sandwich structure with a density of about 1.5 g / cm 3 in the area of about 2 mm on the upper surface and the lower surface of the material, and a density of 0.7 g / cm 3 in the middle layer.

[0052] Example 3

[0053] The embodiment prepares a quartz fiber reinforced silica ceramic matrix composite material with sandwich structure, and the specific preparation process is as follows.

[0054] (1) A needle-punched fabric with a fiber volume density of 1.0 g / cm 3a three-dimensional fabric having a thickness of 20 mm, a length of 200 mm, and a width of 200 mm as a preform; under vacuum, the preform was impregnated with silica sol (solid content 20%) to fill a closed container having the fabric, and after impregnation for 12 h, the fabric was taken out, dried in an oven at 80°C for 4 h, then dried at 100°C for 1 h, and finally dried at 150°C for 1 h to obtain a blank.

[0055] (2) The surface of the blank was ground flat, 100 g of trimethylmethoxysilane was added to 2 L of an ethanol solvent to obtain an ethanol solution of a hydrophobic reagent, and the blank with the ground flat surface was placed in the ethanol solution, taken out after immersion at room temperature for 48 h, and air-dried to obtain a hydrophobized blank.

[0056] (3) A quartz lamp heating temperature control point was arranged on the upper surface and the lower surface of the hydrophobized blank, the surface temperature was controlled at 500°C, and the upper surface and the lower surface were irradiated with a quartz lamp for 10 s respectively to obtain a blank with a surface layer that is hydrophilic and an inner layer that is hydrophobic.

[0057] (4) The preform obtained in step (1) was used as a blank impregnation silica sol to fill a container having the blank with the surface layer that is hydrophilic and the inner layer that is hydrophobic, impregnation was performed for 4 h, the blank was taken out, and the blank was dried according to the drying process of step (1), and then the impregnation process was repeated 7 times to obtain a final blank.

[0058] (5) The final blank was sintered at 600°C for 1 h to obtain a final quartz fiber reinforced silica ceramic matrix composite material with a sandwich structure.

[0059] (6) The material density was tested every 1 mm in the thickness direction to obtain a composite material with a sandwich structure, in which the density of the upper surface and the lower surface of the material is about 1.65 g / cm 3 , and the density of the middle layer is 1.4 g / cm 3 .

[0060] Comparative Example 1

[0061] A quartz fiber reinforced silica ceramic matrix composite material was prepared according to the following specific preparation process.

[0062] (1) A needle-punched fabric with a fiber volume density of 0.4 g / cm 3 was used as a preform, the fabric had a thickness of 20 mm, a length of 200 mm, and a width of 200 mm; under vacuum, the preform was impregnated with silica sol (solid content 20 mass%) to fill a closed container having the fabric, and after impregnation for 12 h, the fabric was taken out, dried in an oven at 80°C for 4 h, then dried at 100°C for 1 h, and finally dried at 150°C for 1 h to obtain a blank.

[0063] (2) The surface of the blank is ground flat, 100 g of trimethylmethoxysilane is added to 2 L of ethanol solvent to prepare an ethanol solution of hydrophobic reagent, the surface-ground blank is put into the ethanol solution, and after being immersed at room temperature for 48 h, it is taken out and dried to obtain a hydrophobized blank.

[0064] (3) The surface of the hydrophobized blank is not subjected to quartz lamp irradiation treatment, and the silica sol prepared in step (1) is directly used as the blank-impregnating silica sol to fill the container containing the hydrophobized blank, and after being immersed for 4 h, the blank is taken out and dried according to the drying process of step (1), and then the immersion process is repeated for 7 times to obtain a final blank.

[0065] (4) The final blank is sintered at 600℃ for 1 h to obtain a final quartz fiber-reinforced silica ceramic matrix composite material.

[0066] (5) The material density is tested every 1 mm in the thickness direction, and the obtained material is a uniform-density (the density is about 0.7 g / cm 3 ) composite material without a sandwich structure.

[0067] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing a quartz fiber-reinforced silica ceramic matrix composite material having a sandwich structure, characterized by, The method comprises the following steps: (1) using a preform to impregnate a silica sol to impregnate a quartz fiber preform, drying to obtain a blank; (2) using a hydrophobic reagent to hydrophobize the blank, drying and then grinding to obtain a hydrophobized blank; (3) irradiating the surface of the hydrophobized blank with a quartz lamp to remove the surface hydrophobic groups of the hydrophobized blank, obtaining a blank with a hydrophilic surface and a hydrophobic interior; (4) using a blank impregnation silica sol to continue to impregnate the blank with a hydrophilic surface and a hydrophobic interior, obtaining a final blank; (5) sintering the final blank to obtain a quartz fiber reinforced silica composite material with a sandwich structure.

2. The preparation method according to claim 1, wherein: The quartz fiber preform is one of the following or a combination of multiple of the following: needle-punched fabric, 2.5D fabric, three-way orthogonal fabric, and stitched fabric.

3. The preparation method according to claim 1, wherein: The preform impregnation silica sol and the blank impregnation silica sol are independently commercially available industrial grade silica sol.

4. The preparation method according to claim 2, wherein: The preform impregnation silica sol and the blank impregnation silica sol are independently commercially available industrial grade silica sol.

5. The preparation method according to any one of claims 1 to 4, wherein: The solid content of the preform impregnation silica sol and the blank impregnation silica sol is independently 20-25 mass%.

6. The preparation method according to any one of claims 1 to 4, wherein: In step (1), after the first use of the preform impregnation silica sol to impregnate the quartz fiber preform to prepare the blank, the density of the blank prepared in step (1) is controlled by adjusting the number of times of subsequent use of the preform impregnation silica sol to impregnate the blank.

7. The preparation method according to any one of claims 1 to 4, wherein: The hydrophobic reagent is an organic silicon small molecule or an organic silicon resin.

8. The preparation method according to any one of claims 1 to 4, wherein: In step (3), the surface temperature of the hydrophobized blank is controlled to be 500-600°C during the irradiation.

9. The preparation method according to any one of claims 1 to 4, wherein: In step (3), the surface temperature of the hydrophobized blank is controlled to be 500-600°C by the irradiation and the irradiation is continued at this temperature for 10s to 50s.

10. The preparation method according to claim 9, wherein: In step (3), the surface temperature of the hydrophobized blank is controlled to be 500-600°C by the irradiation and the irradiation is continued at this temperature for 10s to 30s.

11. The preparation method according to any one of claims 1 to 4, wherein: In step (4), the density of the surface material of the sandwich structure is adjusted by controlling the number of times of using the blank impregnation silica sol to impregnate the blank with a hydrophilic surface and a hydrophobic interior.

12. A quartz fiber-reinforced silica ceramic matrix composite having a sandwich structure produced by the production method according to any one of claims 1 to 11.

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