CN115923257A - Fiber-reinforced ablation-resistant composite board and preparation method thereof - Google Patents
Fiber-reinforced ablation-resistant composite board and preparation method thereof Download PDFInfo
- Publication number
- CN115923257A CN115923257A CN202210897802.1A CN202210897802A CN115923257A CN 115923257 A CN115923257 A CN 115923257A CN 202210897802 A CN202210897802 A CN 202210897802A CN 115923257 A CN115923257 A CN 115923257A
- Authority
- CN
- China
- Prior art keywords
- fiber
- composite board
- resistant composite
- twisting
- fiber reinforced
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
Landscapes
- Reinforced Plastic Materials (AREA)
- Woven Fabrics (AREA)
Abstract
The invention discloses a fiber-reinforced ablation-resistant composite board and a preparation method thereof. Twisting fiber filaments, weaving the twisted fiber filaments into fiber reinforced cloth in a warp-wise and weft-wise staggered weaving mode, and impregnating the fiber reinforced cloth in resin and curing to obtain the fiber reinforced cloth. The method adopts a twisting and weaving process, so that on one hand, the integration of the composite board forming is ensured, and the thickness and compactness of the fiber reinforced cloth are greatly improved; on the other hand has still promoted the expansibility of composite sheet, and the accessible is twisted cellosilk volume and winding diameter and comes the ration control individual layer fabric thickness, and is further, still can strengthen the mechanical properties of composite sheet in different stress directions through weaving the angle. The composite board prepared by the preparation method is light in weight, high in strength, excellent in ablation resistance and good in mechanical property.
Description
Technical Field
The invention relates to an ablation-resistant composite board, in particular to a fiber-reinforced ablation-resistant composite board and a preparation method thereof, and belongs to the field of fiber-reinforced composite materials.
Background
At present, with the further application and popularization of the composite material in the aerospace field, a part of the ablation-resistant composite material is widely applied in the aerospace field by virtue of light weight, good mechanical property and better high-temperature ablation resistance. In early use, metal materials are used as traditional materials, and are mainly used as ablation-resistant core components due to mature processing technology, and along with the gradual improvement of the composite material forming technology, the metal materials are used for further reducing the overall weight of products, reducing energy consumption and ensuring good ablation performance of the materials and easy replacement of ablation components.
Chinese patent CN 110804274A discloses a light heat-proof and heat-insulating composite material based on a fabric reinforcement with a spacing structure and a preparation method thereof, wherein a surface-core functional gradient structure is adopted, a surface layer mainly provides heat release and bearing capacity for a compact material, a middle core mainly plays a role in low density and heat insulation for a porous material, the reinforcement in a material system is a fabric preform with a spacing three-dimensional structure of pure inorganic fibers or organic/inorganic hybrid fibers, the integral structure of the patent is a spacing structure, a plurality of layers of fabrics are adopted, and the layers are linked through linking fiber bundles to form a hollow structure.
In addition, the related mechanism adopts the short cut fiber sheet-shaped compression molding, but the short cut fiber length is too short, the continuity of the fiber is poor, and the overall high-temperature performance is poor.
Disclosure of Invention
Aiming at the problems in the prior art, the first object of the invention is to provide a fiber-reinforced ablation-resistant composite board, wherein the fiber reinforcement in the composite board adopts a twisting process, the thickness of a single layer is 3-10 mm, the high-temperature delamination phenomenon is effectively avoided, the overall weight of the reinforced composite board is light, the ablation resistance is excellent, and after the front surface is ablated for 5' 10s through high-temperature particle flow at 1500-2000 ℃, the back temperature of an ablation center is below 120 ℃.
The second purpose of the invention is to provide a preparation method of the fiber-reinforced ablation-resistant composite board, which can control the thickness of a single-layer fabric by controlling the amount of twisted fiber yarns and the winding diameter, and enhance the mechanical properties of the composite board in different stress directions by weaving angles. The method has simple process, convenient operation and low cost, and is suitable for large-scale industrial production.
In order to achieve the technical purpose, the invention provides a preparation method of a fiber-reinforced ablation-resistant composite board, which comprises the steps of twisting fiber yarns and weaving the fiber yarns into fiber-reinforced cloth in a warp-wise and weft-wise staggered weaving mode, or twisting the fiber yarns and then mixing the fiber yarns with reinforcing wires in the warp-wise and weft-wise staggered weaving mode to form the fiber-reinforced cloth; and (3) fully soaking the fiber reinforcement cloth in resin and then curing, or superposing a reinforcement felt on the upper surface and/or the lower surface of the fiber reinforcement cloth, fully soaking in resin and then curing, thus obtaining the fiber reinforcement cloth.
The preparation method provided by the invention adopts a preparation process of twisting mixed-woven fiber yarns, the single-layer structure of the composite board is ensured, and simultaneously, the high-temperature ablation resistance of the material is greatly improved, furthermore, the mechanical strength and the heat insulation performance of the composite board are enhanced after the obtained fiber reinforced cloth is impregnated with resin, the forming process of the method is simple, the porosity of the product after filling is low, and the obtained composite board has excellent high-temperature mechanical properties.
As a preferable mode, the fiber yarn includes at least one of an aluminum silicate fiber yarn, an aluminum oxide fiber yarn and a silicon carbide fiber.
In a preferred embodiment, the reinforcing wires are at least one of stainless steel wires, carbon fiber wires and high silica fiber wires.
In a preferred embodiment, the twisting is a double-tow unidirectional winding twisting and/or a single-tow unidirectional winding twisting. Preferably, the twisting mode of the radial braided fiber yarn is double-tow unidirectional winding, and the twisting mode of the weft braided fiber yarn is single-tow unidirectional winding twisting.
The double-tow unidirectional winding and twisting mode can not only improve the overall thickness of the fiber cloth, but also greatly improve the strength of the material and is used for enhancing the main stress direction of the material; the effect of unidirectional winding and twisting in the single-tow direction is to support the overall strength of the fiber cloth, ensure that the non-main stress direction has basic mechanical strength, and reduce the overall quality of the material.
As a preferable scheme, the conditions of the double-tow unidirectional winding twisting are as follows: the winding diameter is 2-10 mm, and the weaving angle is 45-90 degrees. The winding diameter of the tows directly determines the thickness of the single-layer fiber cloth, and the maximum diameter of the fiber cloth is the integral diameter of the double-tow unidirectional twisted fiber.
As a preferable scheme, the conditions for unidirectional winding and twisting of the monofilament bundle are as follows: the winding diameter is 1-5 mm, and the weaving angle is 45-90 degrees.
As a preferable proposal, the total density of the fiber reinforced cloth is 0.4 to 1.0g/cm 3 。
Preferably, the resin has a char formation rate of not less than 70%, a normal-temperature viscosity of 150 to 300mPa · S, and a mass of 5 to 10% of the fiber-reinforced fabric. Further preferably, the resin is a phenolic resin.
The resin with high char yield is selected in the invention, which mainly aims to ensure that the resin reacts under the action of high-temperature ablation airflow to form a more temperature-resistant carbonized layer, and the carbonized layer can stably exist under the high-temperature condition and cannot be washed by the airflow, thereby playing the role of protecting the inner layer and preventing the ablation from being too fast.
Preferably, the curing mode is vacuum infusion, RTM forming or hand lay-up molding. The vacuum infusion conditions are preferably: the pressure is controlled to be 0.1KPa negative pressure, the heating temperature is controlled to be 80-150 ℃, and the heating time is 2-2.5 h.
The invention also provides a fiber-reinforced ablation-resistant composite board prepared by any one of the preparation methods.
According to the invention, by adjusting the twisting mode, the weaving mode and the curing forming method of the ceramic fiber fabric fiber yarns, the composite board which is formed by pouring the single-layer fiber-laminated phenolic resin and can endure 1000-1500 ℃ for a long time and instantaneously endure 2000-3000 ℃ for a long time and has excellent performances of light weight, high strength, heat preservation and the like is prepared, and the application range of the fiber-reinforced phenolic resin composite board in the field of high-temperature ablation resistance is expanded.
As a preferable scheme, the thickness of the fiber-reinforced ablation-resistant composite plate is 3-10 mm, and the density is 0.8-1.2 g/cm 3 。
Furthermore, the invention also provides an expanding mode of the composite board, and the reinforced felts are added on the upper surface and the lower surface of the fiber reinforced cloth in the curing stage, and the concrete process is as follows:
1) The method comprises the following steps of mixing and weaving reinforcing wires in a fiber fabric, designing the diameters of warp-wise and weft-wise fiber twisting tows according to the designed thickness, controlling the diameters by the number of the twisting fiber yarns, designing the fiber tow weaving angle aiming at the stress direction, designing the payment of a single-layer woven fabric according to the actually required product size, and controlling the conventional width to be 1-1.5 m;
2) Designing blanking size according to the structure of a required product, cutting the woven fiber cloth, paving 1 or 2 layers of reinforcement felts on the upper surface and the lower surface of the fiber cloth in proper amount on a designed mould, and then, for different processes, impregnating resin, heating and curing, and adopting vacuum infusion, RTM (resin transfer molding) process or hand lay-up mould pressing process; if the process is a hand lay-up mould pressing process, the mould needs to be pressurized, and the layering process ensures that the radial fiber tow direction is consistent with the stress direction.
In a preferred embodiment, the reinforcing wires are at least one of stainless steel wires, carbon fiber wires and high silica fiber wires.
In a preferred embodiment, the reinforcing mat is at least one of a glass fiber mat, a carbon fiber woven fabric and a metal plate.
According to the invention, the high-temperature mechanical strength of the product can be obviously improved by mixing and weaving the reinforcing wires in the fiber bundles, the overall mechanical property can be improved by 20-50% by adding the reinforcing felt in the curing and forming stage, and the heat conductivity coefficient can be increased to 5-10%.
The invention aims at the problems that the traditional metal ablation-resistant material is heavy and is not easy to replace and disassemble, and meanwhile, in the forming process of the existing ablation-resistant fiber reinforced resin matrix composite material of continuous fibers such as carbon fibers, high silica and the like, because the single layer thickness of the fiber fabric is thin and the single layer thickness of most of the fiber fabric is only below 1mm, when a product with the thickness of more than 1mm is prepared, multilayer paving is needed, and the interlayer combination of the composite plate formed by the multilayer paving and vacuum infusion is weak in the high-temperature ablation process, the composite plate is easy to be subjected to thermal expansion delamination, and the delamination and cracking can be ensured only through interlayer weaving and reinforcement in the high-temperature ablation process. Further, when the sheet-like molding of chopped fibers is employed, the high-temperature mechanical properties are weak as a whole due to discontinuity of the fibers. Therefore, the invention adopts the fiber yarn twisting and mixed knitting process, and the single-layer knitting thickness can reach 3 mm-10 mm. The horizontal tensile strength of the compounded product is about 20MPa to 30MPa, the bending strength is about 40MPa to 50MPa, and the impact toughness is 25KJ/m 2 ～35KJ/m 2 Density of 0.8-1.2X 10 3 kg/m 3 The thermal conductivity coefficient is controlled to be 0.13W/(m.K), the linear ablation thickness of the composite plate is controlled to be below 10% after the composite plate is ablated for 1min by oxyacetylene outer flame, the product is not cracked, the ablation area is carbonized uniformly, and the ablation center back temperature is controlled to be below 120 ℃.
Compared with the prior art, the technical scheme of the invention has the beneficial technical effects that:
1) The invention providesThe ablation-resistant composite board can realize the controllable adjustment of the thickness of a single-layer fabric, has light weight, high strength, excellent ablation resistance and good mechanical property, and the test result shows that the horizontal tensile strength of the ablation-resistant composite board is about 20MPa to 30MPa, the bending strength is about 40MPa to 50MPa, and the impact toughness is 25KJ/m 2 ～35KJ/m 2 The density is 0.8-1.2 multiplied by 10 3 kg/m 3 The thermal conductivity coefficient is controlled to be 0.13W/(m.K), and after the composite board is ablated for 1min by acetylene outer flame, the linear ablation thickness is controlled to be below 10%, the product is not cracked, the ablation area is carbonized uniformly, and the ablation center back temperature is controlled to be below 120 ℃.
2) In the technical scheme provided by the invention, the process of fiber twisting and warp-wise and weft-wise staggered weaving is adopted, the thickness and compactness of the fiber reinforced cloth are greatly improved, the thickness of a single-layer fabric is quantitatively controlled by controlling the amount of twisted fiber yarns and the winding diameter, and further, the mechanical properties of the composite board in different stress directions can be enhanced by weaving angles.
3) In the technical scheme provided by the invention, the preparation method of resin impregnation curing molding is adopted, so that the molding integration of the composite board is ensured, the expansibility of the composite board is improved, and the mechanical property and the ablation resistance of the composite board can be further improved by adhering the reinforced felt with the resin in the molding process.
Drawings
Fig. 1 is a schematic structural view of a composite plate obtained in example 1 of the present invention;
1. twisting fiber bundles in the radial direction, 2 twisting fiber bundles in the weft direction, and 3 twisting resin matrix materials;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, those skilled in the art can obtain many other embodiments without creative efforts, and the embodiments are within the protection scope of the present invention.
Example 1
The ablation-resistant composite board is designed to be 5mm in thickness, the fiber yarns are aluminum silicate ceramic fibers, double fiber bundles are adopted for unidirectional winding and twisting, the diameter of a twisted fiber bundle is 2.5mm, and 100 ceramic fiber yarns with the diameter of 0.025mm are used for twisting of a single fiber bundle; weaving in warp and weft directions of 90 deg./0 deg. and pouring 4.0kg/m 2 The phenolic resin is cured to prepare the ceramic fiber reinforced ablation-resistant composite board with the thickness of 5 mm.
Through tests, the horizontal tensile strength of the ablation-resistant composite plate is about 25MPa, the bending strength is about 50MPa, and the impact toughness is 35KJ/m 2 Density of 0.9X 10 3 kg/m 3 The thermal conductivity coefficient is 0.13W/(m.K), and after the composite board is ablated for 1min at 1500 ℃ in acetylene outer flame, the linear ablation thickness is controlled to be 8%, the product does not crack, the ablation area is carbonized uniformly, and the ablation center back temperature is 110 ℃.
Example 2
The ablation-resistant composite board is designed to be 5mm in thickness, the fiber yarns are aluminum silicate ceramic fibers, double fiber bundles are adopted for unidirectional winding and twisting, the diameter of a twisted fiber bundle is 2.5mm, and 100 ceramic fiber yarns with the diameter of 0.025mm are used for twisting of a single fiber bundle; after weaving in the warp and weft directions of 90 degrees/0 degrees, adding 1 layer of glass fiber chopped strand mat layer on the upper side and the lower side of the fiber cloth, and then pouring 4.0kg/m 2 The phenolic resin is cured to prepare the ceramic fiber reinforced ablation-resistant composite board with the thickness of 5 mm. The reinforced composite board has the tensile strength of 55MPa, the bending strength of 65MPa and the heat conductivity coefficient of 0.13W/(m.K), and the added glass fiber felt can be directly carbonized at the high temperature of 1000 ℃ without causing deformation and cracking of the product.
Example 3
The preparation method is the same as that of the embodiment 2, except that 2 layers of glass fiber chopped strand mats are added on the upper side and the lower side for layering, compared with 1 layer of glass fiber chopped strand mats, the overall comprehensive mechanical property is improved by 5%, and the heat conductivity coefficient is unchanged.
Example 4
The preparation method was the same as example 2 except that 1 layer of 400g/m was added to each of both sides of the upper and lower surfaces 2 Composite filling of T300 carbon fiber and reinforced composite board forceThe chemical performance is improved by 20 percent, and the delamination phenomenon does not occur when the oxyacetylene blast burner with the temperature of 1500 ℃ is used for ablation.
Example 5
The preparation method is the same as that of example 1, except that in the twisting process, the tensile strength of the monofilaments is improved by 10% by changing 100 ceramic fiber filaments with the diameter of 0.025mm into 50 ceramic fiber filaments with the diameter of 0.025mm and 50T 300 carbon fiber monofilaments with the diameter of 0.025 mm.
Example 6
The upper and lower surfaces of the ablation-resistant composite board obtained in example 1 are formed into a multilayer structure by using a high-temperature-resistant adhesive high silica fiber reinforced resin composite board, and additional support is added to the surface, so that the composite board can maintain good structural integrity under the impact of particle flow and air flow at 2000 ℃.
Comparative example 1
The preparation method is the same as that of the embodiment 1, except that the adopted fiber yarn is glass fiber, and the test shows that the ablation-resistant composite board is broken down by flame at 900 ℃ and the composite board is peeled off.
Comparative example 2
The preparation method is the same as the embodiment 1, except that the fiber filaments are laid conventionally, the twisting process and the warp and weft staggered weaving are not adopted, and the thickness of the obtained fiber reinforced cloth single layer is only 0.5mm; the 10 layers of fiber reinforced cloth are stacked and poured into the container to form 4.0kg/m 2 The phenolic resin is cured to prepare the ceramic fiber reinforced ablation-resistant composite board with the thickness of 5 mm. Tests show that the obtained ablation-resistant composite board is ablated for 1min at 1500 ℃ in acetylene outer flame, and the composite board cracks and falls off along the interlayer gap.
Claims (10)
1. A preparation method of a fiber-reinforced ablation-resistant composite board is characterized by comprising the following steps: twisting fiber filaments and then weaving the twisted fiber filaments into fiber reinforced cloth in a warp-wise and weft-wise staggered weaving mode, or twisting the twisted fiber filaments and then weaving the twisted fiber filaments and reinforcing filaments into the fiber reinforced cloth in a warp-wise and weft-wise staggered weaving mode; and (3) fully soaking the fiber reinforcement cloth in resin and then curing, or superposing a reinforcement felt on the upper surface and/or the lower surface of the fiber reinforcement cloth, fully soaking in resin and then curing, thus obtaining the fiber reinforcement cloth.
2. The method for preparing a fiber reinforced corrosion resistant composite board according to claim 1, wherein the method comprises the following steps: the fiber wire comprises at least one of an aluminum silicate fiber wire, an aluminum oxide fiber wire and a silicon carbide fiber;
the reinforcing wire is at least one of a stainless steel wire, a carbon fiber wire and a high silica fiber wire.
3. The method for preparing a fiber reinforced corrosion resistant composite board according to claim 1, wherein the method comprises the following steps: the twisting mode is double-tow unidirectional winding twisting and/or single-tow unidirectional winding twisting.
4. The method for preparing the fiber reinforced corrosion-resistant composite plate according to claim 3, wherein the method comprises the following steps: the conditions of the double-tow unidirectional winding and twisting are as follows: the winding diameter is 2-10 mm, and the weaving angle is 45-90 degrees;
the conditions of unidirectional winding and twisting of the single tows are as follows: the winding diameter is 1 to 5mm, and the weaving angle is 45 to 90 degrees.
5. The method for preparing a fiber reinforced corrosion resistant composite board according to claim 1, wherein the method comprises the following steps:
the reinforced felt is at least one of a glass fiber felt, a carbon fiber woven cloth and a metal plate.
6. The method for preparing the fiber reinforced corrosion-resistant composite plate according to claim 1, wherein the method comprises the following steps: the total density of the fiber reinforced cloth is 0.4 to 1.0g/cm 3 。
7. The method for preparing a fiber reinforced corrosion resistant composite board according to claim 1, wherein the method comprises the following steps: the carbon forming rate of the resin is more than or equal to 70%, the normal-temperature viscosity is 150-300mPa.S, and the mass of the resin accounts for 5-10% of that of the fiber reinforced cloth.
8. The method for preparing the fiber reinforced corrosion-resistant composite plate according to claim 1, wherein the method comprises the following steps: the curing mode is vacuum infusion, RTM forming or hand lay-up mould pressing; the vacuum infusion conditions are as follows: the pressure is controlled to be 0.1KPa negative pressure, the heating temperature is controlled to be 80-150 ℃, and the heating time is 2h-2.5 h.
9. A fiber reinforced ablation-resistant composite board is characterized in that: made by the method of manufacture of any of claims 1~8.
10. The fiber reinforced ablation resistant composite panel of claim 8, wherein: the thickness of the fiber-reinforced ablation-resistant composite board is 3-10mm, and the density is 0.8-1.2 g/cm 3 。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210897802.1A CN115923257A (en) | 2022-07-28 | 2022-07-28 | Fiber-reinforced ablation-resistant composite board and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210897802.1A CN115923257A (en) | 2022-07-28 | 2022-07-28 | Fiber-reinforced ablation-resistant composite board and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115923257A true CN115923257A (en) | 2023-04-07 |
Family
ID=86647937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210897802.1A Pending CN115923257A (en) | 2022-07-28 | 2022-07-28 | Fiber-reinforced ablation-resistant composite board and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115923257A (en) |
-
2022
- 2022-07-28 CN CN202210897802.1A patent/CN115923257A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1181260B1 (en) | Chordal preforms for fiber-reinforced articles and method for the production thereof | |
| CN107266075B (en) | C/C-SiC composite material and preparation method and application thereof | |
| US5547737A (en) | Light-weight, high-strength, stiff panels | |
| CN101691684B (en) | Preparation and carbonization method of needle-punched pre-oxidative fiber prefabricated part | |
| CN109320278A (en) | A kind of complement heat conduction ceramic matric composite and preparation method thereof | |
| CN101269981B (en) | Process for producing carbon/carbon heat insulation bottom board for high temperature furnace | |
| EP0179137A1 (en) | Method for forming composite articles of complex shapes. | |
| CN101134678A (en) | High-temperature resistant composite material | |
| WO1993025493A1 (en) | Method of manufacturing carbon fiber-reinforced composite carbon material, carbon fiber-reinforced composite carbon material, and sliding material | |
| CN105237020B (en) | A kind of fibre reinforced ZrB2- ZrN multiphase ceramic matrix composites and preparation method thereof | |
| CN103879076B (en) | Knitted fabric needled felt aggregate and preparation method thereof | |
| CN113603495A (en) | Method for preparing ceramic matrix composite bolt and pin based on long rod-shaped prefabricated body structure | |
| CN113233910A (en) | Method for improving densification density of thick carbon/carbon composite material plate | |
| CN113862773B (en) | Long-life guide cylinder and preparation method thereof | |
| CN110093682A (en) | A kind of preparation method enhancing basalt interface performance | |
| CN115923257A (en) | Fiber-reinforced ablation-resistant composite board and preparation method thereof | |
| CN109866479A (en) | Braided fabric Nomex aggregate and preparation method thereof | |
| CN115823151A (en) | Carbon/ceramic brake disc with sandwich structure | |
| CN105525438A (en) | Boron nitride fiber mat and preparation method thereof | |
| CN114656270A (en) | Carbon-ceramic fiber heat-insulation composite material and preparation method thereof | |
| CN115195215A (en) | Interlaminar toughening method for composite material laminated plate | |
| CN114523734A (en) | Preparation method of high-temperature-resistant light composite ceramic heat shield | |
| CN113373505B (en) | Single crystal furnace thermal field heat preservation cylinder and preparation method thereof | |
| CN115257078B (en) | Light heat-proof and heat-insulating integrated heat-proof material carbon fiber reinforcement and preparation method thereof | |
| CN217545934U (en) | Fiber composite material photovoltaic equipment support section bar |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |